A Manganese(Ⅱ) complex as high-order multiphoton fluorescent probe for detecting nitric oxide content change in idiopathic pulmonary fibrosis mice

Nitric oxide (NO) is an important gas signaling molecule, is present in the alveoli in correlation with the extent of idiopathic pulmonary fibrosis (IPF) patients. In this work, a high-order multiphoton fluorescent probe FS-MnCl2 is designed and synthesized for detecting NO level in mice model of IPF. FS-MnCl2 has the advantage of low detection limit (11 nM) and resistance to photobleaching in vitro. The three-photon absorption cross section is greatly enhanced after FS-MnCl2 recognizes NO. Moreover, the fluorescence intensity of FS-MnCl2-NO is stronger than that of FS-MnCl2 in the presence of RNA. Biological applications suggest that FS-MnCl2 can monitor changes in NO levels in living cells and IPF mice. This work provides a new strategy for reasonably designing Mn(Ⅱ) complex that can respond to NO for predicting IPF at an early stage.