Recombinant human-like collagen modulated the growth of nano-hydroxyapatite on NiTi alloy

With excellent characteristics of bio-adsorption, cell adhesiveness, virus-free, little immunogenic reaction, etc., water soluble recombinant human-like collagen was firstly utilized to modulate the growth of hydroxyapatite on NiTi shape memory alloy so as to better biofunctionalize the alloy. XRD, SEM, IR and TEM were employed to investigate the effect of recombinant human-like collagen on the formation of hydroxyapatite. The results showed that nano-hydroxyapatite coating could be formed on pretreated NiTi alloy in CSBF (Collagen Simulated Body Fluid), and the coprecipitation of hydroxyapatite and recombinant human-like collagen were confirmed by IR spectrum with the typical peaks of phosphate and amide bands. Moreover, hydroxyapatite nanocrystals showed preferential orientation on collagen fibrils with the c-axis of hydroxyapatite being parallel to the longitudinal direction of the collagen fibrils. The nano-hydroxyapatite coating with special structure would benefit for the application of NiTi alloy in the orthopaedic field.