Self-Organized Metal Oxide Exhibiting Enhanced Bioactivity

Self-assembled niobium oxide microcones produced by potentiostatic anodization with varied NaF content (between 100 and 250 mg) in an HF electrolyte are shown to nucleate mineral when immersed in supersaturated solutions emulating mineral content in saliva and blood. The most extensive mineral coverage in 100 mL of 2.5 wt. % HF electrolyte occurs when NaF content is about 100 mg with substantial mineral formation occurring within 24 hours. Higher salt content apparently alters the conditions favoring mineral nucleation by generating smaller nucleation centers that ultimately diminish the extent of mineral coverage. Additionally, nucleation kinetics and morphological contrasts between mineral formed from saliva and blood is briefly discussed in terms of the relative degree of supersaturation with respect to hydroxyapatite. Finally, we show that the integrity of the microcone shape is not critical for mineral nucleation, an observation that builds on our prior hypothesis by promoting the importance of self-assembly and crystal formation. Based on these results, we demonstrate the influence of NaF and stress the role of the self-organization process in producing effective mineral nucleation sites.