Guoming Xie
Chongqing Medical University
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Publication
Featured researches published by Guoming Xie.
Biosensors and Bioelectronics | 2014
Peng Luo; Yi Liu; Yun Xia; Huajian Xu; Guoming Xie
A sensitive electrochemical biosensor was developed to detect toxin A (TOA) of Clostridium difficile based on an aptamer selected by the systematic evolution of ligands using exponential enrichment and gold nanoparticles (GNPS) synthesized by Bacillus stearothermophilus. The thiolated single-stranded DNA used as the capture probe (CP) was first self-assembled on a Nafion-thionine-GNPS-modified screen-printed electrode (SPE) through an Au-thiol interaction. The horseradish peroxidase (HRP)-labeled aptamer probe (AP) was then hybridized to the complementary oligonucleotide of CP to form an aptamer-DNA duplex. In the absence of TOA, the aptamer-DNA duplex modified the electrode surface with HRP, so that an amperometric response was induced based on the electrocatalytic properties of thionine. This was mediated by the electrons that were generated in the enzymatic reaction of hydrogen peroxide under HRP catalysis. After the specific recognition of TOA, an aptamer-TOA complex was produced rather than the aptamer-DNA duplex, forcing the HRP-labeled AP to dissociate from the electrode surface, which reduced the catalytic capacity of HRP and reduced the response current. The reduction in the response current correlated linearly with the concentration of TOA in the range of 0-200 ng/mL. The detection limit was shown to be 1 nM for TOA. This biosensor was applied to the analysis of TOA and showed good selectivity, reproducibility, stability, and accuracy.
Biosensors and Bioelectronics | 2012
Lingsong Lu; Bei Liu; Zhaohui Zhao; Cuixia Ma; Peng Luo; Chenggui Liu; Guoming Xie
A novel electrochemical immunoassay system for the detection of human epididymis-specific protein 4 (HE4) was developed. A chitosan-titanium carbide (TiC) nanocomposition film was first electrodeposited onto a tin-doped indium oxide (ITO) electrode at a constant potential. Gold (Au) nanoparticles were then electrodeposited on the surface of the chitosan-TiC film by cyclic voltammetry (CV). The capture antibody (anti-HE4) was adsorbed onto the Au and TiC nanoparticles. After a specific sandwich immunoreaction among the capture antibody, HE4, and biotinylated secondary antibody, biotinylated primer DNA was immobilized on the secondary antibody by biotin-streptavidin system. Appropriate amounts of circular template DNA and biotinylated primer DNA were used for rolling circle amplification (RCA) under optimal conditions. The RCA products provided a large number of sites to link DNA detection probes. Doxorubicin hydrochloride intercalated the CG-GC steps between the RCA products and the DNA detection probes, which was monitored by differential pulse voltammetry (DPV) based on the current signal of doxorubicin hydrochloride. With the above-mentioned amplification factors, the current responded to HE4 linearly in the concentration range of 3-300 pM under optimal detection conditions, with a detection limit of 0.06 pM. Stepwise changes in the microscopic features of the surfaces and electrochemical properties upon the formation of each layer were confirmed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical impedance spectroscopy (EIS). This system was successfully employed for the detection of HE4 with good accuracy and renewable ability.
Biosensors and Bioelectronics | 2014
Xiaoying Jing; Xianqing Cao; Li Wang; Tian Lan; Yiyan Li; Guoming Xie
A sensitive and selective electrochemical method was developed for the detection of DNA methylation, determination of DNA methyltransferase (MTase) activity and screening of MTase inhibitor. Methylene blue (MB) was employed as electrochemical indicator and DNA-modified gold nanoparticles (AuNPs) were used as signal amplification unit because the DNA strands in this composite have strong adsorption ability for MB. First, the thiolated single-stranded DNA S1 was self-assembled on gold electrode, hybridization between the lower portion of DNA S1 and its complementary DNA S2 formed an identical double-stranded tetranucleotide target sequence for both DNA adenine methylation (Dam) MTase and methylation-resistant endonuclease Mbo I, then the upper portion of DNA S1 was hybridized with its complementary DNA S3 modified on AuNPs to bring the DNA S3-AuNPs amplification units onto the electrode. The DNA S1/S2/S3-AuNPs bioconjugate has lots of DNA strands, and they can adsorb abundant MB. Mbo I endounuclease could not cleave the identical target sequence after it was methylated by Dam MTase. On the contrary, the sequence without methylation could be cleaved, which would decrease the amount of adsorbed MB. The presence of redox-active MB was detected electrochemically by differential pulse voltammetry (DPV). Thus, the activity of Dam MTase and methylation status were sensitively converted to the DNA S3-AuNPs amplified DPV signals. The DPV signal demonstrated a linear relationship with logarithm of Dam concentration ranging from 0.075 to 30U/mL, achieving a detection limit of 0.02U/mL (S/N=3). Also, screening of Dam MTase inhibitor 5-fluorouracil was successfully investigated using this fabricated sensor.
Biosensors and Bioelectronics | 2014
Chao Song; Guoming Xie; Li Wang; Lingzhi Liu; Guang Tian; Hua Xiang
An ultrasensitive and selective electrochemical immunosensor was developed for the detection of Epstein Barr virus nuclear antigen 1 (EBNA-1). Firstly, a suspension of graphene sheets (GS) and multi-walled carbon nanotubes (MWCNTs) was prepared with the aid of chitosan (CS) solution and then modified on a glassy carbon electrode (GCE). Gold nanoparticles (AuNPs) were then electrodeposited onto the surface of the GS-MWCNTs film by cyclic voltammetry (CV) to immobilize the captured antibodies. After that, specific sandwich immunoreactions were formed among the captured antibody, EBNA-1, and secondary antibody, DNA-coated carboxyl multi-wall carbon nanotubes (DNA-MWCNTs-Ab2). DNA initiator strands (S0) and secondary antibodies linked to the MWCNTs and double-helix DNA polymers were obtained by hybridization chain reaction (HCR), and here S0 on the MWCNTs propagates a chain reaction of hybridization events between two alternating hairpins to form a nicked double-helix. Finally, electroactive indicator doxorubicin hydrochloride was intercalated into the CG-GC steps between the HCR products and could produce an electrochemical signal, which was monitored by differential pulse voltammetry (DPV). Under optimum conditions, the amperometric signal increased linearly with the target concentrations (0.05-6.4ngmL(-1)), and the immunosensor exhibited a detection limit as low as 0.7pgmL(-1) (S/N=3). The proposed method showed acceptable stability and reproducibility, as well as favorable recovery for EBNA-1 in human serum. The proposed immunosensor provides a novel avenue for signal amplification and potential applications in bioanalysis and clinical diagnostics.
Colloids and Surfaces B: Biointerfaces | 2013
Shuting Jiang; Erhui Hua; Bei Liu; Guoming Xie
A novel electrochemical immunosensor for detecting toxoplasma gondii-specific IgM (Tg-IgM) was constructed based on goldmag (Au-Fe(3)O(4)) nanoparticles and graphene sheets (GS). Thionine (Thi), as a mediator, was first electropolymerized on a nafion-GS (Nf-GS) modified electrode. Subsequently, gold nanoparticles (AuNPs) were attached onto the poly-thionine film through π-stacking interactions, and then were used to immobilize toxoplasma gondii antigen (Tg-Ag) for immunosensor fabrication. A sandwich-type immunoassay for Tg-IgM was performed using Au-Fe(3)O(4) labeled anti-IgM-horseradish peroxidase (HRP) as trace label. Electrochemical detection was carried out in the presence of H(2)O(2) as HRP substrate. Using Au-Fe(3)O(4) provided a simple, non-chemical damaging method for regeneration, and enhanced the HRP reduction ability toward H(2)O(2). The AuNPs/Thi/Nf-GS nanocomposite also had good conductivity and biocompatibility, which effectively improved the immunosensor sensitivity. Under optimal conditions, the immunosensor can detect Tg-IgM in two linear ranges from 0.0375 to 1.2 AU mL(-1) and from 2.0 to 18 AU mL(-1) with a detection limit of 0.016 AU mL(-1) (S/N=3). The immunosensor exhibited good reproducibility, stability, and selectivity as well.
Biosensors and Bioelectronics | 2015
Lingzhi Liu; Chao Song; Zhang Zhang; Juan Yang; Lili Zhou; Xing Zhang; Guoming Xie
Measurement of microRNA (miRNA) levels in body fluids is a crucial tool for the early diagnosis and prognosis of cancers. In this study, we developed an electrochemical assay to detect miRNA-21 by fabricating the electrode with layer-by-layer assembly of oxidized single-walled carbon nanotubes and nanodiamonds. Tetrahedron-structured probes with free-standing probe on the top served as receptors to hybridize with target miRNA directly. The probes were immobilized on the deposited gold nanoparticles through a well-established strong Au-S bond. The electrochemical signal was mainly derived from an ultrasensitive pattern by combining hybridization chain reaction with DNA-functionalized AuNPs, which provided DNAzyme to catalyze H2O2 reduction. Differential pulse voltammetry was applied to record the electrochemical signals, which was increased linearly with the target miRNA-21, and the linear detection range was 10 fM to 1.0 nM. The limit of detection reached 1.95 fM (S/N=3), and the proposed biosensor exhibited good reproducibility and stability, as well as high sensitivity. Hence, this biosensor has a promising potential in clinical application.
Biosensors and Bioelectronics | 2016
Huawei Shen; Juan Yang; Zhongping Chen; Xueping Chen; Li Wang; Jing Hu; Feihu Ji; Guoming Xie; Wenli Feng
Circulating tumor cells (CTCs) contain a great deal of information of tumor phenotype. Therefore, highly sensitive detection and specific enrichment of CTCs are of intense interest. Herein, a label-free electrochemical impedance spectroscopy cytosensor with effective surface recognition between specific epithelial cell adhesion molecules (EpCAM) over-expressed on the cell membrane and EpCAM aptamer was developed for the detection of CTCs. After immobilization of 6-mercapto-1-hexanol (MCH) onto the gold electrode, the capture probe can be directionally inserted in MCH interspaces, which can improve the sensitivity of the cytosensor. A wide detection range from 30 to 1×10(6)cellsmL(-1) with a detection limit as low as 10cellsmL(-1) is reached on the condition of acceptable stability and reproducibility. The cytosensor can easily distinguish CTCs from the real blood sample due to the specific combination of EpCAM and EpCAM aptamer. Furthermore, the cytosensor can be reused 8 times and enrich CTCs by Uracil DNA Excision Mix specific cleaving the deoxyuridines (dUs) of the aptamer. The collected CTCs can contribute to further study. Thus, we reported that this cytosensor is a promising technique for the early monitoring and therapy of cancer.
Biosensors and Bioelectronics | 2013
Cuixia Ma; Li Wang; Hua Xiang; Yingtao Jiang; Yiyan Li; Guoming Xie
An ultrasensitive and selective electrochemical immunosensor was developed for the detection of hepatitis C virus (HCV) core antigen. The immunosensor consists of graphitized mesoporous carbon-methylene blue (GMCs-MB) nanocomposite as an electrode modified material and a horseradish peroxidase-DNA-coated carboxyl multi-wall carbon nanotubes (CMWNTs) as a secondary antibody layer. After modification of the electrode with GMCs-MB nanocomposite, Au nanoparticles were electrodeposited on to the electrode to immobilize the captured antibodies. The bridging probe and secondary antibodies linked to the CMWNTs, and DNA concatamers were obtained by hybridization of the biotin-tagged signal and auxiliary probes. Finally, streptavidin-horseradish peroxidases (HRP) were labeled on the secondary antibody layer via biotin-streptavidin system. The reduction current of MB were generated in the presence of hydrogen peroxide and monitored by square wave voltammetry. Under optimum conditions, the amperometric signal increased linearly with the core antigen concentration (0.25pgmL(-1) to 300pgmL(-1)). The immunosensor exhibites the detection limit as low as 0.01pgmL(-1) and it has a high selectivity. The new protocol showed acceptable stability and reproducibility, as well as favorable recovery for HCV core antigen in human serum. The proposed immunosensor has great potential for clinical applications.
Talanta | 2013
Erhui Hua; Li Wang; Xiaoying Jing; Changtao Chen; Guoming Xie
A novel strategy to simplify the dehydrogenase-based electrochemical biosensor fabrication through one-step drop-coating nanobiocomposite on a screen printed electrode (SPE) was developed. The nanobiocomposite was prepared by successively adding graphitized mesoporous carbons (GMCs), meldolas blue (MDB), alcohol dehydrogenase (ADH) and cofactor nicotinamide adenine dinucleotide (NAD(+)) in chitosan (CS) solution. MDB/GMCs/CS film was prepared. Cyclic voltammetry measurements demonstrated that MDB was strongly adsorbed on GMCs. After optimizing the concentration of MDB and the working potential, the MDB/GMCs/CS film presented a fast amperometric response (5s), excellent sensitivity (10.36 nA μM(-1)), wide linear range (10-410 μM) toward NADH and without any other interference signals (such as AA, UA, DA, H2O2 and metal ions). Furthermore, concentrations of ADH and NAD(+) in nanobiocomposite and the detection conditions (temperature and pH) were also optimized. The constructed disposable ethanol biosensor showed an excellent linear response ranged from 0.5 to 15 mM with high sensitivity (67.28 nA mM(-1)) and a low limit of detection (80 μM) and a remarkable long-term stability (40 days). The intra-batch and inter-batch variation coefficients were both less than 5% (n=5). The ethanol recovery test demonstrated that the proposed biosensor offered a remarkable and accurate method for ethanol detection in the real blood samples.
Colloids and Surfaces B: Biointerfaces | 2014
Renni Deng; Li Wang; Guangzhao Yi; Erhui Hua; Guoming Xie
A novel electrochemical aptasensor was developed for ultrasensitive detection of staphylococcal enterotoxin B (SEB) by combining signal amplification and target-induced aptamer release strategy. A gold electrode was modified with a nanocomposite made of gold nanoparticles reduced in situ, zirconia nanoparticles, and chitosan. The SEB aptamer was hybridized by anchoring the capture probe on the modified gold electrode surface through AuS binding. In the presence of SEB, the capture probe-aptamer duplex was compelled to open, releasing the aptamer from the electrode. The resulting single-strand capture probe was hybridized with a biotinylated detection probe and labeled with streptavidin-horseradish peroxidase, producing an ultrasensitive enzyme-catalyzed electrochemical signal. Under optimal conditions, the amperometric responses were proportional to the SEB concentrations ranging from 2 to 512ngmL(-1), with a detection limit of as low as 0.24ngmL(-1) (S/N=3). The aptasensor exhibited good stability, outstanding reproducibility, and high selectivity. The as-prepared aptasensor was used to analyze SEB in human serum specimens, and validated through enzyme-linked immunosorbent assay method. Analytical results suggest that the developed assay is a promising alternative approach for detecting SEB in clinical diagnosis.