荧光光谱法研究G3.0 PAMAM树状大分子与牛血清白蛋白的相互作用

聚酰胺-胺型(PAMAM)树状大分子是一类新型的纳米级、球型、高度分支、单分散性的聚合物，并具有安全、低毒、无免疫原性等许多独特的生物学性质。正是由于这些优势使其有望成为一种新型有效的生物材料，用于作为寡核苷酸的转运因子和药物转运载体。因此，深入了解树状大分子的生物学性质对进一步研究其在治疗方面的应用是至关重要的。文章应用荧光光谱法在生理条件下研究了具有表面氨基的3.0代聚酰胺-胺型(G3.0 PAMAM)树状大分子与牛血清白蛋白(BSA)间的相互作用。结果表明，加入G3.0 PAMAM树状大分子后，BSA内源性荧光发生猝灭，其猝灭机制属于静态猝灭，符合Stern-Volmer方程。通过计算得到该树状大分子与BSA间的结合常数为(1.067±0.025)L·mmol-1。通过同步荧光、红边激发荧光位移(REES)等方法的研究发现，树状大分子的存在会改变BSA的构象。此外还考查了体系的pH值和离子强度对该树状大分子与BSA相互作用的影响，由实验结果可推断静电作用是二者结合的主要作用机制。

Fluorescence Study on the Interactions between G3.0 PAMAM Dendrimers and Bovine Serum Albumin

The interaction between amine terminated G3.0 PAMAM dendrimers and bovine serum albumin (BSA) under physiological condition was studied by fluorescence spectroscopy. Our experiments demonstrated that the fluorescence intensity of BSA decreased after the addition of G3.0 PAMAM dendrimers and the quenching mechanism was suggested as static quenching according to the Stern-Volmer equation. The binding constant of G3.0 PAMAM dendrimers with BSA was calculated to be 1. 067 ±0. 025 L ·mmol^-1. At the same time, synchronous fluorescence and red edge excitation shift(REES)were adopted to review the conformational changes of BSA influenced by G3.0 PAMAM dendrimers, which provides important significance for clinical medication. And the results indicated that G3.0 PAMAM dendrimers can change the conformation of BSA. Furthermore, this article also examined the influence of pH and ionic strength on the interactions, from which we can conclude that electrostatic interaction played major roles in the binding process. In conclusion, the fluorescence method is a highly sensitive and convenient way to study intermolecular interaction. Further investigation in this field will provide more important information for understanding the pharmacological effects and toxicities of drugs in human body.