Grafting short-chain amino acids onto membrane surfaces to resist protein fouling

The suppression of nonspecific protein adsorption to synthetic surfaces, especially membrane surfaces, represents a severe challenge in biotechnological, biomedical and biosensor community. In this work, we utilize short-chain molecules rather than long-chain polymers as modifiers for antibiofouling membrane surface construction. Three types of natural amino acids, including lysine, glycine, and serine, were chemically grafted onto membranes via carbodiimide chemistry to render highly hydrophilic surfaces, which displayed the intrinsic advantages in high surface coverage, three-dimensional modification, and unsacrificed permeability. Although hydrophilicity of membranes modified with these three types of amino acids was quite close, only lysine modified membrane surface showed superior protein fouling resistance under both static exposure and dynamic filtration conditions. Molecular dynamics simulation study was performed to tentatively interpret the underlying differences.