On the Behavior of Nanoparticles beyond the Nanopore Interface

Area of Science:

• Nanotechnology
• Colloidal Science
• Analytical Chemistry

Background:

• Nanopore sensors offer advanced in situ characterization of bio-nano colloidal dispersions.
• The precise transport forces governing particle movement in and out of nanopores remain incompletely understood.

Purpose of the Study:

• To investigate particle motion dynamics outside a size-tunable nanopore.
• To correlate external particle motion with known forces acting within the nanopore.
• To develop a combined optoelectronic method for comparing sensing techniques and analyzing particle motion.

Main Methods:

• Studied particle motion near the smaller opening of an elastomeric, size-tunable nanopore.
• Developed a combined optoelectronic approach integrating resistive pulse sensing and single particle tracking.
• Measured ensemble particle motion influenced by electrophoresis, pressure-driven flow, and electroosmotic flow.

Main Results:

• Observed that electrophoretically driven motion can overcome bulk fluid flow, even at distances from the nanopore opening.
• Demonstrated the ability to characterize particle size using the developed combined technique.
• Provided insights into the interplay of different forces acting on particles near the nanopore.

Conclusions:

• The combined optoelectronic approach enhances understanding of fluid behavior at the nanopore interface.
• This study clarifies the dominant transport forces influencing particle migration toward and through nanopore sensors.
• Findings have implications for advancing particle characterization systems and nanopore sensing methodologies.