[Show abstract][Hide abstract] ABSTRACT: Recently, there have been a number of studies on the association between cyclin D1 G870A polymorphism and nasopharyngeal carcinoma risk. However, the results of previous reports remain controversial and ambiguous. Thus, we performed a meta-analysis to explore more precisely the association between cyclin D1 G870A polymorphism and the risk of nasopharyngeal carcinoma. No significant association was found between cyclin D1 G870A polymorphism and nasopharyngeal carcinoma risk in total population analysis. In the subgroup meta-analysis by ethnicity, a negative association was shown in Caucasian subgroup, and no significant association in any genetic models among Asians was observed. In summary, positive results have been shown on the search for polymorphic variants influencing the risk of NPC. This meta-analysis provides evidence of the association between CCND1 G870A polymorphism and NPC risk, supporting the hypothesis that CCND1 870A allele probably acts as an important NPC protective factor in Caucasians but not in Asians. Since the results of our meta-analysis are preliminary and may be biased by the relatively small number of subjects, they still need to be validated by well-designed studies using larger samples in the future.
Preview · Article · Oct 2013 · The Scientific World Journal
[Show abstract][Hide abstract] ABSTRACT: Poly(3,4-ethylendioxythiophene) (PEDOT) films have been electrochemically polymerized on graphene (GR) modified glassy carbon electrode (GCE) simply by a one-step cyclic voltammetry (CV) method in an aqueous media in the absence of any surfactant. The PEDOT/GR composite films were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). This composite film provided an excellent platform for immobilization of antibody with good bioactivity, and conductivity through Au nanoparticles (AuNPs) as a linker. With a sandwich-type immunoassay format, the analyte and then the CdTe quantum dots coated carbon nanosphere (CNS@CdTe)-labeled antibody were successively bound to the immunosensor. The dual-amplification strategy greatly enhanced the sensitivity for point-of-care testing (POCT) of prostate-specific antigen (PSA). Under optimal conditions, the proposed method could detect PSA with a linear range of 0.001–10 ng mL−1 and a detection limit down to 0.8 pg mL−1. The assay results of PSA in clinical serum samples from the Tumor Hospital were in acceptable agreement with the reference values from enzyme-linked immunosorbent assay. The proposed ECL immunosensor exhibited high sensitivity and stability, and could be applied in POCT of other tumor markers for remote regions and developing countries.
No preview · Article · May 2013 · Journal of Inorganic and Organometallic Polymers and Materials
[Show abstract][Hide abstract] ABSTRACT: A facile and ultrasensitive electrochemiluminescent (ECL) immunosensor for detection of prostate-specific antigen (PSA) was designed by using CdTe quantum dots coated silica nanoparticles (SiO2@QDs) as bionanolabels. To construct such an electrochemiluminescence immunosensor, gold nanoparticles-dotted graphene composites were immobilized on the working electrode, which can increase the surface area to capture a large amount of primary antibodies as well as improve the electronic transmission rate. The as-prepared SiO2@QDs used as bionanolabels, showed good ECL performance and good ability of immobilization for secondary antibodies. The approach provided a good linear response ranging from 0.005 to 10 ng mL(-1) with a low detection limit of 0.0032 ng mL(-1). Such immunosensor showed good precision, acceptable stability, and reproducibility. Satisfactory results were obtained for determination of PSA in human serum samples. Therefore, the proposed method provides a new promising platform of clinical immunoassay for other biomolecules.
No preview · Article · Mar 2013 · Analytical and Bioanalytical Chemistry
[Show abstract][Hide abstract] ABSTRACT: A molecular imprinted polymer thin film for photoelectrochemical (PEC) sensing of chlorpyrifos molecules was first constructed by electropolymerizing the o-phenylenediamine (o-PD) monomer and chlorpyrifos template molecule on gold nanoparticles-modified titanium dioxide nanotubes. The resulting PEC sensors were characterized by scanning electron microscopy, ultraviolet (UV)-vis spectra and electrochemical impedance spectra. Clearly, the imprinted film showed high selectivity to chlorpyrifos in our case. Under visible light irradiation, poly(o-phenylenediamine) (PoPD) can generate the photoelectric transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), delivering the excited electrons to the AuNPs, and then to the conduction band (CB) of the titanium dioxide nanotubes (TiO(2) NTs). Simultaneously, it is believed that a positively charged hole (h(+)) of PoPD that took part in the oxidation process was consumed to promote the amplification of photocurrent response. Under the optimal experimental conditions, the photocurrents were proportional to the concentrations of chlorpyrifos ranging from 0.05 to 10 μmol L(-1) with the detection limit of 0.96 nmol L(-1). The PEC sensor had an excellent specificity and could be successfully applied to the detection of reduced chlorpyrifos in green vegetables, indicating a promising application in PEC sensing.
[Show abstract][Hide abstract] ABSTRACT: A low-cost, portable rechargeable battery was firstly used to fabricate a battery-triggered, screen-printed two-electrode electrochemiluminescent immunoassay on a 3D microfluidic origami electronic device.
No preview · Article · Sep 2012 · Chemical Communications
[Show abstract][Hide abstract] ABSTRACT: An ultrasensitive electrochemiluminescence (ECL) immunosensor was developed using PtAg@carbon nanocrystals (CNCs) as excellent labels based on carbon nanotubes-chitosan/AuNPs (CNT-CHIT/AuNPs) composite modified screen-printed carbon electrodes (SPCEs) for prostate protein antigen (PSA) detection. The CNCs were obtained simply by electro-oxidation of graphite with abundant carboxyl groups at their surfaces. The PtAg bimetallic nanocomposites with hierarchically hollow structures were fabricated through simple replacement reaction using dealloyed nanoporous silver (NPS) as both a template and reducing agent. Structure characterization was obtained by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) images. The PtAg@CNCs composites exhibit a 6 times higher ECL intensity than the pure CNCs labeled anti-PSA. The as-prepared CNT-CHIT/AuNPs composite can attach more antibody than pure CNTs. Due to the dual-amplification techniques, the concentrations of PSA were obtained in the range from 1 pg mL(-1) to 50 ng mL(-1) with a detection limit of 0.6 pg mL(-1). Finally, the as-proposed ECL immunosensor has the advantages of high sensitivity, specificity and stability and could become a promising technique for tumor marker detection.