(84d) Molecular Understanding and Design of Zwitterionic Materials

An important challenge in many applications, ranging from medical devices to ship hulls, is the prevention of nonspecific protein adsorption on surfaces. To address this challenge, our goals are twofold. First, we strive to provide a fundamental understanding of nonfouling mechanisms at the molecular level using an integrated experimental and simulation approach. Both simulation and experimental results show that the strong hydration of zwitterionic materials is responsible for their excellent nonfouling properties (JACS, 127, 14473, 2005). Further studies examine zwitterionic structures and reveal the role of these structures in nonfouling properties beyond hydration (Advanced Materials, 27, 15, 2015). Second, we aim to develop biocompatible and environmentally benign ultra low fouling materials based on the molecular principles learned. We have demonstrated that zwitterionic and mixed charge materials and surfaces are highly resistant to nonspecific protein adsorption, cell adhesion and bacteria adhesion/biofilm formation from complex media. Recent results show that zwitterionic materials induce no capsule formation upon implantation (Nature Biotechnology, 31, 553, 2013) and no immunological response in blood circulation (PNAS, 112, 12046, 2015). Furthermore, these materials are shown to preserve protein (Nature Chemistry, 4, 59, 2012) and cell (Angewandte Chemie, 53, 12729, 2014) bioactivity. Because of these unique properties, zwitterionic materials are excellent alternatives to widely used poly(ethylene glycol) (PEG)-based materials.