Two New Near-Infrared Fluorescent Probes Localizated In Mitochondria Or Lysosome

Fluorescent bio imaging offers a unique approach for visualizing morphological details of tissues with subcellular resolution. The fundamental and key point of this technology is the design and synthesis of functional fluorescent probes. The fluorescent probe-based assay has gained increasing attention because of its high sensitivity and selectivity, simplicity for implementation, economy, real-time detection, and good compatibility for biosamples.Hydrazine (N2H4) is a well-known high-energy propellant, and is widely used in industrial and agricultural applications. However, hydrazine is highly poisonous when inhaled or in contact with skin. Therefore, reliable analytical approaches for hydrazine detection with satisfactory sensitivity and selectivity are of great interest and importance. Herein, we have developed a selective ratiometric NIR fluorescent probe Cy7A for hydrazine. Upon addition of hydrazine, the fluorescent excitation and emission profiles of Cy7A changed significantly. Cy7A showed a ratiometric fluorescence response that was selective for hydrazine over other species with a detection limit of0.81ppb. Cy7A has negligible cytotoxity and is mitochondria-localizable, which may facilitate the toxicology study of hydrazine in living cells. Moreover, it could be used to detect hydrazine in real water samples quantitatively, image hydrazine in living cells in a ratiometric manner, and, for the first time, visualize hydrazine in living mice by monitoring the signal changes of two different fluorescence channels.Lysosomes and lysosome-related organelles constitute a system of acidic compartments (pH4.0-5.0), which contain a large number of enzymes and secretory proteins exhibiting a variety of functions. Two-photon fluorescent microscopy (TPFM) is qualified to veritably visualize the distribution of lysosomes and lysosome-related organelles in living cells and tissues. In this context, we have synthesized a small two-photon fluorescent dye PBC which would emit fluorescence in the near-infrared region (NIR) with great Stokes shifts of more than170nm. The living cell imaging experiments established that PBC was living cell membrane permeable. And the subsequent co-staining experiments confirmed that PBC was lysosome-localizable, with a Pearson’s coefficient of ca.0.96.