College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001, PR China.
Colloids Surf B Biointerfaces. 2013 Feb 1;102:76-82. doi: 10.1016/j.colsurfb.2012.08.028. Epub 2012 Aug 25.
Fluorescent quantum dots (QDs) have attracted great attention in biological and biomedical fields. In particular, for any potential application, the interaction of QDs with some biomolecules is much important. Herein, the interactions between QDs with different sizes and human serum albumin (HSA) were systematically investigated by UV-vis absorption spectra, fluorescence spectra and circular dichroism (CD) spectra under the physiological conditions. Four sizes of CdTe QDs with maximum emission of 520 nm (green QDs, GQDs), 568 nm (yellow QDs, YQDs), 620 nm (red QDs, RQDs) and 680 nm (crimson QDs, CQDs) were tested. The fluorescence spectra results indicated that QDs could quench the fluorescence intensity of HSA effectively with a size-dependent relationship. The binding of QDs and HSA is a result of the formation of QDs-HSA complex and the electrostatic interaction plays a major role in stabilizing the complex. The modified Stern-Volmer quenching constants K(a) at different temperatures and corresponding thermodynamic parameters ΔH, ΔG and ΔS were calculated. The conformational changes of HSA induced by QDs have been analyzed by CD spectra, and the results indicated that the biological activity of HSA was weakened in the present of QDs with bigger size.
荧光量子点 (QDs) 在生物和生物医学领域引起了极大的关注。特别是对于任何潜在的应用，QDs 与一些生物分子的相互作用非常重要。在此，在生理条件下，通过紫外可见吸收光谱、荧光光谱和圆二色性 (CD) 光谱系统地研究了不同尺寸的 QDs 与人血清白蛋白 (HSA) 之间的相互作用。测试了四种最大发射波长为 520nm（绿色 QDs，GQDs）、568nm（黄色 QDs，YQDs）、620nm（红色 QDs，RQDs）和 680nm（深红色 QDs，CQDs）的 CdTe QDs。荧光光谱结果表明，QDs 可以有效地猝灭 HSA 的荧光强度，具有尺寸依赖性关系。QDs 和 HSA 的结合是形成 QDs-HSA 复合物的结果，静电相互作用在稳定复合物中起主要作用。在不同温度下计算了修饰后的 Stern-Volmer 猝灭常数 K(a) 以及相应的热力学参数 ΔH、ΔG 和 ΔS。通过 CD 光谱分析了 QDs 诱导的 HSA 构象变化，结果表明在较大尺寸的 QDs 存在下，HSA 的生物活性减弱。
