We demonstrate that the optical stretcher, a fully automated dual-beam laser trap for probing single-cell mechanics, can also be used to trap pairs of cells and manipulate them. More specifically, we can press cells against each other and tear them apart again, enabling us to measure cell adhesion / dissociation dynamics.
We show that we can see differences in adhesion behaviour between cell lines and we see single-molecule dissociation processes. We calculate the forces which we exert on the cells, which are in the pN range.
This "optical micromanipulator" provides high-throughput adhesion measurements with about 50 cell pairs per hour, while allowing for full optical inspection of the cell dissociation process. The method can be combined with other characterization methods readily available in the stretcher such as fluorescence imaging and cell rheology evaluation.
|