Fig. 2
Characterization of W-Exo-L@GelMA. A The protocol of W-Exo-L@GelMA preparation. L, LRRK2-IN-1; EXO, exosome; W, cartilage affinity WYRGRL (W) peptide; UV, ultraviolet. B Western blot analyses showing that MSC exosomes could express characteristic marker proteins, such as TSG101, CD81, and CD9. C Scanning electron microscopy showing that the exosomes were round-shaped and the diameter of target peptide-modified exosomes increased compared with that of unmodified exosomes. D Diameter measurement of MSC exosomes. The diameter measurement showed the diameter of the exosomes after the modification of the targeted peptide increased compared with that of the unmodified exosomes. E Surface potential analysis of MSC exosomes. The surface potential of exosomes was increased after peptide modification. F Optical and fluorescent images of W-Exo-L@Gel. The exosomes containing Dil fluorescence were successfully encapsulated by GelMA microspheres with a size of about 100–200 μm. G Scanning electron microscopy showing the morphology and size of GelMA microspheres. H Infrared spectrum analysis of W-Exo-L@GelMA. The amide I (1646 cm–1), amide II (1534 cm–1), amide III (1316 cm–1), and amide A (3270 cm–1) and amide B (3064 cm–1), are peaks of infrared characterization of amide. 1285 cm−1 and 1420 cm−1 belong to C-N. I The drug release curve of Exo-L@GelMA in vitro. The drug release time of Exo-L@GelMA was prolonged by 1 week. Data represent mean ± SD; N = 3/group; *P < 0.05; **P < 0.01 by Student’s t-test