Smart sensor identifies present molecules by remembering the past
Most sensors are designed to do only one thing: detect what passes through them. But what if a sensor could do more? To create a new generation of technology, researchers have looked to living systems for inspiration. If a sensor could detect molecules, could it also remember previous interactions and selectively respond to them?
Researchers at SANKEN, University of Osaka, have engineered a groundbreaking nanopore sensor capable of detecting molecules, generating electrical signals, and retaining memory of past molecular interactions without external control. The device is an autonomous solid-state nanopore, a minuscule hole measuring a few billionths of a meter across, used to detect biological molecules such as DNA and proteins.
Unlike traditional nanopores that function as passive channels dictated by external electronics, this innovative sensor undergoes chemical reactions within its structure, resulting in a dynamic sensing environment that is responsive to passing molecules. The core functionality of this nanopore lies in its ability to detect changes in electrical current as molecules traverse through it.
However, what sets it apart is its self-modifying nature. As the pore undergoes a continuous cycle of opening and closing, it deposits and dissolves tiny mineral deposits, resulting in the repetitive opening and closing of the nanopore. This process generates bursts of electrical signals that are distinctly influenced by the molecules passing through the pore and the pore's prior states.
Each different molecule leaves behind a unique signature in terms of the size, duration, and timing of the electrical spikes it generates. This unique electrical signature allows for the identification of the molecule based on the nanopore's memory of its previous interactions. To demonstrate the potential of their invention, the research team employed machine learning algorithms to analyze these state-dependent signatures.
In their experiments, they successfully distinguished all four DNA nucleotides, accurately measured mixtures containing multiple nucleotides, and identified seven different amino acids. This autonomous, chemically active nanopore sensor represents a significant shift in the design and functionality of nanopores. Rather than being merely passive channels for molecule transportation, these nanopores can now actively respond to their chemical environment, exhibiting capabilities far beyond conventional sensing technologies.
This development could significantly enhance molecular analysis in biomedical research, diagnostics, and emerging iontronic technologies, opening doors to a new generation of intelligent nanoscale systems.
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