Osaka team builds autonomous nanopore sensor that remembers prior molecules

Researchers at SANKEN at the University of Osaka and collaborators report in ACS Nano an autonomous solid-state nanopore that senses molecules, generates electrical signals, and retains memory of recent events without external switching, phys.org said. Unlike fixed nanopores whose behavior is set by outside electronics, the device continuously reshapes itself through chemical reactions. Lead author Makusu Tsutsui said that under constant voltage, reactions inside the pore repeatedly build and dissolve tiny mineral deposits, so the pore opens and closes on its own and produces bursts of electrical signals. As nucleotides and amino acids pass through, they change how the pore evolves. Senior author Tomoji Kawai said different molecules alter the size, duration, and timing of electrical spikes, leaving distinctive signatures that also depend on the nanopore's recent memory. Using machine learning on those state-dependent signals, the team distinguished all four DNA nucleotides, measured multi-nucleotide mixtures, and identified seven amino acids without actively controlling the pore during sensing. phys.org said such devices could aid biomedical molecular analysis or iontronic computing that uses ions instead of electrons. The paper carries DOI: 10.1021/acsnano.6c08258.