3D bioprinting of a dermal scaffold for full-thickness skin tissue regeneration

Dermal substitutes have provided a template for the regeneration and reconstruction of the dermis. However, the healed skin tissue often exhibits abnormal morphology and functionality, including scarring and inflammation. In this study, a composite bioink composed of methacrylated gelatin (GelMA) and chitosan oligosaccharide (COS) was proposed for printing a dermal scaffold using digital light processing (DLP) technology. The GelMA/COS bioink exhibited suitable porosity, swelling, degradation rate, and mechanical properties. The inclusion of COS demonstrated antibacterial effects against both Grampositive and Gram-negative bacteria, while simultaneously fostering the proliferation of human dermal fibroblasts (HDFs). Additionally, the application of COS could effectively reduce the expression levels of fibrosis-related genes, such as collagen I, collagen III, and fibronectin I. The three-dimensionally printed cell-laden dermal scaffold exhibited excellent shape fidelity and high cellular viability, facilitating the extension of HDFs along the scaffold and the simultaneous secretion of extracellular matrix proteins. Furthermore, the HDF-laden dermal scaffold transplanted into full-thickness skin defect sites in nude mice was shown to accelerate wound closure, reduce inflammation, and improve wound healing. Overall, the DLP-printed dermal scaffold provides an appealing approach for effectively treating full-thickness skin defects in clinical settings.