Sol-gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces

► Formation of tantalum/carbon nanotube composite coatings on titanium plates by sol-gel co-deposition. ► Synthesis and incorporation of MWCNTs bearing bisphosphonic acid moieties. ► Stronger “tantalum capture agent” effect of phosphonic-modified MWCNTs comparing to oxidized ones. ► Bioactivity of the resulting biomaterial qualitatively assessed by in vitro growth tests of hydroxyapatite.