Research Of Multi-layered Skin Model Based On 3D Bio-printing Technique

A large area of skin defects caused by trauma,burns and unhealed ulcers,if not treated in time,will cause significant loss of body fluids and severe infection,which may threat the life of patients.Traditional treatment methods of the skin defect include autologous skin grafts,allografts,cytokines,cell therapy and dermal substitutes.However,there are still shortcomings in terms of skin repair time,treatment cost,and therapeutic effect.Based on the principle of rapid prototyping and layering,3D Bio-printing can accurately transport and localize cells and materials and construct structure and function similar to real skin,providing new theory and technology for the manufacture of nonhomogeneous complex structure of tissues.Compared with traditional skin tissue engineering technology,3D Bio-printing Technology can significantly shorten the manufacturing cycle and improve efficiency with accurate cell localization and efficient printing layer by layer.In this study,with a self-developed 3D Bio-printing device,dermal fibroblasts and epidermal keratinocytes were mixed with biocompatible gelatin,sodium alginate and collagen to print and construct tissues similar to structure of human skin.After submerged culture and air-liquid interface culture,the printed tissues were induced to differentiate to form skin tissues with layered structure.Firstly,this study briefly reviews the research status of tissue engineering skin,and background and development of 3D Bio-printing technology,summarizes the current limitation of tissue engineering skin technology and discusses the feasibility of construction of multi-layer skin tissues with 3D Bio-printing technology.Secondly,it introduces the 3D Bio-Architect?R-WS system developed by our team and the choice of matrix material for skin printing and then present the extraction and culture of keratinocytes and fibroblasts from human skin.Depending on the real structure of human skin,fibroblast/Gelatin/sodium alginate was set as the dermal layer,keratinocytes/ collagen I as the epidermis layer,the multi-layer skin tissue model was precisely fabricated in strict accordance with the real structure of human skin through 3D Bio-printing device.The effect of the printing process on the survival rate of fibroblasts in the scaffolds was detected by MTT.At last the layered structure of human skin was analyzed by fluorescence staining and H & E staining.The results show that it is possible to construct a highly simulated multilayer skin tissue model in vitro based on 3D Bio-printing technology.The study provides a new method for rapid preparation of artificial skin with multilayer bionic structure for skin repair,cosmetic safety testing and drug permeability research.