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Updated: Jun 8, 2026

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment
Published on: March 16, 2018
A responsive europium(III) chelate that provides a direct readout of pH by MRI
Yunkou Wu1, Todd C Soesbe, Garry E Kiefer
1Department of Chemistry, University of Texas at Dallas, P.O. Box 830668, Richardson, Texas 75083, USA.
Abstract:
A europium(III) DO3A-tris(amide) complex is reported for imaging pH by MRI using ratiometric chemical exchange saturation transfer (CEST) principles. Deprotonation of a single phenolic proton between pH 6 and 7.6 results in an ∼5 ppm shift in the water exchange CEST peak that is easily detected by MRI. Collection of two CEST images at two slightly different activation frequencies provides a direct readout of solution pH without the need of a concentration marker.
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