Controlling the Capture Process of 50BP DNA by Solid-State Nanopores

We quantify the frequency of short DNA fragments interacting with solid-state nanopores under different experimental conditions. By measuring the time between adjacent single-molecule translocation events, we can extract the capture rate from the ionic current signal. For this study, we use >50 individual solid-state nanopores ranging in sizes between 2.5 and 4nm and fabricated in ultra-thin 10nm SiN membranes using controlled breakdown (CBD). We investigate the factors that affect the reliability and variability of the capture process of 50bp DNA molecules, such as applied voltage and electrolyte type, and identify the optimal conditions for maximizing the capture rate of such short fragments. These results help establish solid-state nanopores fabricated by CBD as reliable single-molecule Coulter counters for accurately determining molecular concentrations of short DNA polymers in solution.