Fig. 2.

The current and future direction of exosomal miRNAs. Now many researchers are studying and future directions will focus on efficacy and specificity, delivery, safety, quality and production. How to design suitable miRNA promoters and miRNA inhibitors, and how to use gene modification to make MSC-exos more effective and safer. To further explore the mechanism of exosomeal miRNA, conduct in vivo and in vitro experiments to prepare for clinical use. In terms of safety, immunogenicity, tumorigenicity and toxicity should be concerned, and the optimal dose, route of administration schedule and route of administration should be determined. Quality consistency and mass production capacity require constant attention, and remarkable results have been achieved so far. Strategies for Delivering Cells/EXOs currently include cell spray, infusing, injection, hydrogel, matrix carrier, bioprinting, scaffold-guided delivery, engineered skin substitute