A novel near-infrared fluorimetric method for point-of-care monitoring of Fe2+ and its application in bioimaging.

Iron is one of the essential trace elements in the human body, which is involved in many important physiological processes of life. The abnormal amount of iron in the body will bring many diseases. Therefore, a novel near-infrared fluorimetric method was developed. The method is based on a fluorescent probe (E)-4-(2-(3-(dicyanomethylene)-5,5-dimethylcyclohex-1-en-1-yl)vinyl)-N, N-diethylaniline oxide (DDED) which uses N-oxide as a recognition group to real-time monitoring and imaging of Fe2+ in vivo and in vitro. The method exhibits excellent selectivity and high sensitivity (LOD = 27 nM) for Fe2+, fast reaction rate (< 4 min), extremely large Stokes shift (＞ 275 nm), low cytotoxicity. The strip test strongly illustrates the potential application of DDED in real environment. In particular, DDED has been successfully applied to real-time monitoring and imaging of Fe2+ in HepG2 cells and zebrafish. That is, the method has great potential for the detection of Fe2+ in living systems.