Biocompatible scaffolds with high mechanical strengths that contain biodegradable components could boost bone regeneration compared with nondegradable bone repair materials. In this study, porous chitosan (CS)/hydroxyapatite (HA) scaffolds containing mesoporous SiO2-HA particles were fabricated through the freeze-drying process. According to field emission scanning electron microscopy (FESEM) results, combining mesoporous SiO2-HA particles in CS/HA scaffolds led to a uniform porous structure. It decreased pore sizes from 320 ± 1.1 μm to 145 ± 1.4 μm. Moreover, the compressive strength value of this scaffold was 25 ± 1.2 MPa. The in-vitro approaches exhibited good sarcoma osteogenic cell line (SAOS-2) adhesion, spreading, and proliferation, indicating that the scaffolds provided a suitable environment for cell cultivation. Also, in-vivo analyses in implanted defect sites of rats proved that the CS/HA/mesoporous SiO2-HA scaffolds could promote bone regeneration via enhancing osteoconduction and meliorating the expression of osteogenesis gene to 19.31 (about 5-fold higher compared to the control group) by exposing them to the bone-like precursors. Further, this scaffold's new bone formation percentage was equal to 90 % after 21 days post-surgery. Therefore, incorporating mesoporous SiO2-HA particles into CS/HA scaffolds can suggest a new future tissue engineering and regeneration strategy.
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