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Surface Charge Density-Dependent DNA Capture through Polymer Planar Nanopores.
Zheng Jia1, Junseo Choi1, Sunggook Park1
1Mechanical & Industrial Engineering Department and Center for BioModular Multiscale Systems for Precision Medicine , Louisiana State University , Baton Rouge , Louisiana 70803 , United States.
ACS Applied Materials & Interfaces
|October 30, 2018
Summary
Surface charge density significantly impacts double-stranded DNA capture in nanopore sensors. A threshold surface charge density was identified, beyond which DNA translocation is blocked due to opposing forces.
Area of Science:
- Nanotechnology
- Biophysics
- Materials Science
Background:
- Surface charge density of nanopore walls is crucial for DNA capture in nanopore sensing.
- Understanding these interactions is key for optimizing nanopore device performance.
Purpose of the Study:
- To investigate the effect of surface charge density on double-stranded DNA (dsDNA) capture into polymer planar nanopores.
- To determine a threshold surface charge density that impedes DNA translocation.
Main Methods:
- Numerical simulations of effective driving forces (Feff) for dsDNA translocation.
- Experimental verification using dsDNA translocation experiments in 10 nm diameter planar nanopores.
- Utilizing fluorescence observation and ionic current measurements.
Main Results:
- Electrophoretic driving force (FEP) is opposed by electroosmotic flow (FEOF) for negatively charged DNA and nanopore walls.
- A threshold surface charge density (σthreshold) of -50 mC/m² was determined for a 10 nm nanopore in 1× TE buffer.
- Experimental results confirmed that DNA translocation occurs only below this σthreshold.
Conclusions:
- The simulated σthreshold can predict dsDNA translocation in nanopore devices.
- Surface charge density is a critical parameter for designing effective nanopore-based biopolymer sensing platforms.
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