In situ formation of bioactive calcium titanate coatings on titanium screws for medical implants

Abstract

The objective of this study was to improve the biocompatibility of titanium screws using a hydrothermal technique combined with chemical oxidation treatment. Bioactive calcium titanate (CaTiO₃) coatings were synthesized on titanium screws by alkali heat treatment without sintering. A cell-based experiment was conducted to evaluate cell attachment and proliferation on the surface of modified titanium screws. Cells grown on the CaTiO₃-coated surfaces (denoted CT-TI) had a higher proliferation rate than their counterparts grown on titanium screws without any surface modification (denoted TI-TI). The results indicated that the CaTiO₃ coatings improved the surface bioadhesion characteristics of titanium screws. The biocompatibility of CaTiO₃ coatings on titanium was also investigated by implanting titanium screws covered with CaTiO₃ coatings into living bone. The interface between the bone tissue and titanium screws was observed by environmental scanning electron microscopy 2, 4, 8 and 12 weeks after implantation. The boundaries between the bone tissue and the titanium screws coated with CaTiO₃ became indistinguishable more quickly than that between bone tissue and titanium screws without any surface modification. Thus, the biocompatibility of titanium screws coated with CaTiO₃ was higher than that of titanium screws without any surface modification. Therefore, the hydrothermal technique is an excellent surface-modification method to improve the biocompatibility of titanium screws. We have great confidence that these surface-modified titanium screws will be useful in in vivo bone.