Reactive oxygen species (ROS), including hydroxyl radicals, superoxide anions, and hydrogen peroxide, play vital roles in cell signaling and cellular signal transduction; however, the overproduction of ROS has been associated with inflammatory, cardiovascular and neurological diseases. In order to better understand the connections between ROS and disease, we need to develop non-invasive and reliable sensors that are capable of monitoring the production and traffic of ROS within biological systems. Redox-responsive contrast agents for magnetic resonance imaging (MRI) can potentially allow for the non-invasive visualization of oxidative stress. Here, we have synthesized an Fe(II) complex with the redox-active ligand 1,8-bis(2,5-dihydroxybenzyl)-1,4,8,11-tetraazacyclotetradecane (H4qp4), which consists of two quinols covalently tethered to a cyclam macrocycle, and characterized it as a redox-responsive MRI contrast agent. The Fe(II) compound reacts directly with H2O2 to yield a Fe(III) species with a four-fold increase in its T1-related relaxivity (r1), with both the reduced and oxidized forms of the complex being thermodynamically and kinetically stable.

Iron(II) complex with a redox-active ligand displays over a four-fold increase in its T1-weighted relaxivity upon reaction with hydrogen peroxide

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.