Hyaluronic acid–ornithine crosslinked hydrogel as a superior 3D culture platform for high-quality exosome production in advanced wound healing

Background: Extracellular vesicle (EV)-based cell-free therapies have emerged as a powerful alternative to stem cell transplantation in regenerative medicine, owing to their ability to promote tissue repair while avoiding safety concerns associated with live-cell therapies. However, traditional two-dimensional (2D) cell cultures used for EV production are constrained by low exosome (Exo) yields and limited biological activity. Objective: This study introduces a novel and scalable three-dimensional (3D) culture platform based on a hyaluronic acid (HA) and L-ornithine methyl ester (Orn) hydrogel to enhance the production and therapeutic efficacy of stem cell-derived exosomes. Methods: The HA-Orn hydrogel was fabricated via a simple and mild crosslinking strategy, forming a biomimetic matrix that promotes spontaneous spheroid formation. Exosomes derived from 3D cultures (3D-Exo) were compared with those from 2D cultures (2D-Exo) in terms of yield, molecular composition, and biological functions. Results: 3D-Exo exhibited significantly increased yield and superior functional properties, including enhanced stimulation of cell proliferation, migration, angiogenesis, and extracellular matrix remodeling. In vivo, 3D-Exo treatment accelerated wound closure and reduced inflammation in a mouse skin injury model, demonstrating robust therapeutic efficacy and safety. Mechanistic studies revealed distinct miRNA expression profiles and activation of regenerative signaling pathways in 3D-Exo. Conclusion: This work presents a cost-effective, scalable, and bioinspired 3D culture system for high-yield and functionally enhanced Exo production. The HA-Orn hydrogel platform offers significant translational potential for advancing cell-free regenerative therapies, particularly in the context of wound healing.