In vivo EV Biodistribution Imaging

EVs were isolated from HEK293T cell cultures by TFF/BE‐SEC as described above and stored for 2 months in PBS‐HAT buffer at ‐80˚C. After thawing, 2 × 10¹² EVs were labelled with DiR (1,1‐dioctadecyl‐3,3,3,3‐tetramethylindotricarbocyanine iodide, cat D12731, Life Technologies) O/N at 4°C in a total volume of 2 ml as described previously (Wiklander et al., 2015 (link)). In brief, EVs were injected intra‐venously (tail vein) at doses of 2 × 10¹¹ EVs in a volume of 100 μl per mouse (n = 3 C57BL/6 mice). Organs were analysed with IVIS 6 h post injection ex vivo. The animal experiments were approved by the Swedish Local Board for Laboratory Animals. The experiments were performed in accordance with the ethical permissions granted and designed to minimize the suffering and pain of the animals.