Slowing down DNA translocation through solid-state nanopores by edge-field leakage

Area of Science:

• Nanotechnology
• Biophysics
• Analytical Chemistry

Background:

• Solid-state nanopores offer high-throughput single-molecule detection.
• High translocation speeds of small molecules pose challenges for identification and registration.
• Current methods struggle to effectively slow down or selectively capture translocating molecules.

Purpose of the Study:

• To develop a method for selectively pinning and delaying the transport of small molecules through solid-state nanopores.
• To enhance the identification and registration capabilities of nanopore-based detection systems.
• To improve the discrimination between different types of molecules, such as single-stranded and double-stranded DNA.

Main Methods:

• Utilizing bullet-shaped polymer nanopores with a thin, high-permittivity dielectric coating.
• Redirecting the electric field to create a voltage-dependent surface field at the pore entry.
• Employing an electric field-induced edge-pinning mechanism to control molecular transport.

Main Results:

• The electric field redirection successfully created a reversible edge-pinning effect on molecules.
• Molecular entry into the nanopore became an activated process, exponentially dependent on bias voltage and molecular rigidity.
• Translocation times for short single-stranded DNA molecules were prolonged by up to 5 orders of magnitude, reaching minutes.
• Discrimination between single-stranded and double-stranded DNA duplexes was achieved with 97% confidence.

Conclusions:

• The developed dielectric-coated nanopore system effectively controls molecular translocation dynamics.
• This method significantly enhances the dwell time of molecules within the nanopore, enabling precise detection and discrimination.
• The technique shows great promise for advancing single-molecule analysis and diagnostics.