Fig. 1

The characterization of MSC-Exo and ChGel sponges. A Exosomes captured by transmission electron microscopy (TEM, bar: 100 nm). B Exosome specific protein markers including the Alix, CD63, HSC70 and Tsg101, and the negative markers including the Calnexin and Albumin were detected by Western Blot. C Size distribution of MSC-Exo on the basis of nanoparticle tracking analysis. D Correlation between the quantity of particles and the protein concentration. E Morphology and degradability of ChGel sponge. F Changes in the volume and weight of the sponge after absorbing PBS. G Controlled release test of MSC-Exo from the ChGel sponge scaffold. H, I Schematic illustration of the putative cross-linked structure and the pore size distribution of ChGel sponge. J The surface and inner structure of the cross-linked scaffold identified by SEM, which confirmed the effective encapsulation of MSC-Exo within and on the surface of the sponge scaffold. The red arrows indicated the encapsulated exosomes