Preparation of a copper-based fluorescent probe for nitric oxide and its use in mammalian cultured cells

A procedure for the preparation of a copper(II) complex (CuFL) as a fluorescent nitric oxide (NO) detector is described. The fluorescein-based ligand FL can be synthesized in seven reaction steps (overall yield approximately 20%), typically requiring a total time of 9 days. The CuFL probe allows for the detection of NO produced in mammalian cultured cells. The detailed protocol for the use of CuFL for imaging NO in human neuroblastoma SK-N-SH cells takes a total time of approximately 26 h. This includes plating cells on six-well tissue culture plates or imaging dishes, treatment with CuFL, stimulation of NO synthases and imaging by fluorescence microscopy.