Silk fibroin/chondroitin sulfate/hyaluronic acid ternary scaffolds for dermal tissue reconstruction

The fabrication of new dermal substitutes providing mechanical support and cellular cues is urgently needed in dermal reconstruction. Silk fibroin (SF)/chondroitin sulfate (CS)/hyaluronic acid (HA) ternary scaffolds (95-248 μm in pore diameter, 88-93% in porosity) were prepared by freeze-drying. By the incorporation of CS and HA with the SF solution, the chemical potential and quantity of free water around ice crystals could be controlled to form smaller pores in the SF/CS/HA ternary scaffold main pores and improve scaffold equilibrium swelling. This feature offers benefits for cell adhesion, survival and proliferation. In vivo SF, SF/HA and SF/CS/HA (80/5/15) scaffolds as dermal equivalents were implanted onto dorsal full-thickness wounds of Sprague-Dawley rats to evaluate wound healing. Compared to SF and SF/HA scaffolds, the SF/CS/HA (80/5/15) scaffolds promoted dermis regeneration, related to improved angiogenesis and collagen deposition. Further, vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) expression in the SF/CS/HA (80/5/15) groups were investigated by immunohistochemistry to assess the mechanisms involved in the stimulation of secretion of VEGF, PDGF and bFGF and accumulation of these growth factors related to accelerated wound process. These new three-dimensional ternary scaffolds offer potential for dermal tissue regeneration.