Centre for Molecular Nanometrology, Department of Pure and Applied Chemistry, WestCHEM, University of Strathclyde, Technology and Innovation Centre, 99 George Street, Glasgow, G1 1RD, UK.
Analyst. 2020 Mar 2;145(5):1871-1877. doi: 10.1039/c9an01732a.
The use of surface enhanced Raman scattering (SERS) for the detection of DNA has significant potential in terms of sensitivity, multiplex target detection and robust signal detection from nanoparticles. Current methods are usually performed with short chain DNA fragments or require additional separation steps for detection of longer chain fragments. We present an integrated method for the rapid and sensitive detection of extended (≥100-base) nucleic acids with reduced preparation and sample separation steps. Key to this is the DNA sequence-specific assembly of silver nanoparticles labelled with a Raman tag to provide an enhanced signal from the tag and hence molecular recognition of the target DNA. DNA probe orientation and hybridisation procedures are critical for the success of this assay. Effective detection of extended nucleic acids was achieved with head-to-head probes and by adding polyethylene glycol 10 000 (PEG 10 000) to the hybridisation buffer. This gave a 34-fold discriminatory enhancement factor when applied to a synthetic target. A structured approach toward maximising hybridisation procedures and SERS response is described, followed by an initial demonstration of SERS detection of single-stranded DNA target amplified by asymmetric PCR which was used without further separation. This has implications for future developments in using SERS for DNA detection due to the new-found ability to integrate SERS with asymmetric PCR.
表面增强拉曼散射（SERS）在检测 DNA 方面具有很高的灵敏度、多重目标检测和从纳米粒子中稳健信号检测的潜力。目前的方法通常使用短链 DNA 片段进行，或者需要额外的分离步骤来检测更长链的片段。我们提出了一种集成的方法，用于快速灵敏地检测扩展（≥100 个碱基）核酸，减少了制备和样品分离步骤。关键是通过 DNA 序列特异性组装标记有拉曼标签的银纳米粒子，从标签提供增强的信号，从而对靶 DNA 进行分子识别。DNA 探针的取向和杂交程序是该测定成功的关键。通过对头对头探针的有效检测，并在杂交缓冲液中添加聚乙二醇 10000（PEG 10000），对合成靶标进行了 34 倍的区分增强因子。描述了一种最大化杂交程序和 SERS 响应的结构化方法，然后初步展示了 SERS 对不对称 PCR 扩增的单链 DNA 靶标的检测，该方法无需进一步分离即可使用。由于 SERS 与不对称 PCR 集成的新能力，这对未来使用 SERS 进行 DNA 检测的发展具有重要意义。
