A DCM-based NIR sensor for selective and sensitive detection of Zn2+ in living cells

Zinc ion is the 2nd abundant transition metal element in human's body. It is responsible for many physiological and biological functioning in the body, such as growth of people, immunity, endocrine, etc. The deficiency of zinc could result in an increasing risk for growth retardation, neurological disorder and infectious disease. Thus, developing a nondestructive method for detecting Zn2+ in living systems is important. Here we reported a 2-(2-methyl-4H-ylidene)- malononitrile (DCM)-based NIR probe DF-Zn for selective and sensitive detection of Zn2+. The probe DF-Zn is cell-permeable and stable at broad pH range. DF-Zn showed a fast response to Zn2+, big stock's shift, and “nude-eye” recognition for Zn2+. Moreover, the selective binding of probe DF-Zn to Zn2+ was reversible. With the addition of EDTA in buffer solution, reversible response of probe to Zn2+ could be observed in MCF-7 cells imaging.