The human body relies heavily on electrical charges. Lightning-like pulses of energy fly through the brain and nerves and most biological processes depend on electrical ions traveling across the membranes of each cell in our body.
These electrical signals are possible, in part, because of an imbalance in electrical charges that exists on either side of a cellular membrane. Until recently, researchers believed the membrane was an essential component to creating this imbalance. But that thought was turned on its head when researchers at Stanford University discovered that similar imbalanced electrical charges can exist between microdroplets of water and air.
Now, researchers at Duke University have discovered that these types of electric fields also exist within and around another type of cellular structure called biological condensates. Like oil droplets floating in water, these structures exist because of differences in density. They form compartments inside the cell without needing the physical boundary of a membrane.
Inspired by previous research demonstrating that microdroplets of water interacting with air or solid surfaces create tiny electrical imbalances, the researchers decided to see if the same was true for small biological condensates. They also wanted to see if these imbalances sparked reactive oxygen, “redox,” reactions like these other systems.
“In a prebiotic environment without enzymes to catalyze reactions, where would the energy come from? This discovery provides a plausible explanation of where the reaction energy could have come from, just as the potential energy that is imparted on a point charge placed in an electric field.” (https://www.sciencedirect.com/science/article/abs/pii/S2451929423001535)
Because the Chilkoti laboratory specializes in creating synthetic versions of naturally occurring biological condensates, the researchers were easily able to create a test bed for their theory. After combining the right formula of building blocks to create minuscule condensates, with help from postdoctoral scholar Marco Messina in? Christopher J. Chang’s group at the University of California – Berkeley, they added a dye to the system that glows in the presence of reactive oxygen species.
Their hunch was right. When the environmental conditions were right, a solid glow started from the edges of the condensates, confirming that a previously unknown phenomenon was at work. Dai next talked with Richard Zare, the Marguerite Blake Wilbur Professor of Chemistry at Stanford, whose group established the electric behavior of water droplets. Zare was excited to hear about the new behavior in biological systems, and started to work with the group on the underlying mechanism.