State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Biosens Bioelectron. 2010 Apr 15;25(8):1953-7. doi: 10.1016/j.bios.2010.01.013. Epub 2010 Jan 18.
A novel scheme for scanning electrochemical microscopy (SECM) assay of DNA based on hairpin probe and enzymatic amplification biosensor was described. In this method, streptavidin-horseradish peroxidase (HRP) was captured by double-stranded DNA (ds-DNA) modified gold substrate via biotin-streptavidin interaction after hybridization of target DNA to the immobilized hairpin probe functioned with a biotin at its 3' end. In the presence of H2O2, hydroquinone (H2Q) was oxidized to benzoquinone (BQ) at the modified substrate surface through the HRP catalytic reaction, and the generated BQ corresponding to the amount of target DNA was reduced in solution by a SECM tip. The resulting reduction current allowed concentration detection of target DNA and SECM imaging of hybridization between the target DNA and the immobilized hairpin probe. The detection limit of this method was as low as 17 pM for complementary target DNA and it had good selectivity to discriminate between the complementary sequence and one containing base mismatches.
描述了一种基于发夹探针和酶放大生物传感器的扫描电化学显微镜（SECM）测定 DNA 的新方案。在该方法中，双链 DNA（ds-DNA）修饰的金基底通过生物素-链霉亲和素相互作用捕获经修饰的基底表面上的 HRP 催化反应，将目标 DNA 杂交到固定的发夹探针上，该探针的 3'端带有生物素。在 H2O2 的存在下，通过 HRP 催化反应将氢醌（H2Q）氧化为苯醌（BQ），并且生成的 BQ 与目标 DNA 的量相对应，通过 SECM 尖端在溶液中还原。所得还原电流允许对目标 DNA 进行浓度检测，并对目标 DNA 与固定发夹探针之间的杂交进行 SECM 成像。该方法对互补目标 DNA 的检测限低至 17 pM，并且对区分互补序列和含有碱基错配的序列具有良好的选择性。
