Elsevier

Materials Science and Engineering: C

Volume 34, 1 January 2014, Pages 360-368
Materials Science and Engineering: C

Carbon nanotube-based bioceramic grafts for electrotherapy of bone

https://doi.org/10.1016/j.msec.2013.09.028Get rights and content

Highlights

  • Highly pure MWCNTs (> 99 wt.%) were used to prepare dense bone grafts (relative density > 94%).

  • Composites with controlled size CNT agglomerates were homogenously distributed.

  • “Smart” highly electroconductive materials for clinical bone electrotherapy

Abstract

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 pc = 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.

Graphical abstract

“Smart” conductive materials are expected to accelerate bone healing while electrical stimulated due to the increased confinement of the stimuli at the bone defect. A three-dimensional analysis shows controlled size CNT agglomerates homogenously distributed in a bioceramic matrix. This CNT arrangement is closely correlated to the functional properties of the composite.

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Keywords

Carbon nanotubes
Bone grafts
Stimuli-responsive materials
Electrotherapy of bone

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