Optical Tweezers for Mechanical Control Over DNA in a Nanopore
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The translocation of long-chain molecules, such as DNA or peptides, through membranes is an integral process for the function of living cells. During the translocation process, a number of interactions of electrostatic or hydrophobic nature govern the translocation velocity. Most of these interactions remain largely unexplored on the single-molecule level due to a lack of suitable instrumentation. We have shown that a combination of optical tweezers, single solid-state nanopores, and electrophysiological ionic current detection can provide further insight into the behavior of polymers in confinement. Here, we describe the experimental procedures necessary for manipulation of single biopolymers in a single nanopore not only by electrical fields, but also through mechanical forces using optical tweezers.
Key wordsNanopore Optical tweezers DNA translocation Biopolymers Polymer transport Single-molecule sensors Single-channel recording
I would like to thank Cees Dekker, Nynke, Dekker, Serge Lemay, Jelle van der Does, Stijn van Dorp, Bernard Koeleman, Oliver Otto, Benjamin Gollnick, Christof Gutsche, Friedrich Kremer, and Derek Stein for their help and discussions. Peter Veenhuizen, Ya-Hui Chen, and Suzanne Hage are acknowledged for preparing the biotinylated lambda-DNA, and Bernadette Quinn for help with electrochemical questions. Ralph Smeets, Diego Krapf, and Meng-Yue Wu mastered the fabrication of the nanpores. Stijn van Dorp, Bernard Koeleman, and Oliver Otto are especially acknowledged for taking some of the data presented here. I would like to thank Jo Gornall for proofreading the manuscript. Financial support of FOM, NWO, and the Emmy Noether program of the DFG is gratefully acknowledged.
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