PEG-covered ultra-small Gd₂O₃ nanoparticles for positive contrast at 1.5T MR clinical scanning

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DOIResolve DOI: http://doi.org/10.1088/0957-4484/18/39/395501
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TypeArticle
Journal titleNanotechnology
Volume18
Issue39
Pages395501-1395501-9; # of pages: 9
AbstractThe size distribution and magnetic properties of ultra-small gadolinium oxide crystals (US-Gd₂O₃) were studied, and the impact of polyethylene glycol capping on the relaxivity constants (r₁, r₂) and signal intensity with this contrast agent was investigated. Size distribution and magnetic properties of US-Gd₂O₃ nanocrystals were measured with a TEM and PPMS magnetometer. For relaxation studies, diethylene glycol (DEG)-capped US-Gd₂O₃ nanocrystals were reacted with PEG-silane (MW 5000). Suspensions were adequately dialyzed in water to eliminate traces of Gd³⁺ and surfactants. The particle hydrodynamic radius was measured with dynamic light scattering (DLS) and the proton relaxation times were measured with a 1.5 T MRI scanner. Parallel studies were performed with DEG–Gd₂O₃ and PEG-silane–SPGO (Gd₂O₃, < 40 nm diameter). The small and narrow size distribution of US-Gd₂O₃ was confirmed with TEM (∼3 nm) and DLS. PEG-silane–US-Gd₂O₃ relaxation parameters were twice as high as for Gd–DTPA and the r₂/r₁ ratio was 1.4. PEG-silane–SPGO gave low r₁ relaxivities and high r₂/r₁ ratios, less compatible with positive contrast agent requirements. Higher r₁ were obtained with PEG-silane in comparison to DEG–Gd₂O₃. Treatment of DEG–US-Gd₂O₃ with PEG-silane provides enhanced relaxivity while preventing aggregation of the oxide cores. This study confirms that PEG-covered Gd₂O₃ nanoparticles can be used for positively contrasted MR applications requiring stability, biocompatible coatings and nanocrystal functionalization.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Industrial Materials Institute
Peer reviewedYes
NRC number53688
NPARC number15859840
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Record identifierd204616c-f9e6-4780-bb1a-d767a762af42
Record created2010-07-23
Record modified2016-05-09
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