Promoted dermis healing from full-thickness skin defect by porous silk fibroin scaffolds (PSFSs)

Studies on skin substitutes and dermal scaffolds have been extensively carried out in the past several decades and some commercial products derived from collagen and polymers have been in marketing. Yet little research on silk fibroin based dermal scaffolds and products has been reported so far. In the present study, therefore, porous silk fibroin scaffolds (PSFSs) have been prepared by freeze drying method. The effects of PSFSs on skin recovery from full thickness defect have been examined by histological evaluation with respect to neovascularization, dermal regeneration and infiltration of inflammatory cells. In addition, tissue compatibility between PSFSs and polyvinyl alcohol (PVA) sponges (as control) has been semiquantitatively compared by scoring method. The results showed that at day 18 after implantation, new tissues formed in PSFSs whose structure was almost equal to normal skin structure where proportional distribution of functional blood vessels could be found. Furthermore, infiltration of inflammatory cells in PSFSs disappeared within 7 days. By contrast, a variety of interstices, fibrous encapsulization and moderate infiltration of inflammatory cells could be found in PVA sponges at day 18 after implantation. In summary, PSFSs has significantly promoted the skin recovery from full thickness defect, showing fibroin's outstanding tissue compatibility.