Abstract
Purpose:
Osteo-odonto keratoprosthesis (OOKP) is one of the most successful forms of keratoprosthesis surgery for end-stage corneal and ocular surface disease. However, in edentulous patients a synthetic OOKP maybe required. Titanium has been shown to be a possible candidate material for a skirt of a synOOKP. However, Titanium is brittle and a stronger material e.g graphene maybe more appropriate. The aim of this study was to assess the biocompatibility of graphene in the cornea.
Methods:
Test materials included pristine graphene film, graphene foam and titanium discs (TiO2). Human corneal stroma fibroblast attachment was analyzed by immunostaining of focal adhesion proteins. Cell proliferation rates were assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and Click Edu Assay at various time points. Fibroblast attachment on the pores of the graphene foam was confirmed by scanning electronic microscopy whilst cytokine absorption was analyzed by enzyme-linked immunosorbent assay (ELISA). Graphene films were implanted into rabbit corneal stroma pockets and monitored by slit lamp, Anterior Segment Optical Coherence Tomography (AS-OCT) scanning and in vivo confocal microscopy for 3 weeks. Tissue inflammatory responses were further analyzed by Hematoxylin and Eosin (H&E) staining.
Results:
Pristine graphene demonstrated good biointegration with human corneal stromal fibroblasts in terms of cell adhesion and proliferation. Graphene displayed better cell viability at the 7 days compared with Ti. The expression levels of IL-6 and IL-8 were significantly reduced when cells were seeded on graphene foam as compared to those seeded on Ti and graphene film. Rabbit cornea tissue showed no detectable inflammation clinically and minimal inflammatory response was observed by histological analysis.
Conclusions:
Graphene displays excellent biocompatibility with corneal stroma cells and corneal tissue. Hence, graphene has the potential to be developed as a tissue engineering material suitable for use as a synthetic OOKP skirt.