Silver nanoparticles were prepared by NaBH4 reduction procedure. An aptamer-modified Ag nanoprobe (AgSH-ssDNA) for thrombin was prepared. In the media of pH 7.0 Tris-HC1 and KC1, the AgSH-ssDNA specifically combined with thrombin to form G-quadruplex and Ag cluster, which resulted in the resonance scattering intensity at 480 nm (I480 nm) increasing. As the amount of thrombin increased, the amount of Ag clusters increased, and the I480nm value increased. At the same time, Ag/Au nanoparticles of different Ag/Au molar ratio were also prepared for the thrombin RS analysis. The results showed the Ag system had some advantages such as high sensitivity, wide linear range, low-cost, and the simplicity of nanoparticles preparation. Its increased intensity △I480 nm was linear to the thrombin concentration in the range of 0.14～11.5 nmol/L, with a regression equation of △I480nm = 19.1 C+2.2, a correlation coefficient of 0.9833, and a detection limit of 17 pmol/L. This method was applied to detect thrombin in human plasma samples with satisfactory results.%采用四氢硼钠制备了较稳定的纳米银,并用凝血酶(TB)适体修饰纳米银制各了识别凝血酶的适体纳米银探针.在pH 7.0的Tris-HCl缓冲溶液及KCl存在下,适体纳米银探针与凝血酶特异结合生成G-四分体和纳米银聚集体,导致体系在480 nm处的共振散射峰增强.随着凝血酶浓度的增大,生成的纳米银聚集体越多,共振散射强度线性增强.采用不同银金物质的量之比的银金纳米微粒制各其探针并用于凝血酶的共振散射光谱分析.结果表明,适体纳米银探针体系的灵敏度较高、线性范围较宽,且纳米银制备较简便,成本低廉,其共振散射增强值△I480 nm与凝血酶浓度在0.14～11.5 nmol/L范围内存在良好的线性关系,检出限为17 pmol/L凝血酶.
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