Composition-Dependent Protein-Material Interaction of Poly(Methyl Methacrylate-co-styrene) Nanoparticle Series

Polymer nanoparticles continue to be of high interest in life science applications. Still, adsorption processes occurring in protein-containing media and their implications for biological responses are not generally predictable. Here, the effect of nanoparticle composition on the adsorption of bovine serum albumin (BSA), fibronectin (FN) and immunoglobulin G (IgG) as structurally and functionally different model proteins was explored by systematically altering the composition of poly(methyl methacrylate-co-styrene) nanoparticles with sizes in a range of about 550 nm. As determined by protein depletion from the suspension medium via a colorimetric assay, BSA and IgG adsorbed at similar quantities, while FN reached larger masses of adsorbed protein (up to 0.4 +/- 0.06 mu gcm(-2) BSA, 0.42 +/- 0.09 mu gcm(-2) IgG, 0.72 +/- 0.04 mu gcm(-2) FN). A higher content of styrene as the more hydrophobic polymer component enhanced protein binding, which suggests a contribution of hydrophobic interactions despite the particles exhibiting strongly negatively charged surfaces with zeta potentials of -44 to -52 mV. The quantities of adsorbed proteins were estimated to correspond to a confluent surface coverage. Overall, this study illustrated how protein binding can be controlled by systematically varying the nanoparticle bulk composition and may serve as a basis for establishing interfaces with a targeted level of protein retention and/or presentation.

Automated summary

This study investigates the effect of nanoparticle composition on protein adsorption. The results show that an increased content of hydrophobic polymer molecules in the nanoparticles enhances protein binding, despite the particles having negatively charged surfaces. This study provides a method for controlling protein binding.