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.

We are excited to see DNA used as a building block, but we aren’t really sure how we’d duplicate the feat. We also wondered if the Hackaday community had other ideas about how to measure this that might not be so exotic.

We keep meaning to do more biology builds like maybe a fluorescence microscope. Of course, then we’d need a robot helper.