Microactuators with piezoelectric polylactic acid fibers - Toward the realization of tweezers for biological cells

The poly-L-lactic acid (PLLA) shows a high shear piezoelectric constant. We fabricated PLLA fiber samples with large degree of crystallinity and high orientation of crystallites using high-speed spinning. If the electric field is applied to the PLLA fiber in the direction perpendicular to the PLLA fiber axis, the PLLA fiber must be driven by the piezoelectric effect. Therefore, we devised an effective method of applying the electric field to the PLLA fiber. We also developed equipment for measuring the piezoelectric motion of the PLLA fiber, which uses a CCD camera and divided photodiodes. As a result, we could drive the PLLA fiber by the shear piezoelectric effect under the application of ac voltage, and observed the bending motion of the entire PLLA fiber. Finally, we attempted to release and grasp the bead sample using a pair of PLLA fibers like tweezers, and succeeded.