This study use freeze-drying technology prepared a PT-M-CN bioactive porous composite scaffold for bone defects repairing. Results showed it has a great potential to promote osteogenic differentiation and new bone regeneration.

Background Orthopedics has made great progress with the development of medical treatment; however, large bone defects are still great challenges for orthopedic surgeons. A good bone substitute that can be obtained through bone tissue engineering may be an effective treatment method. Artificial hydroxyapatite is the main inorganic component of bones, but its applications are limited due to its fragility and lack of bone-active elements. Therefore, it is necessary to reduce its fragility and improve its biological activity. Methods In this study, we developed micro-hydroxyapatite whiskers (mHAws), which were doped with the essential trace active elements Mg²⁺ and Sr²⁺ through a low-temperature sintering technique, used silica complexes to improve the mechanical properties, and then manufactured the bionic porous scaffolds by extrusion molding and freeze-drying. Results Four types of scaffolds were obtained: mHAw-SiO₂, Mg-doped mHAw-SiO₂, Sr-doped mHAw-SiO₂ and Mg-Sr-codoped mHAw-SiO₂. These composite porous scaffolds have been suggested to have a sufficiently porous morphology with appropriate mechanical strength, are noncytotoxic, are able to support cell proliferation and spreading, and, more importantly, can promote the osteogenic differentiation of rBMSCs. Conclusion Therefore, these doped scaffolds not only have physical and chemical properties suitable for bone tissue engineering, but also have higher osteogenic bioactivity, and can be possibly serve as potential bone repair material.

Bone defects remain a major clinical challenge in orthopedic and reconstructive surgery. However, conventional inorganic ceramic biomaterials are limited b