A mitochondria/lysosome-targeting fluorescence probe based on azonia-cyanine dye and its application in nitroreductase detection.

• Cyanine dye with benzo[e]indol and aromatic azonia unites have dual organelles target abilities. • A probe was designed for the detection of NTR in mitochondria and lysosome simultaneously. • NIR emission, fast OFF-ON response (180 s) and low detection limit (3.2 ng/mL). In this article, a benzo[ e ]indol aromatic azonia skeleton cyanine dye (3) with excellent performance was developed successfully through simple modification of an original aromatic azonia skeleton cyanine dye. Dye 3 had mitochondria/lysosome-targeting ability and its maximum emission wavelength extended to the near infrared region (655 nm). Inspired by this, probe 1a was designed, which connecting 2-bromomethyl-5-nitrofuran to the cyanine dye 3 , and was the first mitochondria and lysosome dual-targeting probe for nitroreductase (NTR) detection. In addition to exhibiting good selectivity and fast response (180 s), probe 1a also exhibited high sensitivity to NTR (the detection limit was 3.2 ng/mL). The cell imaging experiments showed probe 1a could work as a dual mitochondria/lysosome-targeting probe to detect NTR in HeLa cells. [ABSTRACT FROM AUTHOR]