Zero-mode waveguide detection of flow-driven DNA translocation through nanopores

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Understanding DNA transport through nanopores is crucial for applications like sequencing and diagnostics.
• Previous models suggested fluid flow influences DNA translocation, but direct single-molecule measurements were limited.

Purpose of the Study:

• To directly measure and characterize the flow-driven injection of single DNA molecules into nanopores.
• To investigate the physical mechanisms controlling DNA entry, including the role of fluid dynamics and energy barriers.
• To explore methods for modulating DNA transport by altering nanopore properties.

Main Methods:

• Utilized a modified zero-mode waveguide method for single-molecule, single-pore resolution.
• Employed controlled fluid flow to drive DNA injection.
• Systematically varied pore radius, DNA concentration, and DNA length.
• Functionalized nanopores to investigate barrier modulation.

Main Results:

• Observed a distinct flow threshold for DNA injection, independent of pore radius, DNA concentration, and length.
• Demonstrated that DNA injection is governed by an energy barrier, consistent with the de Gennes-Brochard suction model.
• Showed that the energy barrier height can be modulated by nanopore functionalization.

Conclusions:

• Flow-driven DNA injection into nanopores is a threshold phenomenon controlled by an energy barrier.
• Nanopore functionalization offers a means to tune the energy barrier and thus control DNA transport.
• These findings provide fundamental insights into nanopore-DNA interactions and inform the design of nanopore-based devices.