(168u) Protein Resistant Polymer Coatings for Gold Nanoparticles and Surfaces

Protein adsorption on drug carrier surfaces occurs when the carriers interact with protein-rich biological fluids. The proteins in these fluids coat the carriers altering their surface chemistry and retention time in the body. When challenged with single protein solutions, phosphorylcholine forms an effective barrier to protein adsorption. Key factors that influence the effectiveness of the polymer coatings are the grafting density and the molecular weight of the polymers. The goal of this research is to design phosphorylcholine-based polymers and determine how grafting density and molecular weight affect the adsorption of proteins from physiologically relevant protein mixtures. We have synthesized zwitterionic phosphorylcholine-containing polymers using reversible addition-fragmentation chain transfer (RAFT) thermal polymerization with molecular weights ranging from 2 to 30 kDa. Polymers were attached to gold QCM-D crystals and challenged with protein solutions. The coatings show excellent protein resistance at high molecular weights and grafting densities. The polymers were also attached to 100 nm gold nanoparticles, resulting in a more neutral zeta potential. Polymer coated gold nanoparticles showed fainter protein bands in SDS-Page gels when compared to citrate-capped gold nanoparticles. This data shows the potential of these polymers to resist protein adsorption on future drug carriers.