Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang, People's Republic of China.
Nanotechnology. 2011 Jul 29;22(30):305502. doi: 10.1088/0957-4484/22/30/305502. Epub 2011 Jul 1.
DNA single-nucleotide polymorphism (SNP) detection has attracted much attention due to mutation related diseases. Various methods for SNP detection have been proposed and many are already in use. Here, we find that the abasic site (AP site) in the DNA duplex can be developed as a capping scaffold for the generation of fluorescent silver nanoclusters (Ag NCs). As a proof of concept, the DNA sequences from fragments near codon 177 of cancer supression gene p53 were used as a model for SNP detection by in situ formed Ag NCs. The formation of fluorescent Ag NCs in the AP site-containing DNA duplex is highly selective for cytosine facing the AP site and guanines flanking the site and can be employed in situ as readout for SNP detection. The fluorescent signal-on sensing for SNP based on this inorganic fluorophore is substantially advantageous over the previously reported signal-off responses using low-molecular-weight organic ligands. The strong dependence of fluorescent Ag NC formation on the sequences surrounding the AP site was successfully used to identify mutations in codon 177 of cancer supression gene p53. We anticipate that this approach will be employed to develop a practical SNP detection method by locating an AP site toward the midway cytosine in a target strand containing more than three consecutive cytosines.
由于与突变相关的疾病，DNA 单核苷酸多态性 (SNP) 的检测受到了广泛关注。已经提出了各种用于 SNP 检测的方法，其中许多已经在使用。在这里，我们发现 DNA 双链体中的无碱基位点 (AP 位点) 可以作为产生荧光银纳米簇 (Ag NCs) 的盖帽支架。作为概念验证，来自抑癌基因 p53 密码子 177 附近片段的 DNA 序列被用作 SNP 检测的模型，通过原位形成的 Ag NCs 进行 SNP 检测。含有 AP 位点的 DNA 双链体中荧光 Ag NC 的形成对面对 AP 位点的胞嘧啶和侧翼碱基的鸟嘌呤具有高度选择性，并且可以原位用作 SNP 检测的读出信号。与先前使用低分子量有机配体的信号关闭反应相比，基于这种无机荧光团的 SNP 荧光信号开启感测具有明显的优势。荧光 Ag NC 形成对 AP 位点周围序列的强烈依赖性成功地用于鉴定抑癌基因 p53 密码子 177 中的突变。我们预计，通过将 AP 位点定位到含有三个以上连续胞嘧啶的靶链中的中间胞嘧啶，将采用这种方法开发一种实用的 SNP 检测方法。
