“…Stem cell-derived exosomes possess favorable pharmacokinetic property, biocompatibility, and tissue-targeting ability owing to their bilayer structures and constituents of mRNAs, microRNAs, cytokines, chemokines, and immunomodulatory compounds (Mendt et al, 2019;Harrell et al, 2019;Haraszti et al, 2019;Fernández-Francos et al, 2021). Moreover, the ability of the exosomes to suppress inflammation, regulate cell proliferation, and promote damaged tissue repair has been corroborated (Harrell et al, 2019;Massa et al, 2020), for example, in the skin , muscle and bone (Nakamura et al, 2015;Hao et al, 2017;Mianehsaz et al, 2019), nerve (Tsintou et al, 2021), heart (Bahardoust and Baghoi-Hosseinabadi, 2021), liver , kidney (Ishiy et al, 2020), lung (Xu et al, 2020), immune system (Burrello et al, 2016), cancer (Sharma, 2018), and virus infection (Jamshidi et al, 2021) (Figure 2). Introduction of the exosomes into biomaterials, such as exosome-laden hydrogel (Wang et al, 2019a;Wang et al, 2019b), exosome-coated scaffold (Zhai et al, 2020;Kyung Kim et al, 2021), and exosome-based drug delivering vectors (Barile and Vassalli, 2017;Mehryab et al, 2020), has Figure 1 Biogenesis and identification of exosomes.…”