(569e) Rational Design of Charged Nanogels for Differential Protein Capture

Inspired by the natural phenomenon of molecular recognition, we have developed synthetic materials capable of binding specific proteins or protein classes. Polymers can be rationally designed to differentiate proteins based on their properties including isoelectric point, molecular weight, and glycosylation status. While these materials typically have lower specificity than antibodies, their significantly lower cost makes them attractive for use in biomedical and separation science applications. We have designed a set of crosslinked polymer nanoparticles containing varied ionic moieties and investigated how protein binding affinity and selectivity is affected by the amount and type of charge present in the nanogels. Nanogels were synthesized by the copolymerization of N-isopropylacrylamide (NIPAM) and methacrylic acid (MAA) with N,Nâ??-methylene bisacrylamide as a crosslinker. Different charged groups were introduced into the nanogels via a carbodiimide mediated post-synthesis modification. Successful modification of poly(NIPAM-co-MAA) nanogels was confirmed by zeta potential measurements, titration, and FT-IR spectroscopy. The nanogels were incubated with a set of proteins, both individually and in mixtures, to assess their recognition capabilities. Our results suggest that beyond having complementary charge-charge interactions between the protein and polymer, the type of anionic and/or cationic group and charge density strongly influences polymer-protein binding preferences. Collectively these nanogels are able to distinguish among more than eight proteins, making them promising tools for use in separations or differential sensing applications.