Combining Piezoelectric Stimulation and Extracellular Vesicles for Cartilage Regeneration

Figure 4

PLLA, PLLA/DS-EVs, and the retention rate of DS-EVs (a) electrospin PLLA nanofibers could be tailored to fit shapes and sizes for later use in vitro and vivo; (b) piezoelectric amplitude plots of the electrospun PLLA nanofibrous membrane; (c) piezoelectric phase plots of the electrospun PLLA nanofibrous membrane; (d) PFM height image; (e) the PFM amplitude image; (f) the PFM phase image; (g) visualization of PLLA/DS-EVs under confocal laser scanning microscope (CLSM): in bright field, PLLA NFs were fibrillary distributed (bar = 20 µm); DS-EVs labeled with DiI dye showed red signals at excitation wavelengths of 549–565 nm (yellow arrows; bar = 20 µm); it could be seen in the merge image that DS-EVs were distributed along the surface of the fibers (yellow arrows; bar = 20 µm); (h) the generated physiological electrical signals were tested during the knee joint activity in rats; (i) in vivo retention of DS-EVs by PLLA NFs; (j) in vitro retention of DS-EVs by PLLA NFs.

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