Study of the interaction mechanism of silver nanoparticles with γ-globulin, fibrinogen and hyaluronidase

Abstract

In this work, spherical silver nanoparticles (AgNPs) with a mean diameter of 50.4 nm were prepared by sodium citrate reduction. The interaction mechanism of AgNPs with γ-globulin fibrinogen and hyaluronidase (HAase) was studied using multispectral methods. The results presented clearly indicate that the intrinsic fluorescence of γ-globulin, fibrinogen and HAase is effectively quenched by AgNPs through a static quenching mechanism, which is further confirmed by UV-vis analysis. The order of the binding constant and Hill coefficient is the same, fibrinogen–AgNPs > γ-globulin–AgNPs > HAase–AgNPs. The interaction between γ-globulin/fibrinogen and AgNPs is an endothermic and entropy-driven process, and the main non-covalent force is hydrophobic interaction. The interaction between HAase and AgNPs is an exothermic, enthalpy-driven process, and van der Waals force and hydrogen bonding are the main non-covalent forces. The interaction of γ-globulin/fibrinogen with AgNPs reduces the hydrophobicity of the tryptophan (Trp) microenvironment, but has no effect on the tyrosine (Tyr) microenvironment. The interaction between HAase and AgNPs has no obvious effect on the microenvironment of Trp and Tyr. CD spectra indicate that the secondary structure of γ-globulin/fibrinogen/HAase changes with the increase of AgNP concentration, and the content of α-helix (fibrinogen and HAase) or β-sheet (γ-globulin) decreases, inducing partial unfolding of the three proteins.