Physiological and elastic properties of highly porous hydroxyapatite potential for integrated eye implants: Effects of SIRC and L-929 cell lines

Hydroxyapatite (HAp)-based highly porous integrated orbital implants with a property of mimicking the movements of fellow eye have been developed recently. Before designing this kind of scaffolds, vascularization and angiogenesis in the constructs need to be considered. Moreover, eye cells expressed with time on these highly porous implants may exert some compressive load whose effect both mechanically and physiologically may indicate its long-term life in vivo. In the present investigation the effect of expression of eye cell lines [rabbit corneal epithelial cell line (SIRC)] on highly porous HAp scaffolds were compared with the normal fibroblastic cells on HAp in general, in terms of in vitro dissolution studies, cell culture cytotoxicity and cell adhesion properties. Elastic properties of macro-porous HAp with a wide range of porosities have also been estimated by ultrasonic non-destructive test methods and the results were compared with its compressive properties for potential application as integrated ocular implants. Cell viability of HAp in contact with SIRC is far better than the L-929 during the initial periods (48 h) but cell adhesion behavior however showed better results in L-929 than the SIRC during the same initial time period. SIRC cells however eventually formed better adhesion properties on the surface of HAp as the days goes by than L-929. High concentration of both Ca and P in culture media might be another factor in cell growth modification. Both the ions had a counter effect on the L-929 and SIRC cells.