(293c) Reducing Nonspecific Protein Adsorption and Friction Force By Stable Self-Assembled Monolayers of Zwitterionic Polysulfobetaine With Adhesive Bisphosphonic Acid On Titanium Oxide Surfaces

Biocompatibility and surface friction force are of great concern in the application of titanium (Ti) and its alloys as implantable biomaterials, such as artificial joints. To improve protein resistance of implantable device made by titanium or titanium alloy and reduce friction force, zwitterionic poly(sulfobetaine methacrylate)s (pSBMA) with an adhesive group, alendronic acid (ALD), are synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and further terminal modification. The polymer (pSBMA-ALD) can quickly assemble on TiO₂ surfaces from a very low concentration aqueous solution. The self-assembled monolayers (SAMs) of pSBMA-ALD on TiO₂ surfaces were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (FT-IR/ATR) and X-ray photoelectron spectroscopy (XPS), indicating the formation of high quality SAMs through strong bisphosphonate-TiO₂ interaction. The modified TiO₂ surfaces showed both excellent resistance to non-specific protein adsorption with long-term stability and remarkable reduction of friction coefficient by the less than 10 nm thin SAMs of pSBMA-ALD. All these results indicate pSBMA-ALD could be a promising candidate for artificial joints improvement.