Construction Of Sodium Alginate/GelMA Dual Network Active Gel Containing Dermal Papilla Cell Aggregation And Its Application In Wound Repair

Skin is the direct contact interface between the human body and the environment,and plays the barrier function of protecting the human body from external stimulation and maintaining the homeostasis of the human body.At the microscopic level,the barrier function of the skin is actually mainly played by the epidermis,so accelerating the re-epithelialization of the wound site and forming a better epithelial structure is very important for the maintenance of skin barrier function.Dermal papilla cells(DPCs)are specialized fibroblasts that play an important role in the epithelial-mesenchymal process.It can promote keratinocyte migration and stratify differentiation to form artificial epithelium with more complete structure.However,there is little reference to its promotion of skin repair.In order to explore the ability of dermal papilla cells to promote epidermal tissue repair and improve the insufficient activity of gel to promote tissue regeneration.The effect of the active gel on wound repair was investigated by using the full-thickness skin defect model of rats.The specific content is as follows:(1)The isolation and identification of dermal papilla cells and exploring their potentiality of promoting wound repair.The results have showed that the dermal papilla cells had higher secretion levels of epidermal growth factor(EGF),vascular endothelial growth factor(VEGF)and bone morphogen-protein-4(BMP4).The secretion of VEGF and BMP4 have been 4 and20 times higher than that of skin fibroblasts,respectively.Meanwhile the DPCs’ conditional medium could significantly promote the proliferation and migration of HUVCs.(2)A hemispherical microarray platform was constructed for biomimetic culture of the dermal papilla to investigate the influence of the platform on the formation and active function of the dermal papilla cell aggregation.It has been found that the platform had a rapid and efficient effect of promoting cell aggregation and the cells still showed excellent activity and specific expression of ALP,which could be used for long-term culture and observation.At the same time,the relative expression levels of BMP4 and VEGF genes in the aggregated culture have been 2.2 times and 3.7 times higher than that in the two-dimensional culture,respectively,which has realized direct protein concentration and simplified enrichment operation to avoid protein loss.(3)The alginate /GelMA double network gel was constructed and successfully encapsulated the dermal papilla cell aggregation.The effect of the active gel on promoting wound healing was investigated by using the full-thickness defect model of rats.The presence of dermal papilla cells can significantly promote the migration of the epithelial tongue,and the cell masses can promote the formation of new epidermis with a thickness closer to the normal epidermis,and promote the maturation of the gland and vascular network.In this paper,dermal papilla cells are verified the excellent performance of promoting tissue repair.Through the bionic cultivation platform,we get the dermal papilla cells aggregation.A new type of active gel material containing three dimensional cell aggregation was constructed,and its performance in promoting wound repair was studied.It has found that it could accelerate the process of re-epithelialization,and the thickness of epidermal tissue formed was closer to that of normal epidermis,which broadened the application form and range of dermal papilla cells.