​Microtubules, the main constituents of internal cell architecture, possess a rigidity that is one hundred times greater than that of other constituents of the cytoskeleton. For this reason, they travel through intracellular space in a virtually straight line, serving as the route for transporting proteins from the centre of the cell to its periphery. The regulating mechanisms of their mechanical properties are still virtually unknown, however. Their rigidity can be explained by their structure, that of a hollow tube, an efficient way, well-known to bicycle manufacturers, of constructing rigid elements using the least possible amount of material. These mechanical properties could not be studied in detail hitherto since the appropriate tools were lacking. A microfluidic device that can attach itself to microtubules and bend them has been perfected by researchers at the Plant Cell Physiology Laboratory (CNRS/CEA/INRA/Joseph Fourier University) and the Interdisciplinary Physics Laboratory (CNRS/Joseph Fourier University).

Scientists isolated the microtubules in cells in order to overcome the complexity of the intracellular environment and were thus able to study their intrinsic mechanical properties under simple conditions. They then used very weak hydrodynamic flows to apply slight, and well-controlled pressure so as to bend them gently. This is when they discovered that as the pressure cycles were applied repeatedly, the microtubules bent to an increasingly great extent but did not break. The application of external pressure makes them increasingly flexible. Their structure thus seems to be capable of reorganising itself and adapting to pressure. Even more surprising, microtubules are capable of rediscovering their initial rigidity if pressure is interrupted for a few minutes. They repair themselves spontaneously.