Single-nanopore investigations with ion conductance microscopy

Area of Science:

• Nanoscale science and technology
• Surface science and engineering
• Electrochemistry and electroanalysis

Background:

• Understanding ion transport through nanopores is critical for applications in sensing, filtration, and energy storage.
• Characterizing the electrical properties of individual nanopores requires high-resolution techniques.
• Existing methods often lack the precision to differentiate subtle geometric variations within single nanopores.

Purpose of the Study:

• To investigate the local current-voltage (I-V) properties of single nanopores using a modified scanning ion conductance microscope (SICM).
• To correlate measured I-V responses with equivalent circuit models.
• To demonstrate the capability of SICM in distinguishing between different nanopore geometries (cylindrical vs. conical).

Main Methods:

• Fabrication of single-nanopore membranes using an epoxy painting technique on track-etch membranes.
• Utilizing a three-electrode scanning ion conductance microscope (SICM) setup.
• Measuring local current-voltage responses in the vicinity of individual nanopores.

Main Results:

• The measured current-voltage responses closely matched proposed equivalent circuit models.
• Distinct conductance properties were observed for single cylindrical and single conical nanopores.
• The experimental results highlight the sensitivity of SICM to nanopore geometry.

Conclusions:

• The modified SICM effectively probes local current-voltage characteristics of single nanopores.
• Nanopore geometry significantly influences ion migration pathways and conductance properties.
• This approach offers a powerful tool for characterizing nanoscale devices with geometric variations.