Adsorption of proteins on gold nanoparticles: One or more layers?

Publication date: 1 January 2019Source: Colloids and Surfaces B: Biointerfaces, Volume 173Author(s): Dmitriy V. Sotnikov, Anna N. Berlina, Vladislav S. Ivanov, Anatoly V. Zherdev, Boris B. DzantievAbstractAdsorption of proteins on nanoparticles is a complex and poorly studied process. The mechanisms of protein layer formation can fundamentally differ depending on the composition of the medium, the nanoparticles’ structure, the protein’s nature, and other factors. In particular, monolayer or multilayer immobilization may occur. In the present work, the composition of conjugates of bovine serum albumin and immunoglobulin G with gold nanoparticles obtained by the Turkevich-Frens method are analyzed. The composition was studied by protein fluorescence measurement for particles ranging in size from 20 to 48 nm, depending on the pH of the immobilization medium (from 4 to 5 to 8–10). It was found that a pH shift of the immobilization medium from acidic to alkaline values is accompanied by a change in the mechanism of protein adsorption on the gold surface. In acidic pH conditions (4–5), effective binding of bovine serum albumin and gold nanoparticles occurs throughout the entire range of studied protein concentrations. In alkaline pH conditions (8–10), however, effective binding occurs only at concentrations of>10 μg/mL. This effect is not observed for immunoglobulin G, which is efficiently adsorbed onto nanoparticles throughout the entire range of studied concentration...
Source: Colloids and Surfaces B: Biointerfaces - Category: Biochemistry Source Type: research