Visual and quantitative analysis of the trapping volume in dielectrophoresis of nanoparticles

TL;DR

This paper introduces a visual method to analyze nanoparticle trapping volume in dielectrophoresis, enabling better characterization of nanoparticle properties and potential applications in nanoscale matter control.

Contribution

It presents a simple visual technique to measure dielectrophoretic trapping volume, validated by numerical simulations, for improved nanoparticle property analysis.

Findings

Excellent agreement between measured and simulated trapping widths.

The method allows determination of nanoparticle polarizability and size.

Potential extension to bio- and molecular nano-objects.

Abstract

Nanoparticle manipulations require a careful analysis of the forces at play. Unfortunately, traditional force measurement techniques based on the particle velocity do not provide a sufficient resolution, while balancing approaches involving counteracting forces are often cumbersome. Here, we demonstrate that a nanoparticle dielectrophoretic response can be quantitatively studied by a straightforward visual delineation of the dielectrophoretic trapping volume. We reveal this volume by detecting the width of the region depleted of gold nanoparticles by the dielectrophoretic force. Comparison of the measured widths for various nanoparticle sizes with numerical simulations obtained by solving the particle-conservation equation shows excellent agreement, thus providing access to the particles physical properties, such as polarizability and size. These findings can be further extended to investigate various types of nano-objects $-$ including bio- and molecular aggregates $-$ and offer a robust characterization tool that can enhance the control of matter at the nanoscale.