Related Experiment Video
Updated: Jun 14, 2026

A Microfluidic-based Hydrodynamic Trap for Single Particles
Published on: January 21, 2011
Hydrodynamic mobility of an optically trapped colloidal particle near fluid-fluid interfaces
G M Wang1, R Prabhakar, E M Sevick
1Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia.
Abstract:
Using optical tweezers, we measure the anisotropic hydrodynamic mobility of a colloidal particle by tracking its thermal motion in an optical trap located near fluid-fluid interfaces, namely, liquid-vapor and liquid-liquid interfaces. The method requires no controlled fluid flow, is independent of conservative interactions between particle and interface, and resolves distance dependent friction to within a fraction of the particle radius. Near the liquid-vapor interface, the friction decreases below that in the bulk, corresponding to predictions of a "perfect-slip" surface.
Related Concept Videos
The Colloidal State
Colloids and Suspensions
Fluid Mosaic Model
Fluid Mosaic Model
Colloids
Capillarity in Fluid
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...

