**3. Hydrogels/MSCs scaffolds for tissue engineering**

The therapeutic effects of MSC transplantation largely attributed to the paracrine including soluble factors and extracellular vehicles (e.g., exosome and secretome), which could be rapidly sequestered and cleared [80]. Hydrogels are ideally suited for MSCs cultivation and are adequate to offer splendid delivery platforms, enhance vehicles retention rates and thus enhance immunomodulation and tissue regeneration after *in vivo* transplantation (**Figure 1**, **Table 1**) [80–82].
