Phospholipid-linked coumarin: A fluorescent probe for sensing hydroxyl radicals in lipid membranes

A fluorescent probe, DPPEC (1,2-(d) under bari (p) under bar almitoylglycero (p) under bar hosphoryi (e) under bar thanolamine labeled with coumarin) was developed for detecting hydroxyl radical (center dot OH) in lipid membranes. The coumarin moiety contributes to the fluorescent detection of center dot OH and the phospholipids moiety gives a driving force to localize the probe in lipid membranes. DPPEC in liposomal membranes rapidly reacted with center dot OH and increased the fluorescence intensity, depending on the concentration of center dot OH. The increase in the fluorescence intensity induced by center dot OH was effectively suppressed by the addition of DMSO. The probe exhibited a higher fluorescence response to center dot OH over other reactive oxygen species, such as hydrogen peroxide, nitric oxide, peroxynitrite, alkylperoxyl radical, and hypochlorite. DPPEC would be useful as a new type of fluorescent probe that can localize in lipid membranes and detect center dot OH efficiently.