基于SYBR Green I-银纳米粒子表面增强拉曼光谱平台的核酸适配体传感器用于钾离子的高灵敏检测OA

Developing highly sensitive methods for detecting potassium ions(K+)is crucial for studying physiological processes and disease diagnosis.This study proposes a surface-enhance Raman scattering(SERS)aptasensor based on plasmon coupling effect of SYBR Green I(SGI)and silver nanoparticles(AgNPs).The cross-linking interaction of the SGI-aptamer complex with AgNPs enables ultraviolet-visible(UV-Vis)and SERS spectroscopy synergistic dual-mode detection.The plasmon coupling network formed in the absence of K+can not only enable colorimetric detection and rapid naked-eye evaluation by absorbance ratio at 395 and 532 nm(A395/A532)but also generates enhanced SERS signals in the nanogaps.When K+is present,K+induces aptamer to undergo a conformational change,forming G-quadruplex,SGI dissociates from AgNPs surface,causing a significant decrease of characteristic SERS peak signal at 1337 cm-1.The quantitative linear range of this method in SERS spectroscopy mode is 0.8-250.0 μmol/L(limit of detection(LOD)=0.8 μmol/L),and in UV-Vis absorption spectroscopy mode is 7.8-500.0 μmol/L(LOD=5.3 μmol/L).Qwing to the excellent SERS enhancement properties of SGI,this method reduces the detection limit by about 15 times compared to fluorescence method using homologous aptamer(12.5 μmol/L).By using a dual-mode mechanism,this work provides a new paradigm for achieving low-cost and highly sensitive detection of K+.