Piezoelectricity of chiral polymeric fiber and its application in biomedical engineering.

Poly-L-lactic acid (PLLA), which is a type of chiral polymer, exhibits a high shear piezoelectric constant. To realize a higher shear piezoelectric constant, we spun PLLA resin into fibers. We succeeded in controlling the piezoelectric motion of a PLLA fiber by applying a dc voltage and ac voltage, similar to the control of a piezoelectric actuator. On the basis of this experimental result, we designed a catheter using a PLLA fiber (PLLA fiber catheter) and tweezers using a pair of PLLA fibers (PLLA fiber tweezers), controlled by adjusting the applied voltage. Then, using the PLLA fiber tweezers or catheter, we successfully picked up and removed small samples, such as a thrombosis in a blood vessel.