Three-Dimensional Bioprinting Techniques in Skin Regeneration: Current Insights and Future Perspectives

Skin is composed of three layers: the epidermis, dermis, and hypodermis. It is enriched with skin appendages, including hair follicles, sweat glands, and sebaceous glands, which play essential roles in regulating fluid exchange, controlling body temperature, and providing protection against pathogens. Currently, skin regeneration treatments rely on transplantations. However, this approach has several disadvantages, including hemostasis at the recipient site, limitations in donor area closure, increased graft contraction, and hypertrophic scarring. Recent advancements in three-dimensional (3D) bioprinting technologies have enabled the fabrication of structures that closely mimic native tissues, with the aim of enhancing tissue regeneration. Bioprinting offers several advantages, such as high reproducibility, precision, and the ability to create complex geometries. The most promising bioinks combine excellent biocompatibility and biodegradability, with mechanical and rheological stability. This review highlights the most recent and innovative studies on 3D-printed bioinks in the field of skin tissue engineering. In particular, considering the growing interest in the regenerative potential of exosomes, we discuss cutting-edge research involving exosome-loaded bioinks and their potential to support skin regeneration and repair.