60-nt DNA Direct Detection without Pretreatment by Surface-Enhanced Raman Scattering with Polycationic Modified Ag Microcrystal Derived from AgCl Cube
Jikai Mao,
Lvtao Huang,
Li Fan,
Fang Chen,
Jingan Lou,
Xuliang Shan,
Dongdong Yu,
Jianguang Zhou
Affiliations
Jikai Mao
Research Center for Analytical Instrumentation, State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou 310027, China
Lvtao Huang
Research Center for Analytical Instrumentation, State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou 310027, China
Li Fan
Research Center for Analytical Instrumentation, State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou 310027, China
Fang Chen
Department of Chemistry, Zhejiang University, Hangzhou 310027, China
Jingan Lou
The Children’s Hospital Zhejiang University School of Medicine, Hangzhou 310000, China
Xuliang Shan
Hangzhou Green Environment Science & Technology Co., Ltd., Hangzhou 310000, China
Dongdong Yu
Hospital of Zhejiang University, Hangzhou 310027, China
Jianguang Zhou
Research Center for Analytical Instrumentation, State Key Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou 310027, China
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 μm3 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.
