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Perruchoud LH, Jones MD, Sutrisno A, Zamble DB, Simpson AJ, Zhang XA. A ratiometric NMR pH sensing strategy based on a slow-proton-exchange (SPE) mechanism. Chem Sci 2015; 6:6305-6311. [PMID: 30090248 PMCID: PMC6054103 DOI: 10.1039/c5sc02145f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/18/2015] [Indexed: 12/16/2022] Open
Abstract
Real time and non-invasive detection of pH in live biological systems is crucial for understanding the physiological role of acid-base homeostasis and for detecting pathological conditions associated with pH imbalance. One method to achieve in vivo pH monitoring is NMR. Conventional NMR methods, however, mainly utilize molecular sensors displaying pH-dependent chemical shift changes, which are vulnerable to multiple pH-independent factors. Here, we present a novel ratiometric strategy for sensitive and accurate pH sensing based on a small synthetic molecule, SPE1, which exhibits exceptionally slow proton exchange on the NMR time scale. Each protonation state of the sensor displays distinct NMR signals and the ratio of these signals affords precise pH values. In contrast to standard NMR methods, this ratiometric mechanism is not based on a chemical shift change, and SPE1 binds protons with high selectivity, resulting in accurate measurements. SPE1 was used to measure the pH in a single oocyte as well as in bacterial cultures, demonstrating the versatility of this method and establishing the foundation for broad biological applications.
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Affiliation(s)
- L H Perruchoud
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
- Department of Environmental and Physical Sciences , University of Toronto Scarborough , Toronto , ON M1C 1A4 , Canada
| | - M D Jones
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
| | - A Sutrisno
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
- Department of Environmental and Physical Sciences , University of Toronto Scarborough , Toronto , ON M1C 1A4 , Canada
| | - D B Zamble
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
- Department of Biochemistry , University of Toronto , Toronto , ON M5S 1A8 , Canada
| | - A J Simpson
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
- Department of Environmental and Physical Sciences , University of Toronto Scarborough , Toronto , ON M1C 1A4 , Canada
| | - X-A Zhang
- Department of Chemistry , University of Toronto , Toronto , ON M5S 3H6 , Canada . ; ;
- Department of Environmental and Physical Sciences , University of Toronto Scarborough , Toronto , ON M1C 1A4 , Canada
- Department of Biological Sciences , University of Toronto Scarborough , Toronto , ON M1C 1A4 , Canada
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