Three-dimensional electrospun silk-fibroin nanofiber for skin tissue engineering

Tissue-engineered skin substitutes may offer an effective therapeutic option for the treatment of patients with skin damages. In this study, a novel three-dimensional (3D) scaffold composed of electrospun silk fibroin (SF) nanofiber was fabricated using electrospinning with the addition of NaCl crystals. It has well known that the electrospun SF nanofibers were excellent scaffold for tissue. However, it is generally difficult for cells to infiltrate the electrospun silk fibroin due to its small pore size. To resolve this problem, we dropped the NaCl crystals above the rotating collector, which become incorporated into the nanofibers. Three methods (freeze-drying, salt-leaching, and electrospinning with NaCl) for fabrication of SF scaffolds were compared to the difference of their characteristics using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mechanical strength, porosity, swelling abilities, and cell proliferation. Additionally, using air-liquid culture system, keratinocytes were co-cultured with fibroblasts in each type of SF scaffolds to construct an artificial bilayer skin in vitro. In our experimental results, histologic findings in only electrospun SF scaffolds showed more proliferation of fibroblasts in deep layer and more differentiation of keratinocytes in superficial layer. The present study suggests that 3D electrospun SF scaffolds might be a suitable for skin tissue engineering.