Department of Chemistry, University at Buffalo, the State University of New York, Amherst, New York 14260, United States.
Inorg Chem. 2022 Sep 19;61(37):14487-14499. doi: 10.1021/acs.inorgchem.2c02197. Epub 2022 Sep 6.
The presence of multiple oxidation and spin states of first-row transition-metal complexes facilitates the development of switchable MRI probes. Redox-responsive probes capitalize on a change in the magnetic properties of the different oxidation states of the paramagnetic metal ion center upon exposure to biological oxidants and reductants. Transition-metal complexes that are useful for MRI can be categorized according to whether they accelerate water proton relaxation ( or agents), induce paramagnetic shifts of H or F resonances (paraSHIFT agents), or are chemical exchange saturation transfer (CEST) agents. The various oxidation state couples and their properties as MRI probes are summarized with a focus on Co(II)/Co(III) or Fe(II)/Fe(III) complexes as small molecules or as liposomal agents. Solution studies of these MRI probes are reviewed with an emphasis on redox changes upon treatment with oxidants or with enzymes that are physiologically important in inflammation and disease. Finally, we outline the challenges of developing these probes further for in vivo MRI applications.
多种氧化态和自旋态的第一过渡金属配合物促进了可切换 MRI 探针的发展。氧化还原响应探针利用顺磁金属离子中心的不同氧化态在暴露于生物氧化剂和还原剂时磁性质的变化。可用于 MRI 的过渡金属配合物可以根据它们是否加速水质子弛豫（T1 agents）、诱导 H 或 F 共振的顺磁位移（paraSHIFT agents）或化学交换饱和转移（CEST）剂来进行分类。各种氧化态对及其作为 MRI 探针的性质进行了总结，重点是 Co(II)/Co(III) 或 Fe(II)/Fe(III) 配合物作为小分子或作为脂质体试剂。对这些 MRI 探针的溶液研究进行了综述，重点是在与氧化剂或在炎症和疾病中生理上重要的酶进行处理时的氧化还原变化。最后，我们概述了进一步开发这些探针用于体内 MRI 应用的挑战。
