Surface modifications of titanium implants by coating with bioactive and biocompatible poly (ε-caprolactone)/SiO2 hybrids synthesized via sol-gel

Class I organic/inorganic hybrid materials have been synthesized by sol-gel method from a multicomponent solution containing tetraethyl orthosilicate (TEOS), water, ethanol and nitric acid by adding different percentages of poly (ε-caprolactone) (PCL) dissolved in chloroform. Those hybrids have been used, in sol phase, to dip coat commercially pure titanium (CP Ti) grade 4 substrates with the aim of transferring to them the known biological properties of silica-based sol-gel materials. Particular attention has been directed to investigate the effect of PCL amount on both structure and coating performances.The chemical composition of the films was ascertained by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis. Scanning electron microscope (SEM) proved that polymer allows to make crack-free coatings.The biological performances of the un-coated and coated substrates were compared and evaluated by means of bioactivity test and WST-8 assay. SEM and energy dispersive X-ray (EDX) analyses have detected higher hydroxyapatite nucleation on the surface of the coated substrates after soaking in a fluid simulating the composition of the human blood plasma (SBF). Moreover, higher vitality of NIH 3T3 mouse embryonic fibroblast cells seeded on coated specimens was recorded. The results, thus, prove that coating application effectively improves the bioactivity and biocompatibility of CP Ti grade 4 substrates.