title: Combination of transfection agents and magnetic resonance contrast agents for cellular imaging: relationship between relaxivities, electrostatic forces, and chemical composition.
abstract: The purpose of this study was to investigate the changes in electrostatic and magnetic resonance (MR) properties observed when MR contrast agents (CAs) (Feridex, MION-46L, or G5-dendrimer-DOTA-Gd) are combined with transfection agents (TAs) under various conditions for use as a CA-TA complex basis for cellular labeling and MRI. CAs were incubated with various classes of TAs for 0-48 hr in solutions of varying concentrations and pH values. NMR relaxation rates (1/T(1), 1/T(2)), MRI and zeta potential (ZP) of CA-TA solutions were measured. TAs decreased the 1/T(1) and 1/T(2) of G5-DOTA-Gd, Feridex, and MION-46L by 0-95%. Altering the pH of G5-DOTA-Gd-TA decreased the T(1)-weighted signal intensity (SI) on MRI from 0 to 78%. Measured ZP values for G5-DOTA-Gd, Feridex, and MION-46L were -51, -41, and -2.0 mV, respectively. The TA LV had a negative ZP, while the other TAs had ZPs ranging from +20 to +65 mV. The alteration of the ZP and NMR relaxivities of the MR CAs, Feridex, MION-46L, and G5-DOTA-Gd by TAs has been demonstrated. These results enhance our understanding of the relationship between electrostatic and MR properties.
authors.affiliation: Laboratory of Diagnostic Radiology Research (CC), National Institutes of Health, Bethesda, Maryland 20892, USA. hkalish@mail.cc.nih.gov
authors.forename: H
authors.initials: H
authors.lastname: Kalish
authors.forename: A S
authors.initials: AS
authors.lastname: Arbab
authors.forename: B R
authors.initials: BR
authors.lastname: Miller
authors.forename: B K
authors.initials: BK
authors.lastname: Lewis
authors.forename: H A
authors.initials: HA
authors.lastname: Zywicke
authors.forename: J W M
authors.initials: JW
authors.lastname: Bulte
authors.forename: L H
authors.initials: LH
authors.lastname: Bryant
authors.forename: J A
authors.initials: JA
authors.lastname: Frank
mesh_terms: D002478:Cells, Cultured; D003287:Contrast Media / Q000737:chemistry; D003911:Dextrans; D004563:Electrochemistry; D052203:Ferrosoferric Oxide; D005682:Gadolinium; D006571:Heterocyclic Compounds / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D009942:Organometallic Compounds / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D014162:Transfection
chemical_list: D003287:Contrast Media; D003911:Dextrans; D006571:Heterocyclic Compounds; D008055:Lipids; C086724:Lipofectamine; D058185:Magnetite Nanoparticles; D009942:Organometallic Compounds; D010087:Oxides; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate; D005682:Gadolinium; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide