title: Helical conformation endows poly-l-lactic acid fibers with a piezoelectric charge under tensile stress.
abstract: Poly-l-lactic acid (PLLA) has been clinically used as a bioabsorbable material and attains a piezoelectric charge upon molecular orientation by the application of a shear force to the C-axis of the crystal line region. Previous studies showed that implanted drawn PLLA films or rods accelerate the ossification due to piezoelectric effect. In this study, we originally designed helically-twisted PLLA fiber to produce piezoelectricity in bioabsorbable suture upon tensile stress. The piezoelectricity of the helical PLLA fibers was evaluated using a lock-in amplifier system in vitro. The ossification induced by helical PLLA fibers was examined by implanting them in the rat patellar ligament supporting a physiological tensile load. We observed that 57° and 45° twisted PLLA fibers generated a higher piezoelectric potential than did 27° twisted fibers. The animal experiment showed that the formation of osseous tissue around helical PLLA fibers was more significant than around non-helical control fibers at 4 weeks after their implantation. These results suggest that helical PLLA fiber may be useful for the surgical suture or artificial ligament, which connects to the bone.
authors.affiliation: Division of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 180-8602, Japan.
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Harada
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kadono
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Terao
authors.forename: Masakazu
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Ikada
authors.forename: Naohide
authors.initials: N
authors.lastname: Tomita
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D004574:Electromagnetic Fields; D006614:Hindlimb / Q000601:surgery; D007596:Joints / Q000601:surgery; D019344:Lactic Acid / Q000737:chemistry* / Q000494:pharmacology; D008297:Male; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D010012:Osteogenesis / Q000187:drug effects; D011091:Polyesters; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)