Current projects

Methods & Techniques

Optical microscopy: fluorescence microscopy, differential interference contrast, confocal scanning laser microscopy, particle tracking rheology, fluorescence recovery after photobleaching (FRAP), interferometry, high speed video microscopy.

Mechanical measurement techniques: atomic force microscopy (AFM), surface forces apparatus (SFA), various rheometers.

Particle Tracking Rheology

The erratic motions of colloidal particles added to a fluid, can be used to infer about the rheological properties of that fluid. In the given example, 227 nm diameter fluorescent latex particles were added to a water/glycerol mixture. Real-time movies, recorded with a CSLM were analyzed for the positions of particles in all frames; well-resolved particles in the focal plane are marked with a + symbol. For these labeled particles, time-displacement trajectories were determined. By averaging over these trajectories, one obtains the Mean-Squared Displacement vs time function, which is equivalent to a compliance function.

Click here to see an example movie (12MB).