光度法研究L-半胱氨酸修饰的ZnS纳米粒子与牛血红蛋白的作用

Interaction of L-Cysteine-capped-ZnS Nanoparticles with Bovine Hemoglobin by using UV-Vis,Fluorenscence and FTIR Spectroscopy

合成和表征了L-半胱氨酸修饰的ZnS纳米粒子。采用紫外光谱法、荧光光谱法、傅立叶衰减全反射红外光谱法(FTIR-ATR)研究了PBS缓冲体系中L-半胱氨酸修饰的ZnS纳米粒子与牛血红蛋白(BovineHemoglobin,BHb)的相互作用。结果表明,L-半胱氨酸修饰的ZnS纳米粒子与BHb有较强的作用,BHb能使修饰后的ZnS纳米粒子发生荧光猝灭现象。根据Stern-Volmer方程计算得到猝灭常数为1.12×106L/mol。L-半胱氨酸修饰的ZnS纳米粒子很大程度上影响BHb的二级结构,使其构象发生变化。

ZnS nanoparticles were synthesized and characterized. The synthetic and modified conditions of ZnS nanoparticles, such as pH value, reaction temperature, the molar ratio of Zn（Ac）2, Na2S and the stabilizing reagent （EDTA） and the concentration of L-cysteine, were optimized. Under the best conditions of synthesis and modification, functionalized ZnS nanoparticles with sphere shape and a diameter of 150 nm were obtained. UV-Vis, fluorescence and attenuated total reflectance Fourier transform infrared （ATR-FrIR） spectroscopies were used to study the interaction of ZnS nanoparticles modified by L-cysteine and Bovine hemoglobin. The results indicate that the fluorescence of functionalized ZnS nanoparticles was significantly quenched by Bovine hemoglobin. The quenching constant calculated according to Stern-Volmer equation was 1.12 × 10^6 L/mol. It is inferred from this result that the effect of Bovine hemoglobin on the fluorescence of functionalized ZnS nanoparticles was a static quenching and strong interaction taking place between Bovine hemoglobin molecules and functionalized ZnS nanoparticles. The strong interaction significantly affected the second structure of BHb molecules, which was confirmed by ATR-FrIR observations.