(687h) Nonfouling Materials From Zwitterionic and Mixed Charged Groups

A major challenge in the field of biomaterials is the prevention of nonspecific protein adsorption on surfaces. Nonspecific protein adsorption degrades the performance of surface-based diagnostic devices and has an adverse effect on the healing process for implanted biomaterials. Thus, it is desirable to be able to prepare nonfouling materials from a variety of compounds using a simple approach.

Here we investigated nonspecific protein adsorption onto poly(carboxybetaine acrylamide) (polyCBAA)-grafted surfaces. Results show that nonspecific protein adsorption from undiluted human blood serum, plasma, and aged serum on the polyCBAA-grafted surface is undetectable at both 25 °C and 37 °C by a surface plasmon resonance (SPR) sensor when the film thickness of ~21 nm. This is the first time that an effective nonfouling material suitable for applications in complex blood media has been demonstrated. Furthermore, we 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. 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/cm² 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.