Filling nanopipettes with apertures smaller than 50 nm: dynamic microdistillation

Area of Science:

• Nanotechnology
• Biophysics
• Analytical Chemistry

Background:

• Nanopipettes with sub-10 nm apertures enhance spatial resolution in scanning conductance microscopy.
• Applications include single-molecule delivery and studying molecular stretching during translocation.
• Filling these nanopipettes presents a significant challenge.

Purpose of the Study:

• To develop a reliable technique for completely filling nanopipettes of various shapes and sizes.
• To overcome limitations in current nanopipette filling methods.
• To enable advanced scanning conductance experiments requiring precisely filled nanopipettes.

Main Methods:

• A dynamic microdistillation technique was employed for nanopipette filling.
• Initial filling with pure water, followed by electrolyte replacement via electromigration.
• Electrical measurements were used to confirm complete filling.

Main Results:

• The dynamic microdistillation technique successfully filled all tested nanopipettes, irrespective of shape or tip radius.
• Elongated, bent, and small-angle tip nanopipettes were completely filled.
• Electrical measurements confirmed the integrity and completeness of the filling process.

Conclusions:

• Dynamic microdistillation offers a robust solution for filling challenging nanopipettes.
• This technique facilitates improved spatial resolution and molecular studies in scanning conductance experiments.
• The method is versatile and applicable to various nanopipette geometries.