CdS纳米晶与多肽相互作用研究

Investigation on Interaction between CdS Nanocrystals and Peptides

研究了半导体CdS纳米晶的表面功能化及荧光光谱特性,并利用静电/配位自组装方法实现了多肽和CdS纳米晶的生物无机偶联,研究了纳米晶多肽偶联体系的荧光光谱以及多肽与CdS纳米晶之间的相互作用.结果表明:含巯基多肽对CdS纳米晶表面形成完善包覆,消除CdS纳米晶表面缺陷,使CdS纳米晶荧光增强;含端氨基多肽使CdS纳米晶荧光出现先升后降趋势;其余不含巯基和氨基的多肽均猝灭CdS纳米晶荧光,猝灭机制属于形成化合物所引起的静态猝灭,它们的结合常数约为2×104,结合位点数约为0.87～1.00.

CdS nanocrystals were prepared and modified with thiolic acid. The functionalized nanocrystals were water soluble and biocompatible. Bioinorganic conjugates between CdS nanocrystals and peptides were formed via electrostatic/coordinate self-assembly. The photoluminescence properties of CdS nanocrystals and their bioinorganic conjugates have been studied. The photoluminescence intensities of the bioinorganic conjugates between CdS nanocrystals and peptides with mercaptophenols were improved obviously with increasing the concentration of peptides due to the perfect wrapping of CdS nanocrystal surface and the elimination of defects on CdS nanocrystal surface. The emission intensities of the bioinorganic conjugates between CdS nanocrystal and peptide with terminal amino groups exhibit maximum at the appropriate concentration of peptide. The fluorescence of functionalized CdS nanocrystal was quenched in the presence of peptides with no mercaptophenols and no terminal amino-groups, the quenching mechanism of the combination of CdS nanocrystal with this kind of peptide is a static quenching procedure, the equilibrium binding constant is about 2 × 10^4, and the number of binding sites is in the range of 0.87 to 1.00.