Measuring DNA Translocation Forces through MoS2-Nanopores with Optical Tweezers

Abstract

Measuring the minute forces acting on a single charged polymer, like DNA, during the translocation through a nanopore offers valuable insights into translocation mechanics and dynamics. For increased sensitivity, both ultra-thin nanomembranes and small nanometer-sized nanopore diameters are desirable. In this paper, we show the preparation of free-standing monolayer molybdenum disulfide nanomembranes by exfoliation by both wet and dry transfer. We milled nanopores with approximately 40nm diameter into those nanomembranes with a helium ion microscope. Finally, we measured the controlled DNA translocation through such a nanopore with optical tweezers and determined a translocation force of 7pN at a transmembrane voltage of 50mV.