Proteins adsorbing onto surface modified nanoparticles: effect of surface curvature, pHand the interplay of polymers and proteins acid-base equilibrium

GONZALEZ SOLVEYRA, ESTEFANIA; SZLEIFER, IGAL

Evento virtual

Congreso; ACS Spring meeting 2021; 2021

American Chemistry Society

The non-specific protein adsorption that bare nanoparticles (NPs) are subject to in physiological media (protein biofouling) limits their use for any given biomedical application. Common strategies to prevent or control it consist on ?passivating? the NP surface by grafting polymers onto it. The antifouling efficiency depends on the NP properties (size, geometry, surface chemistry), the encountered proteins and the medium. Although there has been extensively studied that NPs with charged surfaces tend to adsorb more proteins than neutral ones, the interplay between curvature and surface chemistry in the final behavior of the system has been only scarcely addressed.In this work, we present a comprehensive and systematic study of the protein adsorption process, analyzing the effect of NP curvature and morphology, the grafting of polymer mixtures on the surface, the type of polymer on surface (neutral, acidic, basic), the proteins in solution, and the conditions of the solution. Figure 1 provides a schematic representation of the systems modeled. The theoretical approach we employed is based on a molecular theory (MT) that takes into account the size, shape, conformation, and charge of each molecular species in the system. And, very importantly, it allows to explicitly consider the acid-base reaction of the titrable amino acids in the protein. MT calculations provided the proteins adsorption isotherms as a function of surface composition, type of polymer, surface density, NP size, and solution conditions (pH, proteins and salt concentrations), reflecting the balance between molecular organization and chemical state of both polymers and proteins, and how it is modulated by the curvature of the underlying surface.