title: Controlled release from bilayer-decorated magnetoliposomes via electromagnetic heating.
abstract: Nanoscale assemblies that can be activated and controlled through external stimuli represent a next stage in multifunctional therapeutics. We report the formation, characterization, and release properties of bilayer-decorated magnetoliposomes (dMLs) that were prepared by embedding small hydrophobic SPIO nanoparticles at different lipid molecule to nanoparticle ratios within dipalmitoylphosphatidylcholine (DPPC) bilayers. The dML structure was examined by cryogenic transmission electron microscopy and differential scanning calorimetry, and release was examined by carboxyfluorescein leakage. Nanoparticle heating using alternating current electromagnetic fields (EMFs) operating at radio frequencies provided selective release of the encapsulated molecule at low nanoparticle concentrations and under physiologically acceptable EMF conditions. Without radio frequency heating, spontaneous leakage from the dMLs decreased with increasing nanoparticle loading, consistent with greater bilayer stability and a decrease in the effective dML surface area due to aggregation. With radio frequency heating, the initial rate and extent of leakage increased significantly as a function of nanoparticle loading and electromagnetic field strength. The mechanism of release is attributed to a combination of bilayer permeabilization and partial dML rupture.
authors.affiliation: Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Road, Kingston, Rhode Island 02881, USA.
authors.forename: Yanjing
authors.initials: Y
authors.lastname: Chen
authors.forename: Arijit
authors.initials: A
authors.lastname: Bose
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Bothun
mesh_terms: D003460:Crystallization / Q000379:methods*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004574:Electromagnetic Fields; D052203:Ferrosoferric Oxide / Q000737:chemistry* / Q000528:radiation effects; D006358:Hot Temperature; D008051:Lipid Bilayers / Q000737:chemistry* / Q000528:radiation effects; D008081:Liposomes / Q000737:chemistry* / Q000528:radiation effects; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003692:Delayed-Action Preparations; D008051:Lipid Bilayers; D008081:Liposomes; D046911:Macromolecular Substances; C427127:superparamagnetic blood pool agent; D052203:Ferrosoferric Oxide