The interaction of silver nanoparticles with papain and bromelain

Abstract

Proteins cover the surface of nanoparticles (NPs), forming what is known as a “protein corona”, which largely determines the reactivity and functionality of NPs. In the study, a comprehensive investigation was performed for clarifying the binding mechanism, adsorption isotherms and kinetic behaviors of silver nanoparticles (AgNPs) with two model cysteine-proteases, papain and bromelain. The experimental results indicate that the binding of papain/bromelain to AgNPs seems to be a static quenching mechanism. Thermodynamic analysis reveals that the binding of papain/bromelain to AgNPs is synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic and electrostatic interactions. The equilibrium adsorption isotherm and kinetics of papain/bromelain on AgNPs were also studied. The adsorption equilibrium isotherms both fit well to the Freundlich model and the kinetics of adsorption both fit best to pseudo-second-order.