Fig. 1

Characterization of PRP-Exo and Exo-Gel. A Morphology of Exo examined by TEM. Scale bar: 200 nm. B Particle size distribution of Exo measured by NTA. C Western blotting analysis of the surface biomarkers CD9, CD63, and CD81 on Exo, and the encapsulated proteins TGFβ1, PDGFBB, VEGF, and SDF-1, as compared with APP. D Photographs of Exo-Gel demonstrated the thermoresponsiveness of the formulation, for which the polymer solution at room temperature (25 °C) reversibly transformed into a hydrogel at 37 °C. E SEM of the morphology of Exo loaded in Gel (bar = 500 nm). F Exo release profles from Gel at 25 and 37 °C. G Thermoresponsive release profile of Exo loaded in Gel detected by Bradford Protein Assay at different time-points. Error bars represent the means ± SEM (n = 3). H Particle size distribution of Exo released from Gel measured by NTA. I In vitro setup to determine uptake of DiR-labeled Exo released from Gel at 48 h by mBMSCs and chondrocytes. J Fluorescent images of mBMSCs and chondrocytes cocultured with Exo-Gel showing that Exo could be taken up by mBMSCs and chondrocytes after release from Gel