Research Center for Analytical Instrumentation, State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou 310027, China.
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Molecules. 2021 Nov 10;26(22):6790. doi: 10.3390/molecules26226790.
Direct detection of long-strand DNA by surface-enhanced Raman scattering (SERS) is a valuable method for diagnosis of hereditary diseases, but it is currently limited to less than 25-nt DNA strand in pure water, which makes this approach unsuitable for many real-life applications. Here, we report a 60-nt DNA label-free detection strategy without pretreatment by SERS with polyquaternium-modified Ag microcrystals derived from an AgCl cube. Through the reduction-induced decomposition, the size of the about 3 × 3 × 3 μm AgCl cube is reduced to Ag, and the surface is distributed with the uniform size of 63 nm silver nanoparticles, providing a large area of a robust and highly electromagnetic enhancement region. The modified polycationic molecule enhances the non-specific electrostatic interaction with the phosphate group, thereby anchoring DNA strands firmly to the SERS enhanced region intactly. As a result, the single-base recognition ability of this strategy reaches 60-nt and is successfully applied to detect thalassemia-related mutation genes.
通过表面增强拉曼散射（SERS）直接检测长链 DNA 是一种用于诊断遗传性疾病的有价值的方法，但目前仅限于在纯水中检测少于 25-nt 的 DNA 链，这使得该方法不适合许多实际应用。在这里，我们报告了一种无预处理的 SERS 60-nt 无标记 DNA 检测策略，该策略使用源自 AgCl 立方体的聚季铵盐修饰的 Ag 微晶。通过还原诱导分解，约 3×3×3μm 的 AgCl 立方体的尺寸减小到 Ag，表面分布着均匀尺寸为 63nm 的银纳米颗粒，提供了一个具有大表面积的强且高电磁增强区域。修饰的聚阳离子分子增强了与磷酸基团的非特异性静电相互作用，从而将 DNA 链牢固地锚定在完整的 SERS 增强区域。结果，该策略的单碱基识别能力达到 60-nt，并成功应用于检测地中海贫血相关突变基因。
