A Narrative Review of Advances in Skin Tissue Engineering: From Physiological Architecture to 3D Bioprinting

The skin is a complex, multilayered organ. Damage from burns, trauma, chronic ulcers, or surgical defects often outstrips the regenerative capacity of conventional healing. Traditional skin grafting, while standard, is limited due to donor site morbidity, lack of appendages, and altered biomechanical/sensory properties. This narrative review traces the evolution of skin repair from autografting to bioengineered substitutes and 3D bioprinting, emphasizing physiological design principles, biomaterials, and translational challenges. The literature synthesis mainly focused on skin architecture and wound-healing phases, limitations of epidermal/dermal grafts, development of acellular and cellular artificial skin, recent advances in bioinks, extrusion/inkjet/laser-assisted bioprinting, and functional appendage regeneration. Ophthalmic applications, including corneal and eyelid reconstruction, were also reviewed. Artificial skin substitutes evolved from acellular scaffolds to cell-seeded constructs using keratinocytes, fibroblasts, and decellularized extracellular matrix (ECM). Key biomaterials include hydrogels, collagen, and gellan gum as well as novel composites like eggshell membrane-alginate bioinks. In vivo models demonstrate accelerated re-epithelialization, organized collagen and vascularization with bioprinted grafts. Emerging technologies, such as 4D bioprinting with shape-memory polymers, smart dressings with biosensors, and in situ robotic bioprinting, promise adaptive, real-time wound repair. Biomaterials and fabrication strategies developed for cutaneous repair are increasingly relevant to ophthalmology and broader regenerative medicine. 3D bioprinting provides a viable translational route to functional, patient-specific artificial skin, overcoming key graft limitations. Future work must advance vascularized, multilayer constructs and move toward standardized, regulatory-aligned fabrication for clinical translation.