Polycaprolactone/fluoride substituted-hydroxyapatite (PCL/FHA) nanocomposite coatings prepared by in-situ sol-gel process for dental implant applications

In this study, polycaprolactone (PCL) and polycaprolactone/fluoride substituted-hydroxyapatite (PCL/FHA) nanocomposite coatings at different composition (10, 20 and 30 wt.% of FHA) are deposited on alkali-treated Ti6Al4V substrate via in-situ sol-gel method to improve its corrosion behavior and in vitro bioactivity. The PCL and PCL/FHA nanocomposite coatings are characterized by scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The in vitro bioactivity and corrosion behavior of the coatings are also investigated to show their potential application for dental implants. The results indicate that the in-situ sol-gel process is capable of forming compact and crack-free coatings with a homogeneous dispersion of FHA as a ceramic phase in the polymeric matrix. By increasing the FHA content, the hydrophilicity, adhesion strength and surface roughness were increased. Furthermore, in vitro bioactivity of the PCL/FHA nanocomposite coatings was improved by increasing the FHA content and the incubation time in simulated body fluid (SBF). The corrosion resistance of the PCL/10 wt.% FHA coatings considerably increased as compared to the pure PCL and PCL/FHA coatings with 20 and 30 wt.% of FHA. Additionally, the MTT assay confirmed that the coatings have no considerable cytotoxicity effect and PCL/20 wt.% FHA coating promoted the proliferation and spreading of MG63 cells. Indeed, the results showed that the PCL/FHA nanocomposite coatings on alkali-treated Ti6Al4V substrate may be a promising candidate for dental implant applications.