Self-composite silk fibroin membranes for guided bone regeneration: 1 material 3 architectures with intrinsic integrity

Abstract

Silk fibroin (SF) takes attention in tissue engineering due to unique features, e.g., excellent biocompatibility/biodegradability with superior mechanical/thermal properties despite its lightweight. Guided bone regeneration (GBR) seeks bilayered GBR membranes to govern bone regeneration, although constituent parts of such membranes may undergo delamination once different biomaterials are combined. Herein, 3-component bilayered SF membranes were prepared for the first time utilizing the same polymer in different forms by eliminating the delamination risk of layers for GBR applications. One side consisted of a non-porous SF film serving as a barrier against penetration of non-osteogenic tissue whereas the other side was porous/fibrous composed of SF sponge and SF fibers for bone regeneration. Proper integration between these layers was confirmed via scanning electron microscopy (SEM). Composites reinforced with high fiber percent (30%) had remarkably enhanced compressive strength and elastic moduli, which were further improved by increasing polymer concentration from 4% to 8%. Non-porous morphology of the barrier side was preserved during 28 days of degradation while pore sizes enlarged on the other surface, which would be beneficial for cell migration into the regenerative side. Saos-2 cells seeded on composites with high fiber percent proliferated more within 14 days; however, alkaline phosphatase (ALP) activity on low-fiber-percent counterparts was elevated more. Osteogenic marker gene expressions were significantly higher than control on day 14. All self-composites were eminent candidates to promote bone regeneration with tailor-made capacity for further improvements. Taken together, 1-material 3-architecture SF fabricated by a green and practical technique holds promise for GBR applications.