Measurement of Local Sodium Ion Levels near Micellar Surfaces with Fluorescent PET (Photoinduced Electron Transfer) Sensors

Na+ near membranes controls our nerve signals, besides several other crucial bioprocesses. We demonstrate that fluorescent PET (photoinduced electron transfer) sensor molecules target Na+ in nanospaces near micellar membranes with excellent discrimination against H+. They find that Na+ near anionic micelles is concentrated by factors of upto 160. Sensor molecules which are not held tight to the micelle surface find a Na+ amplification factor of 8 only. These findings are strengthened by the employment of control compounds whose PET processes are permanently ‘on’ or permanently ‘off’.