Zwitterionic-Based Surface via the Coelectrodeposition of Colloid Particles and Tannic Acid with Bacterial Resistance but Cell Adhesion Properties

Herein, a hydrophobized zwitterionic-based copolymer poly(sulfobetaine methacrylate-co-2-(dimethylamino)ethyl methacrylate-co-isobornyl acrylate) (P(SBMA-co-DMA-co-ISA), PSDI) containing a chiral structure has been successfully synthesized by free radical polymerization and subsequent sulfonation reactions. Together with tannic acid (TA), PSDI colloidal particles (CPs) were anchored onto the Ti alloy surface by the electrophoretic deposition method. The composition, morphology, and surface properties of the CP-TA composite coatings were characterized by  fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), optical contact angle (OCA), and other methods. The results show that the introduction of TA improves the stability of coatings by participating in the noncovalent interactions including ionic pairing and hydrogen bonding. According to the in vitro bacterial adhesion test, the modified titanium surface containing SBMA and chiral ISA functional units can effectively inhibit Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) adhesion. Furthermore, the excellent cytocompatibility and favorable cell adhesion and growth behavior of zwitterionic-based coatings were realized as a result of the appropriate hydrophobicity provided by the ISA moiety. This work provides a new strategy for preparing zwitterionic-based multifunctional coating. The coating with excellent bacterial and cell selective adhesion properties has great potential in the applications of metal implant materials, such as cardiovascular stents and human hard tissue repair and replacement materials.