resumo
Bone complexity demands the engineering of new scaffolding solutions for its reconstructive surgery. Emerging bone grafts should offer not only mechanical support but also functional properties to explore innovative bone therapies. Following this, ceramic bone grafts of Glass/hydroxyapatite (HA) reinforced with conductive carbon nanotubes (CNTs) - CNT/Glass/HA - were prepared for bone electrotherapy purposes. Computer-aided 3D microstructural reconstructions and TEM analysis of CNT/Glass/HA composites provided details on the CNT 3D network and further correlation to their functional properties. CNTs are arranged as sub-micrometric sized ropes bridging homogenously distributed ellipsoid-shaped agglomerates. This arrangement yielded composites with a percolation threshold of p(c) = 1.5 vol.%. At 4.4 vol.% of CNTs, thermal and electrical conductivities of 1.5 W.m(-1).K-1 and 55 S.m(-1), respectively, were obtained, matching relevant requisites in electrical stimulation protocols. While the former avoids bone damaging from Joule's heat generation, the latter might allow the confinement of external electrical fields through the conductive material if used for in vivo electrical stimulation. Moreover, the electrically conductive bone grafts have better mechanical properties than those of the natural cortical bone. Overall, these highly conductive materials with controlled size CNT agglomerates might accelerate bone bonding and maximize the delivery of electrical stimulation during electrotherapy practices. (C) 2013 Elsevier B.V. All rights reserved.
palavras-chave
GLASS-REINFORCED-HYDROXYAPATITE; CORTICAL BONE; COMPOSITES; DEPENDENCE; NANOCOMPOSITES; OSTEOBLASTS; PERCOLATION; POROSITY; GROWTH; MWCNT
categoria
Materials Science
autores
Mata, D; Horovistiz, AL; Branco, I; Ferro, M; Ferreira, NM; Belmonte, M; Lopes, MA; Silva, RF; Oliveira, FJ
nossos autores
Ana Lúcia Horovistiz
Bolseiro de pós-Doutoramento
Diogo Miguel Rodrigues Marinho da Mata
Bolseiro de pós-Doutoramento
Filipe José Alves de Oliveira
Investigador Principal
Marta Ascenção Carmona Ferro
Técnico de Laboratório
Nuno Miguel Freitas Ferreira
Bolseiro de pós-Doutoramento
Rui Ramos Ferreira e Silva
Professor associadoagradecimentos
D. Mata acknowledges the Foundation for Science and Technology (FCT, Portugal) for funding the project PEst-C/CTM/LA0011/2013.