In vivo evaluation of titanium oxide and hydroxyapatite as an artificial cornea skirt Xiao Wei Tan • Roger W. Beuerman • Zhi Long Shi • Koon Gee Neoh • Donald Tan • Khiam Aik Khor • Jodhbir S. Mehta Received: 5 September 2011 / Accepted: 2 February 2012 / Published online: 17 March 2012 Ó Springer Science+Business Media, LLC 2012 Abstract Keratoprosthetic devices are subject to chronic inflammatory, pathological processes and the external envi- ronment that affect their stability and biocompatibility with the ocular surface and adjacent ocular tissues. We compared the corrosion resistance property and tissue-implant reaction of titanium oxide (TiO 2 ) with hydroxyapatite (HA) in artificial tear fluid and a rabbit skin implantation model. The dissolu- tion properties of the implant surfaces were evaluated with scanning electronic microscope (SEM) and atomic force microscope (AFM). Tissue inflammatory reactions were evaluated by Hematoxylin & Eosin staining, avidin biotin peroxidase complex (ABC) immunoassay and immunofluo- rescence. SEM and AFM images showed that there was less pitting corrosion on the surface of TiO 2 implants compared with HA. TiO 2 and HA exhibited a similar pattern of foreign body capsule formation and inflammatory cellular responses. The Collagen I/Collagen III ratio of the TiO 2 capsule was higher than that of the HA capsule. TiO 2 implants possess a high corrosion resistance property both in vitro and in vivo and the inflammatory cellular response to TiO 2 is similar to HA. With regards to corrosion resistance and inflammatory tissue responses, TiO 2 appears to be a promising material for kera- toprosthetic skirt devices. 1 Introduction The Osteo-odonto keratoprosthesis (OOKP) is a keratopros- thesis (KPro) designed for the most severe, end-stage forms of corneal and ocular surface disease conditions such as Stevens Johnson Syndrome, ocular cicatricial pemphigoid and chem- ical/thermal injuries. Patients with these conditions do not benefit from conventional corneal transplantation with or without epithelial stem cell reconstruction, due to the severe dry eye environment, eyelid abnormalities, vascularized and inflamed corneas in these conditions [1–4]. OOKP surgery involves harvesting an autologous canine tooth with attached maxillary bone, and using this as a peripheral skirt to secure a polymethylmethacrylate (PMMA) optical cylinder. This is implanted through the cornea, with an overlying autologous full-thickness buccal mucosal graft to secure the entire osteo- dental-optic device. An initial implantation of the PMMA/ bone/dentine complex in the contra-lateral suborbicularis X. W. Tan Á R. W. Beuerman Á J. S. Mehta (&) Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Drive, Singapore 168751, Singapore e-mail: jodmehta@gmail.com R. W. Beuerman Á D. Tan Á J. S. Mehta Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore R. W. Beuerman Duke-NUS SRP Neuroscience and Behavioral Disorders, National University of Singapore, Singapore, Singapore Z. L. Shi Á K. G. Neoh School of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore D. Tan Á J. S. Mehta Singapore National Eye Centre, Singapore, Singapore D. Tan Singapore Eye Research Institute, 11 Third Hospital Drive, Singapore, Singapore K. A. Khor School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore J. S. Mehta Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore 123 J Mater Sci: Mater Med (2012) 23:1063–1072 DOI 10.1007/s10856-012-4578-6