Magnetically induced controlled release from glucose-modified liposomes loaded with Fe3O4 nanoparticles

Small glucose-modified liposomes (GMLs) were loaded with magnetic Fe3O4 nanoparticles (MNPs) and fluorescein using a standard thin layer preparation procedure and a varying lipid/MNPs ratio. The liposomes were characterized with TEM and DLS measurements, and MNPs encapsulation rate was determined using ICP-OES. Prepared liposomes were stored at 5 °C for 30 days and subsequently exposed to an external magnetic field (20 mT) with varying exposure times (2‒20 min), at room temperature. The release of fluorescein from GMLs induced by the magnetic field exposures was quantified, showing a high release rate (25‒85%) depending on the concentration of MNPs in GMLs. EPR measurements were conducted during the liposomes storage period in order to provide semi-quantitative information of possible MNPs oxidation from Fe3O4 to Fe2O3 inside the liposomes, impacting MNPs magnetic properties. In contrast to the MNPs water dispersion, no significant change in the EPR signal of MNPs encapsulated inside GMLs was detected over the course of 30 days. The data presented in this study indicate that GMLs loaded with MNPs maintain a high stability for prolonged periods of time and that this delivery system may be used for magnetically assisted controlled drug release.