Blood circulation and tissue biodistribution of lipid-quantum dot (L-QD) hybrid vesicles intravenously administered in mice

A strategy to target functionalized quantum dot-liposome (f-QD-L) hybrid vesicles in the solid tumor tissue of tumor-bearing mice is explored. Functionalized polyethylene glycol (PEG)-lipid coated QD (f-QD) were encapsulated into the aqueous core of 100 nm cationic (DOPC:Chol: DOTAP); sterically stabilized, fluid-phase (DOPC:Chol:DSPE-PEG2000); and sterically stabilized, gelphase (DSPC:Chol:DSPE-PEG2000) liposome vesicles. Double tracking of f-QD-L in blood was performed at different time points after intravenous administration in B16F10 melanoma tumorbearing C57BL6 mice. Cholesteryl [-1-14C] oleate lipids probed the vesicle membrane were followed by liquid scintillation counting while QD were determined independently by elemental (Cd2+) analysis using inductively coupled plasma mass spectrometry (ICP-MS). Rapid blood clearance was observed following intravenous administration of the cationic hybrid vesicles, while incorporation of PEG at the surface of zwitterionic vesicles dramatically prolonged their blood circulation half-life after systemic administration.