red-FAAzo-4 A89197 (E)-4-(4-((4-butyl-2,6-dichlorophenyl)diazenyl)-3,5-dichlorophenyl)butanoic acid
red-FAAzo-4 is a red-shifted photoswitchable fatty acid designed as a visible-light–responsive analog of polyunsaturated fatty acids. Its red-shifted chromophore allows for reversible trans–cis isomerization with biocompatible wavelengths, allowing precise optical control of membrane properties. red-FAAzo-4 serves as a modular building block for red-shifted photolipids (e.g., red-azo-PC, red-AzCA-4) and is well suited for photopharmacology, optochemical control of membrane proteins, and studies of membrane mechanics and lipid–protein interactions.
