Napthalimide-based fluorescent probe for selective and sensitive sensing of formaldehyde and biological applications

Abstract

Abstract Formaldehyde (FA) is a colorless, flammable, foul-smelling chemical used in building materials and in the production of numerous household chemical products. To develop a fluorescent chemosensor for FA, a newly prepared probe 1 containing napthalimide as a fluorophore and hydrazine as a binding site of FA was designed and prepared. The amine group of the hydrazine reacts with FA to form an imide bond. Indeed, the absorption band of probe 1\xa0at 438\xa0nm shifted to 443\xa0nm upon the addition of FA, indicating that the condensation reaction occurred. Also, the addition of FA to probe 1 induced a large enhancement of the emission band at 532\xa0nm compared with the relatively very weak fluorescent emission of probe 1 alone. This high specificity toward FA was observed over other competing analytes such as Ca2+, Mg2+, acetaldehyde, benzaldehyde, salicylaldehyde, glucose, glutathione, Na2S, NaHS, H2O2, and tert-butylhydroperoxy radical. The typical two-photon dye present in probe 1 also afforded intense fluorescence upon excitation, even at 800\xa0nm, demonstrating that probe 1 could be used for a two-photon fluorescent probe for FA sensing. Probe 1 had a quick response time in the sensing of FA at room temperature. In addition, breast cancer cells treated with probe 1 exhibited intense fluorescence imaging upon exposure to FA, indicating that probe 1 could be used for monitoring FA in living cells. This probe can lead to new possibilities for unique interactions with biological molecules for applications.