Bone-mimicking scaffold based on silk fibroin incorporated with hydroxyapatite and titanium oxide as enhanced osteo-conductive material for bone tissue formation: fabrication, characterization, properties, and in vitro testing

Bone-mimicking scaffolds based on silk fibroin (SF) mixed with hydroxyapatite nanoparticles (HA NPs) and titanium oxide (TiO2) nanoparticles were created as materials for bone formation. Six scaffold groups were fabricated: S1 (SF), S2 (Silk + (HA: TiO2; 100: 0)), S3 (Silk, (HA: TiO2; 70: 30)), S4 (Silk + (HA NPs: TiO2; 50: 50)), S5 (Silk + (HA: TiO2; 30: 70)), and S6 (Silk + (HA NPs: TiO2; 0:100)). Scaffolds were characterized for molecular formation, structure, and morphology by Fourier transform infrared spectroscopy, element analysis, and X-ray diffraction. They were tested for physical swelling and compressive modulus. Scaffolds were cultured with MC3T3 and tested in vitro to evaluate their biological performance. The results showed that scaffolds with HA and TiO2 demonstrated molecular interaction via amide I and phosphate groups. These scaffolds had smaller pore sizes than those without HA and TiO2. They showed more swelling and higher compressive modulus than the scaffolds without HA and TiO2. They exhibited better biological performance: cell adhesion, viability, proliferation, alkaline phosphatase activity, and calcium content than the scaffolds without HA and TiO2. Their porous walls acted as templates for cell aggregation and supported synthesis of calcium secreted from cells. S3 were the most suitable scaffolds. With their enhanced osteo-conductive function, they are promising for bone augmentation for oral and maxillofacial surgery.