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 mum length microtubules. The origin of the length dependence of the flexural rigidity of microtubules is discussed.
Japanese Journal of Applied Physics: Part 1: Regular Papers, Short Notes and Review Papers, Vol. 41, no. 5A (May 2002), pp. 3015-3019