用核酸适体修饰纳米金制备了识别凝血酶(TB)的适体修饰纳米金(AptAu)共振散射光谱探针.在pH 7.40的Na2HPO4-NaH2PO4缓冲溶液中及NaCl,KCl存在下,AptAu探针中的适配体特异识别凝血酶,生成稳定的G-四分体和大粒径的纳米金聚集体.经微孔滤膜过滤后,纳米金聚集体被分离,以滤液中未反应的AptAu作催化晶种,在20.0 μg/mL,HAuCl4-5.01 mmol/L,HCl-1.83 mg/mL CTMAB-50.1 μg/mL VC条件下,催化维生素C(VC)还原HAuCl4生成较大粒径的金颗粒,体系在600 nm处有一共振散射峰.随着凝血酶浓度的增大,滤液中AptAu浓度降低,催化作用减弱,600 nm处的共振散射峰降低,其降低值△I600nm与凝血酶浓度在6.40×10-3～0.150 U/mL,范围内存在良好线性关系,回归方程为△I=1.26×103C+1.50,相关系数为0.999,检出限为1.30×10-3 U/mL.该法用于定量分析人血浆中凝血酶,结果满意.%An aptamer nanoprobe (AptAu) for thrombin was prepared using the nanogold labeled aptamer.In pH 7.4 Na2HPO4-NaH2PO4 buffer solution and in the presence of NaCl and KCl, the analyte of thrombin reacted with AptAu to form stable G-quartet and release nanogold particles that aggregated to big clusters.After filtration by microporous filter membrane, the big clusters were removed and filtrated solution containing AptAu was obtained. That exhibited catalytic effect on the slow gold particle reaction between HAuC14 and VC at 60 ℃. There is a resonance scattering peak at 600 nm. With the increasing concentration of thrombin, the AptAu content in the filtrated solution decreased, and the resonance scattering intensity at 600 nm decreased. The decreased RS intensity is linear to thrombin concentration in the range from 6.40 ×10-3 U/mL to 0.150 U/mL, with a regression equation of △I=1.26× 103C+1.50 and a detection limit of 1.30× 10-3 U/mL. The method was used for quantitative analysis of thrombin in human plasma with satisfactory results.
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