Distinct Composition-dependent Biodis-tribution Patterns of Phospholipid Liposomes

Phosphatidylserine (PS) and phosphatidylethanolamine (PE) act as an "eat-me" signal for phagocytes to engulf apoptotic cells. The aim of our study was to investigate the biodistribution of PS- or PE-containing liposomes. Three phospholipid liposomes (DOPC/DOPS, DOPC/DOPE, and DOPC/soybean PS) were intravenously injected and analyzed. DOPC/DOPS showed higher average radiant efficiency (intensity/area) in the lung, liver, kidney, and heart than DOPC/DOPE. The total and average radiant efficiency of DOPC/DOPS was higher than that of DOPC/soybean PS in the lung, liver, and kidney. These results suggest that the biodistribution of anionic phospholipid liposomes depends on their phospholipid composition.