CoCEST: cobalt(ii) amide-appended paraCEST MRI contrast agents

Dorazio, Sarina J.; Olatunde, Abiola O.; Spernyak, Joseph A.; Morrow, Janet R.

doi:10.1039/c3cc45000g

Cited by 80 publications

(153 citation statements)

References 18 publications

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“…Lanthanide, Iron, Cobalt and Nickel complexes can also feature exchangeable protons with large chemical shifts from water (on the order of 30-700 ppm) and suitable k ex [7a, 19] . The large chemical shift difference with water for those paramagnetic CEST (paraCEST) agents enables faster exchange while adhering to the slow-intermediate exchange condition mentioned in Eq.…”

Section: Resultsmentioning

confidence: 99%

Tuning Phenols with Intra‐Molecular Bond Shifted HYdrogens (IM‐SHY) as diaCEST MRI Contrast Agents

Yang

Yadav

Song

et al. 2014

Chemistry A European J

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We characterize what the optimal exchange properties are for CEST contrast agents on 3T clinical scanners using CW saturation transfer, and demonstrate that the exchangeable protons in phenols can be tuned to reach these criteria through proper ring substitution. Systematic modification allows the chemical shift of the exchangeable protons to be positioned between 4.8 ppm to 12 ppm from water and enables adjustment of the proton exchange rate to maximize CEST contrast at these shifts. In particular, 44 hydrogen-bonded phenols are investigated for their potential as CEST MRI contrast agents and the stereoelectronic effects on their CEST properties summarized. Furthermore, we identify a pair of compounds, 2,5-dihydroxyterephthalic acid (42) and 4,6-dihydroxyisophthalic acid (43), which produce the highest sensitivity through incorporating two exchangeable protons per ring.

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Section: Resultsmentioning

confidence: 99%

Tuning Phenols with Intra‐Molecular Bond Shifted HYdrogens (IM‐SHY) as diaCEST MRI Contrast Agents

Yang

Yadav

Song

et al. 2014

Chemistry A European J

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“…80 Complexes 57 , 60 , 63 , and 65 displayed pH sensitive CEST effects in the pH range 6.5–7.5. 82 CEST signals for complexes 57 and 60 were at 45 and 32 ppm, respectively, and the signals for complex 65 were at –19 and 59 ppm. 82 Complex 63 displayed four CEST signals (112, 95, 54, and 45 ppm), and all shifts were measured at 11.7 T and 37 °C.…”

Section: Introductionmentioning

confidence: 96%

“…79 A series of Co II -containing complexes 57 , 60 , 63 , 65 , and 67 have also been reported. 80,82 The redox active complex 67 was studied at 11.7 T as a potential probe to map in vivo oxygen levels. 80 Complex 67 with a CEST effect at 135 ppm from bulk water becomes CEST silent in the presence of oxygen.…”

Section: Introductionmentioning

confidence: 99%

Enhancing magnetic resonance imaging with contrast agents for ultra-high field strengths

Kuda-Wedagedara

Allen

2014

Analyst

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Contrast agents are diagnostic tools that often complement magnetic resonance imaging. At ultra-high field strengths (≥7 T), magnetic resonance imaging is capable of generating desirable high signal-to-noise ratios, but clinically available contrast agents are less effective at ultra-high field strengths relative to lower fields. This gap in effectiveness demands the development of contrast agents for ultra-high field strengths. In this minireview, we summarize contrast agents reported during the last three years that focused on ultra-high field strengths.

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“…Bioavailable metals such as iron [105], cobalt [106], and nickel [107] are well suited for paraCEST, which suggests that naturally occurring Ni, Co, and Fe-based metalloproteins could be developed as paraCEST reporter genes. Another approach to boost the sensitivity of MRI is parahydrogen induced polarization (PHIP) [68, 69].…”

Section: Discussionmentioning

confidence: 99%

Biomolecular MRI reporters: Evolution of new mechanisms

Mukherjee

Davis

Ramesh

et al. 2017

Progress in Nuclear Magnetic Resonance Spectroscopy

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Magnetic resonance imaging (MRI) is a powerful technique for observing the function of specific cells and molecules inside living organisms. However, compared to optical microscopy, in which fluorescent protein reporters are available to visualize hundreds of cellular functions ranging from gene expression and chemical signaling to biomechanics, to date relatively few such reporters are available for MRI. Efforts to develop MRI-detectable biomolecules have mainly focused on proteins containing or transporting paramagnetic metals for T1 and T2 relaxation enhancement or large numbers of exchangeable protons for chemical exchange saturation transfer. While these pioneering developments established several key uses of biomolecular MRI, such as imaging of gene expression and functional biosensing, they also revealed that low molecular sensitivity poses a major challenge for broader adoption in biology and medicine. Recently, new classes of biomolecular reporters have been developed based on alternative contrast mechanisms, including enhancement of spin diffusivity, interactions with hyperpolarized nuclei, and modulation of blood flow. These novel reporters promise to improve sensitivity and enable new forms of multiplexed and functional imaging.

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CoCEST: cobalt(ii) amide-appended paraCEST MRI contrast agents

Abstract: The first examples of air-stable CoII paraCEST MRI contrast agents are reported. Amide NH protons on the complexes give rise to CEST peaks that are shifted up to 112 ppm from the bulk water resonance. One complex has multiple CEST peaks that may be useful for ratiometric mapping of pH.

Cited by 80 publications

References 18 publications

Tuning Phenols with Intra‐Molecular Bond Shifted HYdrogens (IM‐SHY) as diaCEST MRI Contrast Agents

Tuning Phenols with Intra‐Molecular Bond Shifted HYdrogens (IM‐SHY) as diaCEST MRI Contrast Agents

Enhancing magnetic resonance imaging with contrast agents for ultra-high field strengths

Biomolecular MRI reporters: Evolution of new mechanisms

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