Polymeric Biomaterials for the Delivery of Stem Cell-Derived Exosomes in Inflammatory Skin Diseases: Engineering...

Skin tissue engineering has emerged as a promising therapeutic strategy for severe wounds and inflammatory skin diseases. Stem cell-derived exosomes (SC-Exos) have recently gained increasing attention as cell-free therapeutic agents with regenerative and immunomodulatory potential, offering possible advantages over direct stem cell transplantation. To fully realize their therapeutic potential, however, efficient delivery platforms are needed to enhance local retention, preserve vesicle integrity, and support sustained release within the diseased skin microenvironment. In this review, we discuss advanced polymeric biomaterials as functional delivery platforms for SC-Exos in skin tissue engineering. We focus on natural and synthetic polymers engineered into nanofibrous scaffolds, hydrogels, and microneedles, and examine how these systems enhance exosome loading, protect vesicle integrity, improve local retention, and modulate release kinetics. We further highlight the therapeutic effects and underlying mechanisms of polymer-exosome systems in skin lesion repair, focusing on their roles in promoting angiogenesis, modulating local inflammation and immune responses, and facilitating extracellular matrix remodeling. Finally, we address remaining challenges and future directions for translating polymer-based SC-Exos delivery platforms into clinically relevant skin regenerative therapies.