Constructing a novel near-infrared fluorescent probe with a large Stokes shift for detection of RNA in the cancer cells

Ribonucleic acid (RNA), a biomolecular compound polymerized by many riboside monomers as one of the most essential substances in life. Monitoring RNA changes within organisms will play an important role in the diagnosis and treatment of major genetically-related diseases. Herein, we synthesized a novel compound QOT-NA as the first example of near-infrared RNA probe with large Stokes shift. It is firstly found that the RNA probe QOT-NA has a large Stokes shift in water and buffer solvents (183–199 nm). When the probe was combined with RNA in buffer solvent, a strong emission peak appeared at about 660 nm and the fluorescence intensity increased 24 times. The imaging experiment showed that the probe QOT-NA could image RNA in cancer cells. In addition, the RNA probe QOT-NA has excellent selectivity, good sensitivity and tolerably good stability. There are good reasons to believe that the probe QOT-NA can be used as a robust RNA detection tool in the study of biological samples. Furthermore, the response principles of the probe to RNA were comprehensively discussed, including structure features, TICT mechanism and intercalative binding.