Mechanics of the Cell Cytoplasm

To examine the mechanics of the cell cytoplasm we inject fluorescent nanoparticles inside of cells and examine their motion using high resolution image capture and particle tracking. By analyzing the trajectories of these particles we can learn if the particles are being actively transported and/or the mechanics of the environment that restricts the particle motion. Our lab specializes in modifying the chemistry of the particle surfaces to control the type of structures that they interact with inside of cells.

The animation is an example of our particle tracking approach. A 200 nm fluorescent particle is moving randomly in the bottom plane. The image intensity is shown in the plane above and a 2-D gaussian fit to the intensity map is shown on the top plane. By identifying the peak of the gaussian we can follow particle movements with ~10 nm resolution. This image illustrates the full procedure, and gives examples of a cell with injected particles and a resulting particle trajectory.

Researcher: James L. McGrath, Ph.D.
Cell Motility and Quantitative light microscopy