Optimization of magnetoliposomes for biomedical multi-tasking; potential dual contrast agents and drug delivery vehicles

Magnetic iron oxide nanoparticles were synthesized and stabilized inside phospholipid vesicles by two different methods. The resulting magnetoliposome suspensions were characterized by dynamic light scattering and NMR. The NMR analysis demonstrated conclusively that the magnetic cores of the magnetoliposomes contained clusters of smaller, superparamagnetic primary particles. The application of magnetic filtration at various flow rates allowed control over the final size of the magnetoliposomes, as well as improved MRI characteristics upon removal of excess phopsholipids from the aqueous suspensions. In all cases the liposome size distribution, with mean values from 70-150 nm, was unchanged over 80 days.