Osteoconductive Silk Fibroin Binders for Bone Repair in Alveolar Cleft Palate: Fabrication, Structure, Properties, and In Vitro Testing.

Osteoconductive silk fibroin (SF) binders were fabricated for the bone repair of an alveolar cleft defect. Binders were prefigureared by mixing different ratios of a mixture of random coils and SF aggregation with SF fibrils: 100:0 (SFB100), 75:25 (SFB75), 50:50 (SFB50), 25:75 (SFB25), and 0:100 (SFB0). The gelation, molecular organization, structures, topography, and morphology of the binders were characterized and observed. Their physical, mechanical, and biological properties were tested. The SF binders showed gelation via self-assembly of SF aggregation and fibrillation. SFB75, SFB50, and SFB25 had molecular formation via the amide groups and showed more structural stability than SFB100. The morphology of SFB0 demonstrated the largest pore size. SFB0 showed a lowest hydrophilicity. SFB100 showed the highest SF release. SFB25 had the highest maximum load. SFB50 exhibited the lowest elongation at break. Binders with SF fibrils showed more cell viability and higher cell proliferation, ALP activity, calcium deposition, and protein synthesis than without SF fibrils. Finally, the results were deduced: SFB25 demonstrated suitable performance that is promising for the bone repair of an alveolar cleft defect.