Real-time noninvasive monitoring of cell mortality using a two-photon emissive probe based on quaternary ammonium

We report that a dicyanyl derivative QN2 containing quaternary ammonium was capable of identifying apoptotic cells by targeting nucleic acid (DNA and RNA) and we were able to observe nuclear ultra-details using a stimulated emission depletion (STED) nanoscopy technique. QN2 could evaluate the anti-cancer drug pesticide effect by monitoring in real-time without interfering with normal cell proliferation. These results suggest the high potential for using QN2 in practice for monitoring apoptosis to evaluate tumor therapy effectiveness or for drug development.