abstract
Electroconductive bone grafts have been designed to control bone regeneration. Contrary to polymeric matrices, the translation of the carbon nanotube (CNT) electroconductivity into oxide ceramics is challenging due to the CNT oxidation during sintering. Sintering strategies involving reactive-bed pressureless sintering (RB + P) and hot-pressing (HP) were optimized towards prevention of CNT oxidation in glass/hydroxyapatite (HA) matrices. Both showed CNT retentions up to 80%, even at 1300 degrees C, yielding an increase of the electroconductivity in ten orders of magnitude relative to the matrix. The RB + P CNT compacts showed higher electroconductivity by similar to 170% than the HP ones due to the lower damage to CNTs of the former route. Even so, highly reproducible conductivities with statistical variation below 5% and dense compacts up to 96% were only obtained by HP. The hot-pressed CNT compacts possessed no acute toxicity in a human osteoblastic cell line. A normal cellular adhesion and a marked orientation of the cell growth were observed over the CNT composites, with a proliferation/differentiation relationship favouring osteoblastic functional activity. These sintering strategies offer new insights into the sintering of electroconductive CNT containing bioactive ceramics with unlimited geometries for electrotherapy of the bone tissue.
keywords
REINFORCED-HYDROXYAPATITE COMPOSITES; OSTEOBLAST-LIKE CELLS; MECHANICAL-PROPERTIES; ELECTRICAL-STIMULATION; IN-VITRO; DIFFERENTIATION; DENSIFICATION; PHASE; BIOMATERIALS; FABRICATION
subject category
Science & Technology - Other Topics; Materials Science; Physics
authors
Mata, D; Oliveira, FJ; Ferreira, NM; Araujo, RF; Fernandes, AJS; Lopes, MA; Gomes, PS; Fernandes, MH; Silva, RF
our authors
Diogo Miguel Rodrigues Marinho da Mata
Post-doc Fellowship
Filipe José Alves de Oliveira
Principal Researcher
Nuno Miguel Freitas Ferreira
Post-Doc Fellowship
Rui Ramos Ferreira e Silva
Associate Professoracknowledgements
The work was carried out with the financial support from the projects Biomaterials for Regenerative Medicine (CENTRO-07-ST24-FEDER-002030), co-financed by QREN, programme Mais Centro-Programa Operacional Regional do Centro and Uniao Europeia/ Fundo Europeu de Desenvolvimento Regional, and PEst-C/CTM/LA0011/2013. Rui F Araujo is grateful to the Foundation for Science and Technology (FCT, Portugal) for funding the project SFRH/BPD/88920/2012.