title: Electrically Tunable Quenching of DNA Fluctuations in Biased Solid-State Nanopores.
abstract: Nanopores offer sensors for a broad range of nanoscale materials, in particular ones of biological origin such as single- and double-stranded DNA or DNA-protein complexes. In order to increase single-molecule sensitivity, it is desirable to control biomolecule motion inside nanopores. In the present study, we investigate how in the case of a double-stranded DNA the single-molecule sensitivity can be improved through bias voltages. For this purpose we carry out molecular dynamics simulations of the DNA inside nanopores in an electrically biased metallic membrane. Stabilization of DNA, namely, a reduction in thermal fluctuations, is observed under positive bias voltages, while negative voltages bring about only negligible stabilization. For positive biases the stabilization arises from electrostatic attraction between the negatively charged DNA backbone and the positively charged pore surface. Simulations on a teardrop-shaped pore show a transverse shift of DNA position toward the sharp end of the pore under positive bias voltages, suggesting the possibility to control DNA alignment inside nanopores through geometry shaping. The present findings open a feasible and efficient route to reduce thermal noise and, in turn, enhance the signal-to-noise ratio in single-molecule nanopore sensing.
authors.affiliation: Beckman Institute for Advanced Science and Technology, ‡Department of Physics, and §Department of Electrical and Computer Engineering, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Hu
authors.initials: H
authors.lastname: Qiu
authors.affiliation: Beckman Institute for Advanced Science and Technology, ‡Department of Physics, and §Department of Electrical and Computer Engineering, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Anuj
authors.initials: A
authors.lastname: Girdhar
authors.affiliation: Beckman Institute for Advanced Science and Technology, ‡Department of Physics, and §Department of Electrical and Computer Engineering, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schulten
authors.affiliation: Beckman Institute for Advanced Science and Technology, ‡Department of Physics, and §Department of Electrical and Computer Engineering, University of Illinois , Urbana, Illinois 61801, United States.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Leburton
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D004247:DNA / Q000032:analysis*; D004058:Diffusion; D004560:Electricity; D008670:Metals / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D058608:Nanopores; D009690:Nucleic Acid Conformation; D010087:Oxides / Q000737:chemistry; D059629:Signal-To-Noise Ratio; D055672:Static Electricity
chemical_list: D008670:Metals; D010087:Oxides; D004247:DNA
keywords: DNA sequencing; biosensor; molecular dynamics; solid-state nanopore; stabilization