Carbon Nanotube Scaffolds in Bone Tissue Engineering

Bone tissue engineering seeks to repair or replace damaged skeletal tissues using biocompatible constructs that mimic the natural bone microenvironment. Carbon nanotubes (CNTs) have emerged as a versatile building block in this field owing to their extraordinary mechanical strength, high electrical conductivity and tunable surface chemistry. When incorporated into polymeric or ceramic matrices, CNTs reinforce scaffold architecture, improve load-bearing capacity and provide conductive pathways that can stimulate osteogenic cell behaviour. These hybrid scaffolds can be fabricated through techniques such as freeze drying, extrusion-based 3D printing and self-assembly, yielding highly porous frameworks that support nutrient transport and cell infiltration. By functionalising CNT surfaces with bioactive molecules or co-assembling them with hydroxyapatite crystals, researchers can further enhance osteoconductivity and deliver growth factors in a controlled manner. Recent advances have also highlighted the ability of CNT scaffolds to modulate immune responses, notably by promoting the anti-inflammatory M2 macrophage phenotype, and to synergise with exogenous electrical stimulation to accelerate mineral deposition. Together, these features position carbon nanotube scaffolds as a promising platform for addressing critical-size defects, improving regeneration rates and customising implants for load-bearing clinical applications.

Research from Nature Portfolio

Researchers have developed polypropylene composites reinforced with functionalised multi-walled carbon nanotubes and hydroxyapatite nanorods. By optimising the composition of nanotubes and mineral rods within the polymer matrix, these biocomposites exhibit significantly enhanced tensile strength, thermal stability and dimensional retention under physiological conditions. Importantly, cytotoxicity assays demonstrate good compatibility with osteoblast-like cells, suggesting potential for lightweight load-bearing implants in subchondral bone repair. The combination of carbon nanotubes and hydroxyapatite also provides a biomimetic interface that supports cell adhesion and may facilitate in vivo integration.

Carbon Nanotube Scaffolds in Bone Tissue Engineering publication trend

The graph below shows the total number of articles in carbon nanotube scaffolds in bone tissue engineering across all publications each year (not limited to Nature Index journals).

Technical terms

Carbon nanotubes: Cylindrical carbon allotropes with nanometre-scale diameters and high aspect ratios.

Osteogenesis: The process of new bone formation by specialised cells.

Macrophage M2 polarisation: Anti-inflammatory activation state that supports tissue repair.

Hydroxyapatite: A calcium phosphate mineral similar to the inorganic component of bone.

Polycaprolactone: A biodegradable polyester commonly used in 3D-printed scaffolds.

Mesenchymal stem cells: Multipotent progenitors capable of differentiating into bone, cartilage and other lineages.

References

1. Multi-walled carbon nanotubes reversing the bone formation of bone marrow stromal cells by activating M2 macrophage polarization. Regenerative Biomaterials (2023).
2. In vivo study of conductive 3D printed PCL/MWCNTs scaffolds with electrical stimulation for bone tissue engineering. Bio-Design and Manufacturing (2021).
3. Acceleration of Bone Regeneration in Critical‐Size Defect Using BMP‐9‐Loaded nHA/ColI/MWCNTs Scaffolds Seeded with Bone Marrow Mesenchymal Stem Cells. BioMed Research International (2019).
4. Functionalized multi-walled carbon nanotubes and hydroxyapatite nanorods reinforced with polypropylene for biomedical application. Scientific Reports (2021).
5. Applications of Carbon Nanotubes in Bone Tissue Regeneration and Engineering: Superiority, Concerns, Current Advancements, and Prospects. Nanomaterials (2019).