The effect of nanometric surface texture on bone contact to titanium implants in rabbit tibia

Designing biomaterial surfaces to control the reaction of the surrounding tissue is still considered to be a primary issue, which needs to be addressed systematically. Although numerous in vitro studies have described different nano-metrically textured substrates capable to influence bone cellular response, in vivo studies validating this phenomenon have not been reported. In this study, nano-grooved silicon stamps were produced by laser interference lithography (LIL) and reactive ion etching (RIE) and were subsequently transferred onto the surface of 5 mm diameter Titanium (Ti) discs by nanoimprint lithography (NIL). Patterns with pitches of 1000 nm (500 nm ridge and groove, 150 nm depth), 300 nm (150 nm ridge and groove, 120 nm depth; as well as a 1:3 ratio of 75 nm ridge and 225 nm groove, 120 nm depth) and 150 nm (75 nm ridge and groove, 30 nm depth) were created. These samples were implanted in a rabbit tibia cortical bone. Histological evaluation and histomorphometric measurements were performed, comparing each sample to conventional grit-blasted/acid-etched (GAE) titanium controls. Results showed a significantly higher bone-to-implant contact at 4 weeks for the 300 nm (1:3) specimens, compared to GAE (p = 0.006). At 8 weeks, there was overall more bone contact compared to 4 weeks. However, no significant differences between the nano-textured samples and the GAE occurred. Further studies will need to address biomechanical testing and the use of trabecular bone models.