Zhang Can, Lou Jing, Tu Wenwen, Bao Jianchun, Dai Zhihui
Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, P. R. China.
Analyst. 2015 Jan 21;140(2):506-11. doi: 10.1039/c4an01284d. Epub 2014 Nov 14.
A universal and sensitive electrochemical biosensing platform for the detection and identification of DNA using CdSe quantum dots (CdSe QDs) as signal markers was designed. The detection mechanism was based on the specific recognition of MspI endonuclease combined with the signal amplification of gold nanoparticles (AuNPs). MspI endonuclease could recognize its specific sequence in the double-strand DNA (dsDNA) and cleave the dsDNA fragments linked with CdSe QDs from the electrode. The remaining attached CdSe QDs can be easily read out by square-wave voltammetry using an electrodeposited bismuth (Bi) film-modified glass carbon electrode. The concentrations of target DNA could be simultaneously detected by the signal of metal markers. Using mycobacterium tuberculosis (Mtb) DNA as a model, under the optimal conditions, the proposed biosensor could detect Mtb DNA down to 8.7 × 10(-15) M with a linear range of 5 orders of magnitude (from 1.0 × 10(-14) to 1.0 × 10(-9) M) and discriminate mismatched DNA with high selectivity. This strategy presented a universal and convenient biosensing platform for DNA assay, and its satisfactory performances make it a potential candidate for the early diagnosis of gene-related diseases.
设计了一种通用且灵敏的电化学生物传感平台，用于以硒化镉量子点（CdSe QDs）作为信号标记物来检测和鉴定DNA。检测机制基于MspI核酸内切酶的特异性识别并结合金纳米颗粒（AuNPs）的信号放大作用。MspI核酸内切酶能够识别双链DNA（dsDNA）中的特定序列，并从电极上切割与CdSe QDs相连的dsDNA片段。剩余附着的CdSe QDs可通过使用电沉积铋（Bi）膜修饰的玻碳电极的方波伏安法轻松读出。目标DNA的浓度可通过金属标记物的信号同时进行检测。以结核分枝杆菌（Mtb）DNA为模型，在最佳条件下，所提出的生物传感器能够检测低至8.7×10⁻¹⁵ M的Mtb DNA，线性范围为5个数量级（从1.0×10⁻¹⁴到1.0×10⁻⁹ M），并能以高选择性区分错配DNA。该策略为DNA检测提供了一种通用且便捷的生物传感平台，其令人满意的性能使其成为基因相关疾病早期诊断的潜在候选者。
