Fabrication and evaluation of carbonate apatite-coated calcium carbonate bone substitutes for bone tissue engineering.

Carbonate apatite-coated calcium carbonate (CO ₃ Ap/CaCO ₃ ) was fabricated through a dissolution-precipitation reaction using CaCO ₃ granules as a precursor to accelerate bone replacement based on superior osteoconductivity of the CO ₃ Ap shell, along with Ca ²⁺ release from the CaCO ₃ core and quicker resorption of the CaCO ₃ core. In the present study, CaCO ₃ , 10% CO ₃ Ap/CaCO ₃ , 30% CO ₃ Ap/CaCO ₃ , and CO ₃ Ap granules were fabricated and examined histologically to evaluate their potential as bone substitutes. Larger contents of CaCO ₃ in the granules resulted in higher Ca ²⁺ release and promoted cell proliferation of murine preosteoblasts at 6 days compared with CO ₃ Ap. Interestingly, in a rabbit femur defect model, 10% CO ₃ Ap/CaCO ₃ induced significantly higher new bone formation and higher material resorption compared with CO ₃ Ap at 8 weeks. Nevertheless, CO ₃ Ap showed a superior osteoconductive potential compared with 10% CO ₃ Ap/CaCO ₃ at 8 weeks. All tested granules were most likely resorbed by cell mediation including multinucleated giant cell functions. Therefore, we conclude that CO ₃ Ap/CaCO ₃ has a positive potential for bone tissue engineering based on well-controlled calcium release, bone formation, and material resorption.
(© 2018 John Wiley & Sons, Ltd.)