Construction Of An In Vitro Skin Wound Healing Model Based On The Cell-substrate And Cell-cell Interactions

Skin is the largest organ in the body and it performs many important roles, such asbarrier protection from physical or chemical insults, sensory functions, and regulation ofhomeostasis. However, damaged skin can not perform these critical functions and numerouscomplications such as infection or fluid loss can occur. As a result, any skin wound must behealed in time. Skin wound healing is a very complex physiological process involvingmultiple cell types, extracellular matrices (ECMs) and growth factors/chemokinesinteractions.Conventional wound models established on scratch assay or laminar flow are convenientto conduct; however, each of them has some limitations. Concerning the scratch assay, thedrawbacks are as follows. First, this method is manual and very tedious which limits theability to perform the wound healing assay with multiple samples and times and then the datamay be subjective and inaccurate. Second, in this assay, various factors, such as smallmolecules released from injured cells, the remnant debris of detached cells, and the suddenavailability of free space, all may contribute to heal the wound. Besides, both of them areestablished on the plane with just one type of cells. However, in our body, cells grow in athree-dimensional environment, embed in an extracellular matrix and interact with other typeof cells.In order to construct a microenvironment that is more alike to the in vivo situation, weestablished this wound model on a micropillar substrate with three types ofphysiologically-related cells including epidermal cells, fibroblasts and endothelial cells. Byusing this designed simple novel wound model，on one hand, we observed how the three cellsrespond to the micropillars with planned various sizes, and on the other hand, positional cellloading was realized, then an injury-free wound was made, and finally an in vitro woundhealing process was reproduced with these three types of cells migrate freely to heal thewound. The result showed that cell attachment, morphology, cytoskeleton distribution andnucleus shape were strongly altered by the micropillars and these cells showed collaborativeresponse to heal the wound. Taken together, these findings highlight the dynamic relationship between cells and their microenvironments. Also, this reproducible device can facilitate the invitro investigation of numerous physiological and pathological processes such asembryogenesis and tissue engineering.