Voltage-driven translocation of DNA through a high throughput conical solid-state nanopore

Area of Science:

• Nanoscience and Nanotechnology
• Biophysics
• Materials Science

Background:

• Solid-state nanopores offer robust platforms for single-molecule detection.
• Fabrication advancements enable controllable nanopore dimensions for tailored applications.

Purpose of the Study:

• To analyze lambda-DNA (λ-DNA) translocations through a conical silicon nitride nanopore.
• To investigate the effect of varying voltage biases on DNA translocation dynamics and event frequency.

Main Methods:

• Fabrication of a 30-60 nm conical nanopore in a 100 nm silicon nitride membrane using focused ion beam (FIB).
• Electrophysiological measurements of λ-DNA translocation events at applied voltages ranging from 200 to 450 mV.
• Analysis of translocation time, current blockage, and event frequency distributions.

Main Results:

• Higher applied voltages increased event rates and induced linear stretching of λ-DNA molecules.
• A threshold voltage of 181 mV was identified for DNA translocation, attributed to pore geometry.
• Translocation speed decreased approximately 5-fold, while the capture radius doubled compared to ultrathin nanopores.

Conclusions:

• Large nanopores in thick membranes provide enhanced stability and throughput for single-molecule detection.
• The pore geometry and applied voltage significantly influence DNA translocation dynamics, enabling controlled analysis.
• These findings support the development of nanopores as versatile sensors for biopolymers and nanomaterials.