Co-reporter:Hongyan Bi;Liang Qiao;Jean-Marc Busnel;Hubert H. Girault
Journal of Proteome Research October 2, 2009 Volume 8(Issue 10) pp:4685-4692
Publication Date(Web):2017-2-22
DOI:10.1021/pr9003954
Proteolysis with proteases preloaded within nanopores of porous material is a very fast process, where proteins can be digested in minutes compared to the conventional bulk enzyme reactions taking place over hours. To model this surprising phenomenon, a modified sequential proteolytic mechanism has been developed to simulate the kinetics of the reaction. Digestion of myoglobin was used as an example to show the high efficiency of the in-nanopore enzymatic reaction, while angiotensin 1 and ACTH (1−14) were selected as model peptides to validate the theoretical considerations. The proteolytic peptides were quantified by capillary electrophoresis and sequenced by mass spectrometry using bottom-up strategy. The simulation clearly shows that the major factor for the very fast digestion kinetics observed stems from a peptide confinement effect, where the generated peptides are trapped within a confined space for further proteolysis to the final products. On the other hand, the ingress and diffusion of the proteins into the porous cavity can accelerate or limit the first proteolytic step requiring the encounter between the substrates and enzymes. The present model can be widely applied to different enzyme catalyzed reactions for high-throughput protein profiling, and can promote the study of enzyme reactions occurring inside the cell.Keywords: kinectics simulation; nanoconfinement effect; nanoporous material; proteolysis;
Co-reporter:Jingjing Zhao;Yixin Li;Ji Ji;Kun Zhang
ACS Applied Materials & Interfaces June 15, 2016 Volume 8(Issue 23) pp:14389-14395
Publication Date(Web):2017-2-22
DOI:10.1021/acsami.6b03352
Although fingerprints have been widely used in forensic investigations, low resolution and poor universality are still the main obstacles for the development of fingerprint visualization. In this paper, a facile and universal imaging protocol for latent fingerprints (LFPs) was developed by combining sandwiched SERS probes with the highly sensitive and selective recognition of aptamers. The embedded SERS probes (Au/pNTP/SiO2) successfully avoid the environment interference, ascertaining the stability and reproducibility of Raman signals, and simultaneously improve the efficiency of the fingerprint identification. This approach is operationally simple without complicated pre- or post-treatments. Moreover, the fingerprint images display the high resolution in which third-level details can be clearly identified. This is a general approach and can be used to detect various types of fingerprints, including sebaceous, eccrine, fresh LFPs, and aged LFPs on different substrates (such as smooth, scratching, semiporous, and porous surfaces).Keywords: aptamers; latent fingerprints; lysozyme; sandwich structure; SERS imaging;
Co-reporter:Xiaoni Fang, Yaokai Duan, Yujie Liu, Gary Adkins, Weijun Zang, Wenwan Zhong, Liang Qiao, and Baohong Liu
Analytical Chemistry July 18, 2017 Volume 89(Issue 14) pp:7365-7365
Publication Date(Web):June 13, 2017
DOI:10.1021/acs.analchem.7b00677
In light of the significance of cytochrome P450 (CYP) catalyzed drug metabolism for drug development and toxicity screening, it is very important to imitate natural metabolic pathways accurately and efficiently in vitro. Herein, a novel and simple photochemical bionanoreactor has been constructed for efficient visible-light-driven in vitro drug metabolism based on eosin-Y-functionalized macroporous ordered silica foams (MOSF-EY). Because of the unique transfer of photoinduced electrons from photosensitizers to CYP heme domain, CYP catalyzed drug metabolism can be in vitro driven by the MOSF-EY nanoreactor under the irradiation of visible light. In such a case, the utilization of expensive electron donors, such as NADPH, can be avoided. Meanwhile, the in vitro drug metabolism approach exhibits high efficiency because of the fast adsorption of both CYP and drug molecules from the bulk solution into the nanopores of MOSF-EY, where the enzyme and substrate are highly concentrated and confined in nanospace to achieve a high reaction rate. Taking advantage of these attractive merits, the first example of photochemical bionanoreactor has been successfully applied in in vitro metabolism of both purified drug molecules and real tablets. Not only excellent CYP-catalyzed drug metabolism but also enzyme inhibition assay has been performed with the MOSF-EY photochemical bionanoreactor.
Co-reporter:Liang Qiao, Christophe Roussel, Jingjing Wan, Pengyuan Yang, Hubert H. Girault and Baohong Liu
Journal of Proteome Research December 2007 Volume 6(Issue 12) pp:4763-4769
Publication Date(Web):November 30, 2007
DOI:10.1021/pr0705284
An on-plate specific enrichment method is presented for the direct analysis of peptides phosphorylation. An array of sintered TiO2 nanoparticle spots was prepared on a stainless steel plate to provide porous substrate with a very large specific surface and durable functions. These spots were used to selectively capture phosphorylated peptides from peptide mixtures, and the immobilized phosphopeptides could then be analyzed directly by MALDI MS after washing away the nonphosphorylated peptides. β-Casein and protein mixtures were employed as model samples to investigate the selection efficiency. In this strategy, the steps of phosphopeptide capture, purification, and subsequent mass spectrometry analysis are all successfully accomplished on a single target plate, which greatly reduces sample loss and simplifies analytical procedures. The low detection limit, small sample size, and rapid selective entrapment show that this on-plate strategy is promising for online enrichment of phosphopeptides, which is essential for the analysis of minute amount of samples in high-throughput proteome research.Keywords: enrichment; MALDI-TOF MS; phosphorylated peptides; TiO2 nanoparticles;
Co-reporter:Kun Zhang, Jiang Qing, Han Gao, Ji Ji, Baohong Liu
Talanta 2017 Volume 162() pp:52-56
Publication Date(Web):1 January 2017
DOI:10.1016/j.talanta.2016.10.020
•A facile method was developed for preparation of a SERS paper substrate modified with shell-isolated nanoparticle.•Simultaneous on-site separation and optical detection of multiple components could be realized on the substrate.•The established method features high sensitivity of plasmon-enhanced sensing strategies and sufficient temporal and spatial resolution of planar chromatographic techniques.By coupling shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) with paper chromatography, two birds with one stone method were developed for simultaneous on-site separation and optical detection of multiple components. The established method features high sensitivity of plasmon-enhanced sensing strategies and sufficient temporal and spatial resolution of planar chromatographic techniques.By coupling shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) with paper chromatography, a facile method was developed for simultaneous on-site separation and optical detection of multiple components. The established method features high sensitivity of plasmon-enhanced sensing strategies and sufficient temporal and spatial resolution of planar chromatographic techniques.
Co-reporter:Kun Zhang, Jingjing Zhao, Ji Ji and Baohong Liu
Nanoscale 2016 vol. 8(Issue 15) pp:7871-7875
Publication Date(Web):23 Mar 2016
DOI:10.1039/C6NR00278A
A single-particle SERS system enabling real-time and in situ observation of Au-catalyzed reactions has been developed. Both the catalytic activity and the SERS effect are coupled into a single bi-functional 3D superstructure comprising Au nanosatellites self-assembled onto a shell-insulated Ag microflower core, which eliminates the interference from photocatalysis.
Co-reporter:Xiaoni Fang, Jingjing Zhao, Kun Zhang, Pengyuan Yang, Liang Qiao, and Baohong Liu
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 10) pp:6363
Publication Date(Web):February 25, 2016
DOI:10.1021/acsami.6b00407
Functional nanomaterials, used as nanoreactors, have shown great advantages in a variety of applications in biomedical fields. Herein, we designed a novel nanoreactor system toward the application in membrane proteomics by using polydopamine-coated nanoporous graphene foams (NGFs-PD) prepared by a facile in situ oxidative polymerization. Taking advantage of the unique 3-D structure and surface functionalization, NGFs-PD can quickly adsorb a large amount of hydrophobic membrane proteins dissolved in sodium dodecyl sulfonate (SDS)/methanol and hydrophilic trypsin in aqueous solution, and then confine the proteolysis in the nanoscale domains to fasten the reaction rate. Therefore, the current nanoreactor system combines the multifunctions of highly efficient solubilization, immobilization, and proteolysis of membrane proteins. With the nanoreactor, digestion of standard membrane proteins can be finished in 10 min. 893 membrane proteins were identified from human glioma cells (U251). All these superiorities indicate that the biocompatible NGFs-PD nanoreactor system is of great promise to facilitate high-throughput membrane proteomic analysis.Keywords: mass spectrometry; membrane protein; nanoreactor; porous graphene; proteolysis
Co-reporter:Ruijun Du, Lina Zhu, Jinrui Gan, Yuning Wang, Liang Qiao, and Baohong Liu
Analytical Chemistry 2016 Volume 88(Issue 13) pp:6767
Publication Date(Web):June 2, 2016
DOI:10.1021/acs.analchem.6b01063
A mass spectrometry signal amplification method is developed for the ultrasensitive and selective detection of low-abundance protein biomarkers by utilizing tag molecules on gold nanoparticles (AuNPs). EpCAM and thrombin as model targets are captured by specific aptamers immobilized on the AuNPs. With laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS), the mass tag molecules are detected to represent the protein biomarkers. Benefiting from the MS signal amplification, the assay can achieve a limit of detection of 100 aM. The method is further applied to detect thrombin in fetal bovine serum and EpCAM in cell lysates to demonstrate its selectivity and feasibility in complex biological samples. With the high sensitivity and specificity, the protocol shows great promise for providing a new route to single-cell analysis and early disease diagnosis.
Co-reporter:Huiying Xu, Jingjing Xiao, Ling Yan, Lina Zhu, Baohong Liu
Journal of Electroanalytical Chemistry 2016 Volume 779() pp:92-98
Publication Date(Web):15 October 2016
DOI:10.1016/j.jelechem.2016.04.032
•A N-G/NiTsPc sensor is facilely prepared for the selective detection of dopamine.•N-G provides abundant binding sites for NiTsPc and facilitates the electron transfer.•The nanocomposites have synergic effect for enhancing electrocatalytic efficiency.•The prepared sensor exhibits wide linear range and low detection limit.A novel electrochemical sensing platform based on nitrogen-doped graphene (N-G)/nickel tetrasulfonated phthalocyanine (NiTsPc) nanocomposites has been developed for selective determination of dopamine (DA). NiTsPc was immobilized on N-G matrix via π-π interaction, while N-G provided a compatible microenvironment for NiTsPc to enhance electron transfer and to retain its electrocatalytic activity as well. The N-G/NiTsPc nanocomposite was characterized by using transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The proposed modified electrode presented superior catalytic efficiency for DA in the presence of ascorbic acid (AA) and uric acid (UA) owing to the synergistic effect of N-G and NiTsPc. The sensors also exhibited a wide linear range from 1 × 10− 7 to 2 × 10− 4 M and a limit of detection as low as 100 nM with high sensitivity of 88.9 μA mM− 1.
Co-reporter:Yujie Liu, Yun Liu, Baohong Liu
Journal of Electroanalytical Chemistry 2016 Volume 781() pp:265-271
Publication Date(Web):15 November 2016
DOI:10.1016/j.jelechem.2016.06.048
•A sensitive and facile electrochemical aptasensor was developed for the detection of bisphenol A.•Avidin-HRP-AuNP and the redox target bisphenol A were chosen as the dual-signaling indicators.•The dual-signaling strategy shows high sensitivity and selectivity for detection of bisphenol A with a lower detection limit.•This aptasensor is a universal protocol for the detection of redox targets, and promising for practical applications.A facile label-free aptamer-based electrochemical biosensor has been developed for sensitive detection of bisphenol A (BPA) based on a dual-signaling amplification strategy. The aptasensor was constructed by electrodeposition of gold nanoparticles (AuNPs) onto a glassy carbon electrode (GCE), where a thiolated-modified BPA aptamer was immobilized through self-assembly and then hybridized with the biotin-modified complementary DNA probe (cDNA) to form a double-stranded DNA. Upon the highly specific interaction between the target BPA and its aptamer, cDNA was released from the electrode surface and BPA was immobilized on the sensing interface. Streptavidin-modified horseradish peroxidase-functionalized gold nanoparticle (avidin-HRP-AuNP) was chosen as the nanoprobe, due to its catalytic activity to the oxidation of hydroquinone (HQ) in the presence of H2O2. As a result, the captured amounts of avidin-HRP-AuNP decrease with the increase of the BPA concentration and produce a series of decreasing catalytic peak currents. In addition, BPA has a redox activity and could provide an additional signal transformation. By superimposing the two signal changes, BPA was detected sensitively in a linear range from 0.001 to 1 nM with a detection limit of 0.41 pM. The aptasensor exhibited good selectivity toward BPA even in the presence of the interferents at 100-fold concentrations. This method would be readily applicable for sensitive detection of other redox analytes, merely by changing the anti-BPA aptamer/cDNA pair with a correspondent anti-target molecule aptamer and cDNA.
Co-reporter:Yixin Li, Kun Zhang, Jingjing Zhao, Ji Ji, Chang Ji, Baohong Liu
Talanta 2016 Volume 147() pp:493-500
Publication Date(Web):15 January 2016
DOI:10.1016/j.talanta.2015.10.025
•Cellulose paper provides a 3-D architecture for plasomonic AgNPs to locate.•Cellulose paper partakes in the fabrication of the AgNPs-arrayed paper strip.•Environmental samples spiked with R6G are detected successfully with this substrate.The fabrication of SERS substrates, which can offer the advantages of strong Raman signal enhancement with good reproducibility and low cost, is still a challenge for practical applications. In this work, a simple three-dimensional (3D) paper-based SERS substrate, which contains plasmonic silver-nanoparticles (AgNPs), has been developed by the silver mirror reaction. This paper strip was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), etc. Pretreatment of the paper as well as the reaction time, temperature, and reagent concentrations for the silver mirror reaction were varied for further studies. With the optimized experimental parameters, the AgNPs synthesized and distributed in-situ on the paper strip could give more favorable SERS performance. The limit of detection (LOD) as low as 10−11 M for Rhodamine 6 G (R6G) and 10−9 M for p-aminothiophenol (p-ATP) plus wide linear range for the log–log plot of Raman intensity versus analyte concentration were achieved. The detection of R6G in rain water was also carried out successfully. The merits of this protocol include low cost, easy operation, high sensitivity and acceptable stability, which make it ideal for the detection of environmental samples in trace amounts.
Co-reporter:Ling Yan, Kun Zhang, Huiying Xu, Ji Ji, Yuning Wang, Baohong Liu, Pengyuan Yang
Talanta 2016 Volume 158() pp:254-261
Publication Date(Web):1 September 2016
DOI:10.1016/j.talanta.2016.05.054
•A facile and rapid platform for both visual detection and Raman quantitation.•High sensitivity and selectivity via the formation of NPs self-assembled interface.•Long-term stability of reaction products for at least three weeks.•Capability for determination of large scale samples.•Successful application of real sample.One of the main problems of the nanoparticle dispersion state change (e.g. from dispersion to aggregation) based surface-enhanced Raman scattering (SERS) detection is that the dynamic process of such in-solution reactions is always uncontrollable. This leads to poor reproducibility from a narrow time window of all such strategies, and finally great difference between the data from the diverse methods, and even between various sample batches. To address such problem, a facile, rapid SERS quantification protocol has been developed relying on target induced nanoparticle self-assembly at oil/water interfaces for copper ions analysis. In response to copper, the core-molecule-shell (CMS) nanoparticles spontaneously migrate to the interface and are assembled into densely packed arrays generating strong plasmonic coupling, which enables stable, sensitive and selective Raman quantitation, as well as visual detection. Also, this strategy shows capability for determination of large scale samples as the products can be stable for at least three weeks, and has been successfully applied to real sample detection. The developed Target Induced Nanoparticle Self-Assembled Interface (TINSAI) can be employed to both visual test and Raman quantitative detection, which would provide a platform for on-site screening as well as high-throughput detection with high sensitivity and selectivity.
Co-reporter:Jingjing Zhao, Kun Zhang, Ji Ji, Baohong Liu
Talanta 2016 Volume 152() pp:196-202
Publication Date(Web):15 May 2016
DOI:10.1016/j.talanta.2016.02.008
•A competitive and lable-free SERS sensor is developed for rapid detection of biothiols.•The method shows much improved sensitivity with LOD down to picomolar levels.•This protocol is facile involving neither pre-concentration nor signal amplification.•The method is reliable and can be applied to directly detect cellular biothiols.A label-free surface-enhanced Raman spectroscopy (SERS)-based method for the rapid quantification detection of cellular biothiols at picomolar levels was developed by using a mechanism of binary competitive adsorption to regulate the plasmon coupling behavior of gold nanoparticles (Au NPs). 4,4′-Dipyridyl (Dpy), a small organic ligand with two symmetrically located pyridine rings, was used to shorten the inter-particle space and generate a multitude of “hot spots”, which in turn amplified the fingerprint signals of Dpy molecules. When biothiols were introduced into the Dpy-containing solution of Au NPs, they competitively adsorbed to the metal surface through the much stronger S–Au linkage, leading to the disaggregation of Au NPs and SERS quenching of Dpy molecules. The change of SERS responses was quantitatively related to biothiols added to the solution, and the detection limit down to 0.14 pM for GSH was facilely achieved without any pre-concentration. The total assay time, including data analysis was within 8 min. Finally, the SERS-based method was successfully applied to measure cellular biothiols, indicating its potential applicability in biological and biomedical research.
Co-reporter:Huiying Xu, Fenghua Geng, Yongxiang Wang, Maotian Xu, Xinhe Lai, Peng Qu, Yintang Zhang and Baohong Liu
Chemical Communications 2015 vol. 51(Issue 41) pp:8622-8625
Publication Date(Web):15 Apr 2015
DOI:10.1039/C5CC02624E
A sensitive and selective assay of DNA is developed by utilizing a signal transduction strategy with the rational redesign of the hairpin structured G-quadruplex molecular switch (G4-MS) assembled using auramine O (AO). By monitoring the changes of the fluorescent signal, we could identify and further quantitatively determine the target DNA in the samples.
Co-reporter:Kun Zhang, Jingjing Zhao, Huiying Xu, Yixin Li, Ji Ji, and Baohong Liu
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 30) pp:16767
Publication Date(Web):July 17, 2015
DOI:10.1021/acsami.5b04534
A smart and multifunctional paper-based SERS sensing card is generated through patterning self-assembled interfacial arrays of gold nanoparticles (AuNPs) on the tip of an arrow-shaped paper strip. It is found that the closely packed monolayer of AuNPs is evenly distributed on the paper surface, resulting in a multitude of SERS hot spots over the detection zone. The paper card, with its inherent ability to separate and preconcentrate analytes by the capillary force and polarity difference between sample components, was exploited successfully as an integrated platform, allowing for sub-attomolar (50 × 10–18 M) detection from microliter-volume (10 μL) samples. Furthermore, the simple preparation (lithography-free process), fast detection (<5 min), and low cost (<3 cents) demonstrate that the paper card is a practical and portable sensing interface for wide application in environmental and food analysis.Keywords: multifunction; oil/water interface; paper-based sensing device; self-assembly; SERS
Co-reporter:Xiaoni Fang, Liang Qiao, Guoquan Yan, Pengyuan Yang, and Baohong Liu
Analytical Chemistry 2015 Volume 87(Issue 18) pp:9360
Publication Date(Web):August 25, 2015
DOI:10.1021/acs.analchem.5b02135
An integrated protocol is proposed here for efficient analysis of membrane proteins based on surface functionalized mesoporous graphene foams (MGF). The inherent hydrophobic nature of MGF and surface modification with hydrophilic chitosan (CS) make it highly suitable for the enrichment of hydrophobic membrane proteins from organic solvent, while remaining well-dispersed in aqueous solution for subsequent proteolysis. Therefore, such a multifunctional reactor ensures a facile solvent adjustment route. Furthermore, as a chitosan modified nanoporous reactor, it also provides a biocompatible nanoenvironment that can maintain the stability and activity of enzymes to realize efficient in situ digestion of the enriched membrane proteins. The concept was first proved with a standard hydrophobic membrane protein, bacteriorhodopsin, where a high number of identified peptides and amino acid sequence coverage were achieved even at extremely low protein concentration. The mesoporous reaction system was further applied to the analysis of complex real-case proteome samples, where 931 membrane proteins were identified in triplicate analyses by 2D LC-MS/MS. In contrast, with in-solution proteolysis, only 73 membrane proteins were identified from the same sample by the same 2D LC-MS/MS. The identified membrane proteins by the MGF-CS protocol include many biomarkers of the cell line. These results suggest that the multifunctional MGF-CS protocol is of great value to facilitate the comprehensive characterization of membrane proteins in the proteome research.
Co-reporter:Kun Zhang, Jingjing Zhao, Ji Ji, Yixin Li, and Baohong Liu
Analytical Chemistry 2015 Volume 87(Issue 17) pp:8702
Publication Date(Web):August 12, 2015
DOI:10.1021/acs.analchem.5b01406
Although surface-enhanced Raman scattering (SERS) has proven to be an effective tool for label-free monitoring of catalytic reactions, quantitative characterization of reaction kinetics via this technique remains challenging owing to the difficulty in integrating catalytic and plasmonic activities into a single platform. In this work, we report on an easy access to highly sensitive plasmonic nanoarrays for direct and label-free monitoring of a gold-catalyzed reaction by SERS. The hierarchically structured three-dimensional assemblies, which consist of small gold catalyst nanoparticles distributed on a self-assembled monolayer of larger gold nanoparticles, were formed through a simple and rapid stepwise interfacial self-assembling process (fabrication time <10 min). The well-defined interparticle distances (<1 nm) lead to efficient plasmonic coupling and ensure both catalytic and SERS-active sites exposed to the environment. Such a versatile bifunctional platform thus allows quantitative determination of the rate constant and activation energy of the catalytic reaction with SERS.
Co-reporter:Q. Wu, L. Liao, Q. Zhang, Y. Nie, J. Xiao, S. Wang, S. Dai, Q. Gao, Y. Zhang, X. Sun, B. Liu, Y. Tang
Electrochimica Acta 2015 Volume 158() pp:42-48
Publication Date(Web):10 March 2015
DOI:10.1016/j.electacta.2015.01.115
•An intercalation-in situ carbonization strategy is reported for multilayer material.•The obtained multilayer hybrid material exhibits enhanced ORR performance.•It is confirmed that the oxygen vacancy and synergetic coupling effect are crucial.Advanced materials for electrocatalytic oxygen reduction reaction (ORR) is crucial to a number of renewable energy applications. Herein, a hybrid of nitrogen-doped graphene (N-graphene) and NbOx (x = 2∼2.5) semiconductor nanosheets with sandwich-like structure has been designed and synthesized via a strategy of intercalation-in situ carbonization. The obtained multilayer hybrid material exhibits quite positive onset potential of ORR, good stability and excellent selectivity for ORR with high methanol tolerance. The enhanced performance could be attributed to the active oxygen vacancy from the partial reduction of Nb (V) during the carbonization process and the synergetic coupling effect resulting from the molecular level contact of N-graphene and NbOx (x = 2∼2.5) nanosheets, which makes it a promising substitute of platinum-based materials for renewable energy applications.
Co-reporter:Kun Zhang, Ji Ji, Xiaoni Fang, Ling Yan and Baohong Liu
Analyst 2015 vol. 140(Issue 1) pp:134-139
Publication Date(Web):10 Oct 2014
DOI:10.1039/C4AN01473A
The facile assembly of three-dimensional (3D) plasmonic substrates has been demonstrated. The assembly is based on the homogeneous decoration of multi-walled carbon nanotube/gold nanoparticle (CNT/AuNP) hybrid nanocomposites on a commercial polyvinylidene difluoride (PVDF) membrane, which is achieved via simple filtration. The CNT/AuNP hybrids with a unique 1D/0D structure remarkably improve the coverage and uniformity of plasmonic nanostructures on the membrane. The effective inter-particle and inter-tube coupling creates a multitude of hot spots within the probe area, and can produce a strong SERS effect. Moreover, the flexible membrane-based scaffold can efficiently collect and concentrate trace targets from large-volume sample solutions at milliliter-scale. The membrane-based SERS sensor shows high sensitivity and good reproducibility. The SERS sensor is employed to detect various molecular contaminants in aqueous samples, demonstrating its excellent field-testing capabilities for applications ranging from food safety to environmental monitoring.
Co-reporter:Jinrui Gan, Xiang Wei, Yixin Li, Jiao Wu, Kun Qian, Baohong Liu
Nanomedicine: Nanotechnology, Biology and Medicine 2015 Volume 11(Issue 7) pp:1715-1723
Publication Date(Web):October 2015
DOI:10.1016/j.nano.2015.06.010
We report a novel platform using optimized SiO2@Au core–shell structures as matrices for highly efficient laser desorption/ionization mass spectrometry analysis of small biomolecules (MW < 700 Da). Owing to the designer structure, SiO2@Au nanoshells can achieve low detection-of-limits (~ pmol–fmol) in mass spectrometry and selective laser desorption/ionization in bio-mixtures towards diverse small molecules. By further surface modification with aptamers, Apt-SiO2@Au nanoshells allowed simultaneously targeted enrichment and detection of kanamycin with a detection limit at 200 pM. Our work not only starts new applications of SiO2@Au nanoshells in mass spectrometry, but also contributes to advanced analysis of either a group of small molecules or one target small molecule from complex bio-samples in a pre-designed manner for bio-diagnostics.From the Clinical EditorExisting methods for the detection of small molecules are often not sensitive enough. Here, the authors developed aptamer functionalized SiO2@Au nanoshells for use in mass spectrometry, with very low detection limits. The new platform appeared to be simple and efficient and should be applicable in detection of clinical samples.A novel platform based on SiO2@Au nanoshells towards sensitive and selective detection of small molecules in laser desorption ionization mass spectrometry.
Co-reporter:Huiying Xu, Jingjing Xiao, Baohong Liu, Sophie Griveau, Fethi Bedioui
Biosensors and Bioelectronics 2015 Volume 66() pp:438-444
Publication Date(Web):15 April 2015
DOI:10.1016/j.bios.2014.12.011
•A N-G/CoPc sensor is facilely prepared for the sensitive detection of thiols.•N-G provides abundant binding sites for CoPc and improves conductivity.•The hybrids have a synergic effect for enhancing the electrocatalytic activity.•The prepared sensor shows wide linear range and low detection limit.A hybrid nanocomposite based on cobalt phthalocyanine (CoPc) immobilized on nitrogen-doped graphene (N-G) (N-G/CoPc) has been developed to modify glassy carbon electrode (GCE) for the sensitive detection of thiols. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Cyclic voltammetric studies showed that cobalt phthalocyanine and nitrogen doped graphene have a synergic effect and significantly enhance the electrocatalytic activity of the modified electrode towards thiols oxidation compared with electrodes modified with solely CoPc or N-G. The electrochemical oxidation responses were studied and the reaction mechanisms were discussed. The sensors exhibited a wide linear response range from 1 μΜ to 16 mM and a low detection limit of 1 μΜ for the determination of l-cysteine, reduced l-glutathione and 2-mercaptoethanesulfonic acid in alkaline aqueous solution. The proposed N-G/CoPc hybrids contribute to the construction of rapid, convenient and low-cost electrochemical sensors for sensitive detection of thiols.
Co-reporter:Lei Liao, Sinong Wang, Jingjing Xiao, Xiaojun Bian, Yahong Zhang, Micheál D. Scanlon, Xile Hu, Yi Tang, Baohong Liu and Hubert H. Girault
Energy & Environmental Science 2014 vol. 7(Issue 1) pp:387-392
Publication Date(Web):17 Oct 2013
DOI:10.1039/C3EE42441C
A highly active and stable electrochemical catalyst of nanoporous molybdenum carbide nanowires (np-Mo2C NWs) has been developed for hydrogen evolution reaction (HER). The np-Mo2C NWs were synthesized simply by pyrolysis of a MoOx/amine hybrid precursor with sub-nanosized periodic structure under an inert atmosphere. The enriched nanoporosity and large reactive surface of these highly dispersed nanowires with uniform Mo2C nanocrystallites provide an efficient electrocatalysis, leading to their superior HER activity with lower onset overpotential and higher current densities than Mo2C microparticles. This study opens a new perspective for the development of highly active non-noble electrocatalysts for hydrogen production from water splitting.
Co-reporter:Jingjing Xiao, Xiaojun Bian, Lei Liao, Song Zhang, Chang Ji, and Baohong Liu
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 20) pp:17654
Publication Date(Web):September 29, 2014
DOI:10.1021/am503895w
To balance the anchoring sites and conductivity of the catalyst supports is a dilemma in electrocatalytic oxygen reduction reaction (ORR). Nitrogen-doped mesoporous graphene (N-MG) with large surface area, high porosity, and superior intrinsic conductivity has been developed to address this issue. Using N-MG as the backbone, a hybrid catalyst of Co3O4 nanocrystals embedded on N-MG (Co3O4/N-MG) was prepared for the electrocatalytic ORR in alkaline media. The Co3O4/N-MG showed high catalytic activity for the four-electron ORR, giving a more positive onset potential (0.93 V vs RHE) and a higher current density. The unique property of N-MG and the synergetic effect of Co3O4 and N-MG are prominent for ORR. With improved electrocatalytic activity and durability, the Co3O4/N-MG can be an efficient nonprecious metal catalyst and potentially used to substitute the platinum-based cathode catalysts in fuel cells and metal–air batteries.Keywords: catalyst; cobalt oxide; electrocatalysis; nitrogen-doped mesoporous graphene; oxygen reduction reaction
Co-reporter:Kun Zhang, Ji Ji, Yixin Li, and Baohong Liu
Analytical Chemistry 2014 Volume 86(Issue 13) pp:6660
Publication Date(Web):June 10, 2014
DOI:10.1021/ac501383x
Surface-enhanced Raman scattering (SERS) has proven to be promising for the detection of trace analytes; however, the precise nanofabrication of a specific and sensitive plasmonic SERS-active substrate is still a major challenge that limits the scope of its applications. In this work, gold nanoparticles are self-assembled into densely packed two-dimensional arrays at a liquid/liquid interface between dimethyl carbonate and water in the absence of template controller molecules. Both the simulation and experiment results show that the particles within these film-like arrays exhibit strong electromagnetic coupling and enable large amplification of Raman signals. In order to realize the level of sensing specificity, the surface chemistry of gold nanoparticles (Au NPs) is rationally tailored by incorporating an appropriate chemical moiety that specifically captures molecules of interest. The ease of fabrication and good uniformity make this platform ideal for in situ SERS sensing of trace targets in complex samples.
Co-reporter:Xiaoni Fang, Peng Zhang, Liang Qiao, Xiaoyan Feng, Xiangmin Zhang, Hubert H. Girault, and Baohong Liu
Analytical Chemistry 2014 Volume 86(Issue 21) pp:10870
Publication Date(Web):October 14, 2014
DOI:10.1021/ac503024h
A rapid and accurate in vitro drug metabolism strategy has been proposed based on the design of a biomimetic nanoreactor composed of amino-functionalized periodic mesoporous organosilica (NH2-PMO) and microsomes. The amphiphilic nature and positive charge of NH2-PMO make it highly suited for the immobilization of hydrophobic and negatively charged microsomes to form nanoreactors, which can in turn extract substrates from solutions. Such nanoreactors provide a suitable environment to confine multiple enzymes and substrates with high local concentrations, as well as to maintain their catalytic activities for rapid and highly effective drug metabolic reactions. Coupled with high-performance liquid chromatography–mass spectrometry analysis, the metabolites of nifedipine and testosterone were quantitatively characterized, and the reaction kinetics was evaluated. Both the metabolism conversion and reaction rate were significantly improved with the NH2–PMO nanoreactors compared to bulk reactions. This strategy is simple and cost-effective for promising advances in biomimetic metabolism study.
Co-reporter:Lei Liao, Xiaojun Bian, Jingjing Xiao, Baohong Liu, Micheál D. Scanlon and Hubert H. Girault
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 21) pp:10088-10094
Publication Date(Web):12 Feb 2014
DOI:10.1039/C3CP54754J
A non-precious metal electrocatalyst has been developed for the oxygen reduction reaction based on nanoporous molybdenum carbide (nano-Mo2C) wires through a facile calcination of sub-nanometer periodic organic–inorganic hybrid nanowires. The highly dispersed Mo2C wires were composed of 10–15 nm nanocrystals with a mesopore size of 3.3 nm. The properties of nano-Mo2C wires were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and N2 adsorption/desorption porosimetry. The highly active surface area and enriched nanoporosity for nano-Mo2C wires are unique features that make them a high-performance electrocatalyst for oxygen reduction in an alkaline medium. The electrocatalysis and reaction kinetics results show that nano-Mo2C-based materials can be developed as new catalysts with high activity at low cost for electrochemical energy conversion applications.
Co-reporter:Lei Liao;Jie Zhu;Xiaojun Bian;Lina Zhu;Micheál D. Scanlon;Hubert H. Girault
Advanced Functional Materials 2013 Volume 23( Issue 42) pp:5326-5333
Publication Date(Web):
DOI:10.1002/adfm.201300318
Abstract
A highly active and stable electrocatalyst for hydrogen evolution is developed based on the in situ formation of MoS2 nanoparticles on mesoporous graphene foams (MoS2/MGF). Taking advantage of its high specific surface area and its interconnected conductive graphene skeleton, MGF provides a favorable microenvironment for the growth of highly dispersed MoS2 nanoparticles while allowing rapid charge transfer kinetics. The MoS2/MGF nanocomposites exhibit an excellent electrocatalytic activity for the hydrogen evolution reaction with a low overpotential and substantial apparent current densities. Such enhanced catalytic activity stems from the abundance of catalytic edge sites, the increase of electrochemically accessible surface area and the unique synergic effects between the MGF support and active catalyst. The electrode reactions are characterized by electrochemical impedance spectroscopy. A Tafel slope of ≈42 mV per decade is measured for a MoS2/MGF modified electrode, suggesting the Volmer-Heyrovsky mechanism of hydrogen evolution.
Co-reporter:Ji Ji, Lei Nie, Yixin Li, Pengyuan Yang, and Baohong Liu
Analytical Chemistry 2013 Volume 85(Issue 20) pp:9617
Publication Date(Web):September 16, 2013
DOI:10.1021/ac4018082
A facile online enrichment protocol has been proposed based on microfluidic droplets acting as an interface between a liquid chromatography separation system and detection systems of ESI-MS/MS and laser-induced fluorescence. Low-abundance species were successfully concentrated and analyzed in this system via droplet shrinkage. The proposed platform significantly increased the enrichment efficiency and detection sensitivity with reduced sample handling steps, short analysis time, and no cross-contamination. The presented system is universal, shows no discrimination, and is easily coupled with other separation and detection approaches.
Co-reporter:Yun Liu, Lina Zhu, Jilie Kong, Pengyuan Yang, Baohong Liu
Electrochemistry Communications 2013 Volume 33() pp:59-62
Publication Date(Web):August 2013
DOI:10.1016/j.elecom.2013.04.018
•AuNPs/APTMS ITO was fabricated for cell capture.•Folic acid-CdSe/ZnS QDs complex has been successfully labeled with tumor cells.•The constructed electrochemical assay was used to the determination of tumor cells.A new electrochemical assay strategy was proposed based on the specific recognition of folate receptors on a cell surface to folic acids. Indium tin oxide glass (ITO) surfaces were silanized by (3-aminopropyl) trimethoxylsilane (APTMS) to associate to Au nanoparticles (AuNPs) which can effectively capture cells. Then, CdSe/ZnS quantum dots (QDs)-labeled folic acids (FAs) can couple with the folate receptors (FRs) on the KB cells, which can overexpress FRs. By square wave stripping voltammetry (SWSV), the developed electrochemical assay showed an excellent analytical performance for the sensitive detection of KB cells as low as 2000 cells mL− 1. The QDs-based electrochemical assay provides a rapid and reliable platform towards the tumor cell quantification and thus has the potential in the improvement of cancer diagnosis and treatment.
Co-reporter:Jie Zhu, Lei Liao, Lina Zhu, Peng Zhang, Kai Guo, Jilie Kong, Chang Ji, Baohong Liu
Talanta 2013 Volume 107() pp:408-415
Publication Date(Web):30 March 2013
DOI:10.1016/j.talanta.2013.01.037
In this study, we investigated and reported the cellular uptake efficiency, mechanism, and cytotoxicity of silica nanoparticles (SNPs) with different sizes. Using confocal laser scanning microscope (CLSM), flow cytometry (FCM), and graphite furnace atomic absorption spectrometry (GFAAS), the qualitative and quantitative experimental results showed that the cellular uptake of SNPs toward HeLa cells is size-dependent. To further examine the uptake process, three different inhibitors including sucrose, Filipin III, and Cytochalasin D (Cyt D) were introduced to pretreat the HeLa cells. It appeared that the largest SNPs (SNPs-307.6) take an energy-dependent uptake pathway (clathrin dependent and caveolin independent) while that for the medium size SNPs-167.8 involves clathrin and caveolin dependent endocytosis. In contrast, the smallest SNPs (SNPs-55.6) follow not only energy required clathrin and caveolin dependent endocytosis but also an energy independent pathway to efficiently enter the cells. Moreover, the cellular uptake efficiency of SNPs, which also show excellent biocompatibility, is size-dependent in the order of 55.6>167.8>307.6 nm. This knowledge is fundamentally important and will facilitate more development of size-defined SNPs as the transporters for various purposes.Highlights► The cellular uptake efficiency of SNPs is size-dependent in the order of 55.6>167.8>307.6 nm. ► The cellular uptake pathways of SNPs toward HeLa cells were found to be size-dependent. ► Different SNPs in size show excellent biocompatibility with little cytotoxicity.
Co-reporter:Ji Ji, Lei Nie, Liang Qiao, Yixin Li, Liping Guo, Baohong Liu, Pengyuan Yang and Hubert H. Girault
Lab on a Chip 2012 vol. 12(Issue 15) pp:2625-2629
Publication Date(Web):02 May 2012
DOI:10.1039/C2LC40206H
A versatile microreactor protocol based on microfluidic droplets has been developed for on-line protein digestion. Proteins separated by liquid chromatography are fractionated in water-in-oil droplets and digested in sequence. The microfluidic reactor acts also as an electrospray ionization emitter for mass spectrometry analysis of the peptides produced in the individual droplets. Each droplet is an enzymatic micro-reaction unit with efficient proteolysis due to rapid mixing, enhanced mass transfer and automated handling. This droplet approach eliminates sample loss, cross-contamination, non-specific absorption and memory effect. A protein mixture was successfully identified using the droplet-based micro-reactor as interface between reverse phase liquid chromatography and mass spectrometry.
Co-reporter:Ji Ji, Yiqing Zhao, Liping Guo, Baohong Liu, Chang Ji and Pengyuan Yang
Lab on a Chip 2012 vol. 12(Issue 7) pp:1373-1377
Publication Date(Web):31 Jan 2012
DOI:10.1039/C2LC40052A
A spherical liquid–liquid interface can be obtained by dispersing one liquid phase into another to form droplets, which will facilitate the two-phase reactions between the immiscible participating fluids. The phase transfer catalysts assembled at the droplet “wall” catalyze the reactions between the aqueous and organic phases. The study illustrates an interfacial synthetic approach which is ideal for the biphasic reaction by taking advantage of the droplet-based microdevice. The improved reaction efficiency can be attributed to the high surface-to-volume ratio and internal flow circulation in the droplets.
Co-reporter:Jinrui Gan, Jie Zhu, Guoquan Yan, Yun Liu, Pengyuan Yang, and Baohong Liu
Analytical Chemistry 2012 Volume 84(Issue 13) pp:5809
Publication Date(Web):May 31, 2012
DOI:10.1021/ac301146a
A versatile protocol has been developed for large-scale characterization of hydrophobic membrane proteins based on the periodic mesoporous organosilica (PMO) acting as both an extractor for hydrophobic substrate capture and a nanoreactor for efficient in situ digestion. With introduction of organic groups in the pore frameworks and the presence of hydrophilic silanol groups on the surface, PMO can be well-dispersed into not only an organic solution to concentrate the dissolved membrane proteins but also an aqueous solution containing enzymes for sequential rapid proteolysis in the nanopores. The unique amphiphilic property of PMO ensures a facile switch in different solutions to realize the processes of substrate dissolution, enrichment, and digestion effectively. Furthermore, this novel PMO-assisted protocol has been successfully applied for identification of complex membrane proteins extracted from mouse liver as proof of general applicability.
Co-reporter:Xiaojun Bian, Jie Zhu, Lei Liao, Micheál D. Scanlon, Peiyu Ge, Chang Ji, Hubert H. Girault, Baohong Liu
Electrochemistry Communications 2012 Volume 22() pp:128-132
Publication Date(Web):August 2012
DOI:10.1016/j.elecom.2012.06.009
An efficient electrocatalyst for hydrogen evolution has been developed based upon in situ reduction of MoS2 on ordered mesoporous carbon nanospheres (MoS2/MCNs). The properties of MoS2/MCNs were characterised by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Polarisation curves and electrochemical impedance measurements were obtained for MoS2/MCNs modified glassy carbon electrodes. The MoS2/MCNs exhibit high catalytic activity for hydrogen evolution with a low overpotential and a very high current density. A theory outlining the origins of the Tafel slope for a Volmer-Heyrovsky (rate determining step) mechanism of hydrogen evolution at MoS2 catalytic edge sites is presented.Highlights► MoS2 was uniformly in situ formed on a novel mesoporous carbon nanosphere matrix. ► The MoS2/MCNs nanocomposites display excellent HER electrocatalytic activity. ► The MoS2/MCNs-GCE exhibits a low overpotential for hydrogen evolution reaction. ► A lower Tafel slope and high current density are achieved based on MoS2/MCNs-GCE. ► The MCNs is a promising support for electrochemical catalysts.
Co-reporter:Ji Ji, Jinrui Gan, Jilie Kong, Pengyuan Yang, Baohong Liu, Chang Ji
Electrochemistry Communications 2012 Volume 16(Issue 1) pp:53-56
Publication Date(Web):March 2012
DOI:10.1016/j.elecom.2012.01.004
An electrochemical approach is described to assess the activities of thrombin and one of its inhibitors. Thrombin is a vital proteinase, which is one kind of serine protease, and plays an important role in coagulation cascade, thrombosis, and hemostasis. A gold electrode immobilized with p-aminodiphenylamine (pADA) modified peptide (H-d-Pro-Phe-Arg-p-aminodiphenylamine) was prepared for the analyses of thrombin and its inhibitor. The peptide was employed as the recognition and cleavage site for thrombin while pADA was used as an electroactive reporter. Experimental results showed that this method is sensitive as a low concentration of 5 fM thrombin can be detected. The inhibition of thrombin activity by argatroban was monitored and IC50 was found to be about 10 μM. The protocol was further applied for the measurement of a healthy human serum sample.Highlights► The protocol provides a facile readout of thrombin activity and its potential for application of human serum sample. ► The method is sensitive as a low concentration of 5 fM thrombin can be detected. ► The strategy offers a possible way to screen the throughput of thrombin inhibitors.
Co-reporter:Ying Wang;Xiaojun Bian;Lei Liao;Jie Zhu;Kai Guo;Jilie Kong
Microchimica Acta 2012 Volume 178( Issue 3-4) pp:277-283
Publication Date(Web):2012 September
DOI:10.1007/s00604-012-0834-1
We report on an amperometric biosensor for hydrogen peroxide. It is obtained via layer-by-layer assembly of ordered mesoporous carbon nanospheres and poly(diallyldimethylammonium) on the surface of an indium tin oxide (ITO) glass electrode and subsequent adsorption of cytochrome c. UV–vis absorption spectroscopy was applied to characterize the process of forming the assembled layers. Cyclic voltammetry revealed a direct and quasi-reversible electron transfer between cytochrome c and the surface of the modified ITO electrode. The surface-controlled electron transfer has an apparent heterogeneous electron-transfer rate constant (ks) of 5.9 ± 0.2 s−1 in case of the 5-layer electrode. The biosensor displays good electrocatalytic response to the reduction of H2O2, and the amperometric signal increase steadily with the concentration of H2O2 in the range from 5 μM to 1.5 mM. The detection limit is 1 μM at pH 7.4. The apparent Michaelis-Menten constant (Km) of the sensor is 0.53 mM. We assume that the observation of a direct electron transfer of cytochrome c on mesoporous carbon nanospheres may form the basis for a feasible approach for durable and reliable detection of H2O2.
Co-reporter:Xiaojun Bian, Kai Guo, Lei Liao, Jingjing Xiao, Jilie Kong, Chang Ji, Baohong Liu
Talanta 2012 Volume 99() pp:256-261
Publication Date(Web):15 September 2012
DOI:10.1016/j.talanta.2012.05.048
Palladium nanoparticles (Pd NPs) were loaded in situ on novel mesoporous carbon nanospheres (MCNs), which possess high specific surface area and large pore volume. The resulting Pd/MCNs hybrid nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). By using Pd/MCNs as the catalyst matrices to modify the surface of glassy carbon electrode, a nonenzymatic sensor was developed for the determination of hydrogen peroxide (H2O2). Cyclic voltammetry (CV) and amperometry (at an applied potential of −0.30 V versus SCE) were used to study and optimize the performance of the electrochemical sensor. It was demonstrated that the sensor not only exhibits good electrocatalytic activity toward the reduction of H2O2 but also has high sensitivity (307.5 μA mM−1 cm−2), low detection limit of 1.0 μM, and wide linear response range from 7.5 μM to 10 mM. Moreover, the sensor shows excellent stability and anti-interference capability for the detection of H2O2.Highlights► Pd nanoparticles are homogeneously in situ loaded on a novel MCNs matrix. ► The hybrid Pd/MCNs show enhanced catalytic activity toward the reduction of H2O2. ► The Pd/MCNs based sensor exhibits high sensitivity and low detection limit to H2O2. ► The MCNs is a promising support for other catalysts.
Co-reporter:Kai Guo, Ying Wang, Hui Chen, Ji Ji, Song Zhang, Jilie Kong, Baohong Liu
Electrochemistry Communications 2011 Volume 13(Issue 7) pp:707-710
Publication Date(Web):July 2011
DOI:10.1016/j.elecom.2011.04.016
An aptamer–SWNT based electrochemical biosensor is developed for sensitive detection of thrombin via mediated signal transduction. To realize this purpose, a dense monolayer of 16-mercaptohexadecanoic acid was modified on the gold electrode. In the presence of thrombin, SWNTs were controllably assembled on this insulating monolayer, which could mediate efficient electron transfer between the electrode and eletroactive species to generate a larger redox current. Through detecting the redox signal mediated by SWNTs, this strategy could present significant signal amplification and a detection limit of 50 pM thrombin was achieved. Such an aptamer–SWNT based biosensor opens a rapid, selective and sensitive route for thrombin detection and offers a promising strategy for specific protein detection.Highlights► An aptamer-SWNT based biosensor via controlled mediated signal transduction ► New bio-assay for sensitive detection of thrombin ► Detection limit of 50 pM with desirable specificity and sensitivity
Co-reporter:Weichao Guo, Hongyan Bi, Liang Qiao, Jingjing Wan, Kun Qian, Hubert H. Girault and Baohong Liu
Molecular BioSystems 2011 vol. 7(Issue 10) pp:2890-2898
Publication Date(Web):29 Jul 2011
DOI:10.1039/C1MB05140G
Tryptic digestion of proteins in trypsin loaded porous silica has been shown to be highly efficient. Enzymatic silica-reactors were prepared by immobilizing trypsin into macroporous ordered siliceous foam (MOSF) and into mesoporous SBA-15 silica which has a smaller pore size. The tryptic products from the silica reactors were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and a higher proteolysis efficiency was obtained with MOSF. These results can be well interpreted by a sequential digestion model taking into account the confinement and concentration enrichment of both the substrates and enzymes within the silica pores. Proteins at low concentrations and proteins in urea and surfactant solutions were also successfully digested with the MOSF-based reactor and identified by MS. Considering that the immobilized trypsin could retain its enzymatic activity for weeks, this MOSF reactor provides many advantages compared to free enzyme proteolysis. As a proof-of-concept, the digest of a real complex sample extracted from the cytoplasm of mouse liver tissue using trypsin loaded MOSF yielded better results than the typical in-solution protocol.
Co-reporter:Cheng Cheng Liu, Yun Liu, Hui Xiang Wang, Yan Bo Qi, Peng Yuan Yang, Bao Hong Liu
Chinese Chemical Letters 2011 Volume 22(Issue 11) pp:1343-1346
Publication Date(Web):November 2011
DOI:10.1016/j.cclet.2011.05.028
Apolipoprotein B100 (apoB-100) is a major protein of the cholesterol-rich low-density lipoprotein (LDL) and reflects a better assessment of total atherogenic burden to the vascular system than LDL. In this work, a simple and sensitive method has been developed to determine picoliter apoB-100s using the PMMA microfluidic chip coupled with electrochemical detection system. This method performs very well with a detectable linear range of 1–800 pg/mL and a detection limit of 1 pg/mL. A real serum sample has further been detected by this microchip-based biosensor. The results show that this kind of method is practicable and has the potential application in clinical analysis and diagnosis.
Co-reporter:Chunping You, Xuewu Yan, Jilie Kong, Dongyuan Zhao, Baohong Liu
Talanta 2011 Volume 83(Issue 5) pp:1507-1514
Publication Date(Web):15 February 2011
DOI:10.1016/j.talanta.2010.11.041
A strategy of protein-entrapment in bicontinuous gyroidal mesoporous carbon (BGMC) nanocomposite films is described. Herein, the quasi-reversible electron transfer of redox proteins (such as glucose oxidase and myoglobin) is probed and the associated biocatalytic activity is revealed. The apparent heterogeneous electron transfer rate constant of the immobilized glucose oxidase is up to 9.4 s−1, much larger than those in carbon nanotubes and some conventional mesoporous carbons. The BGMC based glucose biosensor enables the determination of glucose at a potential of 0.6 V (vs. SCE). Its detection limit is 1.0 × 10−5 M (signal-to-noise ratio, S/N = 3), the linear response is up to 7.49 mM and the detection sensitivity is 52.5 nA mM−1 Furthermore, a series of BGMCs with different pore sizes is designed and synthesized using sucrose or phenol formaldehyde resin to study the influences of pore sizes and carbon sources on the immobilization of redox proteins and on the heterogeneous electron transfer.
Co-reporter:WeiChao Guo;JingJing Wan;Kun Qian;ChengZhong Yu;JiLie Kong
Science China Chemistry 2011 Volume 54( Issue 8) pp:
Publication Date(Web):2011 August
DOI:10.1007/s11426-011-4344-5
Protein phosphorylation as one of the most important post-translational modifications in mammalian cells regulates numerous biological processes. Here we propose a novel strategy for the selective isolation and sensitive analysis of multi-phosphopeptides based on TiO2-gratfed mesoporous materials, in which MCM-41 and SBA-15 were chosen as the hard templates. The commercialized IMAC and TiO2 nanopartices were further investigated in the phosphopeptide analysis for comparison. The enrichment efficiency was evaluated and measured by MALDI-TOF mass spectrometry. The results indicated that both TiO2-SBA-15 and TiO2-MCM-41 exhibited the preferential affinity to multi-phosphopeptides compared with the other two widely used strategies. The mesoporous TiO2 based protocol showed highly selective and sensitive properties, where phosphopeptides could be identified at femtomole.
Co-reporter:Ying Wang;Kun Qian;Kai Guo;Jilie Kong;Jean-Louis Marty
Microchimica Acta 2011 Volume 175( Issue 1-2) pp:
Publication Date(Web):2011 October
DOI:10.1007/s00604-011-0638-8
An amperometric biosensor for hydrogen peroxide (H2O2) has been constructed by immobilizing cytochrome c on an indium/tin oxide (ITO) electrode modified with a macroporous material. Cyclic voltammetry showed that the direct and quasi-reversible electron transfer of cytochrome c proceeds without the need for an electron mediator. A surface-controlled electron transfer process can be observed with an apparent heterogeneous electron-transfer rate constant (ks) of 29.2 s−1. The biosensor displays excellent electrocatalytic responses to the reduction of H2O2 to give amperometric responses that increase steadily with the concentration of H2O2 in the range from 5 μM to 2 mM. The detection limit is 0.61 μM at pH 7.4. The apparent Michaelis-Menten constant (Km) of the biosensor is 1.06 mM. This investigation not only provided a method for the direct electron transfer of cytochrome c on macroporous materials, but also established a feasible approach for durable and reliable detection of H2O2.
Co-reporter:Kai Guo, Kun Qian, Song Zhang, Jilie Kong, Chengzhong Yu, Baohong Liu
Talanta 2011 Volume 85(Issue 2) pp:1174-1179
Publication Date(Web):15 August 2011
DOI:10.1016/j.talanta.2011.05.038
Characterization and application of graphene sheets modified glassy carbon electrodes (graphene/GC) have been presented for the electrochemical bio-sensing. A probe molecule, potassium ferricyanide is employed to study the electrochemical response at the graphene/GC electrode, which shows better electron transfer than graphite modified (graphite/GC) and bare glassy carbon (GC) electrodes. Based on the highly enhanced electrochemical activity of NADH, alcohol dehydrogenase (ADH) is immobilized on the graphene modified electrode and displays a more desirable analytical performance in the detection of ethanol, compared with graphite/GC or GC based bio-electrodes. It also exhibits good performance of ethanol detection in the real samples. From the results of electrochemical investigation, graphene sheets with a favorable electrochemical activity could be an advanced carbon electrode materials for the design of electrochemical sensors and biosensors.
Co-reporter:Jie Zhu;Huixiang Wang;Lei Liao;Lingzhi Zhao;Liang Zhou;Meihua Yu; Yunhua Wang; Baohong Liu; Chengzhong Yu
Chemistry – An Asian Journal 2011 Volume 6( Issue 9) pp:2332-2338
Publication Date(Web):
DOI:10.1002/asia.201100064
Abstract
Small mesoporous silica nanoparticles (MSNs; ca. 37 nm in diameter) have a high loading capacity for a hydrophobic photosensitizer, SiPcCl2 (82.6 % in weight), and excellent endocytosis properties. As a result, the amount of SiPcCl2 being delivered to cancer cells is increased by approximately two orders of magnitude compared to pure SiPcCl2 at the same dosage, and the photodynamic therapy (PDT) efficiency is enhanced by over fourfold. Our method can be widely used to increase the dosage of hydrophobic anti-cancer drugs in cancer cells and therefore increase the cytotoxicity of the drugs.
Co-reporter:Huixiang Wang, Yun Liu, Chengcheng Liu, Jingyu Huang, Pengyuan Yang, Baohong Liu
Electrochemistry Communications 2010 Volume 12(Issue 2) pp:258-261
Publication Date(Web):February 2010
DOI:10.1016/j.elecom.2009.12.008
In this paper, a microchip-based sandwich-type aptasensor is developed for the detection of human thrombin. The SH-aptamer/thrombin/alkaline phosphatase-functionalized aptamer (ALP-aptamer) system was constructed in the microfluidic channels. And the substrate solution containing 4-aminophenyl phosphate (p-APP) was introduced to the microchannels for the end-column electrochemical detection. The on-chip aptasensor has a broad linear response range of 1–100 pM with a detection limit of 1 pM, which shows high sensitivity and specificity. The system was then applied to detect thrombin in human serum sample. Therefore, the on-chip aptasensor has a great promise for detecting and screening ultratrace levels of biomarkers in the complex matrices.
Co-reporter:Jingjing Wan, Kun Qian, Jun Zhang, Fang Liu, Yunhua Wang, Pengyuan Yang, Baohong Liu and Chengzhong Yu
Langmuir 2010 Volume 26(Issue 10) pp:7444-7450
Publication Date(Web):January 22, 2010
DOI:10.1021/la9041698
The analysis of peptides by the mass spectrometry (MS) technique is important in modern life science. The enrichment of peptides can increase the detection efficiency and is sometimes indispensable for collecting the information on proteins with low-abundance. Herein, we first report that functionalized periodic mesoporous organosilica (PMO) materials have a superior peptide enrichment property. It is demonstrated that the PMO materials with an organo-bridged (−CH2−) hybrid wall composition display a highly enhanced peptide enrichment ability compared to the pure silica material (SBA-15) with similar mesostructured parameters and morphology. More importantly, by surface modification of PMO with amino groups (denoted NH2−PMO), PMO and NH2−PMO with opposite charged surfaces (−25.2 and +39.0 mV, respectively) show selective affinities for positively and negatively charged peptides, respectively. By directly adding PMO, NH2−PMO as well as pure silica materials to the peptides solution with a low concentration (1−2 fmol/μL), 36 and 28 peptides can be detected from the BSA digestion in the presence of PMO and NH2−PMO, respectively, while only 6 and 4 are monitored in the case of SBA-15 enrichment and from solution without enrichment, respectively. Moreover, 69.4% (25 of 36) of enriched peptides by PMO have pI ≥ 6 and 80% (21 of 28) of enriched peptides by NH2−PMO possess pI ≤ 6. Combining the results from the NH2−PMO and PMO enrichment together, 51 peptides can be identified with a MOWSE score of 333. It is also noted that similar conclusions can also be obtained from the peptides solution originated from other proteins. This might be an important contribution to the understanding of the interaction between peptides and porous hosts, and the proposed method is promising for the development of both material science and biotechnology.
Co-reporter:Kun Qian;Jingjing Wan;Xiaodan Huang;Pengyuan Yang ;Chengzhong Yu
Chemistry - A European Journal 2010 Volume 16( Issue 3) pp:822-828
Publication Date(Web):
DOI:10.1002/chem.200902535
Abstract
We have developed a smart nanodevice for the highly efficient and selective detection of glycoproteins. This polyfunctional device is fabricated through the rational functionalization of macroporous silica foam (MOSF) materials with a boron species (B-MOSF) and amino groups (NH2-MOSF), and then the integration of MOSF, B-MOSF and NH2-MOSF materials. In such a device, a macroporous structure with very large-pore sizes (diameters≈100 nm) and high-pore volumes (>0.65 cm3 g−1) is advantageous to efficiently fasten the enzymatic reaction. The targeted specific glycopeptides of the products can be selectively isolated and enriched in B-MOSF through the chemo-affinity between boronic acid and glycol groups, while the non-specific peptides are released to the solutions, or further purified by MOSF and NH2-MOSF, which have opposite charges. As a result, the protein digestion and glycol-peptide isolation can be simultaneously achieved in the functionalized macroporous materials in one step, which is a great advantage compared to conventional multi-procedure and time-consuming techniques.
Co-reporter:Kun Qian;Jingjing Wan;Xiaodan Huang;Pengyuan Yang ;Chengzhong Yu
Chemistry - A European Journal 2010 Volume 16( Issue 3) pp:
Publication Date(Web):
DOI:10.1002/chem.201090001
Co-reporter:Ji Ji, Hui Yang, Yun Liu, Hui Chen, Jilie Kong and Baohong Liu
Chemical Communications 2009 (Issue 12) pp:1508-1510
Publication Date(Web):27 Jan 2009
DOI:10.1039/B820738K
An electrochemical biosensor has been developed for sensitive determination of protein kinase activity and inhibition, taking advantage of specific binding of the phosphate groups with TiO2nanoparticles, on which silver nanoparticles are photo-catalytically deposited to achieve signal enhancement.
Co-reporter:Hongyan Bi, Liang Qiao, Jean-Marc Busnel, Valerie Devaud, Baohong Liu and Hubert H. Girault
Analytical Chemistry 2009 Volume 81(Issue 3) pp:1177
Publication Date(Web):January 12, 2009
DOI:10.1021/ac8024448
Single-use aluminum foil-based laser desorption/ionization (LDI) target plates have been developed for mass spectrometry (MS) analysis and provide detection results comparable to those of commercial stainless steel plates while offering a convenient way to avoid the time-consuming surface cleaning process. Additionally, arrays of TiO2 nanoparticle spots are coated on the foil either by screen-printing or rotogravure-printing followed by sintering to form a mesoporous layer spot to act as an anchor for sample deposition. These TiO2 spots offer further functions to the Al foil, such as matrix-free laser desorption/ionization or specific affinity for in situ enrichment of phosphopeptides. The single-use TiO2−Al foils are cheap to produce, easy to use, and well suited for high-throughput proteomics research. They can also be of interest for protein post-translational modifications study.
Co-reporter:Hui Yang, Ji Ji, Yun Liu, Jilie Kong, Baohong Liu
Electrochemistry Communications 2009 Volume 11(Issue 1) pp:38-40
Publication Date(Web):January 2009
DOI:10.1016/j.elecom.2008.10.024
A sensitive aptamer-based sandwich-type sensor is presented to detect human thrombin using quantum dots as electrochemical label. CdSe quantum dots were labeled to the secondary aptamer, which were determined by the square wave stripping voltammetric analysis after dissolution with nitric acid. The aptasensor has a lower detection limit at 1 pM, while the sample consumption is reduced to 5 μl. The proposed approach shows high selectivity and minimizes the nonspecific adsorption, so that it was used for the detection of target protein in the human serum sample. Such an aptamer-based biosensor provides a promising strategy for screening biomarkers at ultratrace levels in the complex matrices.
Co-reporter:Chunping You, Yan Xuewu, Ying Wang, Song Zhang, Jilie Kong, Dongyuan Zhao, Baohong Liu
Electrochemistry Communications 2009 Volume 11(Issue 1) pp:227-230
Publication Date(Web):January 2009
DOI:10.1016/j.elecom.2008.11.011
Co-reporter:Jingjing Wan;Kun Qian;Liang Qiao;Yunhua Wang ;Jilie Kong ;Pengyuan Yang , ;Chengzhong Yu
Chemistry - A European Journal 2009 Volume 15( Issue 11) pp:2504-2508
Publication Date(Web):
DOI:10.1002/chem.200802079
Co-reporter:Liang Qiao;Hongyan Bi;Jean-Marc Busnel Dr.;Jerome Waser ;Pengyuan Yang ;HubertH. Girault
Chemistry - A European Journal 2009 Volume 15( Issue 27) pp:6711-6717
Publication Date(Web):
DOI:10.1002/chem.200802229
Co-reporter:Kun Qian, Jingjing Wan, Fang Liu, Hubert H. Girault, Baohong Liu and Chengzhong Yu
ACS Nano 2009 Volume 3(Issue 11) pp:3656
Publication Date(Web):October 20, 2009
DOI:10.1021/nn900739z
A phospho-directed nanoreactor with multiple functions is reported. Alumina-functionalized macroporous ordered silica foams (Al-MOSF) have been developed with large pore size, high pore volume (1.6 cm3/g), and a surface area of 186 m2/g rich in coordination unsaturated Al species, which can be used as phospho-directed nanoreactors for integrated in situ digestion and in situ phosphoisolation. By directly adding Al-MOSF to the conventional in-solution digestion system, both enzymes and proteins are quickly enriched in the macropores of the reactor to achieve a fast proteolysis without increasing the enzyme/protein concentration or using a preimmobilization process, thus the digestion time and the cost can be greatly reduced. Meanwhile, due to the chemo-affinity between alumina and phosphor groups, the Al-MOSF reactor can in situ isolate specific products of the enzymatic reaction (i.e., phosphopeptides) and release the nonspecific peptides to the solution. This strategy is simple, efficient, and successfully applied in the detection of phosphoproteins in real samples.Keywords: alumina−silica; digestion; macroporous; nanoreactor; phosphoprotein
Co-reporter:Ying Wang;Chunping You;Song Zhang;Jilie Kong;Jean-Louis Marty
Microchimica Acta 2009 Volume 167( Issue 1-2) pp:
Publication Date(Web):2009 November
DOI:10.1007/s00604-009-0217-4
The electrochemical oxidation of β-nicotinamine adenine dinucleotide (NADH) was investigated at a glassy carbon electrode modified with carbon mesoporous materials (CMM). Due to the large surface area and electro-catalytic properties of CMM, the overpotential of the electrodes toward the oxidation of NADH is decreased by 595 mV in aqueous solution at neutral pH. The anodic peak currents increase steadily with the concentration of NADH in the range from 2 µM to 1.1 mM, the detection limit being 1.0 µM at pH 7.2 and a potential of +0.3 V vs. SCE. The apparent Michaelis-Menten constant is ∼21.5 μM. The results enable NADH to be sensed at a low potential and are promising with respect to the design of dehydrogenase-based amperometric biosensors.
Co-reporter:Chunping You, Xin Xu, Bozhi Tian, Jilie Kong, Dongyuan Zhao, Baohong Liu
Talanta 2009 Volume 78(Issue 3) pp:705-710
Publication Date(Web):15 May 2009
DOI:10.1016/j.talanta.2008.12.032
A strategy of protein entrapment within mesoporous carbon matrices is demonstrated to probe the electrochemistry of glucose oxidase. Large surface area and remarkable electro-catalytic properties of carbon mesoporous materials make them suitable candidates for high loading of protein molecules and the promotion of heterogeneous electron transfer. In this work, two kinds of mesoporous carbon nanocomposite films were designed and prepared with highly ordered two-dimensional (2D) and three-dimensional (3D) structures for the immobilization of glucose oxidase, in which the quasi-reversible electron transfer of the redox enzyme was probed, and the apparent heterogeneous electron transfer rate constants (ket0) are 3.9 and 4.2 s−1, respectively. Furthermore, the associated biocatalytic activity was also revealed. Highly ordered 3D-mesoporous carbon material exhibited larger adsorption capacity for glucose oxidase and the immobilized enzymes retained a higher bioactivity compared with 2D-mesoporous carbons. The preparation of protein-entrapped mesoporous carbon nanocomposites expands the scope of carbon-based electrochemical devices and opens a new avenue for the development of biosensors.
Co-reporter:Chunping You;Xiang Li;Song Zhang;Jilie Kong;Dongyuan Zhao
Microchimica Acta 2009 Volume 167( Issue 1-2) pp:
Publication Date(Web):2009 November
DOI:10.1007/s00604-009-0228-1
A method for immobilizing proteins in a carbon mesoporous material (CMM) containing platinum nanoparticles (Pt-NPs) is demonstrated. Compared to pure CMM or carbon nanotubes, CMM containing Pt-NPs enhances the electron transfer and redox properties of redox enzymes, such as glucose oxidase (GOx), due to a cooperative effect of Pt-NPs and CMM. The quasi-reversible electron transfer of GOx in this system is probed, and the apparent heterogeneous electron transfer rate constants are found to be 66% larger than in pure CMM. The GOx/Pt-CMM based glucose biosensor enables the determination of glucose at a potential of 600 mV (vs. SCE). Its detection limit is 10 times lower, and the sensitivity is 16 times higher than that of the respective biosensor without Pt-NPs.
Co-reporter:Liang Qiao, Hongyan Bi, Jean-Marc Busnel, Baohong Liu and Hubert H. Girault
Chemical Communications 2008 (Issue 47) pp:6357-6359
Publication Date(Web):30 Oct 2008
DOI:10.1039/B813283F
A photosensitive plate based on sintered TiO2nanoparticles has been developed to carry out in-source photo-induced reductions for cleavage of disulfide bridges using glucose as a hole scavenger during laser desorption ionization.
Co-reporter:Huixiang Wang, Sheng Meng, Kai Guo, Yun Liu, Pengyuan Yang, Wei Zhong, Baohong Liu
Electrochemistry Communications 2008 Volume 10(Issue 3) pp:447-450
Publication Date(Web):March 2008
DOI:10.1016/j.elecom.2008.01.005
A sensitive enzyme-linked immunosorbent assay system has been constructed on microfluidic chips. The antibodies (anti-IgG) were encapsulated within the network of Al2O3 sol–gel in the microfluidic channels after the (BMA)x-(MAOPTMS)y copolymer modification. The alumina gel-derived microchannel surface can preserve the bioactivity of antibodies and resist nonspecific adsorption. After the immunoreaction of the antibodies, antigen, and alkaline phosphatase-labeled antibodies, a substrate solution containing 4-aminophenyl phosphate was introduced to the microchannels for end-column electrochemical detection. The microchip immunosensor showed a low detection limit (1 pg mL−1), and broad linear response range (1–500 pg mL−1). The results indicate that this method with high sensitivity and fast response has great potential for clinical and environmental analysis.
Co-reporter:Liang Qiao;Christophe Roussel Dr.;Jingjing Wan;Jilie Kong ;Pengyuan Yang ;HubertH. Girault
Angewandte Chemie 2008 Volume 120( Issue 14) pp:2686-2688
Publication Date(Web):
DOI:10.1002/ange.200703876
Co-reporter:Liang Qiao;Christophe Roussel Dr.;Jingjing Wan;Jilie Kong ;Pengyuan Yang ;HubertH. Girault
Angewandte Chemie International Edition 2008 Volume 47( Issue 14) pp:2646-2648
Publication Date(Web):
DOI:10.1002/anie.200703876
Co-reporter:Xiaoqin Zhou, Tao Yu, Yahong Zhang, Jilie Kong, Yi Tang, Jean-Louis Marty, Baohong Liu
Electrochemistry Communications 2007 Volume 9(Issue 7) pp:1525-1529
Publication Date(Web):July 2007
DOI:10.1016/j.elecom.2007.02.018
A biocompatible surface has been constructed on the electrode surface via layer-by-layer assembly of beta-nanozeolites and polydiallyldimethylammonium (PDDA) for the adsorption of enzymes towards sensitive biosensing. The film assembly process and enzyme adsorption were monitored by Quartz Crystal Microbalance measurements. The nanozeolite film exhibited an amazing adsorption capacity (about 350 mg g−1) for tyrosinase as a model enzyme. The tyrosinase biosensor showed a high sensitivity (400 μA mM−1), short response time (reaching 95% within 5 s), broad linear response range from 10 nM to 18 μM, very low detection limit (0.5 nM) and high operational and storage stability (more than 2 months). The apparent Michaelis–Menten constant KMapp was calculated to be 24 μM using phenol as the substrate. The assembly-controlled nanozeolite film could provide a biocompatible surface for the interaction study between enzymes and target molecules.
Co-reporter:Liang Qiao, Christophe Roussel, Jingjing Wan, Pengyuan Yang, Hubert H. Girault and Baohong Liu
Journal of Proteome Research 2007 Volume 6(Issue 12) pp:4763-4769
Publication Date(Web):November 30, 2007
DOI:10.1021/pr0705284
An on-plate specific enrichment method is presented for the direct analysis of peptides phosphorylation. An array of sintered TiO2 nanoparticle spots was prepared on a stainless steel plate to provide porous substrate with a very large specific surface and durable functions. These spots were used to selectively capture phosphorylated peptides from peptide mixtures, and the immobilized phosphopeptides could then be analyzed directly by MALDI MS after washing away the nonphosphorylated peptides. β-Casein and protein mixtures were employed as model samples to investigate the selection efficiency. In this strategy, the steps of phosphopeptide capture, purification, and subsequent mass spectrometry analysis are all successfully accomplished on a single target plate, which greatly reduces sample loss and simplifies analytical procedures. The low detection limit, small sample size, and rapid selective entrapment show that this on-plate strategy is promising for online enrichment of phosphopeptides, which is essential for the analysis of minute amount of samples in high-throughput proteome research.
Co-reporter:Liang Qiao;Yun Liu Dr.;SarahP. Hudson Dr.;Pengyuan Yang ;Edmond Magner Dr.
Chemistry - A European Journal 2007 Volume 14( Issue 1) pp:151-157
Publication Date(Web):
DOI:10.1002/chem.200701102
Abstract
A nanoreactor based on mesoporous silicates is described for efficient tryptic digestion of proteins within the mesochannels. Cyano-functionalized mesoporous silicate (CNS), with an average pore diameter of 18 nm, is a good support for trypsin, with rapid in situ digestion of the model proteins, cytochrome c and myoglobin. The generated peptides were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Proteolysis by trypsin-CNS is much more efficient than in-solution digestion, which can be attributed to nanoscopic confinement and concentration enrichment of the substrate within the mesopores. Proteins at concentrations of 2 ng μL−1 were successfully identified after digestion for 20 min. A biological complex sample extracted from the cytoplasm of human liver tissue was digested by using the CNS-based reactor. Coupled with reverse-phase HPLC and MALDI-TOF MS/MS, 165 proteins were identified after standard protein data searching. This nanoreactor combines the advantages of short digestion time with retention of enzymatic activity, providing a promising way to advance the development of proteomics.
Co-reporter:Yi Huang, Wei Shan, Baohong Liu, Yun Liu, Yahong Zhang, Yue Zhao, Haojie Lu, Yi Tang and Pengyuan Yang
Lab on a Chip 2006 vol. 6(Issue 4) pp:534-539
Publication Date(Web):28 Feb 2006
DOI:10.1039/B517590A
An enzymatic microreactor has been fabricated based on the poly(methyl methacrylate) (PMMA) microchchip surface-modified with zeolite nanoparticles. By introducing the silanol functional groups, the surface of PMMA microchannel has been successfully modified with silicalite-1 nanoparticle for the first time due to its large external surface area and high dispersibility in solutions. Trypsin can be stably immobilized in the microchannel to form a bioreactor using silica sol–gel matrix. The immobilization of enzyme can be realized with a stable gel network through a silicon–oxygen–silicon bridge via tethering to those silanol groups, which has been investigated by scanning electron microscopy and microchip capillary electrophoresis with laser-induced fluorescence detection. The maximum proteolytic rate constant of the immobilized trypsin is measured to be about 6.6 mM s−1. Using matrix assisted laser desorption and ionization time-of-flight mass spectrometry, the proposed microreactor provides an efficient digestion of cytochrome c and bovine serum albumin at a fast flow rate of 4.0 µL min−1, which affords a very short reaction time of less than 5 s.
Co-reporter:Hongyan Bi, Sheng Meng, Yan Li, Kai Guo, Yupeng Chen, Jilie Kong, Pengyuan Yang, Wei Zhong and Baohong Liu
Lab on a Chip 2006 vol. 6(Issue 6) pp:769-775
Publication Date(Web):31 Mar 2006
DOI:10.1039/B600326E
A protein-resistant surface has been constructed on the poly(methyl methacrylate) (PMMA) microfluidic chips based on a one-step modification. The copolymer of butyl methacrylate (BMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) is synthesized to introduce a dense PEG molecular brush-like coating on the PMMA microchannel surfaces via the anchoring effect of the hydrophobic BMA units. The PEGMA segments could produce hydrophilic domains formed on the interface so as to achieve stable electroosmotic flow, and less nonspecific adsorption toward biomolecules. The modification procedure and the properties of the poly(BMA-co-PEGMA)-coated surface have been characterized by FT-IR spectroscopy, confocal fluorescence microscopy, X-ray photoelectron spectroscopy and scanning electron microscopy. The water contact angle and electroosmotic flow of PEG-modified PMMA microchip are measured to be 36° and 5.4 × 10−4 cm2 V−1 s−1, while those of 73° and 1.9 × 10−4 cm2 V−1 s−1 for native one, respectively. The PEG-modified microchip has been applied for the electrophoresis separation of proteins, corresponding to the theoretical efficiencies about 16300 and 412300 plates m−1. In the interest of achieving efficient separation while minimizing biofoulings from the serum and plasma, the fabrication of PEG-coated microfluidic chips would provide a biocompatible platform for complex biological analysis.
Co-reporter:Yun Liu;Wei Zhong Dr.;Sheng Meng;Jilie Kong ;Haojie Lu Dr.;Pengyuan Yang ;Hubert H. Girault
Chemistry - A European Journal 2006 Volume 12(Issue 25) pp:
Publication Date(Web):26 JUN 2006
DOI:10.1002/chem.200501622
A biocompatible interface was constructed on a microchip by using the layer-by-layer (LBL) assembly of charged polysaccharides incorporating proteases for highly efficient proteolysis. The controlled assembly of natural polyelectrolytes and the enzyme-adsorption step were monitored by using a quartz-crystal microbalance and atomic force microscopy (AFM). Such a multilayer-assembled membrane provides a biocompatible interconnected network with high enzyme-loading capacity. The maximum digestion rate of the adsorbed trypsin in a microchannel was significantly accelerated to 1600 mM min−1 μg−1, compared with the tryptic digestion in solution. Based on the Langmuir isotherm model, the thermodynamic constant of adsorption K was calculated to be 1.6×105 M−1 and the maximum adsorption loading Γmax was 3.6×10−6 mol m−2, 30 times more than a monolayer of trypsin on the native surface. The tunable interface containing trypsin was employed to construct a microchip reactor for digestion of femtomoles of proteins and the produced peptides were analyzed by MALDI-TOF mass spectroscopy. The efficient on-chip proteolysis was obtained within a few seconds, and the identification of biological samples was feasible.
Co-reporter:X. Xu;B.Z. Tian;J.L. Kong;S. Zhang;B.H. Liu;D.Y. Zhao
Advanced Materials 2003 Volume 15(Issue 22) pp:
Publication Date(Web):20 NOV 2003
DOI:10.1002/adma.200305424
Co-reporter:Liang Qiao, Hongyan Bi, Jean-Marc Busnel, Baohong Liu and Hubert H. Girault
Chemical Communications 2008(Issue 47) pp:NaN6359-6359
Publication Date(Web):2008/10/30
DOI:10.1039/B813283F
A photosensitive plate based on sintered TiO2nanoparticles has been developed to carry out in-source photo-induced reductions for cleavage of disulfide bridges using glucose as a hole scavenger during laser desorption ionization.
Co-reporter:Lei Liao, Xiaojun Bian, Jingjing Xiao, Baohong Liu, Micheál D. Scanlon and Hubert H. Girault
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 21) pp:
Publication Date(Web):
DOI:10.1039/C3CP54754J
Co-reporter:Ji Ji, Hui Yang, Yun Liu, Hui Chen, Jilie Kong and Baohong Liu
Chemical Communications 2009(Issue 12) pp:NaN1510-1510
Publication Date(Web):2009/01/27
DOI:10.1039/B820738K
An electrochemical biosensor has been developed for sensitive determination of protein kinase activity and inhibition, taking advantage of specific binding of the phosphate groups with TiO2nanoparticles, on which silver nanoparticles are photo-catalytically deposited to achieve signal enhancement.
Co-reporter:Huiying Xu, Fenghua Geng, Yongxiang Wang, Maotian Xu, Xinhe Lai, Peng Qu, Yintang Zhang and Baohong Liu
Chemical Communications 2015 - vol. 51(Issue 41) pp:NaN8625-8625
Publication Date(Web):2015/04/15
DOI:10.1039/C5CC02624E
A sensitive and selective assay of DNA is developed by utilizing a signal transduction strategy with the rational redesign of the hairpin structured G-quadruplex molecular switch (G4-MS) assembled using auramine O (AO). By monitoring the changes of the fluorescent signal, we could identify and further quantitatively determine the target DNA in the samples.
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