EPR Detection of Free Radicals in Vascular Disease: Bruker EMXPlus Spectrometer

Kelley, Eric

Abstract

Reactive species of oxygen and nitrogen are becoming increasingly appreciated for their impact on the onset and progression of disease. It is therefore imperative for medical research institutions to possess robust free radical research technology. Currently, investigators at the University of Pittsburgh, School of Medicine are relegated to the use of inferior methodologies to critically interrogate free radical species in their model systems. For example, all currently available fluorescent, colorimetric, luminescent and chemiluminescent probes used to detect free radical species demonstrate reproducible results with relatively high sensitivity however, they have significant limitations regarding specificity, the propensity to redox cycle, membrane permeability and toxicity. This being noted, electron paramagnetic resonance (EPR) spectroscopy is the only technique currently available that affords direct identification of free radicals in biological systems and as such remains the gold standard for free radical research. The utility of EPR is exemplified in its capacity to provide specific fingerprint spectra that identify the free radical being measured. Thus, EPR can provide direct detection and identification of stable free radical species. For less stable free radical species, EPR spin trapping techniques permit detection and identification in a multitude of in vitro and in vivo systems. This technique has proven extremely informative for investigating formation and identifying sources of radicals in cellular, tissue and in vivo systems as well as investigating protein radical intermediates and studying drug interactions with cell membranes. To date, investigators in the School of Medicine have limited to no access to this technology. As such, acquisition of an EPR spectrometer would serve to uniquely cultivate the development of current research initiatives, incentivize new collaborative efforts and enhance the potential for success in achieving our overarching goal of developing novel strategies to treat disease.