Non-photonic sensing of membrane-delimited reactive species with a Na(+) channel protein containing selenocysteine

Photonic experiments are of key importance in life sciences but light-induced side effects are serious confounding factors. Here we introduce roNa(V)2, an engineered voltage-gated Na(+) channel harboring a selenocysteine in its inactivation motif, as a non-photonic, sensitive, gateable, and reversible sensor for membrane-delimited reactive species. roNa(V)2 allows for the assessment of chemical modification induced in fluorescence microscopy settings with high sensitivity and time resolution and it demonstrates the usefulness of ion channels as highly sensitive reporters of membrane processes.