Many biological processes are regulated by electricity—from nerve impulses to heartbeats to the movement of molecules in and out of cells. A new study by Scripps Research scientists reveals a previously unknown potential regulator of this bioelectricity: droplet-like structures called condensates. Condensates are best known for their role in compartmentalizing the cell, but this study shows that they can also act as tiny biological batteries that charge the cell membrane from within.
The team showed that when the electrically charged condensates collide with cell membranes, they change the cell membrane voltage—which affects the amount of electrical charge that flows across the membrane—at the point of contact. The discovery was published in the journal Small on November 18, 2025, highlights a fundamental new feature of how our cells work and could one day help scientists treat certain diseases.
This represents an entirely new paradigm in bioelectricity that has substantial implications for electrical regulation in biology and health.”
Ashok Deniz, senior author of the new paper and professor at Scripps Research
Condensates are organelles—structures inside cells that perform specific functions—but unlike more familiar organelles such as the nucleus and mitochondria, they are not enclosed within membranes. Instead, condensates are held together by a combination of molecular and electrical forces. They also occur outside cells, such as at neuronal synapses. Condensates are involved in many essential biological processes, including cell division, protein assembly, and signaling both within and between cells. Previous studies have also shown that condensates carry electrical charges on their surfaces, but little is known about how their electrical properties relate to cellular functions.
“You can think of the condensates as electrically charged droplets in the cell, like a tiny battery,” says first author Anthony Gurunian, a doctoral candidate co-advised by Deniz and associate professor and co-author Keren Lasker at Scripps Research. “Since condensates can often be charged, we wanted to test whether they can cause voltage changes across the cell membrane.”
If the condensates can change the electrical properties of cell membranes, it could have big implications because many cellular processes are controlled by changes in cell membrane voltage. For example, ion channels—proteins that rapidly transport molecules across the cell membrane—are activated by changes in cell membrane voltage. In the nervous system, this rapid, one-way transport of electrically charged molecules is what drives the propagation of electrical signals between nerves.
To test whether the condensates can change cell membrane tension, the researchers used cell models called Giant Unilamellar Vesicles (GUVs). To be able to visualize changes in voltage, they painted the GUV films with a dye that changes color in response to changes in electrical charge. They then put GUVs in the same container as the concentrates made in the lab and photographed their interactions under the microscope.
They showed that when the condensates and GUVs collided, it caused a local change in the electrical charge of the GUV films at their point of contact. “That’s one of the interesting things and the new things about it, because cell membrane tension has traditionally been thought of as a larger-scale property,” says Deniz. “Local changes in membrane potential could have important biological implications, for example for the function of ion channels and other voltage-regulated membrane proteins.”
By varying the chemical composition of the condensates, the researchers showed that the more electrical charge a condensate carries, the greater its effect on cell membrane voltage. They also found that the shape of the condensates appears to correlate with variations in voltage change.
“In some cases, the induced voltages are quite significant in magnitude—on the same scale as voltage changes in nerve impulses,” Gurunian says.
More tests are needed to understand the exact mechanisms by which the condensates cause these electrical changes, the researchers say, and to investigate the effect of the phenomenon on cellular function.
“Now that we know that condensates can locally induce these voltages, the next step is to test whether this new physics is functionally important for cells and organisms,” says Deniz. “If we see functional consequences, not only will it tell us something new about cell biology, but it could also help scientists develop therapeutics in the future.”
Source:
Journal Reference:
