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Fine-tuning the Size and Minimizing the Noise of Solid-state Nanopores
Published on: October 31, 2013
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Translocation frequency of double-stranded DNA through a solid-state nanopore.
Nicholas A W Bell1, Murugappan Muthukumar1,2, Ulrich F Keyser1
1Cavendish Laboratory, University of Cambridge, CB3 0HE, United Kingdom.
Physical Review. E
|March 18, 2016
Summary
Solid-state nanopore sensors reveal DNA translocation dynamics. DNA passage frequency depends on salt concentration and polymer length, explained by a convection-diffusion model including entropic barriers.
Area of Science:
- Nanotechnology and Nanoscience
- Biophysics
- Physical Chemistry
Background:
- Solid-state nanopores function as single-molecule sensors, detecting ionic current changes during charged polymer passage.
- Understanding DNA translocation through nanopores is crucial for molecular sensing and diagnostics.
Purpose of the Study:
- To investigate the length, voltage, and salt concentration effects on double-stranded DNA translocation frequency in conical quartz nanopores.
- To develop a unifying model describing DNA translocation dynamics under varying experimental conditions.
Main Methods:
- Fabrication of conical quartz nanopores with a 15 nm mean opening diameter.
- Conducting translocation experiments with double-stranded DNA at different salt concentrations (1M KCl and 4M LiCl) and voltages.
- Analyzing translocation frequency dependence on DNA length and applied voltage.
Main Results:
- Observed length-dependent, entropic barrier-limited translocation frequency at 4M LiCl.
- Observed length-independent, drift-dominated translocation frequency at 1M KCl.
- Developed a convection-diffusion equation incorporating an entropic barrier for polymer entry to unify observations.
Conclusions:
- DNA translocation dynamics through solid-state nanopores are significantly influenced by salt concentration and polymer length.
- A single convection-diffusion model can effectively describe DNA translocation under different ionic conditions, highlighting the role of entropic barriers.
