Wang Jiao, Shi Anqi, Fang Xian, Han Xiaowei, Zhang Yuzhong
College of Chemistry and Materials Science, Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, and Anhui Key Laboratory of Chemo-Biosensing, Anhui Normal University, Wuhu 241000, People's Republic of China.
College of Chemistry and Materials Science, Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Laboratory of Molecule-Based Materials, and Anhui Key Laboratory of Chemo-Biosensing, Anhui Normal University, Wuhu 241000, People's Republic of China.
Anal Biochem. 2015 Jan 15;469:71-5. doi: 10.1016/j.ab.2014.09.023. Epub 2014 Oct 13.
In this article, a supersandwich-type electrochemical biosensor for sequence-specific DNA detection is described. In design, single-strand DNA labeled with methylene blue (MB) was used as signal probe, and auxiliary probe was designed to hybridize with two different regions of signal probe. The biosensor construction contained three steps: (i) capture DNA labeled with thiol was immobilized on the surface of gold nanoparticles decorated reduced graphene oxide (Au NPs/rGO); (ii) the sandwich structure formation contained "capture-target-signal probe"; and (iii) auxiliary probe was introduced to produce long concatamers containing signal molecule MB. Differential pulse voltammetry (DPV) was used to monitor the DNA hybridization event using peak current changes of MB in phosphate-buffered saline (PBS) containing 1.0M NaClO4. Under optimal conditions, the peak currents of MB were linear with the logarithm of the concentration of target DNA in the range of 0.1μM to 0.1fM with a detection limit of 35aM (signal/noise=3). In addition, this biosensor exhibited good selectivity even for single-base mismatched target DNA detection.
本文描述了一种用于序列特异性DNA检测的超三明治型电化学生物传感器。在设计中，用亚甲基蓝（MB）标记的单链DNA用作信号探针，并设计辅助探针与信号探针的两个不同区域杂交。生物传感器的构建包含三个步骤：（i）用硫醇标记的捕获DNA固定在装饰有还原氧化石墨烯的金纳米颗粒（Au NPs/rGO）表面；（ii）三明治结构的形成包含“捕获-靶标-信号探针”；（iii）引入辅助探针以产生包含信号分子MB的长串联体。差分脉冲伏安法（DPV）用于通过含有1.0M NaClO4的磷酸盐缓冲盐水（PBS）中MB的峰值电流变化来监测DNA杂交事件。在最佳条件下，MB的峰值电流与靶标DNA浓度的对数在0.1μM至0.1fM范围内呈线性关系，检测限为35aM（信噪比=3）。此外，该生物传感器即使对于单碱基错配的靶标DNA检测也表现出良好的选择性。
