Single walled carbon nanotubes reinforced mineralized hydroxyapatite composite coatings on titanium for improved biocompatible implant applications

A surface coating strategy encompassing the use of bioactive trace elements and reinforcing material will have a significant influence on the mechanical and osseointegration properties of bioceramic coated implants. Here, we developed mineral substituted hydroxyapatite (M-HAP) and carbon nanotube reinforced mineralized hydroxyapatite (CNT/M-HAP) composite coating on titanium (Ti) by pulsed electrodeposition which is a promising approach to produce bioimplants with better osseointegration capacity and improved mechanical properties. The role of CNT and minerals like strontium, magnesium and zinc, in enhancing the mechanical and biological properties of the HAP coating was investigated using various techniques. The structural and morphological analyses were carried out using Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray analysis and elemental mapping. The mechanical characterization results revealed enhanced adhesion strength for the composite coating. Also, an improved viability of osteoblast cells was observed in vitro on the CNT/M-HAP composite coating. The ability of the composite coated Ti implant to induce bone formation was evaluated in vivo in Wistar rats. Thus, the as-developed composite coated Ti that combines the good osteoconductivity of M-HAP together with the mechanical strength of CNT can be used as a potential implant material for orthopedic applications.