The microstructure of the hydrogel sponge was evaluated by scanning electron microscopy (SEM, HITACHI, S4800). The hydrogel was immersed in distilled water, PBS, simulated body fluid (SBF) and FBS for 24 h at room temperature until swelling equilibrium state. The degree of swelling was calculated as follows:
The m1 and m2 are the weights of the dry and wet hydrogel, respectively. The moisture retention capacity was evaluated by a previously described method. Briefly, after swelling equilibrium of the hydrogel, the wet hydrogel was placed in a glass dryer at room temperature, and the changes in the swelling ratio were determined every 2 h. The functional groups of the hydrogel were detected by Fourier transform infrared (FTIR) spectroscopy (Nicolet 6700).
The exosomes (50 μg) were resuspended in 50 μl PBS and loaded to a 1 × 1 cm hydrogel sponge. The presence of the exosomes on the hydrogel particles were then detected by SEM and laser scanning confocal microscopy (LSCM). The SEM images were taken according to the methods mentioned above. To detect the exosomes under the LSCM, the exosomes were labeled with the DiO cell membrane green fluorescent probe (Beyotime, China). A hydrogel with 50 μl PBS was used as a control.
The m1 and m2 are the weights of the dry and wet hydrogel, respectively. The moisture retention capacity was evaluated by a previously described method. Briefly, after swelling equilibrium of the hydrogel, the wet hydrogel was placed in a glass dryer at room temperature, and the changes in the swelling ratio were determined every 2 h. The functional groups of the hydrogel were detected by Fourier transform infrared (FTIR) spectroscopy (Nicolet 6700).
The exosomes (50 μg) were resuspended in 50 μl PBS and loaded to a 1 × 1 cm hydrogel sponge. The presence of the exosomes on the hydrogel particles were then detected by SEM and laser scanning confocal microscopy (LSCM). The SEM images were taken according to the methods mentioned above. To detect the exosomes under the LSCM, the exosomes were labeled with the DiO cell membrane green fluorescent probe (Beyotime, China). A hydrogel with 50 μl PBS was used as a control.