Nucleic acid detection is becoming increasingly important in the diagnostics of genetic diseases for biological analysis. We herein propose gold nanoparticles as probe for colorimetric detection of nucleic acids with branched DNA nanostructures, which enables a novel and simple colorimetric biosensor. In our system, the target DNA specifically triggered two short-chain ssDNA probes to generate branched DNA nanostructures (Y-shape DNA), which prevent AuNPs from aggregation in aqueous NaCl solution. On the contrary, when the target DNA did not exist, gold nanoparticles were unstable and aggregated easily because there is no anti-aggregation function from Y-shape DNA. Sensor response was found to be proportional to the target DNA concentration from 5 to 100[Formula: see text]nM, with detection limits determined as 5[Formula: see text]nM. The developed platform is for colorimetric nucleic acid detection without enzymes, label and modification holds great promise for practical applications.

中文翻译：

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基于具有支链 DNA 的金纳米粒子的比色核酸检测

核酸检测在用于生物分析的遗传疾病诊断中变得越来越重要。我们在此提出金纳米粒子作为探针，用于比色检测具有分支 DNA 纳米结构的核酸，这使得一种新颖且简单的比色生物传感器成为可能。在我们的系统中，目标 DNA 特异性地触发了两个短链 ssDNA 探针以产生分支的 DNA 纳米结构（Y 形 DNA），从而防止 AuNPs 在 NaCl 水溶液中聚集。相反，当目标 DNA 不存在时，由于 Y 型 DNA 没有抗聚集功能，金纳米粒子不稳定且容易聚集。发现传感器响应与目标 DNA 浓度成正比，范围为 5 至 100[公式：参见文本]nM，检测限确定为 5[公式：参见文本]nM。