Preparation of EVs and Magnetic Capture Beads: EVs derived from bovine milk (EXBM100L, Cosmo Bio, Co., Ltd., Japan) were used as a test sample. To prevent nonspecific adsorption of EVs, a 100-fold dilution of EV-save EV blocking reagent (058-09261, FUJIFILM Wako Pure Chemical Corp., Japan) was added to the original EV sample and was stirred at 10 rpm for 15 min. To capture the EVs, Tim-4 conjugated magnetic beads were prepared (297-79701, FUJIFILM Wako Pure Chemical Corporation, Japan), which showed an affinity for phosphatidylserine on the EV membrane according to the manufacturer's protocol. In summary, the Tim-4 conjugated beads were washed twice with buffer including 4.5 mL ultrapure water, 0.5 mL washing buffer, and 50 µL EV binding enhancer containing Ca 2+ ions. The solution was spun down and subsequently placed on a magnetic stand for 1 min to separate the magnetic beads from the supernatant. The supernatant was then removed.