Self-Referenced Scanning Ion Conductance Microscopy for Bath Solution-Flexible Imaging

Area of Science:

• Nanotechnology
• Surface Science
• Biophysics

Background:

• Scanning ion conductance microscopy (SICM) is vital for in situ imaging in liquids.
• Conventional SICM requires identical electrolyte concentrations, limiting its use in asymmetric or electrolyte-free conditions.

Purpose of the Study:

• To develop a modified SICM technique for high-resolution imaging in solvent-flexible environments.
• To overcome the limitations of conventional SICM in asymmetric or electrolyte-free conditions.

Main Methods:

• Developed a single pipette-based self-referenced SICM (SR-SICM) with a silver-coated nanopipette exterior.
• Utilized Finite Element Method (FEM) simulations to understand SR-SICM operation and optimize parameters.
• Experimentally validated SR-SICM performance with PDMS structures and biological samples.

Main Results:

• SR-SICM enables stable, high-resolution imaging in diverse solvent systems, including electrolyte-free conditions.
• FEM simulations revealed a nonmonotonic current-distance profile due to ion transport effects.
• Experimental results confirmed an extended feedback range compared to conventional SICM.

Conclusions:

• SR-SICM significantly broadens the applicability of SICM technology.
• This method allows stable imaging in environments previously inaccessible to conventional SICM.
• SR-SICM offers a robust and versatile tool for biomedical and materials science research.