Ultra-low fouling peptide surfaces derived from natural amino acids.

This work demonstrated the ultra-low fouling natural peptides composed of certain negatively and positively charged residues such as glutamic acid (E) or aspartic acid (D) and lysine (K), in the form of either alternating or randomly mixed charge. These peptide-based materials are major candidates as biodegradable nonfouling materials since their final metabolized products are natural amino acids. Although hydrophilic materials can generally reduce nonspecific binding to a certain extent, it is very challenging to achieve ultra-low fouling, which is critical for many biomedical applications, such as medical implants, drug delivery carriers, and biosensors. Based on the design principle of uniformly mixed charges and the selection of appropriate amino acid residues, the natural peptides developed exhibit high resistance to nonspecific protein adsorption (<0.3 ng/cm(2) adsorbed proteins) comparable to what is achieved by poly(ethylene glycol) (PEG)-based materials. Mixed charged groups, when uniformly distributed at the molecular level, can achieve ultra-low fouling properties similar to zwitterionic groups due to their strong hydration ability.