Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 25: Posters: DNA/RNA and related enzymes

BP 25.6: Poster

Tuesday, March 17, 2015, 14:00–16:00, Poster A

Measuring DNA translocation forces through various solid state nanopores with Optical Tweezers — •Sebastian Knust, Andy Sischka, and Dario Anselmetti — Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany

We measured the forces acting on a single strand of dsDNA during translocation through nanopores in various solid state membranes by Optical Tweezers. The system includes a video-based force detection and analysis system allowing for virtually interference-free axial force measurements with sub-piconewton precision [1]. All measurements were performed with an overall force resolution of 0.5 pN at a sample rate of 123 Hz.

We show the controlled translocation through Si₂N₃ membranes both uncoated and lipid-coated [2]. Additionally, measurements of controlled dsDNA translocation through carbon nanomembranes (CNM) and through MoS₂ membranes were conducted.

Furthermore, measuring controlled translocation through graphene nanopores was found challenging, due to local heating phenomena encountered upon approaching an optically trapped microbead to a free standing graphene membrane. We analysed these phenomena in detail.

[1] S. Knust et. al., Rev. Sci. Instrum. 83, 103704 (2012)

[2] L. Galla et. al., Nano Lett. 14, 4176 (2014)