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arXiv · 2405.12338

Nano-gap electrode dielectrophoresis for tether-free trapping and interferometric-scattering detection of single 20 nm particles

Jacco Ton·Théo Travers·Jamal Soltani·Daniel Wijnperle·Dmytro Shavlovskyi·Michel Orrit·Sergii Pud
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Abstract

Accurate detection and characterization of nanoparticles within confined spaces is crucial for applications ranging from nanofluidics to biotechnology. We present a novel approach that combines interferometric scattering (iSCAT) detection with trapping by dielectrophoresis (DEP) to achieve label-free detection of nanoparticles that are trapped and/or actuated between nano-gap electrodes. DEP utilizes the interaction between the induced dipole of the particle and the applied electric field to create a trapping potential. We demonstrate our method by trapping and label-free detection of down to 20 nm polystyrene nanoparticles. Additionally, we demonstrate that the signal-to-noise ratio of our detection can be boosted up to 20-fold by periodic actuation of the nanoparticle in the trap. This is done by a digital lock-in detection scheme on the modulated scattering signal. Our method holds promise for various applications, including assembly of nanoparticles, single-particle property analysis, and nanofluidic devices.

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Jacco Ton, Théo Travers, Jamal Soltani, Daniel Wijnperle, Dmytro Shavlovskyi, Michel Orrit, Sergii Pud. 2024-05-20. Nano-gap electrode dielectrophoresis for tether-free trapping and interferometric-scattering detection of single 20 nm particles. https://arxiv.org/abs/2405.12338

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