Scientists are pioneering a new method to measure electricity in cells

Electricity is an important ingredient in living bodies. We know that voltage differences are important in biological systems; they drive the beating of the heart and allow neurons to communicate with each other. But for decades, it has not been possible to measure voltage differences between organelles – the membrane-wrapped structures in the cell – and the rest of the cell.

However, a breakthrough technology created by UChicago scientists allows researchers to look inside cells to see how many different organelles use strains to perform functions.

“Scientists had long noticed that charged dyes used to stain cells would become trapped in the mitochondria,” explains graduate student Anand Saminathan, lead author of the paper, which was published in Nature Nanotechnology. “But little work has been done to investigate the membrane potential of other organelles in living cells.”

UChicago’s Krishnan lab specializes in building tiny sensors to travel inside cells and report on what’s happening, so researchers can understand how cells work – and how they’re broken down in diseases or conditions. They have previously built such machines to study neurons and lysosomes, among other things.

In this case, they decided to use the technique to investigate the electrical activities of the organelles in living cells.

Within the membranes of neurons are proteins called ion channels that act as gateways for charged ions to enter and exit the cell. These channels are essential for neurons to communicate. Previous research had shown that organelles have similar ion channels, but we weren’t sure what role they played.

The researchers’ new tool, called Voltair, makes it possible to further investigate this question. It works like a voltmeter that measures the voltage difference of two different areas in a cell. Voltair is made of DNA, which means it can go straight into the cell and access deeper structures.

In their first studies, the researchers looked for membrane potentials – a difference in stress within an organelle versus outside. They found evidence for such potentials in various organelles, such as trans-Golgi networks and recycling endosomes, which were previously thought to have no membrane potentials at all.

“So I think the membrane potential in organelles could play a bigger role – maybe it helps organelles to communicate,” says Prof. Yamuna Krishnan, an expert in nucleic acid-based molecular devices.

Their studies are just the beginning, the authors said; Voltair offers researchers in many fields a way to answer questions they haven’t even been able to ask. It can even be used in plants.

“In any case, this new development will spark conversation and perhaps even inspire a new area of ​​research,” said Saminathan.