Colloids as Probes

Colloids are proving useful in determining a number of characteristics about lipid bilayer membranes and other materials.  We have found that micron sized glass beads are able to report on some of the mechanical properties of supported bilayers. Additionally, they are able to quickly characterize topological differences or defects in these constructs. 

On the left are three images of 5um glass beads settled on a patterned supported bilayer. The first is a bright field image of beads covering the surface.  The second is a fluorescence image of the same location showing the underlying lipid pattern, where the black regions are bare glass and the red region is lipid with 1% dye. Perturbing the system removes beads resting on the glass regions and exposes the lipid pattern.

A bright-field movie of this process is shown below.