Spectral properties of a bifunctional PARACEST europium chelate: An intermediate for targeted imaging applications

Christopher Adair; Mark Woods; Piyu Zhao; Azhar Pasha; Patrick M. Winter; Gregory M. Lanza; Phillip Athey; A. Dean Sherry; Garry E. Kiefer

doi:10.1002/cmmi.125

Spectral properties of a bifunctional PARACEST europium chelate: An intermediate for targeted imaging applications

Christopher Adair, Mark Woods, Piyu Zhao, Azhar Pasha, Patrick M. Winter, Gregory M. Lanza, Phillip Athey, A. Dean Sherry, Garry E. Kiefer

Research output: Contribution to journal › Article › peer-review

27 Scopus citations

Abstract

This report describes a preliminary study to investigate the effect of structural variations in a bifunctional ligand being developed for targeted PARACEST applications. Utilizing Eu-DOTA-4AmCE as the functional PARACEST core, a nitro-aromatic functionality was incorporated to provide the point for conjugation. This intermediate possesses a coordinated water proton signal at 57 ppm which upon saturation produces a 22% decrease in bulk water signal intensity using 10 mM agent. Curve fitting analysis of the CEST spectrum to an exchange model based upon modified Bloch equations gave an estimate of 687 ± 100 μs for the bound water lifetime (τ_m). Although substantially longer than the 382 μs observed for the parent chelate structure, this water exchange rate remains in the necessary window to produce a significant CEST effect. These findings demonstrate the need to recognize the influence of bifunctional linkers on water exchange rates in lanthanide complexes of this type and the potential for using this functionality as a means of fine-tuning PARACEST performance.

Original language	English (US)
Pages (from-to)	55-58
Number of pages	4
Journal	Contrast Media and Molecular Imaging
Volume	2
Issue number	1
DOIs	https://doi.org/10.1002/cmmi.125
State	Published - 2007

Keywords

Bifunctional ligand
MRI
PARACEST
Water exchange

ASJC Scopus subject areas

Radiology Nuclear Medicine and imaging

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10.1002/cmmi.125

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title = "Spectral properties of a bifunctional PARACEST europium chelate: An intermediate for targeted imaging applications",

abstract = "This report describes a preliminary study to investigate the effect of structural variations in a bifunctional ligand being developed for targeted PARACEST applications. Utilizing Eu-DOTA-4AmCE as the functional PARACEST core, a nitro-aromatic functionality was incorporated to provide the point for conjugation. This intermediate possesses a coordinated water proton signal at 57 ppm which upon saturation produces a 22% decrease in bulk water signal intensity using 10 mM agent. Curve fitting analysis of the CEST spectrum to an exchange model based upon modified Bloch equations gave an estimate of 687 ± 100 μs for the bound water lifetime (τm). Although substantially longer than the 382 μs observed for the parent chelate structure, this water exchange rate remains in the necessary window to produce a significant CEST effect. These findings demonstrate the need to recognize the influence of bifunctional linkers on water exchange rates in lanthanide complexes of this type and the potential for using this functionality as a means of fine-tuning PARACEST performance.",

keywords = "Bifunctional ligand, MRI, PARACEST, Water exchange",

author = "Christopher Adair and Mark Woods and Piyu Zhao and Azhar Pasha and Winter, {Patrick M.} and Lanza, {Gregory M.} and Phillip Athey and Sherry, {A. Dean} and Kiefer, {Garry E.}",

year = "2007",

doi = "10.1002/cmmi.125",

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T2 - An intermediate for targeted imaging applications

AU - Adair, Christopher

AU - Woods, Mark

AU - Zhao, Piyu

AU - Pasha, Azhar

AU - Winter, Patrick M.

AU - Lanza, Gregory M.

AU - Athey, Phillip

AU - Sherry, A. Dean

AU - Kiefer, Garry E.

PY - 2007

Y1 - 2007

N2 - This report describes a preliminary study to investigate the effect of structural variations in a bifunctional ligand being developed for targeted PARACEST applications. Utilizing Eu-DOTA-4AmCE as the functional PARACEST core, a nitro-aromatic functionality was incorporated to provide the point for conjugation. This intermediate possesses a coordinated water proton signal at 57 ppm which upon saturation produces a 22% decrease in bulk water signal intensity using 10 mM agent. Curve fitting analysis of the CEST spectrum to an exchange model based upon modified Bloch equations gave an estimate of 687 ± 100 μs for the bound water lifetime (τm). Although substantially longer than the 382 μs observed for the parent chelate structure, this water exchange rate remains in the necessary window to produce a significant CEST effect. These findings demonstrate the need to recognize the influence of bifunctional linkers on water exchange rates in lanthanide complexes of this type and the potential for using this functionality as a means of fine-tuning PARACEST performance.

AB - This report describes a preliminary study to investigate the effect of structural variations in a bifunctional ligand being developed for targeted PARACEST applications. Utilizing Eu-DOTA-4AmCE as the functional PARACEST core, a nitro-aromatic functionality was incorporated to provide the point for conjugation. This intermediate possesses a coordinated water proton signal at 57 ppm which upon saturation produces a 22% decrease in bulk water signal intensity using 10 mM agent. Curve fitting analysis of the CEST spectrum to an exchange model based upon modified Bloch equations gave an estimate of 687 ± 100 μs for the bound water lifetime (τm). Although substantially longer than the 382 μs observed for the parent chelate structure, this water exchange rate remains in the necessary window to produce a significant CEST effect. These findings demonstrate the need to recognize the influence of bifunctional linkers on water exchange rates in lanthanide complexes of this type and the potential for using this functionality as a means of fine-tuning PARACEST performance.

KW - Bifunctional ligand

KW - MRI

KW - PARACEST

KW - Water exchange

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Spectral properties of a bifunctional PARACEST europium chelate: An intermediate for targeted imaging applications

Abstract

Keywords

ASJC Scopus subject areas

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