We use a lot of voltmeters and we bet you do too. We have some big bench meters and some panel meters and even some tiny pocket-sized meters. But biological researchers at the University of Chicago and Northwestern University have even smaller ones. They’ve worked out a way to use a DNA-based fluorescent reporter to indicate the voltage across cellular membranes.
We don’t know much about biology, but apparently measuring the voltage on the membrane around a cell is easy, but measuring the voltages across membranes inside the cell isn’t. Previous work disrupted cells and measured potentials on isolated organelles.
The indicator — called Voltair — can target specific parts of a cell and includes a reference indicator so that a ratiometric measurement is possible. In fact, there are three main parts to the 38-base pair DNA duplex. One module contains a voltage-sensing dye that fluoresces in a way that indicates voltage. The second module is a reference dye that allows researchers to judge the voltage level. The final module identifies where the probe should attach.