Se-NADA is an orange fluorescent benzoselenadiazole D-amino acid (FDAA) for imaging bacteria. It is covalently incorporated into peptidoglycans in the cell walls of live bacteria. It also acts as a photosensitizer, bringing about bacterial cell death on exposure to visible light. Se-NADA is effective against both Gram-positive and Gram-negative bacteria. Ex/Em = 470/590 nm.