Ten Thousand Recaptures of a Single DNA Molecule in a Nanopore and Variance Reduction of Translocation Characteristics

Nanopores have emerged as highly sensitive biosensors operating at the single-molecule level. However, the majority of nanopore experiments still rely on averaging signals from multiple molecules, introducing systematic errors. To overcome this limitation and obtain accurate information from a single molecule, the molecular ping-pong methodology provides a precise approach involving repeated captures of a single molecule. In this study, we have enhanced the molecular ping-pong technique by incorporating a customized electronic system and control algorithm, resulting in a recapture number exceeding 10,000. During the ping-pong process, we observed a significant reduction in the variance of translocation characteristics, providing fresh insights into single-molecule translocation dynamics. An inhomogeneous translocation velocity of folded DNA has been revealed, illustrating a strong interaction between the molecule and the solid-state nanopore. The results not only promise heightened experimental efficiency with reduced sample volume but also increase the precision in statistical analysis of translocation events, marking a significant stride toward authentic single-molecule nanopore sensing.