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Cell movement is vital to normal tissue growth and regulation. Although not often realized, cells are continually moving relative to each other, and many physically migrating from their original site. Blood and immune cells rely on migrating through other tissues to perform their function. Cell division also needs physical separation of daughter cells, and other cells, e.g. muscle cells have developed their mechanical machinery to perfection. Substrate interactions are complicated. The ability to migrate and stop migrating when needed is a vital part of tissue regeneration. Understanding cell migration and movement is very important to being able to discover how cancer cells are able to continue dividing and why they abnormally migrate. Much other work has established that cells contact substrates through specific attachment points, but it is almost impossible to visualize these in three dimensions since cell cytoplasm is translucent and resolution limited by wavelength of light. We have developed a small senor device of a metalized glass substrate on which we have electron beam lithographically produced arrays of sub-micron circular apertures. A surface plasmon resonance (SPR) wave is set up in the metal by excitation with an incident laser beam. The circular apertures act as discrete centers of optical scattering of the SPR wave and the associated light emanating from these points can be detected and studied using an associated image analysis system. The intensity of the light scattered from each of these apertures is a strong (exponential) function of the changes of local refractive index close to (within 250 nm) the aperture. The contact of the underside of the cell with the aperture bearding surface modulates the intensity pattern of the aperture matrix allowing high resolution of the spatial distribution of the contact points between the cell and the metalized surface.
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