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Bone defects caused by trauma, tumor, fractures or pathological deformations that cannot heal on their own create a great challenge in the field of orthopedics. Traditional methods like autografts and allografts rely on obtaining a suitable tissue from another part of the patient’s/donor’s body to repair the defect. Because of the insufficient supply of donor tissue and the possibility of transmitting diseases, these techniques are not 100% effective[1].
In substitution to the above limitations, an artificial bone graft is identified as an excellent replacement, thanks to Bone Tissue Engineering (BTE). BTE involves a combination of biodegradable composites with or without the use of cells and growth factors to regenerate bones[2].
The excellent mechanical and electrical properties of SWCNT combined with low toxicity at the same scale size as DNA make it an acceptable candidate for such biological systems. SWCNT composites afford structural reinforcement and novel electrical conductivity helping in directing cell growth for tissue repair[3].
Carbon nanotube-based scaffolds offer major advantages with efficient nutrient delivery in the scaffold microenvironment. Functionalized CNTs provide suitable chemical structures for cell-cell communication and improvement in cell spreading for BET[4].
Balaji et al. studied a model of scaffolds coated with three-dimensional 3D-porous Single-Walled Carbon Nanotubes (SWCNT) and Multi-Walled Carbon Nanotubes (MWCNT) for comparative analysis. The investigation revealed that cell adhesion on SWCNT coated scaffolds is comparatively higher than the MWCNT-coated scaffolds. SWCNT with its high specific surface area affords more sites for efficient adhesion of cells on the scaffolds. While the more aggregated state of MWCNT will limit the connection between the cells and the scaffold surface[5].
Sitharaman et al. utilized SWCNT/biodegradable polymer nanocomposites (poly(propylene fumarate) and propylene fumarate diacrylate) for bone tissue engineering using rabbit model. Ultra-short SWCNTwere used as reinforcement to fabricate polymeric scaffold materials. Their results show that SWCNT scaffolds have significant effects on cell behaviour and growth rate in the microenvironment of the scaffold surface. The functionalization of SWCNT enhances the cell-scaffold interactions and cell spreading on the scaffold surface[6].
A model to study the Young’s Modulus of Hydroxyapatite (HAp)/SWCNT composite was created by Saffer et. al. Bone mineral precipitation on an SWCNT scaffold was explored to study the mechanical characteristics of the CNT-HAp composite. SWCNT reinforcement promised a notable increase in the Young’s modulus of CNT-HAp composite. It was explained based on the concept of load transfer through the cross-links between the composite phase. The improvement in Young’s modulus is attributed to the SWCNT’s large aspect ratio and the number of cross-links throughout the CNT- Hap interface[7].
Single-walled carbon nanotubes offer a very high aspect ratio and high surface area with excellent mechanical stability. Commercial deployment of applications of CNT such as BTE is the future we all anticipate. At NoPo, we have kicked this off by achieving industrial scale-production of the material to supply the highest and consistent quality raw material to such industries, and we say “Hello, future”.
References:
[1] C. T. Laurencin, A. M. Ambrosio, M. D. Borden, and J. A. Cooper, “Tissue engineering: orthopedic applications,” Annu. Rev. Biomed. Eng., vol. 1, pp. 19–46, 1999.
[2] “Single walled carbon nanotube composites for bone tissue engineering | Request PDF,” ResearchGate. [Online]. Available: https://www.researchgate.net/publication/236581440_Single_walled_carbon_nanotube_composites_for_bone_tissue_engineering. [Accessed: 30-Oct-2019].
[3] J. Venkatesan and S. K. Kim, “Stimulation of minerals by carbon nanotube grafted glucosamine in mouse mesenchymal stem cells for bone tissue engineering,” J. Biomed. Nanotechnol., vol. 8, no. 4, pp. 676–685, Aug. 2012.
[4] R. Eivazzadeh-Keihan et al., “Carbon based nanomaterials for tissue engineering of bone: Building new bone on small black scaffolds: A review,” J. Adv. Res., vol. 18, pp. 185–201, Jul. 2019.
[5] G. Lalwani et al., “Porous Three-Dimensional Carbon Nanotube Scaffolds for Tissue Engineering,” J. Biomed. Mater. Res. A, vol. 103, no. 10, pp. 3212–3225, Oct. 2015.
[6] B. Sitharaman et al., “In vivo biocompatibility of ultra-short single-walled carbon nanotube/biodegradable polymer nanocomposites for bone tissue engineering,” Bone, vol. 43, no. 2, pp. 362–370, Aug. 2008.
[7] K. P. Saffar, A. R. Arshi, N. JamilPour, A. R. Najafi, G. Rouhi, and L. Sudak, “A cross-linking model for estimating Young’s modulus of artificial bone tissue grown on carbon nanotube scaffold,” J. Biomed. Mater. Res. A, vol. 94A, no. 2, pp. 594–602, 2010.