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

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.