Redox reactions are essential to most living systems on Earth by serving as the energy supply for cells. However, malfunctions in the cellular redox machinery can cause a buildup of reactive oxygen species (ROS) and other oxidants. Oxidative stress occurs when this buildup exceeds the local supply of reductants, which can lead to oxidative damage of critical biomolecules, such as proteins and DNA. Oxidative stress, in turn, can trigger an acute immune response that leads to even more severe cell and tissue damage. The Tennyson Lab is developing organometallic complexes that catalytically reduce ROS and other biologically-relevant oxidants and, in doing so, thereby alleviate or inhibit oxidative stress. Our long-term goal in this research area is to develop catalytic redox therapeutics that are effective in artificial implant failure, diabetic cardiomyopathy, stroke, and transplant rejection, without requiring the use of any immunosuppressive drugs.