Enhancement of relaxivity rates of Gd-DTPA complexes by intercalation into layered double hydroxide nanoparticles.
In this paper we report the preparation and characterization of [Gd(dtpa)](2-) intercalated layered double hydroxide (LDH) nanomaterials. [Gd(dtpa)](2-) (gadolinium(III) diethylene triamine pentaacetate) was transferred into LDH by anionic exchange. The intercalation of [Gd(dtpa)](2-) into LDH was confirmed by X-ray diffraction for the new phase with the interlayer spacing of 3.5-4.0 nm and by FTIR for the characteristic vibration peaks of [Gd(dtpa)](2-). The morphology of the nanoparticles was influenced by the extent of [Gd(dtpa)](2-) loading, in which the poly-dispersity quality decreased as the [Gd(dtpa)](2-) loading was increased. Compared with the morphology of the original Mg(2)Al-Cl-LDH nanoparticles (hexagonal plate-like sheets of 50-200 nm), the modified LDH-Gd(dtpa) nanoparticles are bar-like with a width of 30-60 nm and a length of 50-150 nm. LDH-Gd(dtpa) was expected to have an increased water proton magnetic resonance relaxivity due to the intercalation of [Gd(dtpa)](2-) into the LDH interlayer that led to slower molecular anisotropic tumbling compared with free [Gd(dtpa)](2-) in solution. Indeed, LDH-nanoparticle suspension containing approximately 1.6 mM [Gd(dtpa)](2-) exhibits a longitudinal proton relaxivity r(1) of approximately 16 mM(-1) s(-1) and a transverse proton relaxivity r(2) of approximately 50 mM(-1) s(-1) at room temperature and a magnetic field of 190 MHz, which represents an enhancement four times (r(1)) and 12 times (r(2)) that of free [Gd(dtpa)](2-) in solution under the same reaction conditions. We have thus tailored LDH-nanoparticles into a novel contrast agent with strong relaxivity, promising for great potential applications in magnetic resonance imaging.
Xu
Zhi Ping
ZP
ARC Centre for Functional Nanomaterials, School of Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
Kurniawan
Nyoman D
ND
Bartlett
Perry F
PF
Lu
Gao Qing
GQ
D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry; D016880:Anisotropy; D002614:Chelating Agents / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000737:chemistry*; D006878:Hydroxides; D017616:Magnesium Compounds / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009942:Organometallic Compounds / Q000737:chemistry*; D011522:Protons; D012996:Solutions / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
D017607:Aluminum Compounds; D002614:Chelating Agents; D002712:Chlorides; D003287:Contrast Media; D006878:Hydroxides; D017616:Magnesium Compounds; D009942:Organometallic Compounds; D011522:Protons; D012996:Solutions; D000077410:Aluminum Chloride; C031356:hydroxide ion; D005682:Gadolinium; D019786:Gadolinium DTPA