(561b) Molecular Design Principles of Anti-Biofouling Zwitterionic Moieties

Zwitterionic materials are receiving more and more attention because of their ability to resist biofouling. A better understanding of the molecular basis for the anti-biofouling ability of zwitterionic materials could help in the rational design of new anti-biofouling materials. In this work, we tried to decipher how the properties of zwitterionic moieties depend on their molecular structure and how these properties determine the anti-biofouling ability of zwitterionic materials. We investigated the hydration of zwitterionic carboxybetaine and sulfobetaine moieties, and of carboxybetaine moieties with different distances between charged groups in water using molecular simulations. The hydration free energies of the zwitterionic moieties, and the structural and dynamic properties of the water molecules surrounding them were probed and analyzed. The charge densities of these zwitterionic moieties were calculated using quantum mechanical calculations. We also investigated their self-association and protein interactions. An examination of the anti-biofouling ability of materials prepared from these zwitterionic moieties indicates three key factors to design zwitterionic anti-biofouling materials: strong hydration, weak self-association and “not binding proteins”. We also developed a systematic approach to design new anti-biofouling zwitterionic structure rooted in simulation. Experiment verified that a zwitterionic moiety designed using this approach is indeed a promising candidate for an anti-biofouling material. .