title: Gradient composite materials for artificial intervertebral discs.
abstract: Composites with the gradient of Young's modulus constitute a new group of biomimetic materials which affect the proper distribution of stresses between the implant and the bone. The aim of this article was to examine the mechanical properties of gradient materials based on carbon fibre-polysulfone composite, and to compare them to the properties of a natural intervertebral disc. Gradient properties were provided by different orientation or volume fraction of carbon fibres in particular layers of composites. The results obtained during in vitro tests displayed a good durability of the gradient materials put under long-term static load. However, the configuration based on a change in the volume fraction of the fibres seems more advantageous than the one based on a change of the fibres' orientation. The materials under study were designed to replace the intervertebral disc. The effect of Young's modulus of the material layers on the stress distribution between the tissue and the implant was analyzed and the biomimetic character of the gradient composites was stated. Unlike gradient materials, the pure polysulfone and the non-gradient composite resulted in the stress concentration in the region of nucleus pulposus, which is highly disadvantageous and does not occur in the stress distribution of natural intervertebral discs.
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Biomaterials, Kraków, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Migacz
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Biomaterials, Kraków, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Chłopek
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Biomaterials, Kraków, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Morawska-Chochół
authors.affiliation: Cathedral and Clinic of Orthopaedics and Traumatology of the Motor System at Medical University of Warsaw, Warsaw, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Ambroziak
mesh_terms: D000818:Animals; D040761:Biomimetic Materials / Q000138:chemical synthesis*; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D019245:Compressive Strength / Q000502:physiology; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D006244:Hardness / Q000502:physiology; D006801:Humans; D007403:Intervertebral Disc / Q000737:chemistry* / Q000502:physiology*; D008159:Lumbar Vertebrae / Q000737:chemistry / Q000502:physiology; D008422:Materials Testing; D008954:Models, Biological; D008956:Models, Chemical; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D019736:Prostheses and Implants; D013450:Sulfones / Q000737:chemistry*; D013718:Tensile Strength / Q000502:physiology
chemical_list: D000077482:Carbon Fiber; D011108:Polymers; D013450:Sulfones; C084385:carbon fiber-polysulfone; D002244:Carbon