Stem Cell-Derived Exosomes in Wound Healing and Skin Regeneration: Emerging Therapeutic Strategies and Mechanisms

Chronic cutaneous wounds and traumatic skin injuries remain a major clinical challenge, characterized by dysregulated healing phases, high susceptibility to microbial infection, and suboptimal response to conventional therapies. Stem cell-derived exosomes (SC-Exos) have emerged as a paradigm-shifting, cell-free nanotherapeutic platform that harnesses the paracrine secretome of stem cells while avoiding the immunological and proliferative complications inherent to direct cell transplantation. Exosomes derived from diverse stem cell sources orchestrate multifactorial wound repair by modulating key cellular signaling cascades and transcriptomic programs that collectively regulate inflammation, angiogenesis, re-epithelialization, extracellular matrix (ECM) remodeling, and scar formation. Beyond their intrinsic regenerative capacity, SC Exos can be engineered using direct strategies (cargo loading, surface modification, biomaterial integration, and conjugation) and indirect approaches (genetic engineering, pretreatment, and preconditioning of parental cells), thereby enabling spatially controlled and temporally sustained exosome release at wound sites with enhanced bioavailability and therapeutic efficacy. In parallel, biomaterial-assisted delivery platforms, including hydrogels, scaffolds, and nanofibers, enhance exosome retention, stability, and controlled-release profiles within the wound microenvironment, thereby further potentiating tissue repair. This review provides a comprehensive overview of recent advances in SC Exos for wound healing and skin regeneration. We first summarize exosome biogenesis, molecular composition, and the distinctive characteristics of exosomes derived from different stem cell sources, along with preclinical evidence supporting their efficacy in cutaneous repair. We then critically examine exosome engineering strategies and biomaterial-integrated delivery systems that augment and fine-tune therapeutic outcomes. Finally, we discuss the current status of clinical trials of SC Exo-based therapies, key manufacturing and regulatory challenges, and future directions for translating these nanoscale, cell-free therapeutics into advanced, personalized wound management.