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Enhancement of Relaxivity Rates of Gd–DTPA Complexes by Intercalation into Layered Double Hydroxide Nanoparticles
Author(s) -
Xu Zhi Ping,
Kurniawan Nyoman D.,
Bartlett Perry F.,
Lu Gao Qing
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600571
Subject(s) - gadolinium , intercalation (chemistry) , nanoparticle , hydroxide , materials science , layered double hydroxides , nuclear chemistry , analytical chemistry (journal) , chemistry , nuclear magnetic resonance , nanotechnology , inorganic chemistry , chromatography , physics , metallurgy
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 ≈1.6 m M [Gd(dtpa)] 2− exhibits a longitudinal proton relaxivity r 1 of ≈16 m M −1 s −1 and a transverse proton relaxivity r 2 of ≈50 m M −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.