Rogers Nicola J, Ashok Kumar Chowan, Alexander Carlson, Bowdery Daniel, Pavlovskaya Galina, Harvey Peter
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
Dalton Trans. 2025 Jul 15;54(28):11036-11046. doi: 10.1039/d5dt01149c.
A series of macrocyclic transition-metal complexes, including Fe(II), Co(II), Ni(II), and Cu(II) complexes, have been evaluated for parashift MRI imaging applications, by assessing their paramagnetic NMR properties, including proton chemical shifts, nuclear relaxation rates, and any exchange dynamics in solution, at magnetic fields strengths relevant to clinical and pre-clinical imaging. Among the complexes studied, Fe(II) and Co(II) systems demonstrated significant paramagnetic shifts with desirable relaxation properties, making them potential candidates for lanthanide-free parashift molecular probes for MRI. Field-dependent nuclear relaxation rate analyses provided insights into electronic relaxation times, confirming the suitability of certain complexes for parashift imaging at lower magnetic fields. Phantom imaging experiments at 9.4 T further validated the feasibility of molecular imaging using a cyclen-based macrocyclic Fe(II) complex, making a significant advance toward developing transition metal-based MRI probes using biogenic metal ions, and offer promise for future responsive imaging due to the direct signal detection.
一系列大环过渡金属配合物，包括铁（II）、钴（II）、镍（II）和铜（II）配合物，已通过评估其顺磁核磁共振性质（包括质子化学位移、核弛豫率以及溶液中的任何交换动力学），在与临床和临床前成像相关的磁场强度下，用于顺磁磁共振成像应用进行了评估。在所研究的配合物中，铁（II）和钴（II）体系表现出显著的顺磁位移以及理想的弛豫性质，使其成为无镧系元素的顺磁分子磁共振成像探针的潜在候选物。场依赖的核弛豫率分析提供了有关电子弛豫时间的见解，证实了某些配合物在较低磁场下用于顺磁成像的适用性。在9.4 T下的体模成像实验进一步验证了使用基于环糊精的大环铁（II）配合物进行分子成像的可行性，朝着开发使用生物源金属离子的基于过渡金属的磁共振成像探针迈出了重要一步，并由于直接信号检测为未来的响应性成像带来了希望。
