Moreover, transmission electron microscopy (TEM; Figure 2I) and nanoparticle tracking analysis (NTA; Figure 2J) results showed that OCY‐EVs displayed cup‐shaped morphologies with diameters of 127.1 ± 41.6 nm (OCYYoung‐EVs) or 128.9 ± 45.8 nm (OCYAged‐EVs), consistent with previous reports.[12] To monitor the organ distributions, OCYYoung‐EVs were labeled with DiR near‐infrared fluorescent dye and then intramedullary (the femoral bone marrow) administered into wild type (WT) or APP/PS1 AD mice (genotyping identified in Figure S2C,D, Supporting Information). Here, APP is linked to Alzheimer disease.