BPS2026 – Protein-polymer brush interactions at antifouling interfaces probed by molecular dynamics and SFG spectroscopy

Proteins approaching antifouling materials—surfaces designed to resist nonspecific protein adsorption—encounter complex hydration and interfacial restructuring that govern their stability and function. To capture these processes, we developed a molecular modeling framework that integrates α-quartz substrates, grafted polymer brushes, and proteins at atomistic resolution. Using lysozyme as a model protein, we examined its interactions with three representative brushes: cationic poly(dimethylaminoethyl methacrylate) (PDMAEMA), N-oxide zwitterionic poly(2-(N-oxide-N,N-dimethylamino)ethyl methacrylate) (PNOMA), and sulfobetaine zwitterionic poly(2-(N-3-sulfopropyl-N,N-dimethylammonium)ethyl methacrylate) (PSBMA). We coupled all-atom molecular dynamics (MD) with vibrational sum frequency generation (SFG) spectroscopy to probe brush structure and hydration at antifouling interfaces. SFG provided experimental insight into polymer brush organization, whereas MD enabled characterization of both brush properties and protein interactions. Steered MD shows that PSBMA resists insertion but destabilizes lysozyme by dehydrating its surface and enhancing adsorption forces. PDMAEMA stabilizes proteins through counterion-mediated interactions. In contrast, PNOMA compromises protein structural integrity once hydration layers collapse due to direct electrostatic clashes. These results demonstrate how hydration and ion mediation at polymer brush interfaces dictate whether proteins are repelled, stabilized, or destabilized. This modeling-spectroscopy framework provides molecular-level insight into protein-surface interactions critical for antifouling design.