Affiliations: [a] Department of Pediatric Dentistry, Division of Developmental Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan | [b] Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan
Abstract: Using a wet method, we have synthesized octacalcium phosphate carbonate, in which HPO42− in octacalcium phosphate is replaced with CO32−. The physical, crystal, and chemical properties of this new material were compared to octacalcium phosphate, Ca-deficient hydroxyapatite, and Ca-deficient carbonate apatite using X-ray diffraction, Fourier-transform infrared spectroscopy, inductively coupled plasma spectroscopy, and scanning electron microscopy. Surface roughness and morphology were also characterized, along with the ability to support proliferation and differentiation of MG63 cells, as measured by MTT and alkaline phosphatase assay. We found that octacalcium phosphate carbonate enhanced osteoblast proliferation more strongly than all other materials tested. Similarly, Ca-deficient carbonate apatite, a hydrolysate of octacalcium phosphate carbonate, stimulated osteoblast differentiation to a better extent than Ca-deficient hydroxyapatite, a carbonate-free hydrolysate of octacalcium phosphate. These results indicate that octacalcium phosphate carbonate has good biocompatibility and osteoconduction, and incorporation of carbonate into octacalcium phosphate and apatite enhances bone regeneration.
Keywords: Octacalcium phosphate, calcium-deficient hydroxyapatite, carbonate substitution, osteoblast, bone regeneration
