Constructing Antifouling Porous Surfaces by Grafting Short-Chain Amino Acids Rather Than Long-Chain Polymers

Despite extensive studies, the prevention of nonspecific protein adsorption to artificial surfaces, especially porous surfaces (e.g. membranes), still represents a severe challenge in biotechnological and biomedical community. In this work, we utilize short-chain molecules rather than long-chain polymers as modifying agents for antifouling surface construction. Three types of natural amino acids, including lysine, glycine, and serine, were chemically grafted onto porous membranes to render highly hydrophilic surface, which showed the intrinsic advantages in high coverage, three-dimensional modification, unsacrificed permeability. The contact angle measurement indicated that hydrophilicity of membranes modified with different amino acids was quite close, while only lysine modified membrane surface showed superior protein resistance under both static exposure and dynamic filtration conditions. Molecular dynamic (MD) simulation indicated water molecules around lysine modified membrane surface tended to form compact hydration layer, which were most possibly responsible for the protein fouling resistance.