(112e) Protein Adsorption and Corona Formation on Silica Nanoparticles: Effect of pH and Electrolyte

The adsorption of proteins from aqueous medium leads to the formation of protein corona on nanoparticles. Because the formation of protein corona is governed by a complex interplay of protein–particle and protein–protein interactions, the experimental parameters governing the protein corona formation on nanoparticles are currently poorly understood. Here, we investigate the effect of pH and salinity on the characteristics of corona formed by myoglobin on silica nanoparticles. We experimentally measure and theoretically model the adsorption isotherms of myoglobin binding to silica nanoparticles. By combining adsorption studies with surface electrostatic mapping of myoglobin, we demonstrate that a monolayered hard corona is formed in low salinity dispersions, which transforms into a multilayered hard + soft corona upon the addition of salt. We attribute the observed changes in protein adsorption behavior with increasing pH and salinity to the change in electrostatic interactions and surface charge regulation effects. This study provides insights into the mechanism of protein adsorption and corona formation on nanoparticles, which would guide future studies on optimizing nanoparticle design for maximum functional benefits and minimum toxicity.