title: Development and Testing of X-Ray Imaging-Enhanced Poly-L-Lactide Bone Screws.
abstract: Nanosized iron oxide particles exhibit osteogenic and radiopaque properties. Thus, iron oxide (Fe3O4) nanoparticles were incorporated into a biodegradable polymer (poly-L-lactic acid, PLLA) to fabricate a composite bone screw. This multifunctional, 3D printable bone screw was detectable on X-ray examination. In this study, mechanical tests including three-point bending and ultimate tensile strength were conducted to evaluate the optimal ratio of iron oxide nanoparticles in the PLLA composite. Both injection molding and 3D printing techniques were used to fabricate the PLLA bone screws with and without the iron oxide nanoparticles. The fabricated screws were implanted into the femoral condyles of New Zealand White rabbits. Bone blocks containing the PLLA screws were resected 2 and 4 weeks after surgery. Histologic examination of the surrounding bone and the radiopacity of the iron-oxide-containing PLLA screws were evaluated. Our results indicated that addition of iron oxide nanoparticles at 30% significantly decreased the ultimate tensile stress properties of the PLLA screws. The screws with 20% iron oxide exhibited strong radiopacity compared to the screws fabricated without the iron oxide nanoparticles. Four weeks after surgery, the average bone volume of the iron oxide PLLA composite screws was significantly greater than that of PLLA screws without iron oxide. These findings suggested that biodegradable and X-ray detectable PLLA bone screws can be produced by incorporation of 20% iron oxide nanoparticles. Furthermore, these screws had significantly greater osteogenic capability than the PLLA screws without iron oxide.
authors.affiliation: School of Dentistry, Taipei Medical University, Taipei, Taiwan.
authors.forename: Wei-Jen
authors.initials: WJ
authors.lastname: Chang
authors.affiliation: Department of General Dentistry, Chang Gung Memorial Hospital, Taipei, Taiwan; Chang Gung University, Taoyuan, Taiwan.
authors.forename: Yu-Hwa
authors.initials: YH
authors.lastname: Pan
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei, Taiwan.
authors.forename: Jy-Jiunn
authors.initials: JJ
authors.lastname: Tzeng
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ting-Lin
authors.initials: TL
authors.lastname: Wu
authors.affiliation: Department of Anatomy, School of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Tsorng-Harn
authors.initials: TH
authors.lastname: Fong
authors.affiliation: School of Dentistry, Taipei Medical University, Taipei, Taiwan.
authors.forename: Sheng-Wei
authors.initials: SW
authors.lastname: Feng
authors.affiliation: Graduate Institute of Biomedical Materials and Tissue Engineering, Taipei Medical University, Taipei, Taiwan.
authors.forename: Haw-Ming
authors.initials: HM
authors.lastname: Huang
mesh_terms: D000818:Animals; D001863:Bone Screws / Q000009:adverse effects*; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D005290:Ferric Compounds / Q000737:chemistry; D019344:Lactic Acid / Q000737:chemistry*; D053758:Nanoparticles / Q000009:adverse effects / Q000737:chemistry; D010012:Osteogenesis; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D066330:Printing, Three-Dimensional; D011817:Rabbits; D011859:Radiography; D013718:Tensile Strength; D014965:X-Rays
chemical_list: D005290:Ferric Compounds; D011091:Polyesters; D011108:Polymers; C000499:ferric oxide; D019344:Lactic Acid; C033616:poly(lactide)