Macrophage Response to Zinc Oxide Nanorod Surfaces -Topography and Toxicity

摘要

Macrophages recruited to the site of biomaterial implantation are the primary mediators of the chronic foreign body response to implanted materials. Hence various approaches have been investigated to modulate macrophage interactions with biomaterial surfaces to mitigate the inflammatory response. The extent of the inflammatory response mounted by the body has been shown to be modulated by the implant material and its surface properties. Because of their unique surface properties, there is great interest in exploring nanostructured materials for potential biomedical applications. Nanotopography is known to modulate cell adhesion and viability depending on cell type. As macrophage adhesion to biomaterial surfaces is one of the first steps of the inflammatory response to a foreign body, a surface which inhibits macrophage adhesion and function may serve to modulate the foreign body response. ZnO is used in a number of biomedical applications such as glucose detection, wound healing and dental filling materials. We have evaluated macrophage adhesion and viability on ZnO nanorods as compared to a control sputtered ZnO flat substrates and reference glass surfaces. Macrophage adhesion and viability was reduced by 50 % on nanorods as compared to ZnO flat substrate and glass suggesting that this nanotopography is potentially useful for biomaterial surfaces. Macrophage viability decreased when ZnO nanorods [62%] and flat surfaces [45%] were present in the same media but not in cell contact, suggesting moderate levels of toxicity associated with ZnO due to dissolution in media. The decreased viability when macrophages were in contact compared to non-contact suggests that modulation of cell adhesion and viability on nanorods is dominantly due to topography rather than material toxicity. We therefore plan to further investigate these nanotopographies constructed from other materials which are not toxic to macrophages in order to explore macrophage-modulating surfaces for biomaterial applications.