Co-reporter:Li Zhang, Zhong-Xia Wang, Ru-Ping Liang, and Jian-Ding Qiu
Langmuir July 16, 2013 Volume 29(Issue 28) pp:8929-8935
Publication Date(Web):July 16, 2013
DOI:10.1021/la401887b
Utilizing the principles of metal-ion-mediated base pairs (C-Ag-C and T-Hg-T), the pH-sensitive conformational transition of C-rich DNA strand, and the ligand-exchange process triggered by dl-dithiothreitol (DTT), a system of colorimetric logic gates (YES, AND, INHIBIT, and XOR) can be rationally constructed based on the aggregation of the DNA-modified Au NPs. The proposed logic operation system is simple, which consists of only T-/C-rich DNA-modified Au NPs, and it is unnecessary to exquisitely design and alter the DNA sequence for different multiple molecular logic operations. The nonnatural base pairing combined with unique optical properties of Au NPs promises great potential in multiplexed ion sensing, molecular-scale computers, and other computational logic devices.
Co-reporter:Xiang Chen;Shu-Yun Huang;Ru-Ping Liang;Sheng-Bao Suo;Shao-Ping Shi
Journal of Proteome Research February 1, 2013 Volume 12(Issue 2) pp:949-958
Publication Date(Web):2017-2-22
DOI:10.1021/pr301007j
Next-generation sequencing (NGS) technologies are yielding ever higher volumes of genetic variation data. Given this large amount of data, it has become both a possibility and a priority to determine what the functional implication of genetic variations is. Considering the essential roles of acetylation in protein functions, it is highly likely that acetylation related genetic variations change protein functions. In this work, we performed a proteome-wide analysis of amino acid variations that could potentially influence protein lysine acetylation characteristics in human variant proteins. Here, we defined the AcetylAAVs as acetylation related amino acid variations that affect acetylation sites or their interacting acetyltransferases, and categorized three types of AcetylAAVs. Using the developed prediction system, named KAcePred, we detected that 50.87% of amino acid variations are potential AcetylAAVs and 12.32% of disease mutations could result in AcetylAAVs. More interestingly, from the statistical analysis, we found that the amino acid variations that directly create new potential lysine acetylation sites have more chance to cause diseases. It can be anticipated that the analysis of AcetylAAVs might be useful to screen important polymorphisms and help to identify the mechanism of genetic diseases. A user-friendly web interface for analysis of AcetylAAVs is now freely available at http://bioinfo.ncu.edu.cn/AcetylAAVs_Home.aspx.Keywords: amino acid variations; disease; lysine acetylation; polymorphisms; web service;
Co-reporter:Shaohua Wen;Chengrong Zhang;Ruping Liang;Baozhu Chi;Yanhong Yuan
Microchimica Acta 2017 Volume 184( Issue 10) pp:4047-4054
Publication Date(Web):02 August 2017
DOI:10.1007/s00604-017-2432-8
The authors describe a voltammetric method for the determination of arsenite [As(III)] based on an As(III)-specific binding probe DNA (SBP DNA; a single-stranded DNA) and the electrochemical indicator Methylene Blue (MB). The SBP DNA was first hybridized with a capture probe (CP) DNA on the surface of a gold electrode. Then, MB was intercalated into the SBP/CP hybrid on the electrode. On addition of As(III), it specifically binds to the SBP DNA, and this results in a conformational change and the dissociation of the SBP DNA from the electrode into solution. Consequently, the amount of MB remaining on the modified electrode is reduced, and this decreases the peak current of MB (best measured at −0.28 V vs. SCE). The findings are exploited in an assay for As(III) that has a linear response in the 0.1 to 200 ppb concentration range and a detection limit as low as 75 ppt. Conceivably, this method can be extended by designing various specific ssDNA oligonucleotides for other heavy metal ions or for small molecules.
Co-reporter:Li Zhang, Xiu-Zhi Cheng, Lan Kuang, Ai-Zhen Xu, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2017 Volume 94(Volume 94) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.bios.2017.03.057
•DNA QDs with unique fluorescence properties have been hydrothermally prepared.•The DNA QDs maintain the activity of G-/T-rich sequences to specifically bind with arsenite.•The arsenite's binding induces fluorescence enhancement of DNA QDs at 460 nm.•The sensor demonstrates high selectivity and arsenate does not show any interference.Novel fluorescent DNA quantum dots (QDs) were synthesized by hydrothermal treatment of G-/T-rich ssDNA at relatively low reaction temperature. The obtained DNA QDs demonstrate unique optical properties, maintain the basic structure and biological activities of ssDNA precursors, which makes the DNA QDs able to specifically bind with arsenite, driving the (GT)29 region suffer conformation evolution and form well-ordered assembly rather than random aggregations. We speculate that the strong inter-molecule interaction and efficient stacking of base pairs stiffen the assembly structure, block the nonradiative relaxation channels, populate the radiative decay, and thus making the assembly be highly emissive as a new fluorescence center. The arsenite-induced specific fluorescence enhancement facilitates DNA QDs as light-up probes for arsenite sensing. Under optimal conditions, a linear relationship between the increased fluorescence intensity of DNA QDs and the logarithmic values of arsenite concentration in the range of 1–150 ppb with a detection limit of 0.2 ppb (3σ) was obtained. The nanosensor shows excellent selectivity for “turn on” arsenite determination and arsenate does not show any interference, facilitating its application in complex real water analysis.
Co-reporter:Ting-Xiang Liu, Li Zhang, Ru-Ping Liang, Jian-Ding Qiu
Sensors and Actuators B: Chemical 2017 Volume 238() pp:257-263
Publication Date(Web):January 2017
DOI:10.1016/j.snb.2016.07.030
•A novel probe TAR has been synthesized.•A pyrene-mediated turn-on fluorescent sensor for thioredoxin disulfenylation has been proposed.•Thioredoxin preference of TAR has been proved by fluorometric and cell imaging experiments.•Thioredoxin activity can be detected at nanomolar concentrations.A novel fluorescent probe, 2, 4-cyclohexanedione-1-propyl-pyrene (TAR), has been synthesized to research thioredoxin (Trx) disulfenylation and visualize the activity of Trx in cells. The turn-on fluorescence change was induced by combining the vicinal dithiol proteins with the spatially sensitive fluorescent signal of the pyrene excimer which emitted at 480 nm. Trx activity can be detected at nanomolar concentrations. Trx preference of TAR in vitro and in vivo was proved by fluorometric and confocal microscopic experiments. In addition, it could realize dynamic tracking of protein disulfenylation in situ with minimal disturbance to disulfenylated proteins and less perturbation with cellular function. We herein report the first turn-on fluorescent sensor for the selective detection of proximally disulfenylated protein sites, suitable for application in both aqueous solutions and in cells.
Co-reporter:Yan-Hong Yuan, Yi-Di Wu, Bao-Zhu Chi, Shao-Hua Wen, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2017 Volume 97(Volume 97) pp:
Publication Date(Web):15 November 2017
DOI:10.1016/j.bios.2017.06.022
•Two distinguishable magnetic nanoprobes were synthesized by hydrothermal treatment.•The target-triggered HCR strategy was introduced for sensitive detection of miRNA.•Multiple miRNAs can be assayed simultaneously with good sensitivity, even in the cell lysates.We report a sensor combining two distinguishable magnetic nanoprobes (DNA1/Fe3O4 NPs/Thi and DNA2/Fe3O4 NPs/Fc) with target-triggered hybridization chain reaction (HCR) strategy for the simultaneous detection of microRNA-141 (miR-141) and microRNA-21 (miR-21). In the presence of targets, the thiol-modified hairpin capture probes (HCP1 and HCP2) specifically hybridize with miR-141 and miR-21 on a gold electrode, leading to the conformation change of HCP1 and HCP2, respectively. The conformation change subsequently triggers HCR to generate plentiful bonding sequences of magnetic nanoprobes. Thus, numerous thionine (Thi) modified DNA1/Fe3O4 NPs/Thi and ferrocene carboxaldehyde (Fc-CHO) modified DNA2/Fe3O4 NPs/Fc are captured by the well-designed HCR, via DNA hybridization respectively, giving rise to the dual magnified response of currents. The increase in the electrochemical currents at different potentials of the two magnetic nanoprobes enables us to simultaneously and quantitatively detect miR-141 and miR-21. Target-triggered HCR increases the amount of captured nanoprobes due to the increasing number of bonding sequences, greatly amplifying the currents of the two magnetic nanoprobes in the presence of targets, and ultimately realizing the dual signal amplification with increased sensitivity. The sensor can be applied for detecting miRNAs in cell lysates, thus, promising to be a clinic diagnosis of cancers by means of simultaneous detection of a variety of miRNA biomarkers.
Co-reporter:Zhi-Mei Li, Zhao-Hua Zhong, Ru-Ping Liang, Jian-Ding Qiu
Sensors and Actuators B: Chemical 2017 Volume 238() pp:626-632
Publication Date(Web):January 2017
DOI:10.1016/j.snb.2016.07.087
•We reported a novel colorimetric biosensor for the assay of DNA methyltransferase activity.•Strand displacement amplification was employed for M.SssI activity inhibition assay.•With the advantages of SDA, highly sensitive detection of M.SssI activity and inhibition was achieved.In this paper, we present a colorimetric method for the assay of DNA methyltransferase (MTase) activity based on strand displacement amplification (SDA). In our study, a well-designed hairpin DNA I (HPI) containing the sequence of 5′-CCGG-3′ is specifically recognized by CpG methyltransferase (M.SssI) and HpaII endonuclease. The methylated HPI is able to coexist with all the DNA and enzymes in the solution while the unmethylated HPI can be cleaved into single-stranded DNA (ssDNA) fragments. The amplification can be triggered by the HpaII digestion products hybridization with another hairpin structure DNA II (HPII) to form a duplex, which would be replaced by probe DNA, leading to the aggregation of gold nanoparticles (AuNPs). Simultaneously, ssDNA fragments released from the duplex, and triggered the cycle anew. Varying concentrations of M.SssI in the solution therefore would lead to differences of absorption and color changed from red to pale. A linear response was obtained when the M.SssI concentration ranging from 0.2 to 50 U mL−1 with a detection limit of 0.08 U mL−1. In addition, the developed assay in this study can also be applied to screen the inhibitors of M.SssI.
Co-reporter:Hui-Hui Zeng, Li Zhang, Lian-Qing Rong, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2017 Volume 89(Part 2) pp:721-727
Publication Date(Web):15 March 2017
DOI:10.1016/j.bios.2016.11.020
•Using ATP as bridge ligand, the lanthanide coordination polymer nanoparticle (ATP-Ce/Tb-Tris CPNs) was synthesized.•The green emission of ATP-Ce/Tb-Tris CNPs was demonstrated to come from the efficient energy transfer from Ce3+ to Tb3+.•The interrupt of energy transfer from Ce3+ to Tb3+ results in the fluorescence quenching of ATP-Ce/Tb-Tris CNPs.A bimetal lanthanide coordination polymer nanoparticle (ATP-Ce/Tb-Tris CPNs) with good biocompatibility was synthesized in Tris–HCl buffer using adenosine triphosphate (ATP) molecules as the bridge ligands. The large absorption cross section and suitable emission energy of Ce3+ matching to the adsorption energy of Tb3+(4fn) results in the efficient energy transfer from Ce3+ to Tb3+, thus the synthesized ATP-Ce/Tb-Tris CPNs exhibit the characteristic green emission of Tb3+. Such energy transfer from metal to metal in fluorescent lanthanide coordination polymer nanoparticles (Ln-CPNs) has been demonstrated. It is found that the oxidation of Ce3+ in ATP-Ce/Tb-Tris CNPs to Ce4+ would interrupt the energy transfer from Ce3+ to Tb3+, leading to fluorescence quenching of Tb3+. On the basis of this quenching mechanism, ATP-Ce/Tb-Tris CPNs has been successfully used to detect reactive oxygen H2O2 with detection limit as low as 2 nM. If glucose oxidase is present in the system, glucose can be determined using the ATP-Ce/Tb-Tris CNPs nanosensor.
Co-reporter:Bao-Zhu Chi, Ru-Ping Liang, Wei-Bin Qiu, Yan-Hong Yuan, Jian-Ding Qiu
Biosensors and Bioelectronics 2017 Volume 87() pp:216-221
Publication Date(Web):15 January 2017
DOI:10.1016/j.bios.2016.08.042
•It’s the first time to detect miRNA based on EPEPT reaction and CuNPs nano-dye.•PolyT sequence converted from the miRNA acts as a template for CuNPs formation.•The assay employs CuNPs as reporters, making it more rapid, simple and economic.•The polyT-CuNPs emit red fluorescence with excellent Stokes shifting, avoiding interference.•The turn-on mode offered more sensitivity and reduced the false positive signal.A new strategy based on enzymatically engineered primer extension poly-thymine (EPEPT) and nanomaterials in situ generation technology is reported for direct detection of microRNA (miRNA) in a fluorescence turn-on format using the sequential and complementary reactions catalyzed by Klenow Fragment exo− (KFexo−) and terminal deoxynucleotidyl transferase (TdTase). The short miRNA can be efficiently converted into long poly-thymine (polyT) sequences, which function as template for in situ formation of fluorescence copper nanoparticles (CuNPs) as nano-dye for detecting miRNA. The polyT-CuNPs can effectively form and emit intense red fluorescence under the 340 nm excitation. For the proof of concept, microRNA-21 (miR-21) was selected as the model target to testify this strategy as a versatile assay platform. By directly using miR-21 as the primer, the simple, rapid and sensitive miRNA detection was successfully achieved with a good linearity between 1 pM and 1 nM and a detection limit of 100 fM. Thus, the EPEPT strategy holds great potential in biochemical sensing research as an efficient and universal platform.
Co-reporter:Hui-Hui Zeng, Wei-Bin Qiu, Li Zhang, Ru-Ping Liang, and Jian-Ding Qiu
Analytical Chemistry 2016 Volume 88(Issue 12) pp:6342
Publication Date(Web):May 25, 2016
DOI:10.1021/acs.analchem.6b00630
Lanthanide coordination polymer nanoparticles (Ln-CPNs) have been recently demonstrated as excellent platforms for biomolecule detection. In this work, we synthesized novel cerium coordination polymer nanoparticles ATP-Ce-Tris CPNs in a simple and quick way using ATP molecules as the biocompatible ligands to Ce3+ ions in tris(hydroxymethyl)aminomethane hydrochloric (Tris-HCl) solution. In view of the excellent free radical scavenging property of cerium compounds, which is ascribed to the mixed valence state (Ce3+, Ce4+) and the reversible switch from Ce3+ to Ce4+, the synthesized ATP-Ce-Tris CPNs was used as artificial peroxidase to selectively and sensitively detect H2O2. The sensing mechanism depends on the oxidation of the fluorescent ATP-Ce(III)-Tris CPNs to nonfluorescent ATP-Ce(IV)-Tris CPNs by H2O2. Compared with those inorganic cerium oxide sensors, this kind of fluoresence ATP-Ce-Tris CPNs sensor needs no additional organic redox dye, such as ABTS (2,20-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), TMB (3,3,5,5-tetramethylbenzidine), or fluorescein as signal molecules. Moreover, such ATP-Ce-Tris CPNs sensor exhibited a more sensitive response to H2O2 with a detection limit down to 0.6 nM, which is 2 orders of magnitude lower than those of cerium oxide sensors. This sensing platform was further extended to the detection of glucose in combination with the specific catalytic effect of glucose oxidase (GOx) for the oxidation of glucose and formation of H2O2.
Co-reporter:Ru-Ping Liang, Wei-Bin Qiu, Hui-Fang Zhao, Cai-Yun Xiang, Jian-Ding Qiu
Analytica Chimica Acta 2016 Volume 904() pp:58-64
Publication Date(Web):21 January 2016
DOI:10.1016/j.aca.2015.11.034
•We reported a novel ECL-RET biosensor for sensitive analysis of casein kinase II activity.•The successful ECL-RET between GQDs and GO could be established.•GQDs was employed for casein kinase II activity monitoring and inhibition assay.•Highly sensitive detection of CK2 activity and inhibition was achieved.Herein, a novel electrochemiluminescence resonance energy transfer (ECL-RET) biosensor using graphene quantum dots (GQDs) as donor and graphene oxide (GO) as acceptor for monitoring the activity of protein kinase was presented for the first time. Anti-phosphoserine antibody conjugated graphene oxide (Ab-GO) nonocomposite could be captured onto the phosphorylated peptide/GQDs modified electrode surface through antibody–antigen interaction in the presence of casein kinase II (CK2) and adenosine 5′-triphosphate (ATP), resulting in ECL from the GQDs quenching by closely contacting GO. This ECL quenching degree was positively correlated with CK2 activity. Therefore, on the basis of ECL-RET between GQDs and GO, the activity of protein kinase can be detected sensitively. This biosensor can also be used for quantitative analysis CK2 activity in serum samples and qualitative screening kinase inhibition, indicating the potential application of the developed method in biochemical fundamental research and clinical diagnosis.
Co-reporter:Dong Peng, Ru-Ping Liang, He Huang, Jian-Ding Qiu
Journal of Electroanalytical Chemistry 2016 Volume 761() pp:112-117
Publication Date(Web):15 January 2016
DOI:10.1016/j.jelechem.2015.12.014
•Signal amplification strategy-based electrochemical immunosensor for detection of CEA•GO/CS–Fc was employed as the matrix to immobilize antibodies.•Enhanced sensitivity was achieved by introducing Fe3O4/Au NPs onto electrode surface.•p-Aminophenol redox cycling was utilized to amplify the electrocatalytic current.A novel electrochemical immunosensor based on a signal amplification strategy was developed for sensitive detection of carcinoembryonic antigen (CEA). Graphene/chitosan–ferrocene (GO/CS–Fc) was employed as the matrix to immobilize the primary antibodies (Ab1). Owing to the larger surface area, a large amount of Ab1 was captured on GO/CS–Fc sensor platform, thus amplifying the detection signal. Fe3O4/Au NPs were functionalized as the label to conjugate with the secondary antibodies (Ab2). Due to the homogeneous and narrow size distribution of Fe3O4/Au NPs, several Ab2 were bound on each nanoparticle, thus enhanced sensitivity was achieved by introducing the Fe3O4/Au NPs/Ab2 onto the electrode surface through “sandwich” immunoreactions. On the basis of p-aminophenol (AP) redox cycling amplification strategy, the developed immunosensor showed a 10-fold increase in detection signal compared to the immunosensor without Fe3O4/Au NPs labeling. The proposed immunosensor offered a sensitive determination of CEA in the range of 0.001–30 ng mL− 1 with a detection limit of 0.39 pg/mL. This immunoassay method would open up a promising platform to detect various tumor markers for diagnosis of different cancers.
Co-reporter:Wei Song, Ru-Ping Liang, Ying Wang, Li Zhang, Jian-Ding Qiu
Sensors and Actuators B: Chemical 2016 Volume 226() pp:144-150
Publication Date(Web):April 2016
DOI:10.1016/j.snb.2015.11.134
•We reported a novel and visual ratiometric fluorescence assay for sensitive analysis of PKA activity.•The peptide-AuNCs was synthesized in situ without any coupling and reducing agents.•PKA assay was based on carboxypeptidase Y digestion quenching mechanism.•Highly sensitive detection of PKA activity and inhibition was achieved.A novel and sensitive ratiometric fluorescent assay for monitoring kinase activity based on carboxypeptidase Y (CPY) digestion by using Au nanoclusters (AuNCs) and CdSe/ZnS QDs@SiO2 as the dual-emission nanoparticles is developed. This approach can not only sensitively monitor the kinase activity with affording built-in correction which avoids environmental interferences, but also realize visual detection. Under optimal conditions, a linear relationship between the fluorescence intensity ratio (I415/I630) of CdSe/ZnS QDs@SiO2@peptide-AuNCs and the protein kinase A (PKA) concentration in a range of 0.01 to 40 U mL−1 with a detection limit of 0.004 U mL−1 (3σ) is obtained. The feasibility of this CdSe/ZnS QDs@SiO2@peptide-AuNCs-based ratiometric sensor has been further demonstrated by assessment of kinase inhibition by ellagic acid in cell lysates. The IC50 value (inhibitor concentration producing 50% inhibition) for ellagic acid is estimated to be 0.08 μM. The detection of other enzymes can also be realized with precise design of the peptide substrate sequences. The present assay is universal and visual for kinase assay and promises potential application in kinase-related biochemical fundamental research and inhibitor screening.
Co-reporter:Lan Kuang, Shu-Ping Cao, Li Zhang, Qiu-Hong Li, Zhi-Chao Liu, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2016 Volume 85() pp:798-806
Publication Date(Web):15 November 2016
DOI:10.1016/j.bios.2016.05.096
•Novel bio-dots were synthesized by hydrothermal treatment via aptamer self-assembly.•Bio-dots can induce AuNPs aggregation and retain the inherent structure of aptamer.•Bio-dots/AuNPs nanosensor is firstly constructed with multiple different responses.Thrombin is a crucial multifunctional enzyme involved in many physiological and pathological processes. Its detection is of great importance. In this work, a novel bio-dots nanosensor for detection of thrombin with colorimetric, fluorometric and light-scattering signals is developed. This nanosensor is composed of thrombin-binding aptamer bio-dots (TBA-dots) and gold nanoparticles (AuNPs), where TBA-dots serve as fluorometric reporter and AuNPs function as multiple roles as colorimetric reporter, light scattering reporter and fluorescence quencher. TBA-dots retain inherent structures of aptamer to specifically interact with thrombin and simultaneously induce the aggregation of AuNPs. The mechanism of the sensing system is based on distance-dependent aggregation of AuNPs and fluorescence resonance energy transfer (FRET). The nanosensor needs no further surface functionalization required for the as-prepared bio-dots and AuNPs, which provides a sensitive method for the selective detection of thrombin with a detection limit as low as 0.59 nM. In addition, it provides a brand new perspective for bio-dots and its potential use in bioanalysis.
Co-reporter:Li Zhang, Wei Song, Ru-Ping Liang, and Jian-Ding Qiu
Analytical Chemistry 2016 Volume 88(Issue 23) pp:
Publication Date(Web):October 25, 2016
DOI:10.1021/acs.analchem.6b02522
We design two artificial substrate peptides to synthesize blue-emissive Cu nanoclusters and red-emissive Au nanoclusters, respectively. In addition to the biomineralization function, these two peptides retain the biological activity to be phosphorylated by protein kinase and digested by carboxypeptidase Y. In the absence of protein kinase, the peptides capped on the nanoclusters suffer consecutive exocleavage by carboxypeptidase Y, resulting in oxidation and thus fluorescence quenching of the nanoclusters due to the losing of peptide protection. In the presence of protein kinase A and casein kinase II, the phosphorylation modification on corresponding substrate peptides protects the peptides against carboxypeptidase Y digestion and then the fluorescence of the nanoclusters can be retained. Since a single excitation wavelength can excite the both nanoclusters, blue and red emissive signals can be collected at the same time and then the quantitative determination of protein kinase A and casein kinase II can be achieved simultaneously.
Co-reporter:Hui-Fang Zhao, Ru-Ping Liang, Jing-Wu Wang and Jian-Ding Qiu
Chemical Communications 2015 vol. 51(Issue 63) pp:12669-12672
Publication Date(Web):30 Jun 2015
DOI:10.1039/C5CC03678J
A novel Au NP mediated dual-potential ECL ratiometric approach for highly sensitive protein kinase activity and inhibition assay has been developed based on the simultaneous decrease of cathodic ECL from GQDs and enhancement of anodic ECL from luminol in the same bioanalysis.
Co-reporter:Bao-Zhu Chi, Ru-Ping Liang, Li Zhang and Jian-Ding Qiu
Chemical Communications 2015 vol. 51(Issue 52) pp:10543-10546
Publication Date(Web):18 May 2015
DOI:10.1039/C5CC02864G
This assay, termed branched cascade enzymatic amplification (BCEA), can be a novel and straightforward method for sensitive and specific microRNA detection in crude cellular extracts of cancer cells at physiological temperature, by coupling two ordinary polymerases, Klenow fragment exo− and terminal deoxynucleotidyl transferase.
Co-reporter:Wei Song, Ru-Ping Liang, Ying Wang, Li Zhang and Jian-Ding Qiu
Chemical Communications 2015 vol. 51(Issue 49) pp:10006-10009
Publication Date(Web):11 May 2015
DOI:10.1039/C5CC02280K
A green method was employed for synthesizing peptide-templated nanoclusters without requiring strong reducing agents. Using synthetic peptide–gold nanoclusters as fluorescence probes, a novel assay for detecting protein kinase is developed based on phosphorylation against carboxypeptidase Y digestion.
Co-reporter:Li Zhang, Dong Peng, Ru-Ping Liang, and Jian-Ding Qiu
Analytical Chemistry 2015 Volume 87(Issue 21) pp:10894
Publication Date(Web):October 2, 2015
DOI:10.1021/acs.analchem.5b02450
Small molecules or metal ions can be employed as catalysts to accelerate metalloporphyrin formation. Herein, we for the first time report the coordination reaction between cadmium(II) and 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin can be accelerated by nitrogen-doped graphene quantum dots (NGQDs). This catalytic reaction results in the change of the absorption of porphyrins and the fluorescence of NGQDs as a result of the inner filter effect (IFE) of the porphyrins on the assembled NGQDs. Both signals can be used for rapid and sensitive determination of metal ions. The present work promises a novel strategy for constructing sensors for metal ions.
Co-reporter:Gui-Hong Yao, Ru-Ping Liang, Xiang-Dan Yu, Chun-Fang Huang, Li Zhang, and Jian-Ding Qiu
Analytical Chemistry 2015 Volume 87(Issue 2) pp:929
Publication Date(Web):December 15, 2014
DOI:10.1021/ac503016f
An ultrasensitive protocol for surface plasma resonance (SPR) detection of adenosine is designed with the aptamer-based target-triggering cascade multiple cycle amplification, and streptavidin-coated Au-NPs (Au NPs–SA) enhancement to enhance the SPR signals. The cascade amplification process consists of the aptamer-based target-triggering nicking enzyme signaling amplification (T-NESA), the nicking enzyme signaling amplification (NESA) and the hybridization chain reaction (HCR), the entire circle amplification process is triggered by the target recognition of adenosine. Upon recognition of the aptamer to target adenosine, DNA s1 is released from the aptamer and then hybridizes with hairpin DNA (HP1). The DNA s1 can be dissociated from HP1 under the reaction of nicking endonuclease to initiate the next hybridization and cleavage process. Moreover, the products of the upstream cycle (T-NESA) (DNA s2 and s3) could act as the “DNA trigger” of the downstream cycle (NESA and HCR) to generate further signal amplification, resulting in the immobilization of abundant Au NPs−SA on the gold substrate, and thus significant SPR enhancement is achieved due to the electronic coupling interaction between the localized surface plasma of Au NPs and the surface plasma wave. This detection method exhibits excellent specificity and sensitivity toward adenosine with a detection limit of 4 fM. The high sensitivity and specificity make this method a great potential for detecting biomolecules with trace amounts in bioanalysis and clinical biomedicine.
Co-reporter:Gui-Hong Yao, Ru-Ping Liang, Chun-Fang Huang, Li Zhang, Jian-Ding Qiu
Analytica Chimica Acta 2015 Volume 871() pp:28-34
Publication Date(Web):29 April 2015
DOI:10.1016/j.aca.2015.02.028
•We presented an enhancing strategy for adenosine detection via target-triggering strand displacement cycle and Au NPs.•The method exhibited a low detection limit of 0.21 pM.•High specificity of aptamers to target much favors for the selectivity improvement of the SPR assays.Herein, we combine the advantage of aptamer technique with the amplifying effect of an enzyme-free signal-amplification and Au nanoparticles (NPs) to design a sensitive surface plasmon resonance (SPR) aptasensor for detecting small molecules. This detection system consists of aptamer, detection probe (c-DNA1) partially hybridizing to the aptamer strand, Au NPs-linked hairpin DNA (Au-H-DNA1), and thiolated hairpin DNA (H-DNA2) previously immobilized on SPR gold chip. In the absence of target, the H-DNA1 possessing hairpin structure cannot hybridize with H-DNA2 and thereby Au NPs will not be captured on the SPR gold chip surface. Upon addition of target, the detection probe c-DNA1 is forced to dissociate from the c-DNA1/aptamer duplex by the specific recognition of the target to its aptamer. The released c-DNA1 hybridizes with Au-H-DNA1 and opens the hairpin structure, which accelerate the hybridization between Au-H-DNA1 and H-DNA2, leading to the displacement of the c-DNA1 through a branch migration process. The released c-DNA1 then hybridizes with another Au-H-DNA1 probe, and the cycle starts anew, resulting in the continuous immobilization of Au-H-DNA1 probes on the SPR chip, generating a significant change of SPR signal due to the electronic coupling interaction between the localized surface plasma of the Au NPs and the surface plasma wave. With the use of adenosine as a proof-of-principle analyte, this sensing platform can detect adenosine specifically with a detection limit as low as 0.21 pM, providing a simple, sensitive and selective protocol for small target molecules detection.
Co-reporter:Zhi-Chao Liu, Jian-Wen Qi, Chun Hu, Li Zhang, Wei Song, Ru-Ping Liang, Jian-Ding Qiu
Analytica Chimica Acta 2015 Volume 895() pp:95-103
Publication Date(Web):1 October 2015
DOI:10.1016/j.aca.2015.09.002
•We developed a ratiometric fluorescence probe for ratiometric and visualization detection of copper ions.•Copper nanoclusters was conjugated to silica coated CdSe quantum dots to design a ratiometric fluorescence probe.•Highly sensitive and visualized detection of Cu2+ was achieved.•This method provided a built-in correction for environmental interference.Copper is a highly toxic environmental pollutant with bioaccumulative properties. Therefore, sensitive detection of Cu2+ is very important to prevent over-ingestion, and visual detection is preferred for practical applications. In this work, we developed a simple and environmental friendly approach to synthesize hyperbranched polyethyleneimine-protected copper nanoclusters (hPEI-Cu NCs) with great stability against extreme pH, high ionic strength, thiols etching and light illumination, which were then conjugated to the surface of silica coated CdSe quantum dots (QDs) to design a ratiometric fluorescence probe. In the presence of different amounts of Cu2+ ions, the fluorescence of Cu NCs can be drastically quenched, while the emission from QDs stayed constant to serve as a reference signal and the color of the probe changed from yellow-green to red, resulting in ratiometric and visualization detection of Cu2+ ion with high accuracy. The detection limit for Cu2+ was estimated to be 8.9 nM, much lower than the allowable level of Cu2+ in drinking water (∼20 μM) set by U.S. Environmental Protection Agency. Additionally, this probe can be also applied for the determination of Cu2+ ion in complex real water samples.
Co-reporter:Shao-Hua Wen, San-Guan Cui, Ling Shi, Ru-Ping Liang, Jian-Ding Qiu
Journal of Electroanalytical Chemistry 2015 Volume 738() pp:77-83
Publication Date(Web):1 February 2015
DOI:10.1016/j.jelechem.2014.11.032
•The Pt@MWNTs was obtained by high-temperature decomposition of the precursor.•MWNTs can be used directly without any pretreatment procedures.•The size of the Pt NPs and the coverage density on MWNTs could be tuned easily.•Pt@MWNTs show excellent catalytic activities toward methanol oxidation and oxygen reduction.A novel approach to the synthesis of mono-dispersed platinum nanoparticles (Pt NPs) on multiwalled carbon nanotubes (MWNTs) has been proposed. With this method, we successfully assembled mono-dispersed Pt NPs on MWNTs. The method involved the in situ high-temperature decomposition of the precursor, platinum (II) acetylacetonate (Pt(acac)2), in liquid polyols. We used X-ray diffraction, scanning electron microscopy, and transmission electron microscopy to characterize the resulting MWNTs covered with Pt NPs (Pt@MWNTs). We found that the size of the Pt NPs and the coverage density on MWNTs could be tuned easily by changing the reaction temperature and the initial mass ratio of Pt(acac)2 to MWNTs. Electrocatalytic measurements showed that the Pt@MWNTs had excellent catalytic activities in the electrooxidation of methanol and in the oxygen reduction reaction. These Pt@MWNTs have potential applications in fuel cells and biosensors.
Co-reporter:Shao-Ping Shi, Hao-Dong Xu, Ping-Ping Wen and Jian-Ding Qiu
Molecular BioSystems 2015 vol. 11(Issue 10) pp:2610-2619
Publication Date(Web):03 Jun 2015
DOI:10.1039/C5MB00259A
Protein methylation catalyzed by methyltransferases carries many important biological functions. Methylation and their regulatory enzymes are involved in a variety of human disease states, raising the possibility that abnormally methylated proteins can be disease markers and methyltransferases are potential therapeutic targets. Identification of methylation sites is a prerequisite for decoding methylation regulatory networks in living cells and understanding their physiological roles that have been implicated in the pathological processes. Due to various limitations of experimental methods, in silico approaches for identifying novel methylation sites have become increasingly popular. In this review, we summarize the progress in the prediction of protein methylation sites from the dataset, feature representation, prediction algorithm and online resources in the past ten years. We also discuss the challenges that are faced while developing novel predictors in the future. The development and application of methylation site prediction is a promising field of systematic biology, provided that protein methyltransferases, species and functional information will be taken into account.
Co-reporter:Shao-Ping Shi, Xiang Chen, Hao-Dong Xu and Jian-Ding Qiu
Molecular BioSystems 2015 vol. 11(Issue 3) pp:819-825
Publication Date(Web):15 Dec 2014
DOI:10.1039/C4MB00646A
Compared to well-known and extensively studied protein phosphorylation, protein hydroxylation attracts much less attention and the molecular mechanism of the hydroxylation is still incompletely understood. And yet annotation of hydroxylation in proteomes is a first-critical step toward decoding protein function and understanding their physiological roles that have been implicated in the pathological processes and providing useful information for the drug designs of various diseases related with hydroxylation. In this work, we present a novel method called PredHydroxy to automate the prediction of the proline and lysine hydroxylation sites based on position weight amino acids composition, 8 high-quality amino acid indices and support vector machines. The PredHydroxy achieved a promising performance with an area under the receiver operating characteristic curve (AUC) of 82.72% and a Matthew's correlation coefficient (MCC) of 69.03% for hydroxyproline as well as an AUC of 87.41% and a MCC of 66.68% for hydroxylysine in jackknife cross-validation. The results obtained from both the cross validation and independent tests suggest that the PredHydroxy might be a powerful and complementary tool for further experimental investigation of protein hydroxylation. Feature analyses demonstrate that hydroxylation and non-hydroxylation have distinct location-specific differences; alpha and turn propensity is of importance for the hydroxylation of proline and lysine residues. A user-friendly server is freely available on the web at: http://bioinfo.ncu.edu.cn/PredHydroxy.aspx.
Co-reporter:Wei Song, Ying Wang, Ru-Ping Liang, Li Zhang, Jian-Ding Qiu
Biosensors and Bioelectronics 2015 Volume 64() pp:234-240
Publication Date(Web):15 February 2015
DOI:10.1016/j.bios.2014.08.082
•We reported a novel fluorescence assay base on peptide-AuNCs for sensitive analysis of protein kinase CK2 activity.•The peptide-AuNCs was synthesized in situ without any coupling and reducing agents.•Sensitive detection of CK2 based on the aggregation quenching mechanism.•Highly sensitive detection of CK2 activity and inhibition was achieved.A label-free, sensitive and simple method to detect protein kinase based on the selective aggregation of phosphorylated peptide-gold nanoclusters (peptide-AuNCs) triggered by Zr4+ ion coordination is developed. The AuNCs were synthesized by peptide without any strong reducing agents, which prevent peptides from being disrupted. Under optimal conditions, a linear relationship between the decreased PL intensity of peptide-AuNCs and the concentration of casein kinase II (CK2) in the range of 0.08–2.0 unit mL−1 with a detection limit of 0.027 unit mL−1 (3σ) was obtained. The feasibility of this AuNCs-based sensor was further demonstrated by the assessment of kinase inhibition by ellagic acid, 5,6-dichlorobenzimidazole-1-β-d-ribofuranoside, emodin, and quercetin in human serum. As expected, the PL intensity increased with increasing inhibitor efficiency in the presence of inhibitors. The IC50 value (inhibitor concentration producing 50% inhibition) for ellagic acid was estimated to be 0.045 μM. With more sophisticated design of the peptide substrate sequences, the detection of other enzymes will be realized. With characteristics of homogeneous, facile, universal, label-free, and applicable for kinase assay, the proposed sensor provides potential application in kinase-related biochemical fundamental research and inhibitor screening.
Co-reporter:Shu-Yun Huang, Shao-Ping Shi, Jian-Ding Qiu, Ming-Chu Liu
Journal of Molecular Graphics and Modelling 2015 Volume 56() pp:84-90
Publication Date(Web):March 2015
DOI:10.1016/j.jmgm.2014.12.005
•The proposed method remarkably improves the predictive quality of viral phosphorylation site.•Acidic residues contribute to the occurrence of viral phosphorylation site.•There are distinct residue-conservative differences for virus phosphorylation site.Phosphorylation of viral proteins plays important roles in enhancing replication and inhibition of normal host-cell functions. Given its importance in biology, a unique opportunity has arisen to identify viral protein phosphorylation sites. However, experimental methods for identifying phosphorylation sites are resource intensive. Hence, there is significant interest in developing computational methods for reliable prediction of viral phosphorylation sites from amino acid sequences. In this study, a new method based on support vector machine is proposed to identify protein phosphorylation sites in viruses. We apply an encoding scheme based on attribute grouping and position weight amino acid composition to extract physicochemical properties and sequence information of viral proteins around phosphorylation sites. By 10-fold cross-validation, the prediction accuracies for phosphoserine, phosphothreonine and phosphotyrosine with window size of 23 are 88.8%, 95.2% and 97.1%, respectively. Furthermore, compared with the existing methods of Musite and MDD-clustered HMMs, the high sensitivity and accuracy of our presented method demonstrate the predictive effectiveness of the identified phosphorylation sites for viral proteins.A new method, in which SVM incorporated EBAG + PWAA, is designed to identify viral phosphorylation sites. All training data were retrieved from the NCBI RefSeq and P3DB databases. Then, we used the sliding window strategy to extract positive and negative data from protein sequences as training data, which were represented by peptide sequences with serine, threonine and tyrosine symmetrically surrounded by flanking residues. Meanwhile, to further evaluate the performance of our method and compare with existing methods, an independent testing set was extracted from virPTM. To ensure unbiased and objective results, the ratio of positive and negative samples was 1:1. Subsequently, encoding scheme based on attribute grouping (EBAG) and position weight amino acid composition (PWAA) was utilized to extract sequence features. Feature analyses revealed that acidic residues contributed to the occurrence of viral phosphorylation sites, and there are distinct kinase-specific and residue-conservative differences for serine, threonine, and tyrosine phosphorylation sites of virus proteins.
Co-reporter:Zhi-Jian Li, Xiang-Juan Zheng, Li Zhang, Ru-Ping Liang, Zhi-Mei Li, Jian-Ding Qiu
Biosensors and Bioelectronics 2015 Volume 68() pp:668-674
Publication Date(Web):15 June 2015
DOI:10.1016/j.bios.2015.01.062
•Our approach is convenient, requiring only the mixing of several solutions at room temperature to achieve quantitative detection via UV–vis absorbance spectroscopy, where any usual steps such as modification and separation are therefore successfully avoided.•The detection of biothiols using this approach is sensitive. We achieve, for example, ppb detection limits for biothiols sensing, comparing very favorably with previously reported methods.•We demonstrate the design of an AuNPs colorimetric detection of biothiols based on the anti-aggregation of AuNPs through the competition replacement between biothiols and the aggregation agent SAM.Herein, a sensitive and selective sensor for biothiols based on colorimetric assay is reported. S-adenosyl-l-methionine (SAM) could induce the selective aggregation of unmodified gold nanoparticles (AuNPs) by electrostatic interaction. In the presence of biothiols, such as glutathione (GSH), homocysteine (Hcy), and cysteine (Cys), AuNPs prefer to react with thiols of biothiols rather than SAM due to the formation of Au–S bond. Thus, the AuNPs turn from the aggregation to the dispersion state, and the corresponding color variation in the process of anti-aggregation of AuNPs can be used for the quantitative screening of biothiols through UV–vis spectroscopy or by the naked eye. Under optimized conditions, a good linear relationship in the range of 0.4–1.2 µM is obtained for Cys, 0.2–0.9 µM for GSH, and 0.6–3.0 µM for Hcys. The detection limits of this assay for GSH, Cys and Hcys are 35.8 nM, 21.7 nM, and 62.4 nM, respectively. This colorimetric assay exhibits rapid operation (within 5 min), high selectivity and sensitivity towards biothiols with tunable dynamic ranges.
Co-reporter:Hui-Fang Zhao, Ru-Ping Liang, Jing-Wu Wang, Jian-Ding Qiu
Biosensors and Bioelectronics 2015 Volume 63() pp:458-464
Publication Date(Web):15 January 2015
DOI:10.1016/j.bios.2014.07.079
•We reported a novel ECL biosensor for sensitive analysis of DNA methyltransferase activity.•Click chemistry was used to assemble the ECL reagent.•GO/AgNPs/luminol composites were firstly used as the ECL signal amplification nanoprobe.•Highly sensitive detection of Dam MTase activity and inhibition was achieved.DNA methyltransferases catalyze the transfer of a methyl group from S-adenosylmethionine to the target adenine or cytosine, eventually inducing the DNA methylation in both prokaryotes and eukaryotes. Herein, we developed a novel electrochemiluminescence biosensor to quantify DNA adenine methylation (Dam) methyltransferase (MTase) employing signal amplification of GO/AgNPs/luminol composites to enhance the assay sensitivity. The method was developed by designing a capture probe DNA, which was immobilized on gold electrode surface, to hybridize with azide complementary DNA to form the azide-terminated dsDNA. Then, alkynyl functionalized GO/AgNPs/luminol composites as the signal probe were immobilized to azide-terminated dsDNA modified electrode via click chemistry, resulting in a high electrochemiluminescence (ECL) signal. Once the DNA hybrid was methylated (under catalysis of Dam MTase) and further cleaved by Dpn I endonuclease (a site-specific endonuclease recognizing the duplex symmetrical sequence of 5′-G-Am-T-C-3′), GO/AgNPs/luminol composites release from the electrode surface to the solution, leading to significant reduction of the ECL signal. The change of the ECL intensity is related to the methylation status and MTase activity, which forms the basis of MTase activity assay and site-specific methylation determination. This novel strategy can be further used as a universal method for other transferase determination by designing various transferase-specific DNA sequences. In addition, this method can be used for the screening of antimicrobial drugs and has a great potential to be further applied in early clinical diagnosis.
Co-reporter:Dr. Li Zhang;Dong Peng; Ru-Ping Liang ; Jian-Ding Qiu
Chemistry - A European Journal 2015 Volume 21( Issue 26) pp:9343-9348
Publication Date(Web):
DOI:10.1002/chem.201500803
Abstract
Noncovalent and multifunctional hybrids have been generated via π–π stacking and electrostatic interactions by combining the nanometer-scale graphene structure of graphene quantum dots (GQDs) with FeIII 5,10,15,20-tetrakis(1-methyl-4-pyridyl)porphine (FeTMPyP). The inner filter effect (IFE) of FeTMPyP on the GQDs results in substantial PL quenching of the GQDs. The quenched PL of GQDs by the FeTMPyP can be switched back “on” in response to the reaction between FeTMPyP and H2O2, which causes rupture of the cyclic tetrapyrrolic nucleus with consequential loss of iron from FeTMPyP, and then proceeds further to produce colorless dipyrroles and monopyrroles. This “turn on” system can be applied for simple and convenient H2O2 sensing and can be further extended to the detection of glucose in combination with the specific catalytic effect of glucose oxidase (GOx) through the oxidation of glucose and formation of H2O2. Because of the inherent synthetic control available for the design of metalloporphyrins, the GQDs-based optical sensing approach described here has the potential to be highly versatile for other target analytes.
Co-reporter:Wan Gao;Dr. Li Zhang; Ru-Ping Liang ; Jian-Ding Qiu
Chemistry - A European Journal 2015 Volume 21( Issue 43) pp:15272-15279
Publication Date(Web):
DOI:10.1002/chem.201502122
Abstract
The logic system is obtained by using a series of double-stranded (ds) DNA templates with mismatched base pairs (T–T or C–C) and ion-modulated exonuclease III (Exo III) activity, in which the Exo III cofactors, Hg2+ and Ag+ ions, are used as inputs for the activation of the respective scission of Exo III based on the formation of T–Hg2+–T or C–Ag+–C base pairs. Additionally, two kinds of signal probes are utilized to transduce the logic operations. One is the two split G-rich DNA strands that are used to design the OR, AND, INHIBIT, and XOR gates, whereas the other is the self-assembled split G-quadruplex structure to construct NOR, NAND, IMPLICATION, and XNOR operations based on DNA hybridization and strand displacement. In the presence of hemin, the split G-quadruplex biocatalyzes the formation of a colored product, which is an output signal for the different logic gates. Thus, we have constructed a complete set of colorimetric DNA logic gates based on the Exo III and split G-quadruplex for the first time. In addition, we are able to effortlessly recognize the logic output signals by the naked eye and their simplicity and cost-effective design is the most apparent feature for the logic gates developed in this work.
Co-reporter:Ru-Ping Liang, Xiao-Cui Tian, Ping Qiu, and Jian-Ding Qiu
Analytical Chemistry 2014 Volume 86(Issue 18) pp:9256
Publication Date(Web):August 22, 2014
DOI:10.1021/ac502318x
In this work, we developed a novel multisignal output for simultaneous detection of multiple proteases by using nanoprobes labeled with distinguishable electrochemical probes. First, biotinylated peptide1 (S1) and biotinylated peptide2 (S2) were associated with biotinylated DNA1 and DNA2 via biotin–streptavidin interaction, forming DNA1–S1 and DNA2–S2, respectively. Two distinguishable signal nanoprobes (DNA1′–Au NPs–Thi and DNA2′–Au NPs–Fc) were prepared by initial assembling DNA1′ and DNA2′ on the Au NPs surface, respectively, and then carrying corresponding thionine (Thi) and 6-(Ferrocenyl)hexanethiol (Fc). Then, the peptide substrates (DNA1–S1 and DNA2–S2) were immobilized on gold electrode surface through Au—S bonds, and the DNA1′–Au NPs–Thi and DNA2′–Au NPs–Fc were assembled to the peptide–DNA-modified electrode surface via DNA hybridization. The targets of trypsin and chymotrypsin can specifically recognize and cleave peptides with different sequences, releasing DNA1′–Au NPs–Thi and DNA2′–Au NPs–Fc from the electrode surface into solution, thus decreasing the current of Thi and Fc. The decrease in the electrochemical currents of the two signal nanoprobes enables us to simultaneously and quantitatively determine the targets trypsin and chymotrypsin. More importantly, this strategy can be extended easily by designing various proteases-specific peptide substrates and utilizing corresponding electrochemical detectable elements for simultaneous multiplex protease assay in various biosystems.
Co-reporter:Li Zhang, Zhi-Yi Zhang, Ru-Ping Liang, Ya-Hua Li, and Jian-Ding Qiu
Analytical Chemistry 2014 Volume 86(Issue 9) pp:4423
Publication Date(Web):April 7, 2014
DOI:10.1021/ac500289c
A hydrothermal approach for the cutting of boron-doped graphene (BG) into boron-doped graphene quantum dots (BGQDs) has been proposed. Various characterizations reveal that the boron atoms have been successfully doped into graphene structures with the atomic percentage of 3.45%. The generation of boronic acid groups on the BGQDs surfaces facilitates their application as a new photoluminescence (PL) probe for label free glucose sensing. It is postulated that the reaction of the two cis-diol units in glucose with the two boronic acid groups on the BGQDs surfaces creates structurally rigid BGQDs–glucose aggregates, restricting the intramolecular rotations and thus resulting in a great boost in the PL intensity. The present unusual “aggregation-induced PL increasing” sensing process excludes any saccharide with only one cis-diol unit, as manifested by the high specificity of BGQDs for glucose over its close isomeric cousins fructose, galactose, and mannose. It is believed that the doping of boron can introduce the GQDs to a new kind of surface state and offer great scientific insights to the PL enhancement mechanism with treatment of glucose.
Co-reporter:Ru-Ping Liang, Cai-Yun Xiang, Hui-Fang Zhao, Jian-Ding Qiu
Analytica Chimica Acta 2014 Volume 812() pp:33-40
Publication Date(Web):17 February 2014
DOI:10.1016/j.aca.2013.12.037
•We reported a novel ECL biosensor for sensitive analysis of protein kinase activity.•GOx/Au NPs/DNA-biotin was used as the ECL signal amplification nanoprobe.•This strategy can in situ generate coreactant H2O2 to improve the luminol ECL signal.•Highly sensitive detection of PKA activity and inhibition is achieved.We presented a novel electrogenerated chemiluminescence (ECL) biosensor for monitoring the activity and inhibition of protein kinases based on signal amplification using enzyme-functionalized Au NPs nanoprobe. In this design, the biotin-DNA labeled glucose oxidase/Au NPs (GOx/Au NPs/DNA-biotin) nanoprobes, prepared by conjugating Au NPs with biotin-DNA and GOx, were bound to the biotinylated anti-phosphoserine labeled phosphorylated peptide modified electrode surface through a biotin−avidin interaction. The GOx assembled on the nanoprobe can catalyze glucose to generate H2O2 in the presence of O2 while the ECL reaction occurred in the luminol ECL biosensor. At a higher concentration of kinase, there are more nanoprobes on the electrode, which gives a higher amount of GOx at the electrode interface and thus higher electrocatalytic efficiency to the luminol ECL reaction. Therefore, the activity of protein kinases can be monitored by ECL with high sensitivity. Protein kinase A (PKA), an important enzyme in regulation of glycogen, sugar, and lipid metabolism in the human body, was used as a model to confirm the present proof-of-concept strategy. The as-proposed biosensor presents high sensitivity, low detection limit of 0.013 U mL−1, wide linear range (from 0.02 to 40 U mL−1), and excellent stability. Moreover, this biosensor can also be used for quantitative analysis of kinase inhibition. On the basis of the inhibitor concentration dependent ECL signal, the half-maximal inhibition value IC50 of ellagic acid, a typical PKA inhibitor, was estimated, which is in agreement with those obtained using the conventional kinase assay. The simple and sensitive biosensor is promising in developing a high-through assay of in vitro kinase activity and inhibitor screening for clinic diagnostic and drug development.
Co-reporter:Xiao-Ni Wang, Ru-Ping Liang, Xiang-Ying Meng, Jian-Ding Qiu
Journal of Chromatography A 2014 Volume 1362() pp:301-308
Publication Date(Web):3 October 2014
DOI:10.1016/j.chroma.2014.08.044
•Imprinted Fe3O4@PDA NPs as stationary phase in OT-CEC for enantioseparation was proposed.•Imprinted Fe3O4@PDA NPs are endowed with high binding capacity and magnetism property for easy manipulation.•Such one-pot fabrication facilitates the situation of the imprinted sites on the surface of Fe3O4 NPs.•This novel stationary phase was successfully applied to the separation of various kinds of enantiomers.A facile approach for preparation of molecularly imprinted polymers was developed and successfully used as chiral stationary phase for rapid enantioseparation by open tubular capillary electrochromatography (OT-CEC). In this work, molecularly imprinted polymers were one-step prepared employing Fe3O4 nanoparticles (NPs) as the supporting substrate and dopamine as the functional monomer. By simply mixing Fe3O4 NPs with template molecules in a weak alkaline solution of dopamine, a thin adherent polydopamine (PDA) film imprinted with template molecules was formed by the self-polymerization of dopamine on the surface of Fe3O4 NPs. After extracting the embedded template molecules, the produced imprinted Fe3O4@PDA NPs are of three dimensional shape of template molecules favoring high binding capacity and magnetism property for easy manipulation. The imprinted Fe3O4@PDA NPs prepared with l-tryptophan, l-tyrosine, Gly-l-Phe or s-ofloxacin as template molecules were packed in the PDMS microchannel via magnetic field as novel stationary phase for the successful enantioseparation of corresponding target analysts. In addition, the imprinted Fe3O4@PDA NPs-based OT-CEC system exhibited excellent reproducibility, stability and repeatability, which provides a powerful protocol for separation enantiomers within a short analytical time and opens up a promising avenue for high-throughput screening of chiral compounds.
Co-reporter:Ru-Ping Liang, Xiao-Ni Wang, Chun-Ming Liu, Xiang-Ying Meng, Jian-Ding Qiu
Journal of Chromatography A 2014 Volume 1323() pp:135-142
Publication Date(Web):3 January 2014
DOI:10.1016/j.chroma.2013.11.048
•PDA/GO platform for the facile preparation of protein stationary phase was developed.•PDA/GO is endowed with the adhesive nature and high adsorption capacity.•Integrating BSA onto PDA/GO platform-based PDMS microchip greatly increased the phase ratio.•This protocol simplified the immobilization methodology of proteins in OT-CEC microdevice.A novel chip-based enantioselective open-tubular capillary electrochromatography (OT-CEC) was developed employing bovine serum albumin (BSA) conjugated polydopamine–graphene oxide (PDA/GO) nanocomposites (PDA/GO/BSA) as stationary phase. After the poly(dimethylsiloxane) (PDMS) microfluidic chip was filled with a freshly prepared solution containing dopamine and graphene oxide, PDA/GO nanocomposites were formed and deposited on the inner wall of microchannel as permanent coating via the oxidation of dopamine by the oxygen dissolved in the solution. The PDA/GO-coated PDMS microchips not only have the adhesion of PDA that make them easily immobilized in the microchannel, but also have the larger surface and excellent biocompatibility of graphene which can incorporate much more biomolecules and well maintain their biological activity. In addition, incorporation of GO in PDA film can make surface morphology more rough, which is beneficial for enhancing the loading capacity of proteins in the microchannels and increasing sample capacity of OT-CEC columns. BSA was stably immobilized in the PDMS microchannel to fabricate a protein-stationary phase. Compared with the native PDMS microchannels, the modified surfaces exhibited much better wettability, more stable electroosmotic mobility, and less nonspecific adsorption. The efficient separation of chiral amino acids (tryptophan and threonine) and chiral dipeptide demonstrate that the constructed OT-CEC columns own ideal enantioselectivity. The presented strategy using PDA/GO coating as a versatile platform for facile conjugation of proteins may offer new processing strategies to prepare a functional surface designed on microfluidic chips.
Co-reporter:Cong-Sen Liu, Xiao-Chen Liu, Guo-Chong Wang, Ru-Ping Liang, Jian-Ding Qiu
Journal of Electroanalytical Chemistry 2014 Volume 728() pp:41-50
Publication Date(Web):15 August 2014
DOI:10.1016/j.jelechem.2014.06.024
•Interfacial polymerization method was used to synthesize PANI/GO.•Nitrogen-doped graphene can be obtained by thermally annealing PANI/GO in an inert environment.•NGs were used as catalyst supports for dispersing Pt NPs.•Pt/NGs show excellent electrocatalytic activity toward methanol oxidation and oxygen reduction.A novel synthesis procedure is devised to obtain nitrogen-doping graphene sheets (NGs). Initially, a conducting polymer polyaniline (PANI) is used to form a uniform coating of the polymer over graphene oxide (GO) by interfacial polymerization method for the synthesis of high-quality polyaniline-modified GO nanocomposites (PANI/GO). In polymerization, the liquid–liquid (L/L) interface provides a good soft template, which allows PANI to grow uniformly on the surface of the GO. Subsequently, thermal annealing PANI/GO nanocomposites in an inert environment lead to reduce the GO to graphene (GNs) with simultaneous nitrogen atoms incorporation in the graphene frameworks. The obtained nitrogen-doped graphene (NGs) are used as catalyst supports without any chemical modification for dispersing platinum nanoparticles (Pt NPs) by the chemical reduction method, yielding a uniform dispersion of the catalyst nanoparticles. The obtained nanocomposites are characterized by UV–Vis absorption spectra, X-ray photoelectron spectroscopy, Raman, X-ray diffraction, transmission electron microscopy, and thermogravimetric analysis. Electrochemical characterizations clearly demonstrate that the Pt/NGs nanocomposites show excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. The current density of Pt/NGs is 1.58 and 1.51 times higher than that of Pt/graphene (Pt/GNs) in methanol oxidation and oxygen reduction, respectively. These results demonstrate that the Pt/NGs nanocomposites may be an attractive and advanced electrode material with potential applications for proton exchange membrane fuel cells (PEMFCs).
Co-reporter:Li Zhang, Ru-Ping Liang, Sai-Jin Xiao, Jian-Mei Bai, Lin-Ling Zheng, Lei Zhan, Xi-Juan Zhao, Jian-Ding Qiu, Cheng-Zhi Huang
Talanta 2014 Volume 118() pp:339-347
Publication Date(Web):15 January 2014
DOI:10.1016/j.talanta.2013.09.021
•We prepare the fluorescent indicator facilely and economically.•We propose a simple, sensitive and specific assay for OH.•We extensively study and reveal the sensing mechanism.•We design the fluorescent probe for intracellular imaging of OH.We have developed a simple, rapid and label-free sensor for the essential biological OH radicals based on the fluorescence quenching of DNA-templated Ag nanoclusters (DNA-Ag NCs). The OH radicals generated from the Fenton reagent attack and cleave the DNA template, which disturbs the microenvironments around Ag NCs, resulting in spontaneous aggregation due to the lack of stabilization and further the quenching of the Ag NCs fluorescence. These changes in fluorescence intensity allow sensing of OH radicals with good sensitivity and selectivity under optimal conditions. The sensor can be also applied for quantifying the radical scavenging action of antioxidants. Various characterizations including absorption spectra, fluorescence lifetimes, light scattering (LS) spectra, transmission electron microscopy (TEM), dark field light scattering imaging, and circular dichroism (CD) spectrometry have been employed to illustrate the proposed sensing mechanism. Further investigations demonstrate that the fluorescent probe could penetrate into intact cell membranes to selectively detect intracellular OH radicals induced by the phorbol myristate acetate (PMA) stimulation. These advantageous characteristics make the fluorescent DNA-Ag NCs potentially useful as a new candidate to monitor OH in broad biosystems.
Co-reporter:Wan Gao ; Li Zhang ; Yun-Mei Zhang ; Ru-Ping Liang
The Journal of Physical Chemistry C 2014 Volume 118(Issue 26) pp:14410-14417
Publication Date(Web):June 10, 2014
DOI:10.1021/jp503608t
A horseradish peroxidase (HRP)-mimicking DNAzyme sequence is first blocked by the triplex-based molecular beacon (tMB). Upon hybridization with single-stranded DNA inputs, triplex–helix molecular switch occurs, and the released product strand self-assembles into the hemin/G-quadruplex-HRP-mimicking DNAzyme that biocatalyzes the formation of a colored product and provides an output signal for the different logic gates. On the basis of this principle, a series of logic gates (OR, XOR, INHIBIT, and AND) have been developed. Moreover, a multilevel circuit (MC) that enforces an overall OR Boolean behavior is developed by connecting the AND and XOR logic gates. The logic output signals can be recognized by naked eyes, thus providing a flexible, secure, economic, and simple method for designing a complex DNA-based logic device.
Co-reporter:Xiao-Chen Liu, Guo-Chong Wang, Ru-Ping Liang, Ling Shi and Jian-Ding Qiu
Journal of Materials Chemistry A 2013 vol. 1(Issue 12) pp:3945-3953
Publication Date(Web):18 Jan 2013
DOI:10.1039/C3TA00527E
Pt-based catalysts are widely used in fuel cells and sensors for their exceptional electrocatalytic activity. Among the different methods for producing Pt-based catalysts, chemical reduction is favorable, due to its scalability in volume production and versatility in realizing abundant chemical functionalization. In this paper, an environment-friendly method for the facile synthesis of Pt nanoparticles supported on polydopamine (Pdop) modified carbon materials (multiwalled carbon nanotubes, carbon nanospheres and Vulcan XC-72 carbon black) is reported. Since Pdop is employed as the reductant and crosslinking agent, no reducing agents, surfactants, organic solvents, etc., are needed. The Pt-based catalysts produced using this method have a unique electrocatalytic activity toward methanol oxidation. This environmentally friendly method is promising for the synthesis of high performance catalysts for fuel cells, gas phase catalysis, and sensors.
Co-reporter:Xiang-Juan Zheng, Jian-Ding Qiu, Li Zhang, Zhong-Xia Wang and Ru-Ping Liang
Chemical Communications 2013 vol. 49(Issue 34) pp:3546-3548
Publication Date(Web):12 Mar 2013
DOI:10.1039/C3CC41486H
Using unmodified Au nanorods with enzyme-linkage reaction, a label-free colorimetric method for simple and convenient assay of DNA methylation is presented.
Co-reporter:Ya-Hua Li, Li Zhang, Jing Huang, Ru-Ping Liang and Jian-Ding Qiu
Chemical Communications 2013 vol. 49(Issue 45) pp:5180-5182
Publication Date(Web):18 Apr 2013
DOI:10.1039/C3CC40652K
Using graphene quantum dots (GQDs) with a boronic acid-substituted bipyridinium salt (BBV), a label-free fluorescence assay for glucose detection is presented.
Co-reporter:Ying Wang, Li Zhang, Ru-Ping Liang, Jian-Mei Bai, and Jian-Ding Qiu
Analytical Chemistry 2013 Volume 85(Issue 19) pp:9148
Publication Date(Web):September 5, 2013
DOI:10.1021/ac401807b
A simple and sensitive photoluminescence (PL) assay for the activity of a protein kinase based on the selective aggregation of phosphorylated peptide–graphene quantum dot (GQD) conjugates triggered by Zr4+ ion coordination has been established. With more sophisticated design of the peptide substrate sequences, detecting other enzymes could also be possible. Under optimal conditions, a linear relationship between the decreased PL intensity of peptide–GQD conjugates and the concentration of casein kinase II (CK2) in the range from 0.1 to 1.0 unit mL–1 with a detection limit of 0.03 unit mL–1 (3σ) was obtained. The EC50 value (i.e., the enzyme concentration producing 50% substrate conversion) for CK2 was evaluated to be 0.34 unit mL–1. The proposed method showed potential applications in kinase inhibitor screening. To demonstrate the potential of this GQD-based platform for screening of kinase inhibitors in real biological systems, the inhibition of CK2 phosphorylation activity by four different inhibitors (ellagic acid, 5,6-dichlorobenzimidazole-l-β-d-ribofuranoside, emodin, and quercetin) was tested in human serum by comparing signals from samples incubated with the inhibitors against that without any inhibitor. As expected, in the presence of inhibitors, the PL intensity increased with increasing inhibitor efficiency. The IC50 value (inhibitor concentration producing 50% inhibition) for ellagic acid was estimated to be 0.041 μM. The developed protocol provides a new and promising tool for the analysis of both the enzyme and its inhibitors with low cost and excellent performance.
Co-reporter:Hui Zhang, Li Zhang, Ru-Ping Liang, Jing Huang, and Jian-Ding Qiu
Analytical Chemistry 2013 Volume 85(Issue 22) pp:10969
Publication Date(Web):October 15, 2013
DOI:10.1021/ac402496e
In this work, we designed a novel detection strategy to realize simultaneous determination of multiplex lectin by labeling glucosamine (G1) and galactosamine (G2) with different-colored semiconductor quantum dots (QDs). On the basis of the agglutination of the aminosugar-labeled QDs induced by the exclusive binding between the lectin and sugar on the QDs surfaces, the fluorescence emission of the QDs supernatant after centrifugation decreased with relevant lectin concentration [i.e., when concanavalin A (Con A) exists alone], only green color fluorescence emission from QDs-G1 supernatant decreased, so it is peanut agglutinin (PNA) and red color fluorescence emission from QDs-G2. Moreover, since QDs can be simultaneously excited with multiple fluorescence colors and have a larger Stokes shift than organic fluorophores, when both Con A and PNA are present in the sample, both of the green and red color fluorescence emission from QDs-G1 and QDs-G2 supernatant would decrease, thus realizing the simultaneous determination of Con A and PNA. The detection limits of Con A and PNA are 0.30 and 0.18 nM (3σ), respectively. Furthermore, the present detection method not only can determine the protein/lectins by fluorescence spectral method but also can realize visualization detection by UV lamp illumination. To the best of our knowledge, this is the first report of such analytical method in multiple and simultaneous lectin detection.
Co-reporter:Gui-Hong Yao, Ru-Ping Liang, Chun-Fang Huang, Ying Wang, and Jian-Ding Qiu
Analytical Chemistry 2013 Volume 85(Issue 24) pp:11944
Publication Date(Web):November 22, 2013
DOI:10.1021/ac402848x
We reported here a method to enhance detection sensitivity in surface plasmon resonance (SPR) spectroscopy integrated with a surface molecular imprinting recognition system and employing magnetic molecular imprinting polymer nanoparticles for amplifying SPR response. The proposed magnetic molecular imprinting polymer was designed by self-polymerization of dopamine on the Fe3O4 NPs surface in weak base aqueous solution in the presence of template chlorpyrifos (CPF). The imprinted Fe3O4@polydopamine nanoparticles (Fe3O4@PDA NPs) were characterized by Fourier transform infrared spectroscopy, UV–vis absorption spectroscopy, and transmission electron microscopy. The biosensor showed a good linear relationship between the SPR angle shift and the chlorpyrifos concentration over a range from 0.001 to 10 μM with a detection limit of 0.76 nM. A significant increase in sensitivity was therefore afforded through the use of imprinted Fe3O4@PDA NPs as an amplifier, and meanwhile, the imprinted Fe3O4@PDA NPs had an excellent recognition capacity to chlorpyrifos over other pesticides. The excellent sensitivity and selectivity and high stability of the designed biosensor make this magnetic imprinted Fe3O4@PDA NP an attractive recognition element for various SPR sensors for detecting pesticide residuals and other environmentally deleterious chemicals.
Co-reporter:Chun-Ming Liu, Ru-Ping Liang, Xiao-Ni Wang, Jing-Wu Wang, Jian-Ding Qiu
Journal of Chromatography A 2013 Volume 1294() pp:145-151
Publication Date(Web):14 June 2013
DOI:10.1016/j.chroma.2013.04.022
•Chip-based OT-CEC with PDA/BSA conjugates as stationary phase was fabricated.•PDA coating served as a versatile platform for protein stationary phase preparation.•Good biocompatibility of PDA coatings well maintained the biological activity of BSA.•This protocol simplified protein stationary phase fabrication of OT-CEC microdevice.A novel, simple, and economical method for the preparation of chiral stationary phases for chip-based enantioselective open tubular capillary electrochromatography (OT-CEC) using polydopamine (PDA) coating as an adhesive layer was reported for the first time. After the poly(dimethylsiloxane) (PDMS) microfluidic chip was filled with dopamine (DA) solution, PDA film was gradually formed and deposited on the inner wall of microchannel as permanent coating via the oxidation of DA by the oxygen dissolved in the solution. Due to possessing plentiful catechol and amine functional groups, PDA coating can serve as a versatile multifunctional platform for further secondary reactions, leading to tailoring of the coatings for protein bioconjugation by the thiols and amines via Michael addition or Schiff base reactions. Bovine serum albumin (BSA), acting as a target protein, was then stably and homogeneously immobilized in the PDA-coated PDMS microchannel to fabricate a novel protein stationary phase. Compared with the native PDMS microchannels, the modified surfaces exhibited much better wettability, more stable and enhanced electroosmotic mobility, and less nonspecific adsorption. The water contact angle and electroosmotic flow of PDA/BSA-coated PDMS substrate were measured to be 44° and 2.83 × 10−4 cm2 V−1 s−1, compared to those of 112° and 2.10 × 10−4 cm2 V−1 s−1 from the untreated one, respectively. Under a mild condition, d- and l-tryptophan were efficiently separated with a resolution of 1.68 within 130 s utilizing a separation length of 37 mm coupled with in-column amperometric detection on the PDA/BSA-coated PDMS microchips. This present versatile platform, facile conjugation of biomolecules onto microchip surfaces via mussel adhesive protein inspired coatings, may offer new processing strategies to prepare a biomimetic surface design on microfluidic chips, which is promising in high-throughput and complex biological analysis.
Co-reporter:Ru-Ping Liang, Cai-Yun Xiang, Jing-Wu Wang, Jian-Ding Qiu
Journal of Chromatography A 2013 Volume 1284() pp:194-201
Publication Date(Web):5 April 2013
DOI:10.1016/j.chroma.2013.02.007
For the first time, a simple and ‘green’ approach based on one-step strategy was designed and developed for the modification of a fused-silica capillary with polynorepinephrine (PNE) to separate amino acid enantiomers using capillary electrochromatography coupled with electrogenerated chemiluminescence detection (CEC-ECL). Norepinephrine (NE) was filled into capillary to generate PNE coating on the surface of capillary as permanent coating via the oxidation of NE by oxygen dissolvable in the solution. The formation of the PNE coating was characterized by scanning electron microscopy, UV–vis spectra and contact angle measurements. Compared with the native capillary, the modified capillary had much better wettability, less nonspecific adsorption toward amino acids, and the enantiomers of histidine, phenylalanine, and valine samples received baseline separation with the resolution factors of 1.6, 1.8 and 1.6, respectively, utilizing a separation length of 40 cm of the capillary coupled with ECL detection on the PNE-coated capillary.Highlights► A one-step strategy for the modification of capillary with polynorepinephrine was designed and developed. ► The polynorepinephrine coating exhibited high stability and hydrophilicity. ► First use of polynorepinephrine to be a chiral selctor to efficiently separate amino acids enantiomers. ► This protocol to fabricate capillary stationary phase was simple and “green”.
Co-reporter:Ru-Ping Liang, Xiao-Ni Wang, Chun-Ming Liu, Xiang-Ying Meng, Jian-Ding Qiu
Journal of Chromatography A 2013 Volume 1315() pp:28-35
Publication Date(Web):8 November 2013
DOI:10.1016/j.chroma.2013.09.046
•A strategy for construction of GO/Fe3O4 MNCs-based on-chip enzymatic microreactor was proposed.•The magnetism of Fe3O4 NPs can make enzymatic microreactor conveniently manipulated and replaceable.•Such an enzymatic microreactor was successfully applied to the sensitive detection of pesticide.A new strategy for facile construction of graphene oxide magnetic nanocomposites (GO/Fe3O4 MNCs)-based on-chip enzymatic microreactor and ultrasensitive pesticide detection has been proposed. GO/Fe3O4 MNCs were first prepared through an in situ chemical deposition strategy. Then, acetylcholinesterase (AChE) was adsorbed onto the GO/Fe3O4 surface to form GO/Fe3O4/AChE MNCs which was locally packed into PDMS microchannel simply with the help of external magnetic field to form an on-chip enzymatic microreactor. The constructed GO/Fe3O4/AChE MNCs-based enzymatic microreactor not only have the magnetism of Fe3O4 NPs that make them conveniently manipulated by an external magnetic field, but also have the larger surface and excellent biocompatibility of graphene which can incorporate much more AChE molecules and well maintain their biological activity. On the basis of the AChE inhibition principle, a novel on-chip enzymatic microreactor was constructed for analyzing dimethoate which is usually used as a model of organophosphorus pesticides. Under optimal conditions, a linear relationship between the inhibition rates of AChE and the concentration of dimethoate from 1 to 20 μg L−1 with a detection limit of 0.18 μg L−1 (S/N = 3) was obtained. The developed electrophoretic and magnetic-based chip exhibited excellent reproducibility and stability with no decrease in the activity of enzyme for more than 20 repeated measurements over one week period, which provided a new and promising tool for the analysis of enzyme inhibitors with low cost and excellent performance.
Co-reporter:Chun-Fang Huang, Gui-Hong Yao, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2013 50() pp: 305-310
Publication Date(Web):
DOI:10.1016/j.bios.2013.07.002
Co-reporter:Yun-Mei Zhang;Dr. Li Zhang; Ru-Ping Liang ; Jian-Ding Qiu
Chemistry - A European Journal 2013 Volume 19( Issue 22) pp:6961-6965
Publication Date(Web):
DOI:10.1002/chem.201300625
Co-reporter:Li Zhang, Zhong-Xia Wang, Ru-Ping Liang, and Jian-Ding Qiu
Langmuir 2013 Volume 29(Issue 28) pp:8929-8935
Publication Date(Web):2017-2-22
DOI:10.1021/la401887b
Utilizing the principles of metal-ion-mediated base pairs (C-Ag-C and T-Hg-T), the pH-sensitive conformational transition of C-rich DNA strand, and the ligand-exchange process triggered by dl-dithiothreitol (DTT), a system of colorimetric logic gates (YES, AND, INHIBIT, and XOR) can be rationally constructed based on the aggregation of the DNA-modified Au NPs. The proposed logic operation system is simple, which consists of only T-/C-rich DNA-modified Au NPs, and it is unnecessary to exquisitely design and alter the DNA sequence for different multiple molecular logic operations. The nonnatural base pairing combined with unique optical properties of Au NPs promises great potential in multiplexed ion sensing, molecular-scale computers, and other computational logic devices.
Co-reporter:Jing Huang, Li Zhang, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2013 Volume 41() pp:430-435
Publication Date(Web):15 March 2013
DOI:10.1016/j.bios.2012.09.007
A novel “smart” electrochemical affinity nanobiosensor with “on-off” switchable property was designed for the ultrasensitive determination of glucose. The sensing approach was based on the glucose-ConA-dextran competitive system induced charge evolution in the use of graphene oxide (GO) as transducer element, resulting in the enhancement of interfacial electron transfer kinetics between the redox probe and the electrode. As concanavalin A (ConA) constituent was pH-sensitive, when the ConA-DexP/GO film electrode switched in probe Fe(CN)63−/4− solution between pH 4.0 and 8.0, the film was cycled between the “on” and “off” states by the electrostatic attraction and repulsion of Fe(CN)63−/4− to and from the electrode surface. Upon introduction of glucose into the ConA-DexP/GO complex at the “off” state, glucose competed with DexP for ConA and displaced ConA from the GO platform, resulting in gradual decrease of the surface negative charge as well as the resistance of probe for electron communication on the sensor surface, and making the switching from “off” state to “on” state simultaneously. This ultrasensitive glucose nanobiosensor had a broad linearity between the decrease in electron transfer resistance (ΔR) and the glucose concentration over a range from 5.0 μM to 9.0 mM with a detection limit as low as 0.34 μM. The proposed method showed potential application for fabricating novel biosensors and bioelectronic devices.Highlights► A “smart” pH-switchable electrochemical glucose nanobiosensor ConA-DexP/GO is designed by employing the glucose-ConA-dextran competitive system on a GO-based sensing platform. ► Upon addition of glucose to the ConA-DexP/GO sensing surface, the interfacial electron transfer kinetics between the redox probe and the electrode is enhanced due to the displacement-induced charge evolution of the platform, making the sensor from “off” state to “on” state simultaneously. ► This ultrasensitive glucose nanobiosensor had a broad linearity over a range of 5.0 μM–9.0 mM with a detection limit as low as 0.34 μM and performed excellent selectivity for glucose over other sugars. ► This novel sensing strategy is promising for the preparation of high performance biosensors for other small molecules.
Co-reporter:Hua-Ping Peng, Ru-Ping Liang, Li Zhang, Jian-Ding Qiu
Biosensors and Bioelectronics 2013 Volume 42() pp:293-299
Publication Date(Web):15 April 2013
DOI:10.1016/j.bios.2012.10.074
In this study, a novel biomolecule immobilization approach has been proposed to the synthesis of multi-functional core–shell glucose oxidase–Au–polydopamine–Fe3O4 magnetic bionanoparticles (GOx–Au–PDA–Fe3O4 MBNPs) using the one-pot chemical polymerization method. Then, a high performance biosensor has been constructed by effectively attaching the proposed GOx–Au–PDA–Fe3O4 MBNPs to the surface of the magnetic glassy carbon electrode. Scanning electron microscope, energy dispersive x-ray spectrometer, UV–vis spectroscopy, and electrochemical methods were used to characterize the GOx–Au–PDA–Fe3O4 MBNPs. The resultant GOx–Au–PDA–Fe3O4 MBNPs not only have the magnetism of Fe3O4 nanoparticles which makes them easily manipulated by an external magnetic field, but also have the excellent biocompatibility of PDA to maintain the native structure of the GOx, and good conductivity of Au nanoparticles which can facilitate the direct electrochemistry of GOx in the biofilm. Hence, the present GOx–Au–PDA–Fe3O4 biofilm displays good linear amperometric response to glucose concentration ranging from 0.02 to 1.875 mM. This efficient biomolecule immobilization platform is recommended for the preparation of many other MBNPs with interesting properties and application potentials in many fields, such as biosensing, biocatalysis, biofuel cells, and bioaffinity separation.Highlights► The GOx–PDA–Au–Fe3O4 MBNPs were prepared by in situ chemical polymerization of DA using HAuCl4. ► The proposed MBNPs were effectively deposited on the electrode surface by applying a magnetic field. ► The entrapped GOx remaining bioactivity can communicate electrons with electrode efficiently. ► A high performance glucose sensor has been constructed using the GOx–Au–PDA–Fe3O4 MBNPs. ► This method is highly recommended as a new biosensing platform for biomolecule immobilization.
Co-reporter:Hua-Ping Peng, Ru-Ping Liang, Li Zhang, Jian-Ding Qiu
Journal of Electroanalytical Chemistry 2013 700() pp: 70-76
Publication Date(Web):
DOI:10.1016/j.jelechem.2013.04.016
Co-reporter:Shao-Ping Shi, Xing-Yu Sun, Jian-Ding Qiu, Sheng-Bao Suo, Xiang Chen, Shu-Yun Huang, Ru-Ping Liang
Journal of Molecular Graphics and Modelling 2013 40() pp: 125-130
Publication Date(Web):1 March 2013
DOI:10.1016/j.jmgm.2012.12.006
As an extremely important and ubiquitous post-translational lipid modification, palmitoylation plays a significant role in a variety of biological and physiological processes. Unlike other lipid modifications, protein palmitoylation and depalmitoylation are highly dynamic and can regulate both protein function and localization. The dynamic nature of palmitoylation is poorly understood because of the limitations in current assay methods. The in vivo or in vitro experimental identification of palmitoylation sites is both time consuming and expensive. Due to the large volume of protein sequences generated in the post-genomic era, it is extraordinarily important in both basic research and drug discovery to rapidly identify the attributes of a new protein's palmitoylation sites. In this work, a new computational method, WAP-Palm, combining multiple feature extraction, has been developed to predict the palmitoylation sites of proteins. The performance of the WAP-Palm model is measured herein and was found to have a sensitivity of 81.53%, a specificity of 90.45%, an accuracy of 85.99% and a Matthews correlation coefficient of 72.26% in 10-fold cross-validation test. The results obtained from both the cross-validation and independent tests suggest that the WAP-Palm model might facilitate the identification and annotation of protein palmitoylation locations. The online service is available at http://bioinfo.ncu.edu.cn/WAP-Palm.aspx.Graphical abstractA new computational method WAP-Palm, combining multiple feature extraction, is designed to identify protein palmitoylation site. The multiple feature descriptors are composed of weight amino acid composition (WAAC), auto-correlation functions (ACF) and position specific scoring matrix profiles (PSSM), respectively. WAAC is utilized to extract amino acids sequence position information surrounding palmitoylation sites. ACF is applied to encode the physicochemical properties and the correlation of amino acid residues. PSSM is used to represent evolutionary information around palmitoylation sites. The WAAC, ACF and PSSM features all contributed to the palmitoylation prediction. The WAP-Palm improved the quality of identifying palmitoylation sites and might facilitate the annotation of protein palmitoylation.Download high-res image (309KB)Download full-size imageHighlights► Our predictor achieves a Matthews correlation coefficient of 72.26%. ► The residues around palmitoylation sites have better correlation and dependence. ► Evolution information acts an irreplaceable role for palmitoylation prediction. ► Positively charged residues are enriched at the downstream of palmitoylation sites.
Co-reporter:Li Zhang, Yun-Mei Zhang, Ru-Ping Liang, and Jian-Ding Qiu
The Journal of Physical Chemistry C 2013 Volume 117(Issue 23) pp:12352-12357
Publication Date(Web):May 20, 2013
DOI:10.1021/jp4027892
Two kinds of ion-dependent DNAzymes and tailored substrates enable the design of the logic gates (OR, AND, INHIBIT) using Pb2+ and Cu2+ as inputs; then, a three-input AND logic gate is developed utilizing the unique feature that Hg2+ ions interact with the thymine–thymine (T–T). At first, the substrates are blocked by ion-dependent DNAzymes that include the horseradish peroxidase (HRP)-mimicking DNAzyme sequence. The released product strands then self-assemble into the hemin/G-quadruplex-HRP-mimicking DNAzyme that biocatalyze the formation of a colored product and provide an output signal for the different logic gates. We are able to recognize the logic output signals effortlessly by our naked eyes. It is a simple, economic, and safe approach for the design of a complex multiple-input DNA logic molecular device.
Co-reporter:Jian-Mei Bai;Dr. Li Zhang; Ru-Ping Liang ; Jian-Ding Qiu
Chemistry - A European Journal 2013 Volume 19( Issue 12) pp:3822-3826
Publication Date(Web):
DOI:10.1002/chem.201204295
Co-reporter: Ru-Ping Liang;Zhong-Xia Wang;Dr. Li Zhang ; Jian-Ding Qiu
Chemistry - A European Journal 2013 Volume 19( Issue 16) pp:5029-5033
Publication Date(Web):
DOI:10.1002/chem.201203402
Co-reporter:Ling Shi, Ru-Ping Liang and Jian-Ding Qiu
Journal of Materials Chemistry A 2012 vol. 22(Issue 33) pp:17196-17203
Publication Date(Web):04 Jul 2012
DOI:10.1039/C2JM31859H
We demonstrate a novel and very efficient interfacial polymerization method for the synthesis of high-quality polyaniline-wrapped carbon nanotubes (CNT–PANI), which represent a novel type of CNT–polymer heterostructure. The interfacial polymerization at the liquid–liquid interface is prone to form uniform core–shell CNT–PANI composites due to the presence of π–π interactions between PANI and CNT walls. Then electrocatalytically active platinum nanoparticles (Pt NPs) were loaded on the carbon nanotubes (CNT) through the introduction of electron-conducting PANI to bridge the Pt NPs and CNT walls with the presence of platinum–nitride (Pt–N) bonding and π–π bonding. The Pt NPs with controllable loading density were uniformly dispersed onto the CNT–PANI walls. The Pt/CNT–PANI hybrids possess exceptional electrochemical activity and exhibit excellent electrochemical stability towards methanol oxidation and oxygen reduction.
Co-reporter:Ru-Ping Liang, Gui-Hong Yao, Li-Xia Fan, Jian-Ding Qiu
Analytica Chimica Acta 2012 Volume 737() pp:22-28
Publication Date(Web):6 August 2012
DOI:10.1016/j.aca.2012.05.043
Small molecules or analytes present at low concentrations are difficult to detect directly using conventional surface plasmon resonance (SPR) techniques because only small changes in the refractive index of the medium are typically induced by the binding of these analytes. Here, we present an amplification technique using core–shell Fe3O4@Au magnetic nanoparticles (MNPs) for an SPR bioassay. To evaluate this amplification effect, a novel SPR sensor based on a sandwich immunoassay was developed to detect α-fetoprotein (AFP) by immobilizing a primary AFP antibody (Ab1) on the surface of a 3-mercapto-1-propanesulfonate/chitosan-ferrocene/Au NP (MPS/CS-Fc/Au NP) film employing Fe3O4@Au–AFP secondary antibody conjugates (Fe3O4@Au–Ab2) as the amplification reagent. The stepwise fabrication of the biosensor was characterized using UV-vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. A calibration curve of Fe3O4@Au–Ab2 conjugates amplification for AFP detection was obtained to yield a correlation in the range of 1.0–200.0 ng mL−1 with a detection limit of 0.65 ng mL−1, and a significant increase in sensitivity was therefore afforded through the use of Fe3O4@Au–Ab2 conjugates as an amplifier. This magnetic separation and amplification strategy has great potential for the detection of other biomolecules of interest with low interference and high sensitivity by changing the antibody label used in the Fe3O4@Au–antibody conjugates.Graphical abstractHighlights► We report an amplification technique using Fe3O4@Au MNPs for an SPR bioassay. ► Fe3O4@Au MNPs can function as an amplifier to increase the SPR signal. ► Sensitive detection of AFP is achieved via the purification/amplification protocol. ► This strategy has great potential for detecting other biomolecules of interest.
Co-reporter:Ru-Ping Liang, Chun-Ming Liu, Xiang-Ying Meng, Jing-Wu Wang, Jian-Ding Qiu
Journal of Chromatography A 2012 Volume 1266() pp:95-102
Publication Date(Web):30 November 2012
DOI:10.1016/j.chroma.2012.09.101
Chip-based enantioselective open-tubular capillary electrochromatography (OT-CEC) with β-cyclodextrin (β-CD) conjugated graphene oxide-magnetic nanocomposites (GO/Fe3O4 NCs) as stationary phase was developed. GO/Fe3O4 NCs with high magnetic responsivity, excellent solubility and high dispersibility in water were prepared through a facile and controllable in situ chemical deposition strategy. β-CD was then adsorbed onto the GO/Fe3O4 surface to form GO/Fe3O4/β-CD NCs which were localized to the pre-nominated position in polydimethylsiloxane (PDMS) microchannels with the help of magnets. The resultant GO/Fe3O4/β-CD NCs not only have the magnetism of Fe3O4 NPs that make them easily manipulated by an external magnetic field, but also have the larger surface which can incorporate much more chiral selector molecules. In addition, the successful β-CD decorations endowed GO/Fe3O4/β-CD NCs with excellent wettability and led to enhanced stability against high ionic strength. Compared with the native PDMS microchip, the modified surfaces exhibited more stable and suppressed electroosmotic mobility, and less nonspecific adsorption toward analytes. Successful baseline separation of tryptophan enantiomers was achieved in less than 50 s with a resolution factor of 1.65 utilizing a separation length of 37 mm coupled with in-column amperometric detection. Factors that influence the chiral separation resolution were examined. Under the optimized conditions, the proposed modified chip revealed adequate repeatability concerning run-to-run and day-to-day. These results show that the use of GO/Fe3O4/β-CD NCs within microfluidic channels hold great promise for a variety of analytical schemes.Highlights► Chip-based OT-CEC with magnetic GO/Fe3O4/β-CD conjugates as stationary phase was fabricated. ► GO/Fe3O4 NCs showed high magnetic responsivity, excellent solubility and high dispersibility in water. ► GO/Fe3O4 nanocomposites greatly increased the β-CD phase ratio in OT-CEC. ► This protocol simplified the stationary phase fabrication of chip-based OT-CEC microdevice.
Co-reporter:Shao-Ping Shi, Jian-Ding Qiu, Xing-Yu Sun, Sheng-Bao Suo, Shu-Yun Huang and Ru-Ping Liang
Molecular BioSystems 2012 vol. 8(Issue 5) pp:1520-1527
Publication Date(Web):15 Feb 2012
DOI:10.1039/C2MB05502C
Post-translational lysine methylation and acetylation are two major modifications of lysine residues. They play critical roles in various biological processes, especially in gene regulation. Identification of protein methylation and acetylation sites would be a foundation for understanding their modification dynamics and molecular mechanism. This work presents a method called PLMLA that incorporates protein sequence information, secondary structure and amino acid properties to predict methylation and acetylation of lysine residues in whole protein sequences. We apply an encoding scheme based on grouped weight and position weight amino acid composition to extract sequence information and physicochemical properties around lysine sites. The prediction accuracy for methyllysine and acetyllysine are 83.02% and 83.08%, respectively. Feature analysis reveals that methyllysine is likely to occur at the coil region and acetyllysine prefers to occur at the helix region of protein. The upstream residues away from the central site may be close to methylated lysine in three-dimensional structure and have a significant influence on methyllysine, while the positively charged residues may have a significant influence on acetyllysine. The online service is available at http://bioinfo.ncu.edu.cn/inquiries_PLMLA.aspx.
Co-reporter:Xing-Yu Sun, Shao-Ping Shi, Jian-Ding Qiu, Sheng-Bao Suo, Shu-Yun Huang and Ru-Ping Liang
Molecular BioSystems 2012 vol. 8(Issue 12) pp:3178-3184
Publication Date(Web):05 Sep 2012
DOI:10.1039/C2MB25280E
In vivo, some proteins exist as monomers and others as oligomers. Oligomers can be further classified into homo-oligomers (formed by identical subunits) and hetero-oligomers (formed by different subunits), and they form the structural components of various biological functions, including cooperative effects, allosteric mechanism and ion-channel gating. Therefore, with the avalanche of protein sequences generated in the post-genomic era, it is very important for both basic research and the pharmaceutical industry to acquire the possible knowledge about quaternary structural attributes of their proteins of interest. In view of this, a high throughput method (DWT_DT), a 2-layer approach by fusing discrete wavelet transform (DWT) and decision-tree algorithm (DT) with physicochemical features, has been developed to predict protein quaternary structures. The 1st layer is to assign a query protein to one of the 10 main quaternary structural attributes. The 2nd layer is to evaluate whether the protein in question is composed of homo- or hetero-oligomers. The overall accuracy by jackknife test for the 1st layer identification was 89.60%. The overall accuracy of the 2nd layer varies from 88.23 to 100%. The results suggest that this newly developed protocol (DWT_DT) is very promising in predicting quaternary structures with complicated composition.
Co-reporter:Shu-Yun Huang, Shao-Ping Shi, Jian-Ding Qiu, Xing-Yu Sun, Sheng-Bao Suo, Ru-Ping Liang
Analytical Biochemistry 2012 Volume 428(Issue 1) pp:16-23
Publication Date(Web):1 September 2012
DOI:10.1016/j.ab.2012.06.003
Tyrosine sulfation is a ubiquitous posttranslational modification that regulates extracellular protein–protein interactions, intracellular protein transportation modulation, and protein proteolytic process. However, identifying tyrosine sulfation sites remains a challenge due to the lability of sulfation sequences. In this study, we developed a method called PredSulSite that incorporates protein secondary structure, physicochemical properties of amino acids, and residue sequence order information based on support vector machine to predict sulfotyrosine sites. Three types of encoding algorithms—secondary structure, grouped weight, and autocorrelation function—were applied to mine features from tyrosine sulfation proteins. The prediction model with multiple features achieved an accuracy of 92.89% in 10-fold cross-validation. Feature analysis showed that the coil structure, acidic amino acids, and residue interactions around the tyrosine sulfation sites all contributed to the sulfation site determination. The detailed feature analysis in this work can help us to understand the sulfation mechanism and provide guidance for the related experimental validation. PredSulSite is available as a community resource at http://www.bioinfo.ncu.edu.cn/inquiries_PredSulSite.aspx.
Co-reporter:Ru-Ping Liang, Zhong-Xia Wang, Li Zhang, Jian-Ding Qiu
Sensors and Actuators B: Chemical 2012 Volumes 166–167() pp:569-575
Publication Date(Web):20 May 2012
DOI:10.1016/j.snb.2012.03.011
In this contribution, we develop a novel type of multi-walled carbon nanotubes/silica nanoparticles array (MWCNTs/SiO2) composite by the galvanostatic deposition technique. In this process, MWCNTs were mixed with ammonium fluorosilicate to form a doped precursory sol solution, the electrochemically generated hydroxyl ions at negative potentials promote the hydrolysis of ammonium fluorosilicate, and the simultaneously generated hydrogen bubbles assist the formation of three-dimensional porous silica matrix, further facilitating the construction of SiO2 NPs array with uniform distribution, as confirmed by scanning electron microscopy. The formation of SiO2 NPs array provides a higher surface area and biocompatible microenvironment for retaining the native activity of the immobilized biomolecules. Further incorporation of MWCNTs into SiO2 NPs array improves the electronic conductivity and enhances the electroactive surface area of the film, making the fabricated three-dimensional porous MWCNTs/SiO2 electrode an ideal platform for further immobilization of alpha-fetoprotein (AFP), as a model protein. This method achieves ultrasensitive detection of AFP antigen with ferricyanide as a probe. The obtained results provided a linear response range from 0.1 to 30.0 ng mL−1 AFP antigen with a lower detection limit of 0.018 ng mL−1. This work implies that the biocompatible and controllable three-dimensional porous SiO2 NPs array possessed potential applications for biosensing.
Co-reporter: Jian-Ding Qiu;Ling Shi; Ru-Ping Liang;Guo-Chong Wang; Xing-Hua Xia
Chemistry - A European Journal 2012 Volume 18( Issue 25) pp:7950-7959
Publication Date(Web):
DOI:10.1002/chem.201200258
Abstract
We demonstrate for the first time an interfacial polymerization method for the synthesis of high-quality polyaniline-modified graphene nanosheets (PANI/GNs), which represents a novel type of graphene/polymer heterostructure. The interfacial polymerization at a liquid–liquid interface allows PANI to grow uniformly on the surface of the GNs. An ultra-high loading of Pt nanoparticles was then controllably deposited on the surface of the PANI/GNs to form a Pt/PANI/GNs hybrid. The obtained composites were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Pt/PANI/GNs hybrid shows excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. H2O2 and glucose were used as two representative analytes to demonstrate the sensing performance of a Pt/PANI/GNs-modified electrode. It is found that this sensing element shows high sensitivity and a low detection limit for H2O2 and glucose. The results demonstrate that the Pt/PANI/GNs hybrid may be an attractive and advanced electrode material with potential applications in the construction of electrochemical sensors and biosensors.
Co-reporter:Hua-Ping Peng, Ru-Ping Liang, Li Zhang, Jian-Ding Qiu
Electrochimica Acta 2011 Volume 56(Issue 11) pp:4231-4236
Publication Date(Web):15 April 2011
DOI:10.1016/j.electacta.2011.01.090
In this study, bifunctional Fe3O4@ZrO2 magnetic core–shell nanoparticles (NPs), synthesized by a simple and effective sonochemical approach, were attached to the surface of a magnetic glassy carbon electrode (MGCE) and successfully applied to the immobilization/adsorption of myoglobin (Mb) for constructing a novel biosensor platform. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4@ZrO2 NPs, Mb could be easily immobilized on the surface of the electrode in the present of external magnetic field and well retained its bioactivity, hence dramatically facilitated direct electron transfer of Mb was demonstrated. The proposed Mb/Fe3O4@ZrO2 biofilm electrode exhibited excellent electrocatalytic behaviors towards the reduction of H2O2 with a linear range from 0.64 μM to 148 μM. This presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a simple, effective and inexpensive way to immobilize protein, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices.Graphical abstractHighlights► Magnetic core–shell Fe3O4@ZrO2 nanoparticle was synthesized by sonochemical approach. ► Fe3O4@ZrO2 NPs provided high capacity for trapping Mb on magnetic glassy carbon electrode surface. ► The constructed Mb/Fe3O4@ZrO2 film exhibited excellent electrocatalytic ability for the reduction of H2O2. ► The proposed method simplifies the immobilization methodology of proteins.
Co-reporter:Ruping Liang, Yunxia Chen and Jianding Qiu
Analytical Methods 2011 vol. 3(Issue 6) pp:1338-1343
Publication Date(Web):12 May 2011
DOI:10.1039/C0AY00774A
A novel amperometric immunosensor has been developed by self-assembling gold nanoparticles (Au NPs) onto a toluidine blue–branched chitosan (CHIT–TB) modified electrode for the sensitive determination of hepatitis B surface antigen (HBsAg) as a model protein. The formation of CHIT–TB composite film not only effectively avoids the leakage of TB and retains its electrochemical activity, but also enhances the conductivity and charge–transport properties of the composite. Further adsorption of Au NPs into the CHIT matrix provides both the interactive sites for the immobilization of HBsAb and a favorable microenvironment to maintain the activity of the HBsAb, in addition it prevents leakage of HBsAb molecules from the CHIT–TB/Au NPs/HBsAb film structure efficiently. The morphologies and electrochemistry of the formed nanocomposite film were investigated by using scanning electron microscopy and electrochemical techniques including cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased voltametric values were proportional to the HBsAg concentration in the range of 1 to 200 ng mL−1. The detection of HBsAg levels in five sera obtained from a hospital showed acceptable accuracy.
Co-reporter:Jian-Ding Qiu ; Guo-Chong Wang ; Ru-Ping Liang ; Xing-Hua Xia ;Hong-Wen Yu
The Journal of Physical Chemistry C 2011 Volume 115(Issue 31) pp:15639-15645
Publication Date(Web):June 30, 2011
DOI:10.1021/jp200580u
Platinum nanoparticles (Pt NPs) with uniform size and high dispersion have been successfully assembled on poly(diallyldimethylammonium chloride) functionalized graphene oxide via a sodium borohydride reduction process. The loading concentration of Pt NPs on graphene can be adjusted in the range of 18–78 wt %. The obtained Pt/graphene nanocomposites are characterized by transmission electron microscopy, high resolution transmission electron microscopy, energy dispersive spectrometry, X-ray diffraction, and thermogravimetric analysis. The results show that the Pt NPs with sizes of approximate 4.6 nm uniformly disperse on graphene surface for all Pt loading densities. Electrochemical studies reveal that the Pt/graphene nanocomposites with electrochemically active surface area of 141.6 m2/g show excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. The present method is promising for the synthesis of high performance catalysts for fuel cells, gas phase catalysis, and sensors.
Co-reporter:Jian-Ding Qiu, Sheng-Bao Suo, Xing-Yu Sun, Shao-Ping Shi, Ru-Ping Liang
Journal of Molecular Graphics and Modelling 2011 30() pp: 129-134
Publication Date(Web):1 September 2011
DOI:10.1016/j.jmgm.2011.06.014
In vivo, some proteins exist as monomers (single polypeptide chains) and others as oligomers. Not like monomers, oligomers are composed of two or more chains (subunits) that are associated with each other through non-covalent interactions and, occasionally, through disulfide bonds. These proteins are the structural components of various biological functions, including cooperative effects, allosteric mechanisms and ion-channel gating. However, with the dramatic increase in the number of protein sequences submitted to the public data bank, it is important for both basic research and drug discovery research to acquire the possible knowledge about homo-oligomeric attributes of their interested proteins in a timely manner. In this paper, a high-throughput method, combined support vector machines with discrete wavelet transform, has been developed to predict the protein homo-oligomers. The total accuracy obtained by the re-substitution test, jackknife test and independent dataset test are 99.94%, 96.17% and 96.18%, respectively, showing that the proposed method of extracting feature from the protein sequences is effective and feasible for predicting homo-oligomers. The online service is available at http://bioinfo.ncu.edu.cn/Services.aspx.Graphical abstract. Based on different basis functions, the wavelets have different families; every family has its unique quality fitting for certain signals. As the characteristics of the analyzing wavelet influence the performance of DWT, the better the analyzing wavelet matches the underlying structure in the signal, the better feature values can be extracted from the sequences. Therefore, selection of a suitable wavelet basis which possesses desirable properties such as compactly support, orthogonality, symmetry, smoothness and high order of vanishing moments is necessary for the signal processing. Nine wavelet functions were chosen for investigating the effect of the different wavelets on classification accuracy in the research. The R1568 database prediction results performed by different wavelet functions with Kyte–Doolittle hydrophobicity scales were listed in Fig. 1. As can be seen from Fig. 1, in jackknife test by using SVM, the training accuracy can reach 96.17% when using Bior2.4 wavelet to extract feature. However, when using other wavelet functions, the training accuracy only ranged from 84.82% to 92.66%. This is because wavelet of Bior2.4 is a class of symmetric and biorthogonal wavelets that have good ability to reduce dimension by Mallat decomposition and can remove high-frequency noises by selecting several or even one approximation sub-band. Therefore, Bior2.4 wavelet was selected as the appropriate wavelet function to input SVM to predict homo-oligomeric proteins in this study.Download high-res image (86KB)Download full-size imageHighlights► Discrete wavelet transform (DWT) can effectively grasp the core features of the protein homo-oligomers. ► A new method, in which SVM combines with DWT, is developed to predict the homo-oligomers. ► The proposed approach can remarkably improve the predictive accuracies of the homo-oligomers.
Co-reporter:Ruping Liang;Li Wang;Xiangying Meng;Jingwu Wang
Microfluidics and Nanofluidics 2011 Volume 11( Issue 2) pp:227-233
Publication Date(Web):2011 August
DOI:10.1007/s10404-011-0799-0
Electrochemical determination of amino acids on a Cu electrode was established as an attractive scheme for non-electroactive amino acids after microchip electrophoresis separation. Five amino acids (arginine, proline, histidine, valine, and serine) achieved efficient separation within 60 s on a titanium dioxide nanoparticles (TiO2 NPs) coated poly(dimethylsiloxane) (PDMS) microchip, and then successfully detected on a Cu electrode in end-channel detection mode. In the slightly basic borate medium, anodic currents occur for amino acids due to their ability to form Cu(II) complexes and thereby enhance the electrochemical dissolution of Cu electrode substrate. The increase of the anodic current measured is proportional to the amino acid concentration added to the solution, and therefore, enables direct detection of non-electroactive amino acids on the Cu electrode. The detection limits (S/N = 3) for arginine, proline, histidine, valine, and serine were measured to be 7, 6, 5, 6, and 5 μM, respectively, with the linear ranges all from 25 to 500 μM. In addition, compared with the native PDMS microchip, resolutions and separation efficiencies of amino acids on the modified microchip were considerably enhanced with the theoretical plate numbers of 8.9 × 103, 6.6 × 104, 4.8 × 104, 5.6 × 104, and 4.4 × 104 plates m−1, respectively. The proposed Cu electrode response demonstrated good reproducibility and stability, with no apparent loss of response for periods as long as 4 weeks.
Co-reporter:Jian-Ding Qiu, Jing Huang, Ru-Ping Liang
Sensors and Actuators B: Chemical 2011 160(1) pp: 287-294
Publication Date(Web):
DOI:10.1016/j.snb.2011.07.049
Co-reporter:Hua-Ping Peng, Ru-Ping Liang, Jian-Ding Qiu
Biosensors and Bioelectronics 2011 Volume 26(Issue 6) pp:3005-3011
Publication Date(Web):15 February 2011
DOI:10.1016/j.bios.2010.12.003
In this study, magnetic core–shell Fe3O4@Al2O3 nanoparticles (NPs) attached to the surface of a magnetic glassy carbon electrode (MGCE) were used as a functional interface to immobilize several heme proteins including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP) for fabricating protein/Fe3O4@Al2O3 film. Transmission electron microscope, UV–vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were used to characterize the films. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4@Al2O3 NPs, the protein/Fe3O4@Al2O3 film could be easily fabricated in the present of external magnetic field, and well retained the bioactivity of the immobilized proteins, hence dramatically facilitated direct electron transfer of heme proteins and excellent electrocatalytic behaviors towards H2O2 were demonstrated. The presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a facile, low cost and universal way to immobilize proteins, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices.
Co-reporter:Jian-Ding Qiu;He Huang;Ru-Ping Liang
Microchimica Acta 2011 Volume 174( Issue 1-2) pp:
Publication Date(Web):2011 July
DOI:10.1007/s00604-011-0585-4
An amperometric immunosensor has been developed for sensitive determination of hepatitis B surface antigen as a model protein. A glassy carbon electrode was modified with an assembly of positively charged poly(allylamine)-branched ferrocene (PAA-Fc) and negatively charged gold nanoparticles (Au NPs). The formation of PAA-Fc effectively avoids the leakage of Fc, retains its electrochemical activity, and enhances the conductivity of the composite. The adsorption of Au NPs onto the PAA-Fc matrix provides sites for the immobilization of the antigen and a favorable micro-environment to maintain its activity. The morphologies and electrochemistry of the sensing film were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Factors influencing the performance of the immunosensor were studied in detail. The concentration of the antigen can be quantitated (by measuring the decrease of the amperometric response resulting from the specific binding between antigen and antibody) in the range between 0.1 and 150 ng mL–1, with a detection limit of 40 pg mL–1 (S/N = 3). The method is economical, efficient, and potentially attractive for clinical immunoassays.
Co-reporter:Jian-Ding Qiu, Hua-Ping Peng, Ru-Ping Liang, Xing-Hua Xia
Biosensors and Bioelectronics 2010 Volume 25(Issue 6) pp:1447-1453
Publication Date(Web):15 February 2010
DOI:10.1016/j.bios.2009.10.043
In this work, the magnetic core–shell Fe3O4@Au nanoparticles attached to the surface of a magnetic glassy carbon electrode (MGCE) were applied to the immobilization/adsorption of myoglobin (Mb) for fabricating Mb/Fe3O4@Au biofilm. The morphology, structure, and electrochemistry of the nanocomposite were characterized by transmission electron microscope, UV–vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, respectively. The resultant Fe3O4@Au NPs not only have the magnetism of Fe3O4 NPs that make them easily manipulated by an external magnetic field, but also have the good conductivity and excellent biocompatibility of Au layer which can maintain the bioactivity and facilitate the direct electrochemistry of Mb in the biofilm. The modified electrode based on this Mb/Fe3O4@Au biofilm displayed good electrocatalytic activity to the reduction of H2O2 with a linear range from 1.28 to 283 μM. The proposed method simplified the immobilization methodology of proteins and showed potential application for fabricating novel biosensors and bioelectronic devices.
Co-reporter:Jian-Ding Qiu;San-Guan Cui;Min-Qiang Deng
Journal of Applied Electrochemistry 2010 Volume 40( Issue 9) pp:1651-1657
Publication Date(Web):2010 September
DOI:10.1007/s10800-010-0152-4
A novel matrix, multiwalled carbon nanotubes supported nickel oxide nanoparticles composite nanomaterial (NiO@MWNTs), for immobilization of protein and biosensing was designed using a simple and effective hydrothermal method. Using myoglobin (Mb) as a model, the direct electrochemistry of immobilized Mb indicated the matrix could accelerate the electron transfer between protein’s active sites and the electrode. The modified electrode shows excellent electrocatalytic activity toward the reduction of H2O2 without the help of an electron mediator. The simple operation, fast response, acceptable stability, and reproducibility of the proposed biosensor indicated its promising application in protein immobilization and preparation of the third generation biosensors.
Co-reporter:Jian-Ding Qiu;San-Guan Cui;Ru-Ping Liang
Microchimica Acta 2010 Volume 171( Issue 3-4) pp:333-339
Publication Date(Web):2010 December
DOI:10.1007/s00604-010-0440-z
A novel myoglobin-based electrochemical biosensor was developed. It is based on a nanocomposite prepared from multiwalled carbon nanotubes that were coated with ceria nanoparticles. UV-vis and electrochemical measurements displayed that the nanocomposite provides a biocompatible matrix for the immobilization of myoglobin (Mb) and also facilitates direct electron transfer between its active center and the surface of the electrode. Immobilized Mb exhibits excellent electrocatalytic activity toward the reduction of hydrogen peroxide (HP). The low apparent Michaelis-Menten constant of 63.3 μM indicates high bioactivity and enhanced affinity to HP. This study also shows that the nanocomposite is a promising support for immobilization of proteins and for the preparation of third-generation biosensors.
Co-reporter:Jian-Ding Qiu;Xing-Yu Sun;Jian-Hua Huang;Ru-Ping Liang
The Protein Journal 2010 Volume 29( Issue 2) pp:114-119
Publication Date(Web):2010 February
DOI:10.1007/s10930-010-9230-z
Membrane proteins are crucial for many biological functions and have become attractive targets for both basic research and drug discovery. With the unprecedented increasing of newly found protein sequences in the post-genomic era, it is both time-consuming and expensive to determine the types of newly found membrane proteins solely with traditional experiment, and so it is highly demanded to develop an automatic method for fast and accurately identifying the type of membrane proteins according to their amino acid sequences. In this study, the discrete wavelet transform (DWT) and support vector machine (SVM) have been used for the prediction of the types of membrane proteins. Maximum accuracy has been obtained using SVM with a wavelet function of bior2.4, a decomposition scale j = 4, and Kyte–Doolittle hydrophobicity scales. The results indicate that the proposed method may play an important complementary role to the existing methods in this area.
Co-reporter:Ruping Liang, Minqiang Deng, Sanguan Cui, Hong Chen, Jianding Qiu
Materials Research Bulletin 2010 45(12) pp: 1855-1860
Publication Date(Web):
DOI:10.1016/j.materresbull.2010.09.016
Co-reporter:Jian-Ding Qiu, Wen-Mei Zhou, Jin Guo, Rui Wang, Ru-Ping Liang
Analytical Biochemistry 2009 Volume 385(Issue 2) pp:264-269
Publication Date(Web):15 February 2009
DOI:10.1016/j.ab.2008.12.002
A kind of nanocomposite with good dispersion in water was prepared through covalent adsorption of ferrocenecarboxaldehyde on multiwalled carbon nanotubes (MWNTs) for electrical communication between glucose oxidase (GOD) and electrode. The ferrocene-modified multiwalled carbon nanotube nanocomposites (MWNTs-Fc) could be conveniently cast on electrode surfaces. With the aid of chitosan, GOD was then immobilized on the nanostructure film to form a reagentless amperometric sensor for glucose determination. FTIR spectra and cyclic voltammetry were used to characterize the nanocomposites. The presence of both ferrocene as mediator of electron transfer and MWNTs as conductor enhanced greatly the enzymatic response to the oxidation of glucose. The novel biosensor exhibited a fast response toward glucose with a detection limit of 3.0 × 10−6 mol/L and the linear range extended up to 3.8 × 10−3 mol/L.
Co-reporter:Jian-Ding Qiu, Jian-Hua Huang, Ru-Ping Liang, Xiao-Quan Lu
Analytical Biochemistry 2009 Volume 390(Issue 1) pp:68-73
Publication Date(Web):1 July 2009
DOI:10.1016/j.ab.2009.04.009
Being the largest family of cell surface receptors, G-protein-coupled receptors (GPCRs) are among the most frequent targets. The functions of many GPCRs are unknown, and it is both time-consuming and expensive to determine their ligands and signaling pathways by experimental methods. It is of great practical significance to develop an automated and reliable method for classification of GPCRs. In this study, a novel method based on the concept of Chou’s pseudo amino acid composition has been developed for predicting and recognizing GPCRs. The discrete wavelet transform was used to extract feature vectors from the hydrophobicity scales of amino acid to construct pseudo amino acid (PseAA) composition for training support vector machine. The prediction accuracies by the current method among the major families of GPCRs, subfamilies of class A, and types of amine receptors were 99.72%, 97.64%, and 99.20%, respectively, showing 9.4% to 18.0% improvement over other existing methods and indicating that the proposed method is a useful automated tool in identifying GPCRs.
Co-reporter:Jian-Ding Qiu, Rui Wang, Ru-Ping Liang, Xing-Hua Xia
Biosensors and Bioelectronics 2009 Volume 24(Issue 9) pp:2920-2925
Publication Date(Web):15 May 2009
DOI:10.1016/j.bios.2009.02.029
A simple and controllable electrodeposition method is described to fabricate a homogeneous chitosan-ferrocene/Au nanoparticles/glucose oxidase (CS-Fc/Au NPs/GOx) nanocomposite film. The morphologies and electrochemistry of the nanocomposite film were investigated by using scanning electron microscopy (SEM) and electrochemical techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. The ferrocene group (Fc) covalently bounded chitosan hybrid (CS-Fc) can effectively avoid the leakage of Fc and retain its electrochemical activity. Further immobilization of Au NPs into the CS-Fc matrix enhances both the charge-transport properties of the composite and bioaffinity to enzyme. Biosensor based on this CS-Fc/Au NPs/GOx film has advantages of fast response, excellent reproducibility and high stability. This biosensor shows a linear response to glucose in the concentration range from 0.02 to 8.66 mM with a detection limit of 5.6 μM at a signal-to-noise ratio of 3. The present method offers a facile way to fabricate biosensors and bioelectronic devices.
Co-reporter:Jian-Ding Qiu, Ru-Ping Liang, Rui Wang, Li-Xia Fan, Yi-Wang Chen, Xing-Hua Xia
Biosensors and Bioelectronics 2009 Volume 25(Issue 4) pp:852-857
Publication Date(Web):15 December 2009
DOI:10.1016/j.bios.2009.08.048
A novel experimental methodology based on the unique characteristics of chitosan-branched ferrocene (CS-Fc) and gold nanoparticles (Au NPs) was developed to design a label-free amperometric immunosensor for the sensitive detection of hepatitis B surface antigen (HBsAg) as a model protein. The controllable electrodeposition of CS-Fc solution formed a three-dimensional robust film with good biocompatibility and large surface area for the assembly of Au NPs and further immobilization of hepatitis B surface antibody (HBsAb) on an electrode. The morphologies and electrochemistry of the formed nanocomposite biofilm were investigated by using scanning electron microscopy and electrochemical techniques including cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased differential pulse voltametric values were proportional to the HBsAg concentration in the range of 0.05–305 ng mL−1 with a detection limit 0.016 ng. This would provide an approach for the application of mediator in immunoassays.
Co-reporter:Jian-Ding Qiu, Meng Xiong, Ru-Ping Liang, Hua-Ping Peng, Fen Liu
Biosensors and Bioelectronics 2009 Volume 24(Issue 8) pp:2649-2653
Publication Date(Web):15 April 2009
DOI:10.1016/j.bios.2009.01.022
A novel dopamine sensor was fabricated by forming the 6-ferrocenylhexanethiol (HS(CH2)6Fc) functionalized Fe3O4@Au nanoparticles (NPs) films on the surface of a carbon paste electrode with the aid of a permanent magnet. HS(CH2)6Fc, which acted as the redox mediator, was self-assembled to Fe3O4@Au NPs via Au–S bond. Transmission electron microscopy, UV–visible absorption spectroscopy, Fourier transform infrared spectra, and cyclic voltammetry were used to characterize the properties of the Fe3O4@Au NPs/HS(CH2)6Fc nanocomposite. It is shown that the prepared ferrocene-functionalized Fe3O4@Au NPs composite shuttled electrons between analyte and electrode, increased the mediator loading, and more importantly prevented the leakage of the mediator during measurements, which resulted in the substantially enhanced stability and reproducibility of the modified electrode. The electrooxidation of dopamine could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of Fe3O4@Au NPs. The nanocomposite modified electrode exhibited fast response (3 s) and the linear range was from 2.0 × 10−6 to 9.2 × 10−4 M with a detection limit of 0.64 μM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of other sensors and bioelectronic devices.
Co-reporter:Ruping Liang, Pengfei Hu, Guihua Gan, Jianding Qiu
Talanta 2009 Volume 77(Issue 5) pp:1647-1653
Publication Date(Web):15 March 2009
DOI:10.1016/j.talanta.2008.09.056
In this paper, deoxyribonucleic acid (DNA) was employed to construct a functional film on the PDMS microfluidic channel surface and apply to perform electrophoresis coupled with electrochemical detection. The functional film was formed by sequentially immobilizing chitosan and DNA to the PDMS microfluidic channel surface using the layer-by-layer assembly. The polysaccharide backbone of chitosan can be strongly adsorbed onto the hydrophobic PDMS surface through electrostatic interaction in the acidic media, meanwhile, chitosan contains one protonatable functional moiety resulting in a strong electrostatic interactions between the surface amine group of chitosan and the charged phosphate backbone of DNA at low pH, which generates a hydrophilic microchannel surface and reveals perfect resistance to nonspecific adsorption of analytes. Aminophenol isomers (p-, o-, and m-aminophenol) served as a separation model to evaluate the effect of the functional PDMS microfluidic chips. The results clearly showed that these analytes were efficiently separated within 60 s in a 3.7 cm long separation channel and successfully detected on the modified microchip coupled with in-channel amperometric detection mode at a single carbon fiber electrode. The theoretical plate numbers were 74,021, 92,658 and 60,552 N m−1 at the separation voltage of 900 V with the detection limits of 1.6, 4.7 and 2.5 μM (S/N = 3) for p-, o-, and m-aminophenol, respectively. In addition, this report offered an effective means for preparing hydrophilic and biocompatible PDMS microchannel surface, which would facilitate the use of microfluidic devices for more widespread applications.
Co-reporter:Ru-Ping Liang;Gui-Hua Gan
Journal of Separation Science 2008 Volume 31( Issue 15) pp:2860-2867
Publication Date(Web):
DOI:10.1002/jssc.200800149
Abstract
A novel and simple method based on layer-by-layer (LBL) technique has been developed for the modification of the channel in PDMS electrophoresis microchip to create a hydrophilic surface with a stable EOF. The functional surface was obtained by sequentially immobilizing chitosan and deoxyribonucleic acid (DNA) onto the microfluidic channel surface using the LBL assembly technique. Compared to the native PDMS microchips, the contact angle of the chitosan–DNA modified PDMS microchips decreased and the EOF increased. Experimental conditions were optimized in detail. The chitosan–DNA modified PDMS microchips exhibited good reproducibility and long-term stability. Separation of uric acid (UA) and ascorbic acid (AA) performed on the modified PDMS microchip generated 43 450 and 46 790 N/m theoretical plates compared with 4048 and 19 847 N/m with the native PDMS microchip. In addition, this method has been successfully applied to real human urine samples, without SPE, with recoveries of 97–105% for UA and AA.
Co-reporter:Jian-Ding Qiu;Hui-Ying Xie;Ru-Ping Liang
Microchimica Acta 2008 Volume 162( Issue 1-2) pp:57-64
Publication Date(Web):2008 July
DOI:10.1007/s00604-007-0871-3
A simple and controllable electrodeposition method is described to fabricate a homogeneous porous chitosan/single-walled carbon nanotubes (CHIT/SWNTs) nanocomposite film. The thickness of the nanocomposite film can be controlled through the change of concentration of SWNTs, SiO2 nanoparticles and chitosan solution, deposition time. Glucose oxidase (GOx) served as a model enzyme to demonstrate the potential application of the macroporous structured films in fabrication of amperometric glucose sensor with negligible mass transport limitation. The glucose biosensor was constructed by entrapping GOx molecules to the porous SWCNTs/CHIT nanocomposite film using glutaraldehyde as a cross-linker. The fabricated biosensor with three-dimension porous structures can provide a biocompatible microenvironment for maintaining the bioactivity of the immobilized enzyme, enhance mass transport of glucose substrate, and increase enzyme loading. Therefore, the biosensor exhibits a rapid response (<5 sec), a wide linear range (10 µM to 35 mM) and a low detection limit of 2.5 µM.
Co-reporter:Jian-Ding Qiu, Min-Qiang Deng, Ru-Ping Liang, Meng Xiong
Sensors and Actuators B: Chemical 2008 Volume 135(Issue 1) pp:181-187
Publication Date(Web):10 December 2008
DOI:10.1016/j.snb.2008.08.017
A novel amperometric sensor for glucose was constructed by entrapping glucose oxidase (GOD) in a new chitosan composite doped with ferrocene monocarboxylic acid-modified 3-(aminopropyl) triethoxysilane enwrapping multiwalled carbon nanotubes (FMC-AMWNTs). The approach was very simple, timesaving and effectively prevented the leakage of the ferrocene monocarboxylic acid mediator during measurements. The entrapped FMC-AMWNTs composite performed excellent redox electrochemistry and acted as an electron transfer mediator. This matrix showed a biocompatible microenvironment for retaining the native activity of the entrapped GOD and a very low mass transport barrier to the substrate. Under optimal conditions, this biosensor was able to detect glucose in the linear range of 0.01–4.2 mM with a detection limit of 3.4 μM (S/N = 3), the value of KMapp was 6.3 mM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of biosensor and bioelectronic devices.
Co-reporter:Ruping Liang, Yunxia Chen and Jianding Qiu
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 6) pp:NaN1343-1343
Publication Date(Web):2011/05/12
DOI:10.1039/C0AY00774A
A novel amperometric immunosensor has been developed by self-assembling gold nanoparticles (Au NPs) onto a toluidine blue–branched chitosan (CHIT–TB) modified electrode for the sensitive determination of hepatitis B surface antigen (HBsAg) as a model protein. The formation of CHIT–TB composite film not only effectively avoids the leakage of TB and retains its electrochemical activity, but also enhances the conductivity and charge–transport properties of the composite. Further adsorption of Au NPs into the CHIT matrix provides both the interactive sites for the immobilization of HBsAb and a favorable microenvironment to maintain the activity of the HBsAb, in addition it prevents leakage of HBsAb molecules from the CHIT–TB/Au NPs/HBsAb film structure efficiently. The morphologies and electrochemistry of the formed nanocomposite film were investigated by using scanning electron microscopy and electrochemical techniques including cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased voltametric values were proportional to the HBsAg concentration in the range of 1 to 200 ng mL−1. The detection of HBsAg levels in five sera obtained from a hospital showed acceptable accuracy.
Co-reporter:Xiang-Juan Zheng, Jian-Ding Qiu, Li Zhang, Zhong-Xia Wang and Ru-Ping Liang
Chemical Communications 2013 - vol. 49(Issue 34) pp:NaN3548-3548
Publication Date(Web):2013/03/12
DOI:10.1039/C3CC41486H
Using unmodified Au nanorods with enzyme-linkage reaction, a label-free colorimetric method for simple and convenient assay of DNA methylation is presented.
Co-reporter:Hui-Fang Zhao, Ru-Ping Liang, Jing-Wu Wang and Jian-Ding Qiu
Chemical Communications 2015 - vol. 51(Issue 63) pp:NaN12672-12672
Publication Date(Web):2015/06/30
DOI:10.1039/C5CC03678J
A novel Au NP mediated dual-potential ECL ratiometric approach for highly sensitive protein kinase activity and inhibition assay has been developed based on the simultaneous decrease of cathodic ECL from GQDs and enhancement of anodic ECL from luminol in the same bioanalysis.
Co-reporter:Ya-Hua Li, Li Zhang, Jing Huang, Ru-Ping Liang and Jian-Ding Qiu
Chemical Communications 2013 - vol. 49(Issue 45) pp:NaN5182-5182
Publication Date(Web):2013/04/18
DOI:10.1039/C3CC40652K
Using graphene quantum dots (GQDs) with a boronic acid-substituted bipyridinium salt (BBV), a label-free fluorescence assay for glucose detection is presented.
Co-reporter:Xiao-Chen Liu, Guo-Chong Wang, Ru-Ping Liang, Ling Shi and Jian-Ding Qiu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 12) pp:NaN3953-3953
Publication Date(Web):2013/01/18
DOI:10.1039/C3TA00527E
Pt-based catalysts are widely used in fuel cells and sensors for their exceptional electrocatalytic activity. Among the different methods for producing Pt-based catalysts, chemical reduction is favorable, due to its scalability in volume production and versatility in realizing abundant chemical functionalization. In this paper, an environment-friendly method for the facile synthesis of Pt nanoparticles supported on polydopamine (Pdop) modified carbon materials (multiwalled carbon nanotubes, carbon nanospheres and Vulcan XC-72 carbon black) is reported. Since Pdop is employed as the reductant and crosslinking agent, no reducing agents, surfactants, organic solvents, etc., are needed. The Pt-based catalysts produced using this method have a unique electrocatalytic activity toward methanol oxidation. This environmentally friendly method is promising for the synthesis of high performance catalysts for fuel cells, gas phase catalysis, and sensors.
Co-reporter:Ling Shi, Ru-Ping Liang and Jian-Ding Qiu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 33) pp:NaN17203-17203
Publication Date(Web):2012/07/04
DOI:10.1039/C2JM31859H
We demonstrate a novel and very efficient interfacial polymerization method for the synthesis of high-quality polyaniline-wrapped carbon nanotubes (CNT–PANI), which represent a novel type of CNT–polymer heterostructure. The interfacial polymerization at the liquid–liquid interface is prone to form uniform core–shell CNT–PANI composites due to the presence of π–π interactions between PANI and CNT walls. Then electrocatalytically active platinum nanoparticles (Pt NPs) were loaded on the carbon nanotubes (CNT) through the introduction of electron-conducting PANI to bridge the Pt NPs and CNT walls with the presence of platinum–nitride (Pt–N) bonding and π–π bonding. The Pt NPs with controllable loading density were uniformly dispersed onto the CNT–PANI walls. The Pt/CNT–PANI hybrids possess exceptional electrochemical activity and exhibit excellent electrochemical stability towards methanol oxidation and oxygen reduction.
Co-reporter:Wei Song, Ru-Ping Liang, Ying Wang, Li Zhang and Jian-Ding Qiu
Chemical Communications 2015 - vol. 51(Issue 49) pp:NaN10009-10009
Publication Date(Web):2015/05/11
DOI:10.1039/C5CC02280K
A green method was employed for synthesizing peptide-templated nanoclusters without requiring strong reducing agents. Using synthetic peptide–gold nanoclusters as fluorescence probes, a novel assay for detecting protein kinase is developed based on phosphorylation against carboxypeptidase Y digestion.
Co-reporter:Bao-Zhu Chi, Ru-Ping Liang, Li Zhang and Jian-Ding Qiu
Chemical Communications 2015 - vol. 51(Issue 52) pp:NaN10546-10546
Publication Date(Web):2015/05/18
DOI:10.1039/C5CC02864G
This assay, termed branched cascade enzymatic amplification (BCEA), can be a novel and straightforward method for sensitive and specific microRNA detection in crude cellular extracts of cancer cells at physiological temperature, by coupling two ordinary polymerases, Klenow fragment exo− and terminal deoxynucleotidyl transferase.
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