Maintaining Inducibility of Dermal Follicle Cells on Silk Fibroin/Sodium Alginate Scaffold for Enhanced Hair Follicle Regeneration

SIMPLE SUMMARY: Patients with severe skin damage need to transplant artificial skin substitutes to achieve repair, and often the repaired part cannot achieve the regeneration of accessory organs such as hair follicles. It is very important to study artificial skin substitutes that can promote the regeneration of hair follicles. Dermal papilla cells in hair follicles can express a variety of growth factors, which play an important role in the growth of hair follicles. Dermal papilla cells were used as seed cells and cultured with a biomimetic silk fibroin/sodium alginate scaffold similar to the extracellular matrix around the dermal papilla to explore cell-compatibility on the scaffold. Our research found that a silk fibroin/sodium alginate scaffold is a good biomimetic of the extracellular matrix structure, and that the dermal papilla cells could maintain normal morphology and aggregate growth characteristics on the scaffold. We then proved through animal experiments that this scaffold can promote skin repair and induce hair follicle regeneration. ABSTRACT: The extracellular matrix (ECM) is important for maintaining cell phenotype and promoting cell proliferation and differentiation. In order to better solve the problem of skin appendage regeneration, a combination of mechanical/enzymatic digestion methods was used to self-extract dermal papilla cells (DPCs), which were seeded on silk fibroin/sodium alginate scaffolds as seed cells to evaluate the possibility of skin regeneration/regeneration of accessory organs. Scanning electron microscopy (SEM) graphs showed that the interconnected pores inside the scaffold had a pore diameter in the range of 153–311 μm and a porosity of 41–82%. Immunofluorescence (IF) staining and cell morphological staining proved that the extracted cells were DPCs. The results of a Cell Counting Kit-8 (CCK-8) and Calcein-AM/PI live-dead cell staining showed that the DPCs grew well in the composite scaffold extract. Normal cell morphology and characteristics of aggregation growth were maintained during the 3-day culture, which showed that the silk fibroin/sodium alginate (SF/SA) composite scaffold had good cell-compatibility. Hematoxylin-eosin (H&E) staining of tissue sections further proved that the cells adhered closely and aggregated to the pore wall of the scaffold, and retained the ability to induce differentiation of hair follicles. All these results indicate that, compared with a pure scaffold, the composite scaffold promotes the adhesion and growth of DPCs. We transplanted the SF/SA scaffolds into the back wounds of SD rats, and evaluated the damage model constructed in vivo. The results showed that the scaffold inoculated with DPCs could accelerate the repair of the skin and promote the regeneration of the hair follicle structure.