Cyclen-Based Phenylboronate Ligands and Their Eu3+ Complexes for Sensing Glucose by MRI
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- 作者：Robert Trokowski ; Shanrong Zhang ; and A. Dean Sherry
- 刊名：Bioconjugate Chemistry
- 出版年：2004
- 出版时间：November 2004
- 年：2004
- 卷：15
- 期：6
- 页码：1431 - 1440
- 全文大小：299K
- 年卷期：v.15,no.6(November 2004)
- ISSN：1520-4812
文摘
Novel cyclen-based phenylboronate ligands and their corresponding Eu3+ complexes have beenexamined as glucose sensors using chemical exchange saturation transfer (CEST) MR imaging fordetection. Two isomeric bis-phenylboronate complexes, Eu(4) and Eu(10), and a mono-phenylboronatecomplex, Eu(12), had been prepared and characterized by UV and circular dichroism spectroscopy,mass spectrometry, and CEST imaging. Both the free ligands and their Eu3+ complexes bind to simplesugars, but their selectivity and binding affinities vary with sugar structure. Interestingly, the freeligands, 4 and 10, are selective for fructose over glucose, but this selectivity order switches in therespective Eu3+ complexes. Of the complexes examined, Eu(4) shows the highest selectivity and bindingaffinity for glucose (2275 ± 266 M-1 at pH 10.2 and 339 ± 29 M-1 at pH 7). Glucose acts as a "capping"moiety in the Eu(4)·glucose binary complex and modulates water exchange between a single Eu3+-bound water molecule and bulk water, an effect that can be detected by CEST imaging. Thus, Eu(4)represents a new class of metabolite-specific imaging agents that may allow mapping of metabolitesby MRI of the bulk water signal.