HSA-磷钼杂多酸缔合纳米微粒体系荧光猝灭机理研究

Study on Fluorescence Quenching Mechanism of HSA-PMA Associated Nanoparticle System

在 pH 7 4 0的Tris HCl缓冲溶液中 ,磷钼杂多酸 (PMA)呈浅黄色 ,在可见光区没有明显的吸收峰 ;人血清白蛋白 (HSA)呈无色 ,在可见光区也没有明显的吸收峰 ,但在 35 0nm处有一荧光峰。当有PMA存在时 ,HSA与PMA形成缔合纳米微粒 ,HSA PMA缔合纳米微粒的粒径约为 80nm。经研究发现HSA对PMA有增色和减色效应 ,PMA对HSA有荧光猝灭作用 ;PMA对色氨酸 (Trp)和酪氨酸 (Tyr)也有一定的荧光猝灭作用 ,但这两种荧光猝灭机理不同 ,且没有形成缔合纳米微粒。PMA对色氨酸 (Trp)和酪氨酸的荧光猝灭作用主要是由于PMA在发射波长范围内存在一定的分子吸收 ,即通常所报道过的能量转移所至。研究结果表明 ,HSA PMA缔合纳米微粒和界面的形成是导致该体系的荧光猝灭。

In pH 7.40 Tris-HCl buffer solution, PMA is light yellow and has no absorption peak in the visible region. HSA has no color and no absorption peak in the visible region either. There is a fluorescence peak at 350 nm for HSA in pH 7.40 Tris-HCl buffer solution. HSA and PMA can combine into HSA-PMA association nanoparticles with a diameter about 80 nm by means of static gravitation. HSA has both hypochromic and color enhancement effects on PMA through our research. The fluorescence of Trp, Tyr and HSA can be quenched by PMA, but their quenching mechanisms are different. The fluorescence quenching of Trp and Tyr by PMA is due to molecule absorption in the range of emission wavelength, namely because of energy transfer often reported. The investigation results demonstrated that the formation of HSA-PMA associated nanoparticle and interface is the ultimate reason for fluorescence quenching, resonance scattering, and enhanced and hypochromic color.