Mao Xun, Jiang Jianhui, Xu Xiangmin, Chu Xia, Luo Yan, Shen Guoli, Yu Ruqin
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Biosens Bioelectron. 2008 May 15;23(10):1555-61. doi: 10.1016/j.bios.2008.01.019. Epub 2008 Jan 24.
We described a novel electrochemical DNA biosensor based on molecular beacon (MB) probe and enzymatic amplification protocol. The MB modified with a thiol at its 5' end and a biotin at its 3' end was immobilized on the gold electrode through mixed self-assembly process. Hybridization events between MB and target DNA cause the conformational change of the MB, triggering the attached biotin group on the electrode surface. Following the specific interaction between the conformation-triggered biotin and streptavidin-horseradish peroxidase (HRP), subsequent quantification of DNA was realized by electrochemical detection of enzymatic product in the presence of substrate. The detection limit is obtained as low as 0.1nM. The presented DNA biosensor has good selectivity, being able to differentiate between a complementary target DNA sequence and one containing G-G single-base mismatches.
我们描述了一种基于分子信标（MB）探针和酶促扩增方案的新型电化学DNA生物传感器。5'端用硫醇修饰、3'端用生物素修饰的MB通过混合自组装过程固定在金电极上。MB与靶DNA之间的杂交事件导致MB的构象变化，触发电极表面附着的生物素基团。在构象触发的生物素与链霉亲和素-辣根过氧化物酶（HRP）之间发生特异性相互作用后，通过在底物存在下对酶产物进行电化学检测实现了DNA的后续定量。检测限低至0.1 nM。所提出的DNA生物传感器具有良好的选择性，能够区分互补靶DNA序列和含有G-G单碱基错配的序列。
