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Chang K.,Chongqing Medical University | Pi Y.,Chongqing Medical University | Lu W.,Chongqing Medical University | Wang F.,Chongqing Medical University | And 6 more authors.
Biosensors and Bioelectronics | Year: 2014

A label-free and high-sensitive sensing technology for tumor cell recognition and detection was developed based on a novel 2×3 model of leaky surface acoustic wave (LSAW) aptasensor array. In this methodology, every resonator crystal unit of the LSAW aptasensor array had an individual oscillator circuit to work without mutual interference, and could oscillate independently with the phase shift stability of ±0.15° in air phase and ±0.3° in liquid phase. The aptamer was firstly assembled to the gold electrode surface of 100MHz LiTaO3 piezoelectric crystal, which could effectively captured target cells (MCF-7 cells) based on the specific interaction between aptamer and the overexpression of MUC1 protein on tumor cell surface. The aptamer-cell complexes increased the mass loading of LSAW aptasensor and led to phase shifts of LSAW. The plot of phase shift against the logarithm of concentration of MCF-7 cells was linear over the range from 1×102cellsmL-1 to 1×107cellsmL-1 with a correlation coefficient of 0.994. The detection limit as low as 32cellsmL-1 was achieved for MCF-7 cells. The LSAW aptasensor also exhibited excellent specificity and stability. In addition, this aptasensor could be regenerated for ten times without irreversible loss of activity. Therefore, the LSAW aptasensor may offer a promising approach for tumor cell detection and have great potential in clinical applications. © 2014 Elsevier B.V.


Chang K.,Chongqing Medical University | Wang F.,Chongqing Medical University | Ding Y.,Chinese Electronic Scientific and Technical Group Company | Pan F.,Chongqing Medical University | And 6 more authors.
Biosensors and Bioelectronics | Year: 2014

This manuscript described a novel 2×3 model of leaky surface acoustic wave (LSAW) immunosensor array for label-free and high-sensitive detection of Cyclosporin A (CsA) in whole-blood samples. In this technique, every resonator crystal unit of the LSAW immunosensor array had an individual oscillator circuit to work without mutual interference. The LSAW immunosensor was first immobilized with protein A from Staphylococcus aureus and monoclonal anti-CsA antibody on the gold electrode surface of 100MHz LiTaO3 piezoelectric crystals, which then captured the CsA. The CsA increased the mass loading of LSAW immunosensor and leaded to phase shifts of LSAW. Consequently, under optimal conditions, the designed LSAW immunosensor exhibited a detection limit of 0.89ng/mL, quantification limit of 2.96ng/mL, and wide dynamic linear range from 1ng/mL to 1000ng/mL for CsA detection. Application of the LSAW immunosensor array to clinical sample revealed that consistency and comparability between LSAW immunosensor and the enzyme multiplied immunoassay method were good. Moreover, the immunosensor could be regenerated for ten times without appreciable loss of activity. Therefore, the self-designed LSAW immunosensor array provided a rapid, accurate, label-free, easy handling, and dynamic real-time method for the detection of immunosuppressive drugs in clinical laboratory.© 2013 Elsevier B.V.


Zhang L.,Chongqing Medical University | Wang Y.,Chongqing Medical University | Wang J.,Chongqing Medical University | Shi J.,Chinese Electronic Scientific and Technical Group Company | And 2 more authors.
Biosensors and Bioelectronics | Year: 2013

This research established a non-labeled electrochemical biosensor for discrimination of recombinant human erythropoietin (rhEPO) and endogenous erythropoietin (EPO). We prepared a glassy carbon electrode (GCE) modified by a unique sandwich-like nano-Au/ZnO sol-gel/nano-Au compound membrane for signal amplification. The porous sol-gel structure facilitates protein activity maintenance and thermostability. Nano-Au is characterized by a large specific surface area, high surface activity, high absorbability, and good electro-conductivity and biocompatibility. By combining the advantages of both ZnO sol-gel and nano-Au, the amount of erythropoietin receptor (EPOR) increased substantially, and electron transfer of EPOR protein and electrode surface increased accordingly. In the present study, the effects of experimental conditions such as nano-Au electrodeposition time and nano-Au concentration were investigated by cyclic voltammetry, and the process of GCE modification was characterized electrochemically. We successfully developed a new method for electrochemical detection of trace rhEPO/EPO. More importantly, the response current change (δ. I) of the nano-Au/ZnO sol-gel/nano-Au modified GCE increases 3-fold when compared with that of the unmodified electrode and the sensor detection sensitivity increases significantly. In conclusion, this electrochemical biosensor is simple to prepare and allows fast, accurate, and specific detection of trace rhEPO in clinical monitoring and stimulant discrimination. © 2013 Elsevier B.V.


Xu Q.,Chongqing Medical University | Chang K.,Chongqing Medical University | Lu W.,Chongqing Medical University | Chen W.,Chongqing Medical University | And 8 more authors.
Biosensors and Bioelectronics | Year: 2012

This manuscript describes a new technique for detecting single-nucleotide polymorphisms (SNPs) by integrating a leaky surface acoustic wave (LSAW) biosensor, enzymatic DNA ligation and enzymatic signal amplification. In this technique, the DNA target is hybridized with a capture probe immobilized on the surface of a LSAW biosensor. Then, the hybridized sequence is ligated to biotinylated allele-specific detection probe using Taq DNA ligase. The ligation does not take place if there is a single-nucleotide mismatch between the target and the capture probe. The ligated detection probe is transformed into a streptavidin-horseradish peroxidase (SA-HRP) terminal group via a biotin-streptavidin complex. Then, the SA-HRP group catalyzes the polymerization of 3,3-diaminobenzidine (DAB) to form a surface precipitate, thus effectively increasing the sensitivity of detecting surface mass changes and allowing detection of SNPs. Optimal detection conditions were found to be: 0.3mol/L sodium ion concentration in PBS, pH 7.6, capture probe concentration 0.5μmol/L and target sequence concentration 1.0μmol/L. The detection limit was found to be 1×10 -12mol/L. Using this technique, we were able to detect a single-point mutation at nucleotide A2293G in Japanese encephalitis virus. © 2011 Elsevier B.V.


PubMed | Chongqing Medical University and Chinese Electronic Scientific and Technical Group Company
Type: | Journal: Biosensors & bioelectronics | Year: 2014

This manuscript described a novel 23 model of leaky surface acoustic wave (LSAW) immunosensor array for label-free and high-sensitive detection of Cyclosporin A (CsA) in whole-blood samples. In this technique, every resonator crystal unit of the LSAW immunosensor array had an individual oscillator circuit to work without mutual interference. The LSAW immunosensor was first immobilized with protein A from Staphylococcus aureus and monoclonal anti-CsA antibody on the gold electrode surface of 100 MHz LiTaO3 piezoelectric crystals, which then captured the CsA. The CsA increased the mass loading of LSAW immunosensor and leaded to phase shifts of LSAW. Consequently, under optimal conditions, the designed LSAW immunosensor exhibited a detection limit of 0.89 ng/mL, quantification limit of 2.96 ng/mL, and wide dynamic linear range from 1 ng/mL to 1000 ng/mL for CsA detection. Application of the LSAW immunosensor array to clinical sample revealed that consistency and comparability between LSAW immunosensor and the enzyme multiplied immunoassay method were good. Moreover, the immunosensor could be regenerated for ten times without appreciable loss of activity. Therefore, the self-designed LSAW immunosensor array provided a rapid, accurate, label-free, easy handling, and dynamic real-time method for the detection of immunosuppressive drugs in clinical laboratory.


PubMed | Chongqing Medical University and Chinese Electronic Scientific and Technical Group Company
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2016

Staphylococcus epidermidis is a critical pathogen of nosocomial blood infections, resulting in significant morbidity and mortality. A piezoelectric quartz crystal microbalance (QCM) nucleic acid biosensor array using Au nanoparticle signal amplification was developed to rapidly detect S. epidermidis in clinical samples. The synthesized thiolated probes specific targeting S. epidermidis 16S rRNA gene were immobilized on the surface of QCM nucleic acid biosensor arrays. Hybridization was induced by exposing the immobilized probes to the PCR amplified fragments of S. epidermidis, resulting in a mass change and a consequent frequency shift of the QCM biosensor. To further enhance frequency shift results from above described hybridizations, streptavidin coated Au nanoparticles were conjugated to the PCR amplified fragments. The results showed that the lowest detection limit of current QCM system was 1.310 CFU/mL. A linear correlation was found when the concentration of S. epidermidis varied from 1.310 to 1.310

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