Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Polymer Science & Technology Laboratory, Chennai 600020, India.
Council of Scientific and Industrial Research (CSIR) - Central Leather Research Institute (CLRI), Chemical Engineering, Chennai 600020, India.
Colloids Surf B Biointerfaces. 2019 Dec 1;184:110524. doi: 10.1016/j.colsurfb.2019.110524. Epub 2019 Sep 25.
To investigate the interaction between bovine serum albumin (BSA) and silver nanoparticles (AgNPs) at five different pHs (below (3.0 and 4.0), above (7.4 and 9.2) and at the isoelectric point (4.7) of BSA) by spectroscopic (viz., UV-vis, fluorescence, circular dichroism (CD)), microscopic (viz., atomic force microscopy (AFM), transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM)) and thermodynamic (viz., isothermal titration calorimetry (ITC)) methods. The fluorescence quenching spectra provided binding constants via Stern-Volmer plot, quenching constant (K) and rate constant (K) were calculated. From the CD spectra, it is clear that the α-helix decreases by increasing the AgNP's concentration. However, at isoelectric point (pH = 4.7), BSA shows more helicity in the presence of AgNPs, which indicates that the structures of BSA become more ordered and stable, and aggregation occurs at strong acidic (3.0), and basic medium (9.2) Fluorescence spectra also indicate the aggregation of the protein at strong acidic (pH = 3.0) and basic medium (pH = 9.2). Furthermore, the morphological and topographical evolute ion upon the interaction was examined using TEM, FESEM, and AFM. The studies conclude the effect of the pH in the medium and behavior of AgNPs with BSA by using different spectroscopic and microscopic techniques.
采用光谱（即紫外-可见分光光度法、荧光分光光度法、圆二色性（CD））、显微镜（即原子力显微镜（AFM）、透射电子显微镜（TEM）、场发射扫描电子显微镜（FESEM））和热力学（即等温热滴定法（ITC））方法研究了牛血清白蛋白（BSA）与银纳米粒子（AgNPs）在五个不同 pH 值（低于（3.0 和 4.0）、高于（7.4 和 9.2）和 BSA 的等电点（4.7））下的相互作用。荧光猝灭光谱通过 Stern-Volmer 图提供结合常数，计算猝灭常数（K）和速率常数（K）。从 CD 光谱可以清楚地看出，随着 AgNP 浓度的增加，α-螺旋减少。然而，在等电点（pH=4.7）时，BSA 在存在 AgNPs 时显示出更多的螺旋性，这表明 BSA 的结构变得更加有序和稳定，并且在强酸性（3.0）和碱性介质（9.2）中发生聚集。荧光光谱也表明蛋白质在强酸性（pH=3.0）和碱性介质（pH=9.2）中聚集。此外，还使用 TEM、FESEM 和 AFM 研究了相互作用时形貌和形貌演变。这些研究通过使用不同的光谱和显微镜技术，总结了介质 pH 值对 AgNPs 与 BSA 相互作用的影响和行为。
