Facile synthesis of nanostructured hydroxyapatite–titania bio-implant scaffolds with different morphologies: their bioactivity and corrosion behaviour

Abstract

A facile synthesis to fabricate HAp–titania scaffolds with different morphological features has been presented. The hydrothermal approach explored for HAp growth leads to the formation of HAp coating onto titania substrate with distinct morphological features such as cauliflower, urchin, porous nanofibres network, nanorods, etc. under different reaction microenvironments. The XRD analysis done for all HAp–titania scaffold samples revealed the formation of hydroxyapatite phase. Furthermore, the detailed FTIR, SAED and EDS analysis performed confirmed the formation of hydroxyapatite. The addition of H₂O₂ to the reaction mixture led to the high degree of self-assembly of the formed nanosheets into urchin or consolidated sphere like structures when NaOH or KOH was used in hydrothermal reaction, respectively. The detailed TEM analysis reveals that the formation of such HAp structures takes place by (i) formation of localized corrosion sites on titanium substrate with NaOH/KOH and (ii) the subsequent recrystallization of HAp sol onto the corrosion sites which act as nucleation site. The Tafel plot measurements and MTT assay test indicate that the HAp–titania scaffold samples are corrosion resistance as compared to bare titanium foil and are biocompatible. The structural characterization, growth mechanism, corrosion behaviour in SBF medium and cellular biocompatibility of these scaffold samples are discussed in detail.