In vivo imaging of xenograft tumors

Mice were anesthetized via isoflurane inhalation, and intraperitoneally injected with 100 μL of 150 mM DiR iodide (DiR)-labeled exosomes. Bioluminescence imaging was performed with an IVIS (Xenogen), 10 min post injection. The section of interest was defined manually, and bioluminescence expressed as photon flux values (photons/s/cm²/steradian). Background photon flux was defined using an area of the tumor that did not receive an intraperitoneal injection of luciferin.