title: 64Cu loaded liposomes as positron emission tomography imaging agents.
abstract: We have developed a highly efficient method for utilizing liposomes as imaging agents for positron emission tomography (PET) giving high resolution images and allowing direct quantification of tissue distribution and blood clearance. Our approach is based on remote loading of a copper-radionuclide ((64)Cu) using a new ionophore, 2-hydroxyquinoline, to carry (64)Cu(II) across the membrane of preformed liposomes and deliver it to an encapsulated copper-chelator. Using this ionophore we achieved very efficient loading (95.5 ± 1.6%) and retention stability (>99%), which makes the (64)Cu-liposomes highly applicable as PET imaging agents. We show the utility of the (64)Cu-liposomes for quantitative in vivo imaging of healthy and tumor-bearing mice using PET. This remote loading method is a powerful tool for characterizing the in vivo performance of liposome based nanomedicine, and has great potential in diagnostic and therapeutic applications.
authors.affiliation: Technical University of Denmark, DTU Nanotech, Department of Micro- and Nanotechnology, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors.forename: Anncatrine L
authors.initials: AL
authors.lastname: Petersen
authors.forename: Tina
authors.initials: T
authors.lastname: Binderup
authors.forename: Palle
authors.initials: P
authors.lastname: Rasmussen
authors.forename: Jonas R
authors.initials: JR
authors.lastname: Henriksen
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Elema
authors.forename: Andreas
authors.initials: A
authors.lastname: Kjær
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Andresen
mesh_terms: D000818:Animals; D002151:Calorimetry; D003301:Copper Radioisotopes / Q000493:pharmacokinetics; D019073:HT29 Cells; D006801:Humans; D008024:Ligands; D008081:Liposomes / Q000737:chemistry*; D051379:Mice; D009369:Neoplasms / Q000000981:diagnostic imaging; D010316:Particle Size; D049268:Positron-Emission Tomography / Q000379:methods*; D055672:Static Electricity; D014018:Tissue Distribution
chemical_list: D003301:Copper Radioisotopes; D008024:Ligands; D008081:Liposomes