Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
Univ. Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.
Biosens Bioelectron. 2015 Jun 15;68:49-54. doi: 10.1016/j.bios.2014.12.033. Epub 2014 Dec 16.
We report a label-free aptasensor to make direct detection of prostate specific antigen (PSA, a biomarker of prostate cancer) using a quinone-containing conducting copolymer acting as redox transducer and grafting matrix for immobilization of the short aptamer strands. It is shown that capture of PSA generates a current decrease (signal-off) measured by Square Wave Voltammetry. This current decrease is specific for PSA above a limit of quantification in the ng mL(-1) range. The change in current is used to determine the PSA-aptamer dissociation constant K(D), of ca. 2.6 nM. To consolidate the proof of concept, a heterogeneous competitive exchange with a complementary DNA strand which breaks PSA-aptamer interactions is studied. This double-check followed by a current increase provides full assurance of a perfectly specific recognition.
我们报道了一种无标记适体传感器，使用含有醌的导电共聚物作为氧化还原转导体，并作为固定短适体链的接枝基质，直接检测前列腺特异性抗原 (PSA，前列腺癌的生物标志物)。结果表明，通过方波伏安法测量到 PSA 的捕获会产生电流下降（信号关闭）。这种电流下降是 PSA 在 ng mL(-1) 范围内定量限以上的特异性。电流的变化用于确定 PSA-适体解离常数 K(D)，约为 2.6 nM。为了巩固概念验证，研究了与互补 DNA 链的非均相竞争交换，该链会破坏 PSA-适体相互作用。这种双检查后电流增加，完全保证了完全特异性识别。
