Fabrication of Versatile Antifouling Coatings Inspired by Melanogenesis Using a Tyrosine-Conjugated Carboxybetaine Derivative.

In this study, we developed zwitterionic surface coatings of carboxybetaine by mimicking natural melanogenesis. We synthesized an unnatural tyrosine-conjugated carboxybetaine (Tyr-CB) that undergoes melanin-like oxidation upon treatment with tyrosinase under various aqueous conditions. The thickness of the resulting poly(Tyr-CB) film was tuned by adjusting the pH during the coating process. The poly(Tyr-CB)-coated surfaces demonstrated excellent antifouling performance against proteins and cells and imparted (super)hydrophilicity to various substrates. Additionally, post-functionalization with external biotin-PEG-thiol was achieved by targeting the oxidized quinone groups within the poly(Tyr-CB) film network. This enabled biospecific binding to streptavidin, while non-specific interactions were suppressed due to the antifouling background. As our one-step antifouling coating method is simple, involves aqueous conditions, and could be generically used to coat various substrates, it can be a versatile and valuable tool for biosensing, high-throughput screening, and cell-surface engineering.