Highly Sensitive Cyanine Dyes for Rapid Sensing of NAD(P)H in Mitochondria and First-Instar Larvae of .

We have developed two highly sensitive cyanine dyes, which we refer to as probes and . These dyes are capable of quick and sensitive sensing of NAD(P)H. The dyes were fabricated by connecting benzothiazolium and 2,3-dimethylnaphtho[1,2-]thiazol-3-ium units to 3-quinolinium through a vinyl bond. In the absence of NAD(P)H, both probes have low fluorescence and absorption peaks at 370 and 400 nm, correspondingly. This is because of their two electron-withdrawing acceptor systems with high charge densities. However, when NAD(P)H reduces the probes' electron-withdrawing 3-quinolinium units to electron-donating 1,4-dihydroquinoline units, the probes absorb at 533 and 535 nm and fluoresce at 572 and 586 nm for and correspondingly. This creates well-defined donor-π-acceptor cyanine dyes. We successfully used probe to monitor NAD(P)H levels in live cells during glycolysis, under hypoxic conditions induced by CoCl treatment and after treatment with cancer drugs, including cisplatin, camptothecin, and gemcitabine. Probe was also employed to visualize NAD(P)H in first-instar larvae. We observed an increase in NAD(P)H levels in A549 cancer cells both under hypoxic conditions and after treatment with cancer drugs, including cisplatin, camptothecin, and gemcitabine.