Development of bioactive and biocompatible ceramic composites based on potassium polytitanate

Abstract

Bioactive and biocompatible composites were successfully prepared by reactive sintering of mixtures of a crystalline titanate precursor and 45S5 Bioglass®. The polytitanate/glass precursor ratios were 20/80, 40/60, 60/40 or 80/20 (wt.%). The powder mixtures were uniaxially pressed and heat treated at 1000 °C for 1 h. During sintering, intensive interactions between raw materials occurred. The formed main crystalline phases were: potassium hexatitanate (K2Ti6O13), calcium titanate (CaTiO3), calcium silicate (CaSiO4) and sodium-calcium silicate (Na6Ca3Si6O18). Additionally, a Si-rich glassy phase was also observed. The mechanism of apatite formation indicated that both crystalline and amorphous phases play important roles in this process. A homogeneous apatite layer was formed on Si–OH, Ti–H-rich interfaces. In vitro bioactivity was assessed using simulated body fluid (SBF K-9). The in vitro cytotoxicity behaviour was evaluated using a human osteoblastlike cells model and compressive strength by ASTM C-773 standard. All the composites demonstrated high bioactivity as cytotoxicity assays indicated a biocompatibility similar to that of the negative control. The samples showed high cell adherence and elongation cell characteristics similar to those observed on biocompatible systems. The compressive strength of the sintered samples decreased as the polytitanate content precursor was increased. The results obtained indicate that these materials are highly promising composites for medical applications.

Keywords

• silicate glasses
• potassium titanate
• apatite formation
• cytotoxicity
• cell adhesion