<p class="MDPI12title">The Contacting Layer on Piezoelectric Poly-L-Lactide Biomaterial

The main limitation of high-temperature drawing approach for tailoring crystallization and molecular orientation of poly-l-lactide (PLLA) toward ultrasound- active piezoelectric structures is set by intrinsic properties of the processed polymer, including low melting / softening elasticity and slow crystallization kinetics. Here we found that application of different contacting layers, including polytetrafluoroethylene (PTFE) (as Teflon and Teflon S), cellulose (paper) or polyimine (Kapton) deposited at the surface of PLLA, significantly affects the drawing process and tailors its oriented crystallization and molecular chain orientation. Consequently the contacting layers contribute to piezoelectric properties of PLLA, affect their activation by ultrasound and generated electro-signal. Human keratinocytes (HaCaT cells) grown stimulated on these surfaces are shown to receive and respond to the transferred stimuli by activation of the cytoskeleton and directional migration. The high-temperature drawing approach with contacting layers is simple, solvent-free and economically continent way for broadening limitations of classical high-temperature drawing which opens new possibilities for further tailoring piezoelectricity of organic piezoelectrics.