title: Magnetoresponsive smart capsules formed with polyelectrolytes, lipid bilayers and magnetic nanoparticles.
abstract: Magnetoresponsive smart capsules formed with polyelectrolytes, lipid bilayers and magnetic nanoparticles were fabricated by a colloid-templating technique. Melamine-formaldehyde core particles with polyelectrolyte multilayer shell were prepared by layer-by-layer assembly. Magnetite (Fe(3)O(4)) nanoparticles were selectively deposited on the capsular surface by aqueous solution deposition using Pd catalysts. Hollow capsules were obtained by the removal of the melamine formaldehyde core particles. Vibrating sample magnetometer (VSM) measurement of the capsules revealed the ferromagnetic behavior of deposited Fe(3)O(4) nanoparticles. Alternating magnetic field irradiation generates heat in the capsular dispersion. Additional lipid bilayer coating was carried out on the obtained hollow capsules. Dye molecules were loaded by exploiting the temperature-dependence of the lipid membrane permeability. An encapsulated dye was released on-demand by irradiation with an alternating magnetic field, due to a phase transition in the lipid membrane, induced by heating of the magnetic nanoparticles. The magnetically induced release is attributed to the phase transition of the lipid membrane, caused by heat of Fe(3)O(4) nanoparticles under magnetic stimuli, and not to rupture of the capsules.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. katagiri@apchem.nagoya-u.ac.jp
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Katagiri
authors.forename: Masato
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kunihito
authors.initials: K
authors.lastname: Koumoto
mesh_terms: D002214:Capsules / Q000737:chemistry* / Q000528:radiation effects; D004573:Electrolytes / Q000737:chemistry* / Q000528:radiation effects; D004574:Electromagnetic Fields; D052203:Ferrosoferric Oxide / Q000737:chemistry* / Q000528:radiation effects; D008051:Lipid Bilayers / Q000737:chemistry* / Q000528:radiation effects; D008422:Materials Testing; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size
chemical_list: D002214:Capsules; D004573:Electrolytes; D008051:Lipid Bilayers; D052203:Ferrosoferric Oxide