Metal ion sensing using ion chemical exchange saturation transfer 19F magnetic resonance imaging.
Metal ion sensing using ion chemical exchange saturation transfer 19F magnetic resonance imaging.
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DOI：
10.1021/ja403542g
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发表时间：
2013-08-21
影响因子：
15
通讯作者：
McMahon MT
中科院分区：
文献类型：
--
作者：
Bar-Shir A;Gilad AA;Chan KW;Liu G;van Zijl PC;Bulte JW;McMahon MT
Although metal ions are involved in a myriad of biological processes, a non-invasive means of detecting free metal ions in a deep tissue remains a formidable challenge. We present an approach for specifically sensing the presence of Ca2+ in which the amplification strategy of chemical exchange saturation transfer (CEST) is combined with the broad range in chemical shifts found in 19F NMR to obtain MR images of Ca2+. We exploit the chemical shift change (Δω) of 19F upon binding of Ca2+ to the difluoro derivative of [1,2,-bis(o-aminophenoxy) ethane-N,N,-N′,N′, tetra-acetic acid] (5F-BAPTA), by RF labeling at the bound-19F frequency, ω[Ca-5F-BAPTA], and detecting the label transfer to the free-19F frequency, ω5F-BAPTA. Through the substrate binding kinetics we were able to amplify the signal of Ca2+ onto free 5F-BAPTA and thus indirectly detect low Ca2+ concentrations with high sensitivity.
