Lanthanide-Loaded Erythrocytes As Highly Sensitive Chemical Exchange Saturation Transfer MRI Contrast Agents

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• 作者：Giuseppe Ferrauto ; Daniela Delli Castelli ; Enza Di Gregorio ; Sander Langereis ; Dirk Burdinski ; Holger Grüll ; Enzo Terreno ; Silvio Aime
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：January 15, 2014
• 年：2014
• 卷：136
• 期：2
• 页码：638-641
• 全文大小：312K
• ISSN：1520-5126

文摘

Chemical exchange saturation transfer (CEST) agents are a new class of frequency-encoding MRI contrast agents with a great potential for molecular and cellular imaging. As for other established MRI contrast agents, the main drawback deals with their low sensitivity. The sensitivity issue may be tackled by increasing the number of exchanging protons involved in the transfer of saturated magnetization to the 鈥渂ulk鈥?water signal. Herein we show that the water molecules in the cytoplasm of red blood cells can be exploited as source of exchangeable protons provided that their chemical shift is properly shifted by the intracellular entrapment of a paramagnetic shift reagent. The sensitivity of this system is the highest displayed so far among CEST agents (less than 1 pM of cells), and the natural origin of this system makes it suitable for in vivo applications. The proposed Ln-loaded RBCs may be proposed as reporters of the blood volume in the tumor region.