Substrate-Independent Photografting of Hyaluronic Acid for Antifouling Coatings

This work introduces a substrate-independent method for covalently immobilizing pristine hyaluronic acid (HA) as an antifouling coating on various surfaces. A tyrosine-conjugated perfluorophenyl azide (Tyr-PFPA) was synthesized, containing a tyrosine moiety that undergoes tyrosinase-mediated oxidation to form a melanin-mimetic film on various substrates and a PFPA moiety that undergoes photolysis to generate nitrenes. The resulting poly(Tyr-PFPA) film enabled the covalent grafting of HA via simple photoirradiation following physical adsorption, forming a poly(Tyr-PFPA)-HA film. The coating, composed of a thin layer of HA, rendered the surface superhydrophilic and suppressed the nonspecific adsorption of proteins and adhesion of fibroblasts. The same coating procedure was applied to a range of substrates, and spatially selective HA immobilization was achieved by using a photomask to create well-defined protein and cell patterns. The proposed strategy provides a promising solution for covalently anchoring chemically inert HA onto various substrates in a facile manner, which is valuable for antifouling surface modifications for biosensors, medical stents, and marine coatings.