Dual-functional near-infrared fluorescent probe for H2S detection and precise COX-2-positive cancer imaging.

Cancer poses a great threat to the health of human beings. The precise visualization of cancer is significant for the development of new cancer diagnostic technology. The contrast ratio between normal and cancer tissue is still unsatisfactory. To meet the challenges, a low-toxic near-infrared hemicyanine-derived fluorescent probe NFA-DNP was developed to image the cancers with highly expressive level of COX-2. With the H2S-responsive site of the 2,4-dinitrophenol group, NFA-DNP could detect H2S sensitively and fast-responsively with remarkable fluorescence enhancement both in solution and biological environments. NFA-DNP showed good lysosomal-targeting ability in living cells. With the COX-2 targeting group niflumic acid, NFA-DNP exhibited excellent COX-2-positive cancer cells and tissue targeting property over the normal one. NFA-DNP can differentiate the normal and cancer tissue in vivo with a high contrast ratio, which indicates that it is a potential tool for precise COX-2-positive cancer visualization.