Nonfouling Coatings from Synthetic Intrinsically Disordered Proteins

The antifouling performance of a previously developed triblock protein, B-M-E is optimized, that self-assembles on gold surfaces to form a nonfouling layer by modifying the sequence of its E block. In this protein, B is a gold-binding domain, M is a trimerization domain, and E is a synthetic intrinsically disordered protein (IDP) that confers nonfouling behavior. To identify optimal sequences for the nonfouling E block, a few candidate IDPs are screened that provide a proxy for nonfouling behavior, such as extending the half-life of their fusion partners in systemic circulation and sequences that promote soluble expression of their fusion partners in E coli. One IDP is identified with the sequence [(GAGAIP)₃-(GAGEIP)]₄ as the E block in B-M-E brush on gold, forming a nonfouling coating with performance comparable to a self-assembled monolayer (SAM) of a tetraethylene glycol-terminated alkanethiol on gold. These B-M-E brushes also render gold surfaces resistant to E. coli attachment for at least seven days. The B-M-E protein can be synthesized at scale in bacterial expression systems using the upstream fermentation and downstream purification capabilities of the biotechnology industry. It may provide a useful and robust alternative to existing nonfouling coatings based on small molecules or synthetic polymers.