Titanium Coating of the Boston Keratoprosthesis

Abstract

Purpose: We tested the feasibility of using titanium to enhance adhesion of the Boston Keratoprosthesis (B-KPro), ultimately to decrease the risk of implant-associated complications. Methods: Cylindrical rods were made of poly(methyl methacrylate) (PMMA), PMMA coated with titanium dioxide (TiO[subscript 2]) over a layer of polydopamine (PMMA[subscript TiO2]), smooth (Ti) and sandblasted (Ti[subscript SB]) titanium, and titanium treated with oxygen plasma (Ti[subscript ox] and Ti[subscript SBox]). Topography and surface chemistry were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Adhesion force between rods and porcine corneas was measured ex vivo. Titanium sleeves, smooth and sandblasted, were inserted around the stem of the B-KPro and implanted in rabbits. Tissue adhesion to the stem was assessed and compared to an unmodified B-Kpro after 1 month. Results: X-ray photoelectron spectroscopy demonstrated successful deposition of TiO[subscript 2] on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and Ti[subscript SB]), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMA[subscript TiO2], smooth titanium treated with oxygen plasma (Ti[subscript ox]), and sandblasted titanium rods (Ti[subscript SB], Ti[subscript SBox]) showed significantly higher adhesion forces than PMMA ex vivo. In vivo, the use of a Ti[subscript SB] sleeve around the stem of the B-KPro induced a significant increase in tissue adhesion compared to a Ti sleeve or bare PMMA. Conclusions: Sandblasted titanium sleeves greatly enhanced adherence of the B-KPro to the rabbit cornea. This approach may improve adhesion with the donor cornea in humans as well. Translational Relevance: This approach may improve adhesion with donor corneas in humans.