3D printed scaffold based on GelMA/Gelatin hydrogel for full thickness wounds

Full thickness wounds are wounds that extend beyond the two layers of skin. The conventional skin tissue engineering approaches have developed several skin substitute products such as Integra and Matriderm. Although these products have already been applied in clinic as the substitutes of autologous split-thickness skin grafts, the fixed shape and dimensions of these skin equivalents could not satisfy the personalized skin treatment. Moreover, these commercial skin products must be changed multiple times during healing process which also greatly increases the cost and the complexity of wound care and management. Nowadays, 3D bioprinting, a high-throughput technology for precise fabrication of 3D construction, is used to raise applicability and function of cell-laden scaffolds. Currently, natural hydrogels used to support epidermal regeneration are mainly gelatin-based, which mimic the natural dermal extracellular matrix but often suffer from insufficient and uncontrollable mechanical and degradation properties. GelMA, which forms covalently cross-linked hydrogels under UV light exposure with the presence of a photoinitiator, has recently gained increasing attention, especially in the field of biomedical applications. Method: Briefly, GelMA is synthesized by the direct reaction of gelatin with MA in phosphate buffer (pH = 7.4) at 50 °C. This reaction introduces methacryloyl substitution groups on the reactive amine and hydroxyl groups of the amino acid residues. We present a method to create multi-layered engineered tissue composites consisting of human skin fibroblasts and keratinocytes which mimic skin layers. In this study multiple layers of fibroblast (FB)-containing GelMA hydrogel precursor will be print and crosslink using LAP (PI), constituting the dermal layer. Keratinocytes (KCs) will be sequentially printed and then, by collagen, these two layers of print will be attached to form two layers of skin (below figure). Discussion and Cunclusion: GelMA is developed from a natural polymer gelatin via one-step chemical modification. GelMA has a lot of advantage such as high adhesive, high biocompatibility, and high gelation but in return has a limitation such as low mechanical properties, non-elasticity and fast degradation rate in vivo. To eliminate these constraints, various concentrations of gelatin were added to GelMA before printing, which improved the printing process and increased cell survival.

کلیدواژه ها:

3D printed ، GelMA ، Full thickness ، wound healling