Abstract Due to the inherent brittleness and low mechanical strength, it is still a challenge for calcium phosphate (Ca‐P) ceramics to be used in load‐bearing bone defect repair. To achieve a good balance between mechanical strength and osteogenic activity, hollow‐tube‐whisker‐modified biphasic calcium phosphate (BCP) ceramics (BCP‐HW) are successfully fabricated by an in situ growth process in the present study. Compared to the initial BCP ceramics (BCP‐C) and those with solid whiskers, BCP‐HW exhibits larger specific surface area (3.9 times vs BCP‐C) and higher mechanical strength (3.4 times vs BCP‐C), endowing it with stronger stimulation on adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. In an intramuscular implantation model of canine, BCP‐HW shows excellent osteoinductivity and promotes the maturation of new bone, and the resultant compressive strength of the implant increases to ≈12 MPa at 3 months postoperatively. In another critical‐sized segmental bone defect model of rabbit femur, BCP‐HW has the best repairing effect. After implantation for 6 months, much more new bone ingrowth and higher bending load are observed in BCP‐HW than BCP‐C. Collectively, these findings suggest that the in situ hollow‐tube whisker construction possesses immense potential in expanding the applications of Ca‐P ceramics to load‐bearing bone defect repair.
Abstract Calcium phosphate (CaP) bioceramics are widely applied in the bone repairing field attributing to their excellent biological properties, especially osteoinductivity. However, their applications in load-bearing or segmental bone defects are severely restricted by the poor mechanical properties. It is generally considered that it is challenging to improve mechanical and biological properties of CaP bioceramics simultaneously. Up to now, various strategies have been developed to enhance mechanical strengths of CaP ceramics, the achievements in recent researches need to be urgently summarized. In this review, the effective and current means of enhancing mechanical properties of CaP ceramics were comprehensively summarized from the perspectives of fine-grain strengthening, second phase strengthening, and sintering process optimization. What’s more, the further improvement of mechanical properties for CaP ceramics was prospectively proposed including heat treatment and biomimetic. Therefore, this review put forward the direction about how to compatibly improve mechanical properties of CaP ceramics, which can provide data and ideas for expanding the range of their clinical applications.
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