Article

Graphene-based immunosensor for electrochemical quantification of phosphorylated p53 (S15)

Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, PR China.
Analytica chimica acta (Impact Factor: 4.51). 08/2011; 699(1):44-8. DOI: 10.1016/j.aca.2011.05.010
Source: PubMed

ABSTRACT

We reported a graphene-based immunosensor for electrochemical quantification of phosphorylated p53 on serine 15 (phospho-p53(15)), a potential biomarker of gamma-radiation exposure. The principle is based on sandwich immunoassay and the resulting immunocomplex is formed among phospho-p53 capture antibody, phospho-p53(15) antigen, biotinylated phospho-p53(15) detection antibody and horseradish peroxidase (HRP)-labeled streptavidin. The introduced HRP results in an electrocatalytic response to reduction of hydrogen peroxide in the presence of thionine. Graphene served as sensor platform not only promotes electron transfer, but also increases the surface area to introduce a large amount of capture antibody, thus increasing the detection sensitivity. The experimental conditions including blocking agent, immunoreaction time and substrate concentration have been optimized. Under the optimum conditions, the increase of response current is proportional to the phospho-p53(15) concentration in the range of 0.2-10 ng mL(-1), with the detection limit of 0.1 ng mL(-1). The developed immunosensor exhibits acceptable stability and reproducibility and the assay results for phospho-p53(15) are in good correlation with the known values. This easily fabricated immunosensor provides a new promising tool for analysis of phospho-p53(15) and other phosphorylated proteins.

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    • "In that case graphene was integrated on the sensing platform instead of the sandwich conjugate platform. For the fabrication of the immunosensor the SPCE was functionalized with graphene and chitosan for primary antibody attachment phospho-p5315 (Ab1/graphene–CHI/SPCE)[111]. The sandwich immunocomplex was formed among phospho-p5315 capture antibody, phosphop5315 antigen, biotinylated phospho-p5315 detection antibody and HRP-labeled streptavidin, resulting in the following system: HRP–streptavidin–biotinAb2/phospho-p5315/Ab1/graphene–CHI/SPCE. "
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    • "TH has been used to induce photodynamic inactivation of bladder cancer cells, Escherichia coli, and Saccharomyces cerevisiae [17]. The biological activity of TH has also been employed in graphene-based inmuno sensors [18]. In addition to its favorable applications, TH possess mutagenic activity in eukaryotic cells, demonstrating its potential cytotoxic and genotoxic activity in prokaryotic cells and photo induced mutagenic action upon binding to DNA [19] [20] [21]. "
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