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We have developed a technique to disrupt submicrometer-sized organelles within living cells or tissue without affecting the surrounding material or compromising viability of the cell or organism. When a femtosecond laser pulse is tightly focused into a nearly-transparent biological material, energy is deposited by nonlinear absorption only in the focus where laser intensity is high, resulting in disruption of the structure in the focal volume. Because the absorption is confined to the small focal volume, the surrounding material is unaffected, allowing micrometer precision in the disruption of biological tissue.
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Microtubules depolymerize following laser cut |
Microtubules lengths across the spindle |
In collaboration with the Needleman group, we have used this technique for disrupting spindle microtubules. Spindles are arrays of microtubules that segregate chromosomes during cell division. It has been difficult to validate models of spindle assembly due to a lack of information on the organization of microtubules in these structures. Based on femtosecond laser nanosurgery, we have measured the detailed architecture of spindles and showed that microtubules are shortest near poles and become progressively longer towards the center of the spindle. These data, in combination with mathematical modeling, high resolution imaging, and biochemical perturbations, are sufficient to propose a new model of spindle assembly.
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| Plainly speaking | To unveil information about cell mechanisms, cell-biologists rely on chemical or biological inhibition of functions, lacking spatially discrimination.
With the use of a laser focused by a microscope objective, one can achieve spatial resolutions in the �m-range. Near infrared femtosecond lasers are especially well suited for this kind of micromanipulation, as the energy deposited into the cell is very low and, thus, side effects, as high pressures or thermal damage, are minimized...
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Cytoskeleton network in a fixed BCE-cell...
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The detailed architecture of spindle microtubules, involved in cell division, was revealed using femtosecond laser nanosurgery. This work was performed in collaboration with the Needleman group (results published in Cell).
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