Preparation of hydrophilic and antifouling coatings via tannic acid and zwitterionic polymers

The attachment and colonization of proteins and bacteria on the surface of implantable medical materials can lead to biofilm formation, which in turn promotes inflammation and increases the treatment burden. This study developed a hydrophilic coating with excellent adhesion and antifouling lubrication properties, by exploiting the adhesive capability of tannic acid (TA) and the antifouling zwitterionic polymer. TA-Fe³⁺ complex via coordination interactions formed a thin layer on the surface of polyethylene terephthalate (PET) and then poly(ethylenimine)-g-sulfobetaine methacrylate (PEI-g-SBMA) underwent a Schiff-base reaction with the TA layer, allowing the zwitterionic copolymer to be anchored onto the PET surface. Elemental and morphological surface analyses successfully confirmed the deposition of TA-Fe³⁺ complex and PEI-g-SBMA onto the surfaces. Water contact angle and friction coefficient tests indicated an improvement in the hydrophilic and lubricating properties of the surface after modification. Importantly, the modified surfaces exhibited a significant reduction in the adsorption of bovine serum albumin (BSA), demonstrating the excellent antifouling ability. Hemolysis tests were also conducted to assess the hemocompatibility of the coatings. The results indicated that lubricative and antifouling coatings can be easily prepared on medical material surfaces using the approach, which showed significant potential for applications in biomedical fields.