At the Wellman Center, his research interests focus on basic understanding and utilization of photochemical reactions in biological environments, such as cells or tissue. Particular interest was focused on how the biological microenvironment impacts on photochemical reaction pathways and the way this can be harnessed for therapeutic purposes. Dr. Redmond's group has studied reaction pathways on a more encompassing temporal and spatial scale using methods like transient absorption spectroscopy and time-lapse microscopy that allows reaction processes to be followed from nanoseconds to days in duration. Photo-oxidation process and propagation of oxidative stress in cells have been of particular interest with the combination of spectroscopy and microscopy providing novel insights on oxidative stress mechanisms. Primary reactive species and their targets lead to secondary reactive species and the relationship between inherent reactivity and spatial range of influence of these different reactive oxygen species has been explored. More recent work had focused on cell-cell signaling and the impact of bystander effects in oxidative stress caused by photosensitization and by ultraviolet light.