title: Gd-DTPA-Dopamine-Bisphytanyl Amphiphile: Synthesis, Characterisation and Relaxation Parameters of the Nanoassemblies and Their Potential as MRI Contrast Agents.
abstract: Here, a new amphiphilic magnetic resonance imaging (MRI) contrast agent, a Gd(III)-chelated diethylenetriaminepentaacetic acid conjugated to two branched alkyl chains via a dopamine spacer, Gd-DTPA-dopamine-bisphytanyl (Gd-DTPA-Dop-Phy), which is readily capable of self-assembling into liposomal nanoassemblies upon dispersion in an aqueous solution, is reported. In vitro relaxivities of the dispersions were found to be much higher than Magnevist, a commercially available contrast agent, at 0.47 T but comparable at 9.40 T. Analysis of variable temperature (17)O NMR transverse relaxation measurements revealed the water exchange of the nanoassemblies to be faster than that previously reported for paramagnetic liposomes. Molecular reorientation dynamics were probed by (1)H NMRD profiles using a classical inner and outer sphere relaxation model and a Lipari-Szabo "model-free" approach. High payloads of Gd(III) ions in the liposomal nanoassemblies made solely from the Gd-DTPA-Dop-Phy amphiphiles, in combination with slow molecular reorientation and fast water exchange makes this novel amphiphile a suitable candidate to be investigated as an advanced MRI contrast agent.
authors.affiliation: Manufacturing Flagship CSIRO, P.O. Box 52, North Ryde, NSW, 1670 (Australia).|Nanoscale Organisation and Dynamics Group, University of Western Sydney, Penrith, NSW, 2751 (Australia).
authors.forename: Abhishek
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Nanoscale Organisation and Dynamics Group, University of Western Sydney, Penrith, NSW, 2751 (Australia).
authors.forename: Scott A
authors.initials: SA
authors.lastname: Willis
authors.affiliation: Manufacturing Flagship CSIRO, 343 Royal Parade, Parkville, VIC, 3052 (Australia).
authors.forename: Lynne J
authors.initials: LJ
authors.lastname: Waddington
authors.affiliation: Nanoscale Organisation and Dynamics Group, University of Western Sydney, Penrith, NSW, 2751 (Australia).
authors.forename: Tim
authors.initials: T
authors.lastname: Stait-Gardner
authors.affiliation: Manufacturing Flagship CSIRO, P.O. Box 52, North Ryde, NSW, 1670 (Australia).|Bragg Institute ANSTO, Lucas Heights, NSW, 2234 (Australia).
authors.forename: Liliana
authors.initials: L
authors.lastname: de Campo
authors.affiliation: Department of Chemistry and Biochemistry, National Chung Cheng University, Min-Hsiung Township Chiayi, 621 (Taiwan).
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Hwang
authors.affiliation: Australian Synchrotron, 800 Blackburn Road, Clayton, VIC, 3168 (Australia).
authors.forename: Nigel
authors.initials: N
authors.lastname: Kirby
authors.affiliation: Nanoscale Organisation and Dynamics Group, University of Western Sydney, Penrith, NSW, 2751 (Australia). w.price@uws.edu.au.
authors.forename: William S
authors.initials: WS
authors.lastname: Price
authors.affiliation: Manufacturing Flagship CSIRO, P.O. Box 52, North Ryde, NSW, 1670 (Australia). minoo.moghaddam@csiro.au.
authors.forename: Minoo J
authors.initials: MJ
authors.lastname: Moghaddam
mesh_terms: D003287:Contrast Media / Q000138:chemical synthesis* / Q000737:chemistry; D004298:Dopamine; D005682:Gadolinium / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000138:chemical synthesis* / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy
chemical_list: D003287:Contrast Media; D008081:Liposomes; D005682:Gadolinium; D019786:Gadolinium DTPA; D004298:Dopamine
keywords: 17O NMR spectroscopy; contrast agents; gadolinium-DTPA-amphiphiles; liposomes; relaxation