Scientists have discovered how microscopic pores made from proteins—tiny holes found in cell membranes—can act like electrical gates.
This finding could open the door to new kinds of computers that use ions instead of electrons to process information, similar to how the human brain works.
Pore-forming proteins exist everywhere in nature. In humans, they help the immune system defend against infections.
In bacteria, they can work as toxins that punch holes in the membranes of other cells.
These pores allow ions and molecules to pass through cell walls, helping control many biological processes.
Because they are so good at controlling molecular flow, scientists have also turned them into valuable tools for biotechnology. They are used in DNA sequencing and for detecting single molecules.
However, these biological nanopores can behave unpredictably. Researchers have long been puzzled by two particular effects: rectification and gating.
Rectification happens when ions flow more easily in one direction than the other, depending on whether the voltage is positive or negative.
Gating occurs when the flow of ions suddenly stops, as if the pore temporarily shuts down. Both effects can interfere with sensitive measurements and have been hard to explain—until now.
A research team led by Matteo Dal Peraro and Aleksandra Radenovic at EPFL (École Polytechnique Fédérale de Lausanne) has revealed the physical basis of these mysterious effects.
Using experiments, simulations, and theoretical models, they showed that both rectification and gating are caused by the electrical charges along the nanopore’s inner surface and how those charges interact with passing ions.
Their study, published in Nature Nanotechnology, focused on a bacterial pore called aerolysin, which is commonly used in sensing experiments.
The researchers created 26 different versions of the aerolysin pore by changing specific charged amino acids along its interior.
This allowed them to see how different charge patterns affected ion flow. They also applied alternating voltages to study how the pores responded over different time periods, which helped them separate the effects of rectification and gating.
They found that rectification occurs because the charge distribution inside the pore makes it easier for ions to move in one direction—like a one-way valve. Gating, in contrast, happens when a strong flow of ions creates a charge imbalance that destabilizes the pore, causing it to partly collapse and temporarily block the current. By altering the position and sign (positive or negative) of the charges, the team could control when gating occurred. Making the pore more rigid prevented gating altogether, showing that flexibility is key to this process.
The results give scientists a way to design nanopores with specific behaviors—either preventing gating for better sensing devices or using it deliberately for bio-inspired computing. In fact, the team even built a nanopore that could “learn” from electrical pulses, mimicking how brain synapses strengthen connections through repeated signals.
Such ion-based learning systems could become the foundation for a new kind of computing that operates more like the human brain.
Source: EPFL.
