Imaging oxidative and nitrative stress in membranes

Membrane integrity is essential for cellular homeostasis, signal transduction, and cell-to-cell communication. Dysregulated and excessive production of reactive oxygen and nitrogen species causes oxidative, nitrative, or nitrosative stress, which can damage membranes. Investigations of redox species in lipid compartments therefore advance the understanding of complex redox biochemistry and how it impacts membranes at the organelle, cellular, and tissue levels. Phospholipid-based redox probes that are based on a natural lipid architecture can offer reliable detection of redox species interacting with membranes. These lipidoids and their fluorescently activated products can localize specifically within bilayer membranes, allowing site-specific imaging. We describe detailed steps for the use of designer lipidoids to image biomimetic membranes and subcellular compartments of live mammalian cells under redox stress. In addition, we present a synopsis of how these lipidoids are chemically prepared and utilized to detect nitrative stress on the epithelial surface of the lungs.