Naphthalimide-based macrophage nucleus imaging probes.

The photophysical properties of naphthalimide-based fluorophores can be easily tuned by chemical manipulation of the substituents on that privileged scaffold. Replacement of a OMe group at position 6 in 2-(hydroxyl)ethyl-naphthalimide derivatives by diverse amines, including 2-(hydroxyl)ethylamine, trans-(4-acetamido)cyclohexylamine and azetidine increases the solvatochromic (ICT) character, while this replacement in 2-(dimethylamino)ethyl-naphthalimide analogues (PET fluorophores) decrease their solvent polarity sensitivity or even reversed them to solvatochromic fluorophores. These fluorophores resulted macrophage nucleus imaging probes, which bind DNA as intercalants and showed low cytotoxicity in human cancer cells.