Size-Wise Effect of Agricultural By-Product-Derived Calcium Phosphate Composites on Stem Cell Osteogenesis

Introduction Collagen and other natural polymers including hyaluronic acid and chitosan (CS) are common additives for improving the bone forming capacity and retain the structures of xenografts. The topography of the cell-attaching region on implants has a significant role in the cell behavior. To control the topography of calcium phosphate composites (CPCs) in the cell-attaching regions, equine bone powders (EBPs) with various sizes and CS solutions were used to fabricate CPCs. A correlation between the particle size distribution of the equine bone-derived calcium phosphate composites (EB-CPCs) and behavior of mesenchymal stem cells was observed. The EBPs were classified according to the granule size. The main crystal was hydroxyapatite. Results The results of the surface roughness measurements revealed that in the groups containing hydroxyapatite particles with sizes of 5 µm, 50 µm, and 100 µm, the R z values were 23.199, 43.274, and 69.701 µm, respectively. The ultimate compressive strengths for the groups with hydroxyapatite sizes of 5 µm, 50 µm, and 100 µm were 1.98 ± 0.058 MPa, 1.36 ± 0.17 MPa, and 1.96 ± 0.14 MPa, respectively. A cell viability analysis revealed that a higher R z led to elongated shape, resulting in an enhanced cell proliferation. A lower R z led to rounded shape, resulting in an increased osteogenic differentiation. Conclusion In conclusion, control of the powder particle size in the fabrication of CPCs is an important factor affecting osteogenesis.