Polyethylene glycol-covered ultra-small Gd2O3 nanoparticles for positive contrast at 1.5 T magnetic resonance clinical scanning
Polyethylene glycol-covered ultra-small Gd2O3 nanoparticles for positive contrast at 1.5 T magnetic resonance clinical scanning
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DOI：
10.1088/0957-4484/18/39/395501
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发表时间：
2007-10-03
期刊：
影响因子：
3.5
通讯作者：
Uvdal, Kajsa
中科院分区：
文献类型：
--
作者：
Fortin, Marc-Andre;Petoral, Rodrigo M., Jr.;Uvdal, Kajsa
研究了超小尺寸氧化钆晶体（US-Gd 2 O3）的尺寸分布和磁性，并研究了聚乙二醇封端对该造影剂弛豫常数（r（1），r（2））和信号强度的影响。用TEM和PPMS磁强计测量了US-Gd 2 O3纳米晶的尺寸分布和磁性。对于弛豫研究，二甘醇（DEG）封端的US-Gd 2 O3纳米晶体与PEG-硅烷（MW 5000）反应。悬浮液在水中充分透析以消除痕量的Gd 3+和表面活性剂。用动态光散射（DLS）测量颗粒流体动力学半径，用1.5 T MRI扫描仪测量质子弛豫时间。用DEG-Gd 2 O3和PEG-硅烷-SPGO（Gd 2 O3，< 40 nm直径）进行平行研究。用TEM（近似3 nm）和DLS证实了US-Gd 2 O3的小而窄的尺寸分布。PEG-硅烷-US-Gd 2 O3的弛豫参数是Gd-DTPA的两倍，r（2）/r（1）比值为1.4。PEG-硅烷-SPGO产生低的r（1）弛豫率和高的r（2）/r（1）比，与阳性造影剂要求不太相容。与DEG-Gd 2 O3相比，PEG-硅烷获得更高的r（1）。用PEG-硅烷处理DEG-US-Gd 2 O3提供增强的弛豫性，同时防止氧化物核的聚集。该研究证实PEG覆盖的Gd 2 O3纳米颗粒可用于需要稳定性、生物相容性涂层和生物相容性功能化的正对比MR应用。
The 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 (r(1), r(2)) 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 (similar to 3 nm) and DLS. PEG-silane-US-Gd2O3 relaxation parameters were twice as high as for Gd-DTPA and the r(2)/r(1) ratio was 1.4. PEG-silane-SPGO gave low r(1) relaxivities and high r(2)/r(1) ratios, less compatible with positive contrast agent requirements. Higher r(1) 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.