Electro-biorheology

Studies on piezoelectricity in biopolymers are reviewed with some examples. By measuring anisotropy of elastic and piezoelectric constants in fish skin, the direction of preferred orientation of collagen fibers is determined. Temperature and moisture dependence of real and imaginary parts of the piezoelectric constant observed for oriented film of fibrin gel indicates that temperature-time equivalence holds for the piezoelectric relaxation. The piezoelectric constant for oriented film of polyhydroxybutyrate decreases above glass transition temperature, which is related to the elastic and dielectric relaxations. When alpha-helical molecules of poly-gamma-methyl-L-glutamate are electrically oriented in ethylene dichloride solution and shear stress is given by ultrasound, the piezoelectric polarization is observed. When the film of poly-gamma-methyl-glutamate is wrapped around the femur of rat, the formation of new bone is produced.