CISMM

Our single and multiple unit magnetic systems, the 3D force microscope (3DFM) and Magnetic High Throughput Systems (MHTS), have proven very useful in probing the mechanical properties of cells and cellular components. Cells maintain their physical integrity and withstand and exert forces via complex interactions involving their cytoskeleton, cytoplasm, plasma membrane components and other structures. The nucleus breaks down, chromosomes condense and divide. Cancer cells change shape and invade healthy tissue. Cells react to external and internal signals by changing shape, changing tension or activity.

By applying forces to cells via magnetic beads of various sizes and surface chemistries, or resisting the forces exerted by cells or organelles, our magnetic systems can assess the forces being exerted by cells, or the responses of cells to various forces, from the thermal floor to tens of nN. We can also apply forces in many different regimes, from steady pulls, to ramps, to oscillations. Data can be recorded with video at rates of up to 200/s, or with laser tracking in 3D at 10,000 points/s.

Cell Mechanics studies also include the manufacture and analysis of micropattened posts and pillars that can be deformed by cells under various conditions and binding regimes. The pillars can be calibrated and thus forces assessed.

Pictured above is an example of a cell mechanics experiment, recently published in Methods in Cell Biology and Biophysical Journal (O’Brien et al 2008) shows 2.8 μm magnetic beads on IMR cells, with the dark shadow a magnetic pole tip. The data, B-D show high resolution tracking of the bead before during and after the application of force. The magenta line shows when the activation of the poles takes place. Links from the beads to the cells take place via antibodies to the actin cytoskeleton via intergrins (B,D), or a GPI-anchored, non-cytoskeletal linker (C). D shows the response of an integrin-linked bead after treatment with latrunculin B, which destabilizes the actin cytoskeleton.

References:

O’Brien, E.T., J. Cribb, D. Marshburn, R.M.T. II, and R. Superfine, Magnetic Manipulation for Force Measurements in Cell Biology, in Methods in Cell Biology. 2008, Elsevier. p. 433-450

PubMed