ABSTRACT
@#Abstract: Objective To prepare a microparticle delivery system that regulates the release rate of extracellular vesicles (EVs), and to exert long-term enhancement of liver cell proliferation after only one intervention. Methods EVs was extracted by differential centrifugation. The structure of the EVs was observed by transmission electron microscopy and the membrane marker protein of EVs was detected by Western blotting. EVs-PLA microspheres with "core-shell" structure were prepared by emulsion-solvent evaporation method. Scanning and transmission electron microscopy were used to detect the morphology of EVs-PLA microspheres and EVs. The release test detected the release behavior of EVs in EVs-PLA microspheres. Scanning electron microscopy was used to detect the morphological changes of EVs-PLA microspheres at 8 weeks of release. EVs-PLA microspheres were co-cultured with hepatocytes, and Phalloidin/DAPI staining was used to observe the cell morphology and evaluate the cytotoxicity of the microspheres. CCK8-test was used to evaluate the cell proliferation activity. Western blot analysis was used to detect extracellular vesicles membrane marker protein expression. Results Comparing the ability of hepatocyte proliferation in the group treated with EVs-PLA microspheres and the control group, it was found that EVs-PLA microspheres did not cause cell apoptosis and mutation in cell structure, had biocompatibility and no cytotoxicity. The EVs-PLA microspheres with "core-shell" structure regulated the release behavior of EVs, which can continuously release EVs, exerting a continuous biological role in promoting hepatocyte proliferation after a single intervention. Conclusions The EVs-PLA microspheres can control-release EVs and promote hepatocyte proliferation continuously after a single intervention, providing a reference for further exploration of EVs-loaded delivery systems in promoting liver regeneration.