An optical voltage sensor with sub-millivolt resolution reveals bioelectric contact inhibition

The development of rEstus2s, an ultra-sensitive, genetically encoded voltage indicator, has enabled the detection of sub-millivolt electrical fluctuations in non-excitable cells. When healthy cells connect through gap junctions, these miniature voltage fluctuations are strongly suppressed—a process we term bioelectric contact inhibition.  We hypothesize that this electrical stabilization effect serves as an environmental cue, signaling cells to halt proliferation once an organ reaches its terminal size. In cancer cells, however, this electrical dampening fails, restoring high voltage volatility and potentially fueling uncontrolled tumor growth.