Composite bone graft of CaO-MgO-SiO₂ glass-ceramics and CaSO₄ ceramics for boosting bone formation rate

This study develops a composite bone graft of CaO-MgO-SiO₂ glass-ceramic and CaSO₄ [abbreviated as (CMS)_3-x(CS)_x] via the sponge replication technique with weight fractions of x = 0, 1, 1.5, 2, and 3. The (CMS)_1.5(CS)_1.5 composite displays a superior degradability and, a suitable compressive strength of ∼3 MPa, and excellent cell proliferation and differentiation. The in vivo rat femur test in the hybrid-pore (CMS)_1.5(CS)_1.5 composite granules achieves a higher rate of bone formation, which is ∼2.7 times better than that of the commercial HAP/β-TCP at 12 weeks. Improved expressions of osteocyte and mature osteocyte marker genes, namely (Spp1, Dmp1, and Fgf23), were observed in the (CMS)_1.5(CS)_1.5 group, indicating a faster differentiation into mature bone tissue. The ions release of (CMS)_1.5(CS)_1.5 through the ERK1/2 signaling pathway promotes osteogenic differentiation. The high bone generation rate can be attributed to faster active ions release and modified surface topography. This work highlights an excellent bone graft candidate for clinical applications in orthopedic surgery.