Flexural Rigidity of a Single Microtubule

Microtubules, which are flexible biopolymers, can be used for nanotechnology applications ( e.g. , nano-actuator) as they have a rigidity similar to that of plexyglass and other plastic materials. The flexural rigidity, or bending stiffness, of microtubules was measured using a laser trapping technique and dark-field microscopy. One end of a microtubule rod was chemically bound to a glass microsphere, while the other end was bound to a silica glass substrate. Then, the microsphere was laser-trapped and manipulated to exert three different deformation modes on the microtubule. The values of flexural rigidity for these deformations were between 10 -25 and 10 -23 Nm 2 as measured for the 5–25 µm length microtubules. The origin of the length dependence of the flexural rigidity of microtubules is discussed.