Cyanine fluorophores for cellular protection against ROS in stimulated macrophages and two-photon ROS detection.

We report the first example of a novel two-photon active, biocompatible, and macrophage cell-membrane permeable carbazole-based cyanine fluorophore for the detection of three biologically important ROS, namely, ˙OH, O2(-) and OCl(-) in solution. This versatile probe shows cellular protection not only in stimulated macrophages from phorbol-12-myristate-13-acetate-induced morphological changes but also lipopolysaccharide-induced cytotoxicity by quenching with the O2(-) and OCl(-) production, respectively. Such protection could be visualized by a distinct change in the fluorescence intensity of the probe.