Related Experiment Video
Updated: Jul 4, 2026

Preparation and 3D Tracking of Catalytic Swimming Devices
Published on: July 1, 2016
Single-particle tracking of janus colloids in close proximity
Stephen M Anthony1, Minsu Kim, Steve Granick
1Department of Chemistry, University of Illinois, Urbana, IL 61801, USA.
Abstract:
We describe algorithms and an experimental method based on differential interference contrast microscopy to discriminate optically anisotropic colloidal spheres under situations where diffraction owing to their close proximity causes overlapping images. The data analysis is applied to modulated optical nanoprobes (MOONs) that are coated with metal on one hemisphere. These methods enable single-particle tracking of rotation in addition to translation not only in concentrated suspensions but also in dilute suspensions when particles come into transient hydrodynamic contact. An illustrative example is given.
Related Concept Videos
Colloids and Suspensions
Colloidal precipitates
Colloids
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...

