In vivo evaluation of microbial infection on surface functionalized titanium as artificial cornea candidate material

Abstract

Purpose: Artificial keratoprosthesis skirts are prone to microbiological infection after implantation. Previous studies have shown that coating titanium surface with antimicrobial peptide (AMP), human beta-defensin analogue SESB2V, could improve the bactericidal effect of the titanium alloy in an in vitro environment. Here we aimed to test the bactericidal effect of the functionalized titanium oxide (TiO2) with a rabbit cornea infection model.

Methods: SESB2V AMP was bound onto the surface of titanium oxide via crosslinking with polydopamine. A corneal stroma pocket was created by a femtosecond laser assisted LASIK surgery. TiO2 discs were inserted into the pocket through a small corneal incision. After 1 week of wound healing, 50 ul S.aureus (1X103 CFU/ml) were injected into the pocket right above the TiO2 inserts. The implanted corneas were compared with normal and sham-operated corneas through slit lamp observation and anterior segment optical coherence tomography (AS-OCT). After 2 days of infection, rabbit cornea tissue was collected for haematoxylin and eosin (H&E) staining. Inflammatory response was also evaluated by staining with CD11b and MMP9 antibodies

Results: There were less incidence of corneal infection and less extent of infection on rabbit corneas with SESB2V coated implants compared to those corneas with non-coated implant. Histological analysis also revealed that less inflammatory cells were found in the cornea pocket tissue with the AMP coated TiO2 discs compared to those with non-coated TiO2 discs.

Conclusions: SESB2V AMP significantly improved the bactericidal effect of TiO2 discs in vivo, which is a potential candidate biomaterial for artificial cornea skirt. This would further expand the usage of TiO2 in the development of keratoprosthesis device.

Keywords: 480 cornea: basic science • 575 keratoprostheses • 594 microbial pathogenesis: experimental studies