In vivo evaluation of titanium oxide and hydroxyapatite as an artificial cornea skirt

Abstract

Keratoprosthetic devices are subject to chronic inflammatory, pathological processes and the external environment 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 dissolution 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 immunofluorescence. 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 keratoprosthetic skirt devices.

Application of Graphene as Candidate Biomaterial for Synthetic Keratoprosthesis Skirt

“…9,15 Bioactive materials, including glass and hydroxyapatite (HA) ceramics, have shown good tissue integration. 16,17 However, serious complications such as aqueous leakage, retroprosthetic membrane formation, and endophthalmitis are frequently observed due to the degradation of these bioactive materials. 9,15 Bioinert materials, such as titanium (Ti) or titanium alloys, aluminum, or their modified compounds have also been used as Kpro skirt materials.…”

“…18 We have previously shown that sintered titanium dioxide (TiO 2 ) exhibited excellent biocompatibility and corrosion resistance properties in an in vitro simulated ocular environment and in vivo animal model. 16,17 To further improve the biocompatibility and bactericidal properties of the implants, we functionalized the surface of TiO 2 with antimicrobial peptide coating. 19,20 The nonoxidized, metallic Ti has been used in the Boston KPro, due to its better compatibility compared to PMMA, 21 and the decreased formation of retroprosthetic membranes when Ti was used as a backing plate.…”

In Vitro and In Vivo Assessment of Titanium Surface Modification for Coloring the Backplate of the Boston Keratoprosthesis

“…The color is solely based on the controlled thickness of the Ti oxide layer. Characterization of the anodized Ti was undertaken using scanning electron microscopy, 9 XRD, 7 FTIR, 10 and AFM, 11 as previously described. High-resolution scanning electron microscopy images (10 nm) were acquired using the field emission scanning electron microscopy (FESEM) Ultra Plus (Carl Zeiss Microscopy GmbH, Jena, Germany) for surface morphology evaluation as previously described.…”

How can bioactive glasses be useful in ocular surgery?

“…It is worth underlining that the ideal implantation site for ophthalmic biomaterials is the eye with its unique physiological and microenvironmental characteristics; however, this requires the expertise and availability of an ophthalmic surgeon to perform operation, which can represent an additional difficulty in building interdisciplinary research teams. In order to simplify the experiments, some authors proposed a rabbit skin subcutaneous model to investigate the in vivo suitability of new keratoprosthetic biomaterials . Special care should be dedicated to the development of methods to correlate and interpret the results deriving from different in vivo studies, the selection of the most appropriate animal models and the sequence to follow in performing the experiments.…”