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Updated: Jan 29, 2026

A Microfluidic-based Hydrodynamic Trap for Single Particles
Published on: January 21, 2011
Decoupling conservative forces and hydrodynamic interactions between optically trapped spheres
Roman Kreiserman1,2, Omri Malik2,3, Ariel Kaplan2,3
1Faculty of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Abstract:
Characterizing the interactions between colloidal particles is important, both from a fundamental perspective as well as due to its technological importance. However, current methods to measure the interaction forces between two colloids have significant limitations. Here we describe a method that exploits the fluctuation spectra of two optically trapped microspheres in order to extract, and decouple, the conservative forces acting between them and their hydrodynamic coupling. We demonstrate the proposed method with two silica microspheres, and find good agreement between our results and previous predictions for the hydrodynamic and electrostatic interactions between the spheres.
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