A sodium-enabled 'Pourbaix sensor': a three-input AND logic gate as a 'lab-on-a-molecule' for monitoring Na+, pH and pE.

A novel supramolecular three-input AND logic gate is demonstrated as a 'lab-on-a-molecule' for monitoring the Na(+), pH and pE levels in solution by communicating a fluorescence signal. The fluorescence signal is modulated by three photoinduced electron transfer reactions that are controlled by an unprecedented combination of two cation binding events and one redox reaction.