Benzopyrylium conjugated quinolone constructing 705 nm long wavelength emission for evaluation of sulfur dioxide in brain slices

Although sulfur dioxide shows a variety of physiological and pathological functions in the body, the lack of detection tools still limits its in situ analysis. Fluorescent probes have the advantages of visualization, nondestructive and multi-level imaging, and have potential application prospects for in-situ detection of organisms. However, fluorescent probes capable of in-situ resolution of substances need to have specific and rapid response to targets, as well as near-red and long-wavelength emission. In our study, benzopyrylium moiety as a versatile fluorophore with a built-in site for SO2, good water solubility and the ability to target mitochondria was employed to construct probe Mito-NQ together with quinoline moiety for extension of conjugate. The probe Mito-NQ exhibited a near infrared emission at 705 nm based on the designed D-pi-A-pi-D structure. Moreover, we have successfully applied Mito-NQ to the detection of SO2 targeting mitochondria in cells, zebrafish and nude mice. Brain slice imaging showed that long wavelength emission has deep tissue penetration compared to short wavelength emission.

Automated summary

The fluorescent probe Mito-NQ, designed with a benzopyrylium moiety and quinoline moiety, showed the ability to target mitochondria for in-situ detection of sulfur dioxide. It exhibited near infrared emission at 705 nm and was successfully applied in cells, zebrafish, and nude mice. The long wavelength emission of Mito-NQ allowed for deep tissue penetration compared to short wavelength emission, as shown in brain slice imaging.