Observation of co-culturing cells on porous silk fibroin films

Porous silk fibroin films (PSFFs) are widely used in skin regeneration. Prevascularization of PSFFs is a successful strategy for enhancing the survival of engineered tissues in vivo. The adhesion and migration of human umbilical vein endothelial cells (HUVECs) and fibroblasts on PSFFs were observed by scanning electron microscopy and confocal laser scanning microscopy after vital staining of the cells. PSFFs could attract a large number of HUVECs and fibroblasts to pores in an interesting alignment and support them to spread well from the outside of pores to the center of PSFFs to form cell layers. PSFFs showed minor structural changes due to less degradation for 12 d culture, and cell layers overlapped from pores to the center in PSFFs. The total DNA assay indicated excellent cell proliferation on PSFFs on days 1 and 6 and no difference between co-culturing HUVECs and mono-HUVECs and monofibroblasts. PSFFs could guide cell migration and arrangement to form pore-centered and vessel-like structures without additional coating of proteins. The authors' aim was to study the potential prevascularization of porous silk fibroin scaffolds by co-culturing HUVECs and fibroblasts. This model has potential application for angiogenesis in dermis regeneration in the future and provides a suitable microenvironment for the development of capillary-like structures.