Scientists have developed a tiny sensor that does something unusual: it can “remember” the molecules it has previously encountered.
Inspired by the way living systems respond to their surroundings, the new technology could lead to smarter sensors for medical testing, biological research and future computing devices.
The research, published in ACS Nano, was carried out by scientists at the University of Osaka’s SANKEN research institute and their collaborators.
Their new device is an advanced version of a nanopore, a microscopic opening that is already widely used to detect biological molecules such as DNA and proteins.
A nanopore is an extremely small hole, only a few billionths of a meter across. As molecules pass through it, they cause tiny changes in an electrical current.
By measuring these changes, scientists can identify different molecules. This technology has become an important tool in fields such as DNA sequencing and medical diagnostics.
However, conventional nanopores are passive devices. Their size and behavior remain fixed, and they simply record whatever passes through them. The new nanopore behaves very differently.
Instead of staying the same, the researchers designed a nanopore that constantly changes its own structure while it operates. When a steady electrical voltage is applied, chemical reactions inside the tiny opening repeatedly create and dissolve microscopic mineral deposits. As a result, the nanopore naturally opens and closes over and over again without requiring any external control.
These continuous changes create a constantly shifting environment inside the sensor. As molecules such as DNA building blocks and amino acids travel through the nanopore, they influence the ongoing chemical reactions. In turn, the reactions change how the nanopore behaves during future measurements.
This means every molecule leaves behind more than a simple electrical signal. It also affects the nanopore’s future responses, allowing the device to retain a short-term memory of previous interactions. Because the sensor remembers its recent history, the electrical signals become richer and contain more information than those produced by traditional nanopores.
The researchers then used machine learning to study these complex electrical patterns. The computer system successfully distinguished all four of the DNA nucleotides, the chemical building blocks that make up DNA. It could also correctly analyze mixtures containing several different nucleotides.
The team expanded the approach even further by identifying seven different amino acids, the molecules that combine to form proteins. Importantly, all of these measurements were performed without actively controlling the nanopore while it was sensing the molecules.
According to the researchers, this represents a new way of thinking about molecular sensors. Instead of acting as simple detectors, future nanopores could actively respond to their surroundings and adapt as they work.
The technology could have many practical applications. Smarter nanopores may improve disease diagnosis, speed up biological research and make it easier to analyze complex mixtures of molecules.
The work may also contribute to the growing field of iontronics, an emerging technology that processes information using charged atoms, known as ions, rather than electrons.
Although the technology is still in the research stage, the study demonstrates that tiny sensors can combine detection, memory and signal processing in a single device.
By giving nanopores the ability to remember previous events, scientists have taken an important step toward creating a new generation of intelligent nanoscale sensors.
