Quantitative imaging of cell-permeable magnetic resonance contrast agents using x-ray fluorescence
Quantitative imaging of cell-permeable magnetic resonance contrast agents using x-ray fluorescence
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DOI：
10.2310/7290.2006.00026
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发表时间：
2006-10-01
影响因子：
2.8
通讯作者：
Meade, Thomas J.
中科院分区：
文献类型：
--
作者：
Endres, Paul J.;MacRenaris, Keith W.;Meade, Thomas J.
无法转导细胞膜是当前在生物和临床环境中使用的磁共振成像探针的一个限制。这种限制将造影剂限制在身体的细胞外和血管区域，大大降低了它们研究发育生物学过程和周期的可行性。相反，具有渗透细胞膜能力的造影剂可用于可视化细胞模式、细胞命运图谱、基因治疗以及最终的非侵入性癌症诊断。因此，我们描述了四种造影剂的合成和定量成像，这些造影剂能够以足够的量穿过细胞膜进行检测。每种试剂均基于 Gd(III) 螯合剂与细胞转导部分的缀合。具体来说，我们将 Gd(iii)-二亚乙基三胺五乙酸 DTPA 和 Gd(iii)-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸与 8-氨基酸聚精氨酸低聚物和两亲性二苯乙烯分子 4-氨基-4'-(NN二甲基氨基)二苯乙烯偶联。为直接检测造影剂提供最佳灵敏度和空间分辨率的成像方式是同步辐射 X 射线荧光 (SR-XRF)。与光学显微镜不同，SR-XRF 提供的二维图像的分辨率比 Gd-153 伽马计数好 10(3)，且无需通过有机荧光团结合来改变试剂。通过 T 分析和电感耦合等离子体质谱法评估细胞内试剂的转导效率，以确定每种螯合物-转运蛋白组合的功效。
The inability to transduce cellular membranes is a limitation of current magnetic resonance imaging probes used in biologic and clinical settings. This constraint confines contrast agents to extracellular and vascular regions of the body, drastically reducing their viability for investigating processes and cycles in developmental biology. Conversely, a contrast agent with the ability to permeate cell membranes could be used in visualizing cell patterning, cell fate mapping, gene therapy, and, eventually, noninvasive cancer diagnosis. Therefore, we describe the synthesis and quantitative imaging of four contrast agents with the capability to cross cell membranes in sufficient quantity for detection. Each agent is based on the conjugation of a Gd(Ill) chelator with a cellular transduction moiety. Specifically, we coupled Gd(iii)-diethylenetriaminepentaacetic acid DTPA and Gd(iii)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid with an 8-amino acid polyarginine oligomer and an amphipathic stilbene molecule, 4-amino-4'-(NNdimethylamino)stilbene. The imaging modality that provided the best sensitivity and spatial resolution for direct detection of the contrast agents is synchrotron radiation x-ray fluorescence (SR-XRF). Unlike optical microscopy, SR-XRF provides two-dimensional images with resolution 10(3) better than Gd-153 gamma counting, without altering the agent by organic fluorophore conjugation. The transduction efficiency of the intracellular agents was evaluated by T, analysis and inductively coupled plasma mass spectrometry to determine the efficacy of each chelate-transporter combination.