title: Bilayer heating in magnetite nanoparticle-liposome dispersions via fluorescence anisotropy.
abstract: Temperature measurements have been made within magnetite (Fe(3)O(4)) nanoparticle-liposome dispersions subjected to electromagnetic field at radiofrequency (RF) heating based on the fluorescence anisotropy of diphenylhexatriene (DPH) embedded within the bilayer. Incorporating cholesterol within dipalmitoylphosphatidylcholine (DPPC) bilayers broadened the anisotropy window associated with lipid melting. Cryogenic transmission electron microscopy showed that the dispersions contained magnetoliposomes with nanoparticle aggregates at both low and high encapsulation densities. RF heating results demonstrated the ability to measure the temperature of the ML bilayer with on/off RF cycles using DPH anisotropy. These measurements reflected the temperature of the bulk aqueous phase, which is consistent with previous work showing rapid heat dissipation from a nanoparticle surface during RF heating and a negligible difference between surface and bulk temperature.
authors.affiliation: Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Road, Kingston, RI 02881, USA. bothun@egr.uri.edu
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Bothun
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Preiss
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; D003287:Contrast Media; D005454:Fluorescence Polarization / Q000379:methods*; D006361:Heating; D008051:Lipid Bilayers; D008081:Liposomes / Q000737:chemistry*; D058185:Magnetite Nanoparticles; D013696:Temperature
chemical_list: D003287:Contrast Media; D008051:Lipid Bilayers; D008081:Liposomes; D058185:Magnetite Nanoparticles; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol