Co-reporter:Yong Huang, Jing Zhu, Guiyin Li, Zhencheng Chen, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Biosensors and Bioelectronics 2013 Volume 42() pp:526-531
Publication Date(Web):15 April 2013
DOI:10.1016/j.bios.2012.10.033
In this work, we developed an electrochemical detection method based on allele-specific polymerase chain reaction (AS-PCR) and surface hybridization assay technique for the point mutation detection. A high-fidelity VentR™(exo−) DNA polymerase, which eliminated the 3′→5′ proofreading exonuclease activity by genetical engineering, was used to discriminate and extend the detection probe that perfectly matched with mutant target DNA and generate a redox-active DNA replica which folded into a molecular beacon structure by intramolecular hybridization. After hybridized with capture probe modified on gold electrode by self-assembly reaction, the redox tags can be closed to electrode, resulting in a substantial current with the maximized sensitivity for point mutation analysis. However, when there is an allele mismatch in the wild target DNA, and so no the redox-active replica DNA can be obtained. In this case, no remarkable current signal can be trigged. The proposed approach has been successfully implemented for the identification of single base mutation at the −28 position in human β-globin gene with a detection limit of 0.5 fM, demonstrating that this method provides a highly specific, sensitive and cost-efficient approach for point mutation detection.Highlights► A biphasic architecture of electrochemical point mutation detection technique was developed. ► The redox-active replica DNA can be obtained with allele-specific PCR. ► The redox tags of replica DNA can be closed to electrode surface via surface hybridization. ► The immobilization of capture probes on electrode surface via disulfide anchors. ► This method has been implemented for the detection of single base mutation of human β-globingene.
Co-reporter:Zhan Wu, Hongqi Wang, Min Guo, Li-Juan Tang, Ru-Qin Yu, and Jian-Hui Jiang
Analytical Chemistry 2011 Volume 83(Issue 8) pp:3104
Publication Date(Web):March 25, 2011
DOI:10.1021/ac1033769
Assays of small molecule−protein interactions are of tremendous importance in chemical genetics, molecular diagnostics, and drug development. This work reports a new finding of generalized terminal protection that small molecule-DNA chimeras are protected from degradation by various DNA exonucleases, when the small molecule moieties are bound to their protein targets. This generalization converts small molecule−protein interaction assays into the detection of DNA of various structures, affording a useful mechanism for the analytics of small molecules. On the basis of this mechanism, a label-free biosensor strategy has been developed for a homogeneous assay of protein−small molecule interactions based on the fluorescence staining detection. Also, a label-free SNP genotyping technique is proposed based on polymerase extension of a single nucleotide with a small molecule label. The developed techniques are demonstrated using a model protein−small molecule system of biotin/streptavidin and a model SNP system of human β-globin gene around the position of codon 39. The results revealed that the protein−small molecule interaction assay strategy shows dynamic responses in the concentration range from 0.5 to 100 nM with a detection limit of 0.1 nM, and the SNP typing technique gives dynamic responses in the concentration range from 0.1 to 200 nM with a detection limit of 0.02 nM. Besides desirable sensitivity, the developed strategies also offer high selectivity, excellent reproducibility, low cost, and simplified operations, implying that these techniques may hold considerable potential for molecular diagnostics and genomic research.
Co-reporter:Qiong Zeng;Jinsheng Cheng;Longhua Tang;Xiaofei Liu;Yanzhe Liu;Jinghong Li;Jianhui Jiang
Advanced Functional Materials 2010 Volume 20( Issue 19) pp:3366-3372
Publication Date(Web):
DOI:10.1002/adfm.201000540
Abstract
The self-assembly of sodium dodecyl benzene sulphonate (SDBS) functionalized graphene sheets (GSs) and horseradish peroxidase (HRP) by electrostatic attraction into novel hierarchical nanostructures in aqueous solution is reported. Data from scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction demonstrate that the HRP–GSs bionanocomposites feature ordered hierarchical nanostructures with well-dispersed HRP intercalated between the GSs. UV-vis and infrared spectra indicate the native structure of HRP is maintained after the assembly, implying good biocompatibility of SDBS-functionalized GSs. Furthermore, the HRP–GSs composites are utilized for the fabrication of enzyme electrodes (HRP–GSs electrodes). Electrochemical measurements reveal that the resulting HRP–GSs electrodes display high electrocatalytic activity to H2O2 with high sensitivity, wide linear range, low detection limit, and fast amperometric response. These desirable electrochemical performances are attributed to excellent biocompatibility and superb electron transport efficiency of GSs as well as high HRP loading and synergistic catalytic effect of the HRP–GSs bionanocomposites toward H2O2. As graphene can be readily non-covalently functionalized by “designer” aromatic molecules with different electrostatic properties, the proposed self-assembly strategy affords a facile and effective platform for the assembly of various biomolecules into hierarchically ordered bionanocomposites in biosensing and biocatalytic applications.
Co-reporter:Haixin Chang, Longhua Tang, Ying Wang, Jianhui Jiang and Jinghong Li
Analytical Chemistry 2010 Volume 82(Issue 6) pp:2341
Publication Date(Web):February 24, 2010
DOI:10.1021/ac9025384
Combining nanomaterials and biomolecule recognition units is promising in developing novel clinic diagnostic and protein analysis techniques. In this work, a highly sensitive and specific fluorescence resonance energy transfer (FRET) aptasensor for thrombin detection is developed based on the dye labeled aptamer assembled graphene. Due to the noncovalent assembly between aptamer and graphene, fluorescence quenching of the dye takes place because of FRET. The addition of thrombin leads to the fluorescence recovery due to the formation of quadruplex−thrombin complexes which have weak affinity to graphene and keep the dyes away from graphene surface. Because of the high fluorescence quenching efficiency, unique structure, and electronic properties of graphene, the graphene aptasensor exhibits extraordinarily high sensitivity and excellent specificity in both buffer and blood serum. A detection limit as low as 31.3 pM is obtained based on the graphene FRET aptasensor, which is two orders magnitude lower than those of fluorescent sensors based on carbon nanotubes. The excellent performance of FRET aptasensor based on graphene will also be ascribed to the unique structure and electronic properties of graphene.
Co-reporter:Huan Chen, Qing-Yuan Hu, Yue-Zheng, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Analytica Chimica Acta 2010 Volume 657(Issue 2) pp:204-209
Publication Date(Web):11 January 2010
DOI:10.1016/j.aca.2009.10.036
A novel piezoelelctric biosensor has been developed for cholera toxin (CT) detection based on the analyte-mediated surface-agglutination of ganglioside (GM1)-functionalized liposomes. To achieve a CT-specific agglutination at the surface, the gold electrode is modified by a GM1-functionalized supported lipid membrane via spontaneous spread of the liposomes on a self-assembled monolayer of a long-chain alkanethiol. In the presence of CT, the GM1-incorporated liposomes in assay medium will rapidly specifically agglutinate at the electrode surface through the binding of CT to GM1 on the electrode surface and the liposome interface. This results in an enormous mass loading on the piezoelelctric crystal as well as a significant increase of density and viscosity at the interface, thereby generating a decrease in frequency of the piezoelelctric crystal. The combination of mass loading with interfacial change in the surface-agglutination reaction allows the developed piezoelelctric biosensor to show substantial signal amplification in response to the analyte CT. The detection limit can be achieved as low as 25 ng mL−1 CT. This is the first demonstration on CT detection based on specific surface-agglutination of GM1-modified liposomes. The supported lipid layer based sensing interface can be prepared readily and renewably, making the developed technique especially useful for simple, reusable and sensitive determination of proteins.
Co-reporter:Fenglin Wang, Zhan Wu, Yixia Lu, Jing Wang, Jian-Hui Jiang, Ru-Qin Yu
Analytical Biochemistry 2010 Volume 405(Issue 2) pp:168-173
Publication Date(Web):15 October 2010
DOI:10.1016/j.ab.2010.06.026
A label-free sensor was developed for sensitive detection of lead(II), combining high selectivity of a Pb2+-dependent DNAzyme with enormous signal amplification of quantitative polymerase chain reaction (QPCR). Specifically, a substrate strand was designed to have two primer–hybridization sequences at either terminus. The presence of lead ion (Pb2+) catalyzed cleavage of the substrate strands. This resulted in a concentration decrease of the substrate strand that could be detected by QPCR. Compared with existing DNAzyme-based protocols for Pb2+ assay, this strategy circumvented the use of various optical or electrical labels that might be difficult to be synthesized. Also, the incorporation of QPCR furnished our approach with high sensitivity and superb reproducibility. In addition, QPCR allowed an immediate quantification of the cleavage efficiency that could be useful for evaluation of the DNAzyme activity. The results obtained revealed that our approach exhibited a dynamic response toward Pb2+ within a three-decade concentration range from 10 nM to 5 μM with a detection limit of 1 nM. This approach also demonstrated good selectivity against other metal ions that commonly coexisted with Pb2+.
Co-reporter:Ting Deng, Jishan Li, Liang-Liang Zhang, Jian-Hui Jiang, Jie-Nan Chen, Guo-Li Shen, Ru-Qin Yu
Biosensors and Bioelectronics 2010 Volume 25(Issue 7) pp:1587-1591
Publication Date(Web):15 March 2010
DOI:10.1016/j.bios.2009.11.014
Based on the aptamer-conjugated core–shell near-infrared fluorescent nanoparticles (NIR-Nps) and fluorescence anisotropy measurement, the present study reported proof-of-principle for a rapid homogeneous assay approach that can detect target cancer cells without the need of the complicated separation steps in whole blood samples. Experimental investigation showed that the novel NIR-Nps have negligible background fluorescence and low inner filtration interference in complex biologic systems such as whole blood. The specific recognition characteristic of aptamer in whole blood samples was investigated by using the proposed fluorescence anisotropy method. The results showed that the fluorescent nanoparticle-tagged aptamer probes sequence could achieve specific recognition of the target cancer cells from complex mixtures including whole blood samples. And the reaction conditions for the binding between fluorescent nanoparticle-conjugated aptamer probes and target cancer cells were optimized. The present approach can exhibit sensitive and reproducible fluorescence anisotropy responses to the target cells concentration and the calibration curve showed good linearity when the target cells concentration is in the range from 4.0 × 103 to 7.0 × 105 cells/mL. Moreover, the present fluorescence anisotropy assay technique could be practically utilized for the detection of acute leukemia samples with improved capabilities and be comparable to the immunophenotyping methods clinically used.
Co-reporter:Yanli Zhang, Ying Wang, Haibo Wang, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu and Jinghong Li
Analytical Chemistry 2009 Volume 81(Issue 5) pp:1982
Publication Date(Web):January 27, 2009
DOI:10.1021/ac802512d
This paper describes a novel electrochemical DNA (E-DNA) biosensor for simple, rapid, and specific detection of nucleic acids based on the proximity-dependent surface hybridization assay. This E-DNA biosensor was constructed by self-assembly of a 3′ short thiolated capture probe on the gold electrode. DNA detection was realized by outputting a remarkable redox current of the 5′ ferrocene (Fc) tail labeled probe. When the target DNA was introduced into the system, it was complementary to the 5′ Fc labeled probe at the one-half-segment and complementary to the 3′ short thiolated capture probe at the other half-segment, resulting in forming a stable duplex complex. As a result, the Fc probe was proximate to the electrode surface, and the Faradaic current was observed. This E-DNA biosensor was proved to have a low detection limit (1 fM) and a wide dynamic range (from 1 fM to 1 nM) due to the stable hybridization mode. In addition, the sensing system could discriminate the complementary sequence from mismatch sequences, with high sensitivity, stability, and reusability.
Co-reporter:Si-Jia Liu, Hua-Gui Nie, Jian-Hui Jiang, Guo-Li Shen and Ru-Qin Yu
Analytical Chemistry 2009 Volume 81(Issue 14) pp:5724
Publication Date(Web):June 12, 2009
DOI:10.1021/ac900527f
A novel electrochemical sensor was developed for sensitive and selective detection of mercury(II), based on thymine−Hg2+−thymine (T−Hg2+−T) coordination chemistry. This strategy exploited the cooperativity of proximate poly-T oligonucleotides in coordination with Hg2+. Ferrocene (Fc)-tagged poly-T oligonucleotides were immobilized on the electrode surface via self-assembly of the terminal thiol moiety. In the presence of Hg2+, a pair of poly-T oligonucleotides could cooperatively coordinate with Hg2+, which triggered a conformational reorganization of the poly-T oligonucleotides from flexible single strands to relatively rigid duplexlike complexes, thus drawing the Fc tags away from the electrode with a substantially decreased redox current. The response characteristics of the sensor were thoroughly investigated using capillary electrophoresis and electrochemical measurements. The results revealed that the sensor showed a sensitive response to Hg2+ in a concentration range from 1.0 nM to 2.0 μM, with a detection limit of 0.5 nM. Also, this strategy afforded exquisite selectivity for Hg2+ against a reservoir of other environmentally related metal ions, compared to existing anodic stripping voltammetry (ASV) techniques. In addition, this sensor could be implemented using minimal reagents and working steps with excellent reusability through mild regeneration procedure. It was expected that this cost-effective electrochemical sensor might hold considerable potential in on-site applications of Hg2+ detection.
Co-reporter:Lu Xu, Xiao-Ping Yu, Xiu-Lian Lu, Yi-Hang Wu, Hai-Long Wu, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Analytica Chimica Acta 2009 Volume 644(1–2) pp:25-29
Publication Date(Web):30 June 2009
DOI:10.1016/j.aca.2009.04.030
In the traditional framework of multivariate spectroscopic calibration, the most popular method, partial least squares (PLS), shrinks the regression coefficients based on the information of training sample concentrations. Motivated by the concept of parallel calibration, the second direction for shrinkage of regression coefficients, the direction towards unknown sample spectra is investigated in this paper. A different multivariate calibration method, parallel calibration model based on partial least squares, PCPLS is proposed. With both theoretical support and analysis of some real data sets, it is demonstrated that the second shrinkage direction is at least as natural and necessary as the traditional one. An interesting difference of the proposed method from traditional methods is the involvement of unknown sample spectra and consideration of their error in the training process. Some new related problems and potential applications of this method are also briefly discussed.
Co-reporter:Li-Juan Tang, Wen Du, Hai-Yan Fu, Jian-Hui Jiang, Hai-Long Wu, Guo-Li Shen and Ru-Qin Yu
Journal of Chemical Information and Modeling 2009 Volume 49(Issue 8) pp:2002-2009
Publication Date(Web):July 31, 2009
DOI:10.1021/ci900032q
One problem with discriminant analysis of microarray data is representation of each sample by a large number of genes that are possibly irrelevant, insignificant, or redundant. Methods of variable selection are, therefore, of great significance in microarray data analysis. A new method for key gene selection has been proposed on the basis of interval segmentation purity that is defined as the purity of samples belonging to a certain class in intervals segmented by a mode search algorithm. This method identifies key variables most discriminative for each class, which offers possibility of unraveling the biological implication of selected genes. A salient advantage of the new strategy over existing methods is the capability of selecting genes that, though possibly exhibit a multimodal distribution, are the most discriminative for the classes of interest, considering that the expression levels of some genes may reflect systematic difference in within-class samples derived from different pathogenic mechanisms. On the basis of the key genes selected for individual classes, a support vector machine with block-wise kernel transform is developed for the classification of different classes. The combination of the proposed gene mining approach with support vector machine is demonstrated in cancer classification using two public data sets. The results reveal that significant genes have been identified for each class, and the classification model shows satisfactory performance in training and prediction for both data sets.
Co-reporter:Yan-Ping Zhou, Li-Juan Tang, Jian Jiao, Dan-Dan Song, Jian-Hui Jiang and Ru-Qin Yu
Journal of Chemical Information and Modeling 2009 Volume 49(Issue 5) pp:1144-1153
Publication Date(Web):April 14, 2009
DOI:10.1021/ci800374h
The configuration of classification and regression trees (CART) used to include tree-growing by greedy recursive partitioning, which selects the splitting parameters (i.e., splitting variables and values) involved in tree, and tree-pruning, which aims to obtain a final tree of right size. This method is successful for most applications; however, it presents some well-known limitations and drawbacks, such as, less comprehensibility, inclination to overfitting, and suboptima. In the present study, the modified discrete particle swarm optimization method was invoked to adaptively configure the globally optimal CART (MPSOCART) via simultaneously selecting the optimal splitting parameters in CART and the appropriate structure of CART. A new objective function was formulated to decide the appropriate CART architecture and the optimum splitting parameters. The proposed MPSOCART was applied to predict the bioactivities of flavonoid derivatives and inhibitory activities of inhibitors of epidermal growth factor receptor tyrosine kinase, compared with partial least-squares and CART induced by greedy recursive partitioning. The comparison revealed that MPSO was a useful tool for inducing a globally optimal CART, which converges fast to the optimal solution and avoid overfitting in great extent.
Co-reporter:Xue-Ping Liu, Ya-Juan Deng, Xiao-Yong Jin, Li-Guo Chen, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Analytical Biochemistry 2009 Volume 389(Issue 1) pp:63-68
Publication Date(Web):1 June 2009
DOI:10.1016/j.ab.2009.03.019
A convenient, specific, and highly sensitive electrochemical immunosensor based on an indirect competitive assay format was developed for the determination of ochratoxin A (OTA), a common toxic contaminant in various kinds of agricultural products. The sensing substrate was prepared using a gold electrode modified with a self-assembled monolayer of 1,6-hexanedithiol that mediated the assembly of a gold colloid layer, which could enhance the surface loading of OTA–ovalbumin conjugate and improve the sensitivity in electrochemical readouts. After competition of the limited anti-OTA mouse monoclonal antibody between immobilized hapten and OTA analyte in sample solution, alkaline phosphatase (ALP)-labeled horse anti-mouse immunoglobulin G (IgG) antibody was selectively bound onto the surface of the electrode, affording an indicator for OTA concentration in the sample. Electrochemical response arising from the oxidation of enzymatic product of 1-naphthyl phosphate was observed to be inversely proportional to OTA concentration in the range from 10 pg/ml to 100 ng/ml with a detection limit as low as 8.2 pg/ml. Furthermore, a negligible matrix effect and good recoveries were obtained in the determination of corn samples, evidencing the feasibility of the proposed method for accurate determination of OTA in corn samples.
Co-reporter:Li-Juan Tang, Jian-Hui Jiang, Hai-Long Wu, Guo-Li Shen, Ru-Qin Yu
Talanta 2009 Volume 79(Issue 2) pp:260-267
Publication Date(Web):15 July 2009
DOI:10.1016/j.talanta.2009.03.044
One problem with discriminant analysis of microarray data is representation of each sample by a large number of genes that are possibly irrelevant, insignificant or redundant. Methods of variable selection are, therefore, of great significance in microarray data analysis. To circumvent the problem, a new gene mining approach is proposed based on the similarity between probability density functions on each gene for the class of interest with respect to the others. This method allows the ascertainment of significant genes that are informative for discriminating each individual class rather than maximizing the separability of all classes. Then one can select genes containing important information about the particular subtypes of diseases. Based on the mined significant genes for individual classes, a support vector machine with local kernel transform is constructed for the classification of different diseases. The combination of the gene mining approach with support vector machine is demonstrated for cancer classification using two public data sets. The results reveal that significant genes are identified for each cancer, and the classification model shows satisfactory performance in training and prediction for both data sets.
Co-reporter:Huan Chen, Xiang-Jun Liu, Ya-Li Liu, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Biosensors and Bioelectronics 2009 Volume 24(Issue 7) pp:1955-1961
Publication Date(Web):15 March 2009
DOI:10.1016/j.bios.2008.09.029
MutS protein is an important part of the DNA repair system which can specifically recognize and bind all possible single-base mismatches as well as 1–4 base insertion or deletion loops with varying affinities independent of other proteins or cofactors. In this paper, a new approach for electrochemical gene mutation detection based on the utilization of MutS protein for the mutation recognition and spontaneously intercalated methylene blue (MB) markers for electrochemical signal generation is described. This method involves the immobilization of MutS protein onto the gold electrode, the hybridization of target DNA to form homoduplex or heteroduplex DNA, the application of MutS protein for the mutation recognition, and finally the intercalation of MB. The background is very low because MutS protein binds DNA containing mispaired and unpaired bases but does not bind equally well to DNA without mismatches or single-stranded DNA. The proposed approach has been successfully implemented for the identification of single-base mutation in −28 site of the β-thalassemia gene with a detection limit of 5.6 × 10−13 M, demonstrating that this method provides a highly specific and cost-efficient approach for point mutation detection.
Co-reporter:Bao-Zhu Chi, Qiong Zeng, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Sensors and Actuators B: Chemical 2009 140(2) pp: 591-596
Publication Date(Web):
DOI:10.1016/j.snb.2009.05.025
Co-reporter:Huagui Nie Dr.;Sijia Liu Dr.;Ruqin Yu ;Jianhui Jiang Dr.
Angewandte Chemie International Edition 2009 Volume 48( Issue 52) pp:9862-9866
Publication Date(Web):
DOI:10.1002/anie.200903503
Co-reporter:Huagui Nie Dr.;Sijia Liu Dr.;Ruqin Yu ;Jianhui Jiang Dr.
Angewandte Chemie 2009 Volume 121( Issue 52) pp:10046-10050
Publication Date(Web):
DOI:10.1002/ange.200903503
Co-reporter:Lu Xu, Li-Juan Tang, Chen-Bo Cai, Hai-Long Wu, Guo-Li Shen, Ru-Qin Yu, Jian-Hui Jiang
Analytica Chimica Acta 2008 Volume 613(Issue 2) pp:121-134
Publication Date(Web):21 April 2008
DOI:10.1016/j.aca.2008.02.061
Most traditional chromatographic separation criteria or response functions are defined on chromatograms recorded by single-channel detectors, e.g. a spectrometer measuring the absorbance at a single wavelength or a thermal conductivity detector. When the peaks are seriously overlapped, usually there is a lack of the information concerning the total number of chemical components, overlap degree of the peaks and peak purity. Such information characterizes some crucial aspects of separation process and lack of it will lead to an inaccurate and misleading evaluation of separation quality as well as some computational ambiguity for many traditional response functions. In contrast, hyphenated chromatography–(multi-channel) spectroscopy instruments together with chemometric methods will largely increase the information content available in chromatographic detection. Such information, if properly used, can cast a new light on evaluation of chromatographic separation quality. The main objective of this article is to review chemometric methods devoted to estimation of the number of chemical components, determination of elution sequence and assessment of peak purity. Some newly defined response functions or separation criteria based on extracted information by chemometric methods are also introduced. The methods reviewed are limited to those for treating two-way data obtained by hyphenation of high-performance liquid chromatography with multi-channel detectors. We prefer to provide a comprehensive view of such methods rather than present a full list of all the methods developed. Further details of some important methods are touched upon in favor of employment and understanding of them by researchers not very familiar with chemometrics.
Co-reporter:Lu Xu, Yan-Ping Zhou, Li-Juan Tang, Hai-Long Wu, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Analytica Chimica Acta 2008 Volume 616(Issue 2) pp:138-143
Publication Date(Web):2 June 2008
DOI:10.1016/j.aca.2008.04.031
Preprocessing of raw near-infrared (NIR) spectral data is indispensable in multivariate calibration when the measured spectra are subject to significant noises, baselines and other undesirable factors. However, due to the lack of sufficient prior information and an incomplete knowledge of the raw data, NIR spectra preprocessing in multivariate calibration is still trial and error. How to select a proper method depends largely on both the nature of the data and the expertise and experience of the practitioners. This might limit the applications of multivariate calibration in many fields, where researchers are not very familiar with the characteristics of many preprocessing methods unique in chemometrics and have difficulties to select the most suitable methods. Another problem is many preprocessing methods, when used alone, might degrade the data in certain aspects or lose some useful information while improving certain qualities of the data. In order to tackle these problems, this paper proposes a new concept of data preprocessing, ensemble preprocessing method, where partial least squares (PLSs) models built on differently preprocessed data are combined by Monte Carlo cross validation (MCCV) stacked regression. Little or no prior information of the data and expertise are required. Moreover, fusion of complementary information obtained by different preprocessing methods often leads to a more stable and accurate calibration model. The investigation of two real data sets has demonstrated the advantages of the proposed method.
Co-reporter:Jishan Li, Jian-Hui Jiang, Xiang-Min Xu, Xia Chu, Cheng Jiang, Guoli Shen and Ru-Qin Yu
Analyst 2008 vol. 133(Issue 7) pp:939-945
Publication Date(Web):24 Apr 2008
DOI:10.1039/B717853K
Multiplex single nucleotide polymorphisms analysis has found a great demand in human genetics and pharmacogenetics. The present study reports a novel approach for a genotyping assay that could achieve simultaneous identification of multiple point mutations via a ligase-mediated gold nanoparticle assembly. Based on the allelic specificity of DNA ligase, gold nanoparticles modified by oligonucleotide probes perfectly matched to the DNA targets were assembled into a thermally-stable aggregate, while a single-base mismatch would result in the dissociation of the gold nanoparticle assembly at high temperature. Then, DNA targets and their point mutations could be differentiated using a multi-step temperature elevation analysis monitored by ultraviolet-visible measurements. This approach offered a direct colorimetric discrimination of multiple point mutations without stringent temperature control. The proposed approach is demonstrated using a model system for the identification of single-base mutations in codon 17 and position −28 of the β-thalassemia gene. The results reveal that the wild and the mutant types could be simultaneously determined successfully. Owing to its ease of operation and high specificity, it was expected that the proposed procedure might hold great promise in both research-oriented and clinical genomic assays.
Co-reporter:Yong Huang, Xin-Min Nie, Shao-Long Gan, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Analytical Biochemistry 2008 Volume 382(Issue 1) pp:16-22
Publication Date(Web):1 November 2008
DOI:10.1016/j.ab.2008.07.008
A new method for the determination of platelet-derived growth factor BB (PDGF-BB) was developed using an electrochemical immunosensor with an aptamer-primed, long-strand circular detection probe. Rabbit anti-human PDGF-B polyclonal antibody was immobilized on the electrode to serve as the capture antibody. The detection probe was synthesized via polymerase extension along a single-stranded circular plasmid DNA template with a primer headed by the anti-PDGF-B aptamer. In the presence of the analyte, the aptamer-primed circular probe was captured on the electrode via the formation of an antibody/PDGF-BB/aptamer sandwiched complex. The electroactivity indicator methylene blue was adsorbed on the electrode surface via the analyte-sandwiched complex with long-strand circular DNA, thus yielding a strong electrochemical signal for the quantification of PDGF-BB. This strategy allowed electrochemical detection with enormous signal amplification arising from the long-strand localized circular probe. The oxidation peak current of methylene blue in square wave voltammetric measurements showed a linear dependence on the concentration of PDGF-BB in the range from 50 to 500 ng mL−1, with a detection limit as low as18 pg mL−1.
Co-reporter:Xun Mao, Jianhui Jiang, Xiangmin Xu, Xia Chu, Yan Luo, Guoli Shen, Ruqin Yu
Biosensors and Bioelectronics 2008 Volume 23(Issue 10) pp:1555-1561
Publication Date(Web):15 May 2008
DOI:10.1016/j.bios.2008.01.019
We described a novel electrochemical DNA biosensor based on molecular beacon (MB) probe and enzymatic amplification protocol. The MB modified with a thiol at its 5′ end and a biotin at its 3′ end was immobilized on the gold electrode through mixed self-assembly process. Hybridization events between MB and target DNA cause the conformational change of the MB, triggering the attached biotin group on the electrode surface. Following the specific interaction between the conformation-triggered biotin and streptavidin-horseradish peroxidase (HRP), subsequent quantification of DNA was realized by electrochemical detection of enzymatic product in the presence of substrate. The detection limit is obtained as low as 0.1 nM. The presented DNA biosensor has good selectivity, being able to differentiate between a complementary target DNA sequence and one containing G–G single-base mismatches.
Co-reporter:Yan Luo, Xun Mao, Zhao-Feng Peng, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Talanta 2008 Volume 74(Issue 5) pp:1642-1648
Publication Date(Web):15 February 2008
DOI:10.1016/j.talanta.2007.10.026
A novel, sensitive electrochemical immunoassay in a homogeneously dispersed medium is described herein based on the unique features of agarose beads and the special amplified properties of biometallization. The immunochemical recognition event between human immunoglobulin G (IgG) and goat anti-human IgG antibody is chosen as the model system to demonstrate the proposed immunoassay approach. Avidin-agarose beads rapidly react with the biotinylated goat anti-human IgG antibody to form agarose beads-goat anti-human IgG conjugate (agarose bead-Ab). Agarose bead-Ab, alkaline phosphatase conjugated goat anti-human IgG antibody (ALP-Ab) and the human IgG analyte are mixed to form sandwich-type immunocomplex followed by the addition of the enzymatic silver deposition solution to deposit silver onto the surface of proteins and agarose beads. The silver deposited are dissolved and quantified by anodic stripping voltammetry. The influence of relevant experimental variables was examined and optimized. The logarithm of the anodic stripping peak current depended linearly on the logarithm of the concentration of human IgG in the range from 1 to 1000 ng/ml. A detection limit as low as 0.5 ng/ml human IgG was attained by 3σ-rule. The R.S.D. of the approach is 9.65% for eight times determination of 10 ng/ml human IgG under same conditions. Optical microscope and TEM graphs were also utilized to characterize agarose beads and silver nanoparticles formed.
Co-reporter:Jiwei Chen;Jianhui Jiang ;Xing Gao;Guokun Liu;Guoli Shen ;Ruqin Yu
Chemistry - A European Journal 2008 Volume 14( Issue 27) pp:8374-8382
Publication Date(Web):
DOI:10.1002/chem.200701307
Abstract
The present study reports the proof of principle of a reagentless aptameric sensor based on surface-enhanced Raman scattering (SERS) spectroscopy with “signal-on” architecture using a model target of cocaine. This new aptameric sensor is based on the conformational change of the surface-tethered aptamer on a binding target that draws a certain Raman reporter in close proximity to the SERS substrate, thereby increasing the Raman scattering signal due to the local enhancement effect of SERS. To improve the response performance, the sensor is fabricated from a cocaine-templated mixed self-assembly of a 3′-terminal tetramethylrhodamine (TMR)-labeled DNA aptamer on a silver colloid film by means of an alkanethiol moiety at the 5′ end. This immobilization strategy optimizes the orientation of the aptamer on the surface and facilitates the folding on the binding target. Under optimized assay conditions, one can determine cocaine at a concentration of 1 μM, which compares favorably with analogous aptameric sensors based on electrochemical and fluorescence techniques. The sensor can be readily regenerated by being washed with a buffer. These results suggest that the SERS-based transducer might create a new dimension for future development of aptameric sensors for sensitive determination in biochemical and biomedical studies.
Co-reporter:Yue Zheng, Huan Chen, Xue-Ping Liu, Jian-Hui Jiang, Yan Luo, Guo-Li Shen, Ru-Qin Yu
Talanta 2008 Volume 77(Issue 2) pp:809-814
Publication Date(Web):15 December 2008
DOI:10.1016/j.talanta.2008.07.038
A highly sensitive chemiluminescence immunosensor for the detection of prostate-specific antigen (PSA) was developed based on a novel amplification procedure with the application of enzyme encapsulated liposome. Horseradish peroxidase (HRP) encapsulated and antibody-modified liposome acts as the carrier of a large number of markers and specific recognition label for the amplified detection of PSA. In the detection of PSA, the analyte was first bound to the specific capture antibody immobilized on the microwell plates, and then sandwiched by the antibody-modified liposomes encapsulating HRP. The encapsulated markers, HRP molecules were released by the lysis of the specifically bound liposomes in the microwell with Triton X-100 solution. Then, the analyte PSA could be determined via the chemiluminescence signal of HRP-catalyzed luminol/peroxide/enhancer system. The “sandwich-type” immunoassay provides the amplification route for the PSA detection in ultratrace levels. The CL emission intensity exhibits dynamic correlation to PSA concentration in the range from 0.74 pg/ml to 0.74 μg/ml with readily achievable detection limit of 0.7 pg/ml.
Co-reporter:Yun-Long Zeng, Hao-Wen Huang, Jian-Hui Jiang, Mei-Na Tian, Chun-Xiang Li, Chun-Ran Tang, Guo-Li Shen, Ru-Qin Yu
Analytica Chimica Acta 2007 Volume 604(Issue 2) pp:170-176
Publication Date(Web):5 December 2007
DOI:10.1016/j.aca.2007.09.055
We report the synthesis of a novel looped enzyme–polyamidoamine nanocomposite with high enzyme loading density and long-term retention of bioactivity. The horseradish peroxidase (HRP) is first immobilized on fourth-grade (G4) poly(amidoamine) (PAMAM) dendrimer to form relatively a small enzyme–PAMAM composite, which is allowed to grow up into a larger one. The looped horseradish peroxidase-polyamidoamine (HRP-PAMAM) nanohybrid was characterized by TEM. The material obtained shows promising features as applied to the fabrication of high sensitive and long lifetime biosensors. In the presence of the hydroquinone mediator in the solution, the immobilized HRP exhibited excellent electro-catalytical response to H2O2. Under the optimal conditions, the resulting biosensor showed a linear response to H2O2 over a concentration range from 3.1 × 10−6 to 2.0 × 10−3 mol L−1 with a sensitivity of 0.36 A L mol−1 cm−2 and a detection limit of 8.0 × 10−7 mol L−1. The sensitivity of the sensor response maintained over 70% of the original over 10 weeks. The catalytic activity of the looped enzyme–PAMAM nanohybrid form of HRP enzyme was obviously stabilized. As an extension, bienzyme sensor modified with glucose oxidase and HRP enzymatic PAMAM nanocomposites was constructed. The sensor exhibited improved performance and can be applied to the detection of glucose in real samples.
Co-reporter:Fengli Qu, Aiwu Shi, Minghui Yang, Jianhui Jiang, Guoli Shen, Ruqin Yu
Analytica Chimica Acta 2007 Volume 605(Issue 1) pp:28-33
Publication Date(Web):12 December 2007
DOI:10.1016/j.aca.2007.10.013
Prussian blue nanowire array (PBNWA) was prepared via electrochemical deposition with polycarbonate membrane template for effective modification of glassy carbon electrode. The PBNWA electrode thus obtained was demonstrated to have high-catalytic activity for the electrochemical reduction of hydrogen peroxide in neutral media. This enabled the PBNWA electrode to show rapid response to H2O2 at a low potential of −0.1 V over a wide range of concentrations from 1 × 10−7 M to 5 × 10−2 M with a high sensitivity of 183 μA mM−1 cm−2. Such a low-working potential also substantially improved the selectivity of the PBNWA electrode against most electroactive species such as ascorbic acid and uric acid in physiological media. A detection limit of 5 × 10−8 M was obtained using the PBNWA electrode for H2O2, which compared favorably with most electroanalysis procedures for H2O2. A biosensor toward glucose was then constructed with the PBNWA electrode as the basic electrode by crosslinking glucose oxidase (GOx). The glucose biosensor allowed rapid, selective and sensitive determination of glucose at −0.1 V. The amperometric response exhibited a linear correlation to glucose concentration through an expanded range from 2 × 10−6 M to 1 × 10−2 M, and the response time and detection limit were determined to be 3 s and 1 μM, respectively.
Co-reporter:Hideyuki Shinzawa, Jian-Hui. Jiang, Makio Iwahashi, Isao Noda, Yukihiro Ozaki
Analytica Chimica Acta 2007 Volume 595(1–2) pp:275-281
Publication Date(Web):9 July 2007
DOI:10.1016/j.aca.2006.12.004
Particle swarm optimization (PSO) combined with alternating least squares (ALS) is introduced to self-modeling curve resolution (SMCR) in this study for effective initial estimate. The proposed method aims to search concentration profiles or pure spectra which give the best resolution result by PSO. SMCR sometimes yields insufficient resolution results by getting trapped in a local minimum with poor initial estimates. The proposed method enables to reduce an undesirable effect of the local minimum in SMCR due to the advantages of PSO. Moreover, a new criterion based on global phase angle is also proposed for more effective performance of SMCR. It takes full advantage of data structure, that is to say, a sequential change with respect to a perturbation can be considered in SMCR with the criterion. To demonstrate its potential, SMCR by PSO is applied to concentration-dependent near-infrared (NIR) spectra of mixture solutions of oleic acid (OA) and ethanol. Its curve resolution performances are compared with SMCR with evolving factor analysis (EFA). The results show that SMCR by PSO yields significantly better curve resolution performances than those by EFA. It is revealed that SMCR by PSO is less sensitive to a local minimum in SMCR and it can be a new effective tool for curve resolution analysis.
Co-reporter:Yun-Long Zeng, Yu-Fang Huang, Jian-Hui Jiang, Xiao-Bing Zhang, Chun-Ran Tang, Guo-Li Shen, Ru-Qin Yu
Electrochemistry Communications 2007 Volume 9(Issue 1) pp:185-190
Publication Date(Web):January 2007
DOI:10.1016/j.elecom.2006.08.052
By grafting with poly(amidoamine) (PAMAM) dendrimer, novel carbon nanotube (CNT) nano-composites have been successfully prepared. The novel functionalized matrix with plenty amino groups circumvents the troublesome solubility problem of CNTs in solvents, especially in water, greatly expanding the scope of the application of carbon nanotubes. The GOx and HRP immobilized CNT-PAMAM based on the functional CNTs was synthesized. The bi-enzymatic CNT-PAMAM nano-composites are highly dispersible in water and show very promising applications in the fabrication of mediator-free bi-enzymatic biosensors for sensitive detection of glucose. The cooperation of nano-composite between CNT and high dense GOx and HRP results in very high sensitivity to glucose with a current response of 2200 nA mM−1 and fast response (∼1 s). The modified electrode exhibits a wide linear response range for glucose from 4.0 μM to 1.2 mM (R = 0.9971, N = 15), with a detection limit of 2.5 μM. The negative electrode potential of −0.34 V is favorable for glucose detection in real samples without interference caused by other biomolecules.
Co-reporter:Yan-Ping Zhou, Chen-Bo Cai, Shi Huan, Jian-Hui Jiang, Hai-Long Wu, Guo-Li Shen, Ru-Qin Yu
Analytica Chimica Acta 2007 Volume 593(Issue 1) pp:68-74
Publication Date(Web):12 June 2007
DOI:10.1016/j.aca.2007.04.031
In the current study, robust boosting partial least squares (RBPLS) regression has been proposed to model the activities of a series of 4H-1,2,4-triazoles as angiotensin II antagonists. RBPLS works by sequentially employing PLS method to the robustly reweighted versions of the training compounds, and then combing these resulting predictors through weighted median. In PLS modeling, an F-statistic has been introduced to automatically determine the number of PLS components. The results obtained by RBPLS have been compared to those by boosting partial least squares (BPLS) repression and partial least squares (PLS) regression, showing the good performance of RBPLS in improving the QSAR modeling. In addition, the interaction of angiotensin II antagonists is a complex one, including topological, spatial, thermodynamic and electronic effects.
Co-reporter:Ting Deng Dr.;Jishan Li Dr. Dr.;Guo-Li Shen ;Ru-Qin Yu
Chemistry - A European Journal 2007 Volume 13(Issue 27) pp:
Publication Date(Web):2 JUL 2007
DOI:10.1002/chem.200700195
The present study reports a proof-of-principle for a sensitive genotyping assay approach that can detect single nucleotide polymorphisms (SNPs) based on fluorescence anisotropy measurements through a core–shell fluorescent nanoparticles assembly and ligase reaction. By incorporating the core–shell fluorescent nanoparticles into fluorescence anisotropy measurements, this assay provided a convenient and sensitive detection assay that enabled straightforward single-base discrimination without the need of complicated operational steps. The assay was implemented via two steps: first, the hybridization reaction that allowed two nanoparticle-tagged probes to hybridize with the target DNA strand and the ligase reaction that generated the ligation between perfectly matched probes while no ligation occurred between mismatched ones were implemented synchronously in the same solution. Then, a thermal treatment at a relatively high temperature discriminated the ligation of probes. When the reaction mixture was heated to denature the duplex formed, the fluorescence anisotropy value of the perfect-match solution does not revert to the initial value, while that of the mismatch again comes back as the assembled fluorescent nanoparticles dispart. The present approach has been demonstrated with the discrimination of a single base mutation in codon 12 of a K-ras oncogene that is of significant value for colorectal cancers diagnosis, and the wild type and mutant type were successfully scored. Due to its ease of operation and high sensitivity, it was expected that the proposed detection approach might hold great promise in practical clinical diagnosis.
Co-reporter:Xun Mao, Jianhui Jiang, Yan Luo, Guoli Shen, Ruqin Yu
Talanta 2007 Volume 73(Issue 3) pp:420-424
Publication Date(Web):30 September 2007
DOI:10.1016/j.talanta.2007.04.004
We demonstrate herein a novel electrochemical protocol for quantification of human IgG based on the precipitation of copper on gold nanoparticle tags and a subsequent electrochemical stripping detection of the dissolved copper. The immunoassay was conducted by following the typical procedure for sandwich-type immunoreaction. Goat anti-human IgG was immobilized on the wells of microtiter plates. The human IgG analyte was first captured by the primary antibody and then sandwiched by secondary antibody labeled with gold nanoparticles. The copper enhancer solution was then added to deposite copper on the gold nanoparticle tags. After dissolved with HNO3, the released copper ions were then quantified by ASV. The detection limit is 0.5 ng/mL by 3σ-rule. In order to investigate the feasibility of the newly developed technique to be applied for clinical analysis, several standard human IgG serum specimens were also examined by the method. To our knowledge, the copper enhancing procedure is the first time to be developed for immunoassay. The new strategy of using copper-enhanced gold nanoparticle tags for electrochemical stripping detection holds great promise for immunoassay and DNA detection.
Co-reporter:Yi Liang, Ji-Lai Gong, Yong Huang, Yue Zheng, Jian-Hui Jiang, Guo-Li Shen, Ru-Qin Yu
Talanta 2007 Volume 72(Issue 2) pp:443-449
Publication Date(Web):30 April 2007
DOI:10.1016/j.talanta.2006.11.002
A novel, highly selective DNA hybridization assay has been developed based on surface-enhanced Raman scattering (SERS) for DNA sequences related to HIV. This strategy employs the Ag/SiO2 core-shell nanoparticle-based Raman tags and the amino group modified silica-coated magnetic nanoparticles as immobilization matrix and separation tool. The hybridization reaction was performed between Raman tags functionalized with 3′-amino-labeled oligonucleotides as detection probes and the amino group modified silica-coated magnetic nanoparticles functionalized with 5′-amino-labeled oligonucleotides as capture probes. The Raman spectra of Raman tags can be used to monitor the presence of target oligonucleotides. The utilization of silica-coated magnetic nanoparticles not only avoided time-consuming washing, but also amplified the signal of hybridization assay. Additionally, the results of control experiments show that no or very low signal would be obtained if the hybridization assay is conducted in the presence of DNA sequences other than complementary oligonucleotides related to HIV gene such as non-complementary oligonucleotides, four bases mismatch oligonucleotides, two bases mismatch oligonucleotides and even single base mismatch oligonucleotides. It was demonstrated that the method developed in this work has high selectivity and sensitivity for DNA detection related to HIV gene.
Co-reporter:Yan-Ping Zhou, Jian-Hui Jiang, Wei-Qi Lin, Lu Xu, Hai-Long Wu, Guo-Li Shen, Ru-Qin Yu
Talanta 2007 Volume 71(Issue 2) pp:848-853
Publication Date(Web):15 February 2007
DOI:10.1016/j.talanta.2006.05.058
Co-reporter:T. Deng;J.-S. Li;J.-H. Jiang;G.-L. Shen;R.-Q. Yu
Advanced Functional Materials 2006 Volume 16(Issue 16) pp:
Publication Date(Web):19 SEP 2006
DOI:10.1002/adfm.200600149
A class of novel core/shell near-IR fluorescent nanoparticles have been prepared through co-hydrolysis of a hydrophobic silicon alkoxide, hexadecyltrimethoxysilane, and tetraethyl orthosilicate as the dye-doped core, followed by the formation of a hydrophilic shell via hydrolysis of tetraethyl orthosilicate in a water-in-oil microemulsion. The co-hydrolysis of hexadecyltrimethoxysilane and tetraethyl orthosilicate produces a highly hydrophobic core for the entrapment of a low-cost near-IR fluorescence dye, methylene blue. Experimental investigation of this particular core/shell nanoparticle in comparison with conventional dye-doped silica nanoparticles demonstrates that the hydrophobic core enables the doped dye to exhibit enhanced fluorescence and show improved stability to dye leaching and exogenous quenchers. In contrast to rhodamine B doped silica nanoparticles, the near-IR fluorescent nanoparticles also show negligible background fluorescence and low inner-filtration interference in complex biological systems such as whole blood. This advantage is utilized for the development of an immunoagglutination assay method based on fluorescence-anisotropy measurement for the detection of alpha fetoprotein (AFP) in whole-blood samples. The results reveal that increase in fluorescence anisotropy is linearly correlated with AFP concentration in the range 1.9–51.9 ng mL–1.
Co-reporter:Ji-Lai Gong, Jian-Hui Jiang, Hai-Feng Yang, Guo-Li Shen, Ru-Qin Yu, Yukihiro Ozaki
Analytica Chimica Acta 2006 Volume 564(Issue 2) pp:151-157
Publication Date(Web):6 April 2006
DOI:10.1016/j.aca.2006.01.055
An approach to prepare novel glass-coated gold core-shell nanoparticles embedded with Raman active molecules has been developed. This strategy eliminates the need of a coupling agent and enables efficient embedding of most of commercially available Raman active dyes, even those with weak affinity to a gold surface. Our experiments have demonstrated the hypothesis that the glass encapsulation chemistry is based on the reaction between silanol groups hydrolyzed by TEOS and citrate anion groups adsorbed onto the gold nanoparticles leading to the formation of a silica layer through further reaction with silanol groups of other hydrolyzed TEOS. Furthermore, it has been demonstrated the potential of these novel nanoparticls as Raman tags in ultrasensitive immunoassays for human IgG antigen with a detection limit of 4.9 ng/ml.
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