Kralj's group pioneered bacterial electrophysiology using genetically encoded voltage indicators, building high-throughput fluorescence-imaging platforms to map the proteins and dynamics governing membrane voltage in bacteria and to study bioelectric signaling and mechanosensation in cells. For context, this complements the established paradigm of NV-diamond ensemble magnetometry (Hahn-echo/DEER, nanoscale NMR, T1 relaxometry) operating near pT/√Hz sensitivity.