Assistant Professor of Radiology Harvard Medical School

Associate Investigator Athinoula A. Martinos Center for Biomedical Imaging, Mass General Research Institute

biomimetic materials; catalytic domain; coordination complexes; gadolinium-free mri contrast media; molecular imaging; molecular imaging probe technology; mri; nickel; organometallic compounds; superoxide dismutase

Dr. Gale’s research applies chemistry to solve unmet challenges in radiology and biomedical imaging. His team is currently focused on developing transition metal complexes as MRI contrast agents.

One project is focused on developing complexes of divalent manganese (Mn2+) as an alternative to commercially available gadolinium (Gd) based contrast agents (GBCAs). GBCAs are the standard of care for contrast enhanced MRI examinations to diagnose abnormalities in soft tissues and blood vessels, but recent concerns over long-term Gd retention and delayed toxicity have led to apprehension in the radiologic community and triggered new regulatory scrutiny. Like Gd, the Mn2+ ion is a potent relaxation agent that leads to strong MR signal enhancement. Unlike Gd, Mn is a nutritional element that can be processed and excreted by humans. Dr. Gale’s Mn2+-based contrast agents are rationally designed to function as direct replacements for commercial GBCA formulations.

A second project capitalizes on the transition metal properties of Mn and iron (Fe) to develop biochemically responsive MRI contrast agents. Rationally designed complexes of Mn2+ and Fe3+ can function as strong relaxation agents, whereas complexes of their sister Mn3+ and Fe2+ oxidation states are generally very poor relaxation agents. Switching between metal oxidation states provides a mechanism by which MR contrast can be turned “off” or “on” selectively in the presence of biochemical stimuli. Dr. Gale’s group is currently developing redox active complexes of Mn and Fe as sensors for reactive oxygen species, various oxidase