In vitro osteoconductivity evaluation of alumina treated hydrothermally in CaCl2 solution

Alumina (Al2O3) is classified as bioinert materials and thus, no direct bonding to bone was observed when implanted. In the present investigation, possibility of osteoconductive Al2O3 was evaluated based on hydrothermal treatment in calcium chloride (CaCl2) solution. Based on X-ray photoelectron spectroscopy measurement, Ca2p peaks were detected on Al2O3 after hydrothermal treatment with 10 and 50 mmol/L CaCl2 solution at 125°C. The Ca2p peak intensity for Al2O3 treated with 50 mmol/L CaCl2 was higher than that treated with 10 mmol/L CaCl2. Then, in vitro osteoconductivity screening evaluation was made using simulated body fluid (SBF). After being soaked in SBF for 14 days, calcium phosphate deposition could be observed on Al2O3 treated with 10 and 50 mmol/L CaCl2 solution at 125°C for 7 days whereas no deposition was observed on Al2O3 treated at 150 and 200°C as well as non-treated Al2O3. We concluded, therefore, osteoconductive Al2O3 could be fabricated based on the hydrothermal treatment of bioinert Al2O3 with CaCl2.