Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
Biosens Bioelectron. 2013 May 15;43:165-72. doi: 10.1016/j.bios.2012.12.025. Epub 2012 Dec 20.
A highly sensitive and selective electronic sensor array for label-free detection of single-nucleotide polymorphisms (SNPs) is described in this work. Its sensing mechanism relies on building target DNA-templated silver nanowires (conductive paths) across a nanogap. Following hybridization with a SNP target, a cocktail of nucleases is applied to the nanogap sensor array. Free capture probes (CPs) and imperfectly hybridized CPs are digested while the perfectly hybridized CPs are covalently joined together over the nanogap at the mutation site. Detection of SNPs down to 0.10 fM is realized by measuring the conductance of the nanogap after a simple DNA metallization step. The engagement of the nucleases grants the nanogap sensor excellent ability to discriminate against mismatched sequences and allows hybridization to be carried out at very low stringency (room temperature), enabling a highly selective approach for SNP genotyping. And hybridization at low stringency ensures that all targets will be preferably hybridized at equilibrium. A selectivity factor of 3000 is observed when a mixture of a wild-type and a mutated gene is analyzed by the sensor array. Attempts are made in applying the sensor array to the detection of SNPs in DNA samples extracted from tissues and cultured cells.
本工作中描述了一种用于无标记检测单核苷酸多态性（SNP）的高灵敏度和选择性电子传感器阵列。其传感机制依赖于在纳米间隙中构建目标 DNA 模板化的银纳米线（导电路径）。与 SNP 靶标杂交后，将核酸酶混合物应用于纳米间隙传感器阵列。游离的捕获探针（CP）和不完全杂交的 CP 被消化，而完美杂交的 CP 在突变位点的纳米间隙处通过共价键连接在一起。通过简单的 DNA 金属化步骤测量纳米间隙的电导，实现了低至 0.10 fM 的 SNP 检测。核酸酶的参与赋予了纳米间隙传感器优异的区分错配序列的能力，并允许在非常低的严格性（室温）下进行杂交，从而实现 SNP 基因分型的高选择性方法。并且在低严格性下的杂交确保所有靶标都将在平衡时优选杂交。当通过传感器阵列分析野生型和突变型基因的混合物时，观察到 3000 的选择性因子。尝试将传感器阵列应用于从组织和培养细胞中提取的 DNA 样本中的 SNP 检测。
