Titanium Coating of the Boston Keratoprosthesis

Borja Salvador-Culla; Kyung Jae Jeong; Paraskevi Evi Kolovou; Homer H Chiang; James Chodosh; Claes H Dohlman; Daniel S Kohane

doi:10.1167/tvst.5.2.17

Titanium Coating of the Boston Keratoprosthesis

Transl Vis Sci Technol. 2016 Apr 28;5(2):17. doi: 10.1167/tvst.5.2.17. eCollection 2016 Apr.

Authors

Borja Salvador-Culla¹, Kyung Jae Jeong², Paraskevi Evi Kolovou³, Homer H Chiang⁴, James Chodosh³, Claes H Dohlman³, Daniel S Kohane⁵

Affiliations

¹ Department of Ophthalmology Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA ; Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA ; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
² Department of Chemical Engineering, University of New Hampshire, Durham, NH, USA.
³ Department of Ophthalmology Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA.
⁴ Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA ; David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁵ Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA ; Department of Ophthalmology Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA.

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 (TiO₂) over a layer of polydopamine (PMMA_TiO2), smooth (Ti) and sandblasted (Ti_SB) titanium, and titanium treated with oxygen plasma (Ti_ox and Ti_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 TiO₂ on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and Ti_SB), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMA_TiO2, smooth titanium treated with oxygen plasma (Ti_ox), and sandblasted titanium rods (Ti_SB, Ti_SBox) showed significantly higher adhesion forces than PMMA ex vivo. In vivo, the use of a Ti_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.

Keywords: Boston Keratoprosthesis; artificial cornea; biointegration; corneal adhesion; keratoprosthesis; titanium adhesion; titanium coating; titanium oxide; titanium skirt.

Grants and funding

R01 GM073626/GM/NIGMS NIH HHS/United States