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Redox‐ and Hypoxia‐Responsive MRI Contrast Agents
Author(s) -
Do Quyen N.,
Ratnakar James S.,
Kovács Zoltán,
Sherry A. Dean
Publication year - 2014
Publication title -
chemmedchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.817
H-Index - 100
eISSN - 1860-7187
pISSN - 1860-7179
DOI - 10.1002/cmdc.201402034
Subject(s) - redox , chemistry , ligand (biochemistry) , magnetic resonance imaging , biophysics , receptor , biochemistry , inorganic chemistry , biology , medicine , radiology
The development of responsive or “smart” magnetic resonance imaging (MRI) contrast agents that can report specific biomarker or biological events has been the focus of MRI contrast agent research over the past 20 years. Among various biological hallmarks of interest, tissue redox and hypoxia are particularly important owing to their roles in disease states and metabolic consequences. Herein we review the development of redox‐/hypoxia‐sensitive T 1 shortening and paramagnetic chemical exchange saturation transfer (PARACEST) MRI contrast agents. Traditionally, the relaxivity of redox‐sensitive Gd 3+ ‐based complexes is modulated through changes in the ligand structure or molecular rotation, while PARACEST sensors exploit the sensitivity of the metal‐bound water exchange rate to electronic effects of the ligand‐pendant arms and alterations in the coordination geometry. Newer designs involve complexes of redox‐active metal ions in which the oxidation states have different magnetic properties. The challenges of translating redox‐ and hypoxia‐sensitive agents in vivo are also addressed.