适体
检出限
拉曼光谱
DNA
拉曼散射
化学
表面增强拉曼光谱
材料科学
基质(化学分析)
纳米技术
胶体金
纳米颗粒
生物传感器
生物物理学
色谱法
分子生物学
生物化学
生物
光学
物理
作者
Enlai Yang,Dan Li,Pengkun Yin,Qiyue Xie,Li Yu,Qingyu Lin
标识
DOI:10.1016/j.bios.2020.112758
摘要
Bacteria seriously endanger human life and health, and the detection of bacteria is vital for the prevention and treatment of related diseases. Surface-enhanced Raman scattering (SERS) is considered as a powerful technique for bacterial detection due to the inherent richness of spectral data. In this work, a novel SERS strategy based on three-dimensional (3D) DNA walker was developed for quantitative analysis of Salmonella typhimurium (S. ty). The complimentary DNA of S.ty-recognizing aptamer (cApt) was replaced from the double-stranded DNA (dsDNA) of [email protected] in the presence of S.ty, which can trigger the endonuclease mediated “DNA walker” on the surface of gold modified magnetic nanoparticles (AuMNPs). The DNA residues on the surface of AuMNPs can bind to SERS tag through base complementary pairing, and the complex of “[email protected] tag” can be separated from the fluid by an external magnetic field for SERS analysis. It was found that the SERS intensity showed a good linear relationship with both lower (10–104 CFU/mL) and higher (104–106 CFU/mL) S.ty concentration. A superior limit of detection (LOD) as low as 4 CFU/mL was achieved due to the signal amplification effect of “DNA walker”, and the preeminent selectivity of the proposed method was determined by the selectivity of the aptamer sequence. This strategy of separating the SERS tag from the biological matrix enables high stability and good repeatability of the SERS spectra, which presents a new method for SERS detection of biomaterials that can benefit various application scenarios.
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