Carbon Nanotube Reinforced Polylactide−Caprolactone Copolymer: Mechanical Strengthening and Interaction with Human Osteoblasts in Vitro

Abstract

This study proposes the use of carbon nanotubes (CNTs) as reinforcement to enhance the mechanical properties of a polylactide-caprolactone copolymer (PLC) matrix. Biological interaction of PLC-CNT composites with human osteoblast cells is also investigated. Addition of 2 wt % CNT shows very uniform dispersion in the copolymer matrix, whereas 5 wt % CNT shows severe agglomeration and high porosity. PLC-2 wt % CNT composite shows an improvement in the mechanical properties with an increase in the elastic modulus by 100% and tensile strength by 160%, without any adverse effect on the ductility up to 240% elongation. An in vitro biocompatibility study on the composites shows an increase in the viability of human osteoblast cells compared to the PLC matrix, which is attributed to the combined effect of CNT content and surface roughness of the composite films.

Nanocomposite and Nanostructured Carbon-based Films as Growth Substrates for Bone Cells

“…Thus, carbon nanotubes could be utilized in hard tissue surgery, e.g., to reinforce artificial bone implants, particularly scaffolds for bone tissue engineering made of relatively soft synthetic or natural polymers. Carbon nanotubes have been used in combination with poly(carbonate) urethane (Khang et al, 2007(Khang et al, , 2008, biodegradable polymers such as polylactic acid (Supronowicz et al, 2002), propylene fumarate (Shi et al, 2006), poly(3-hydroxybutyrate) (Misra et al, 2010), a copolymer of polylactide-caprolactone (Lahiri et al, 2009) or a copolymer of polypyrrole-hyaluronic acid (Pelto et al, 2010). Also hydroxyapatite (HAp), i.e., a ceramic material widely used in bone tissue engineering, but known for its high brittleness, has been reinforced with carbon nanotubes (Balani et al, 2007;Hahn et al, 2009).…”

“…Also hydroxyapatite (HAp), i.e., a ceramic material widely used in bone tissue engineering, but known for its high brittleness, has been reinforced with carbon nanotubes (Balani et al, 2007;Hahn et al, 2009). Carbon nanotubes not only improved the mechanical properties of the mentioned materials, such as tensile (Young's) modulus, compressive and flexural moduli and compressive, flexural and tensile strength in the polymeric materials (Shi et al, 2006;Lahiri et al, 2009;Misra et al, 2010), and fracture toughness, hardness, elastic modulus and adhesion to the underlying substrate in HAp coatings (Balani et al, 2007;Hahn et al, 2009), but also increased the attractiveness of these materials for the adhesion, growth, differentiation and phenotypic maturation of cells, such as osteoblasts, chondrocytes and stem cells. One of the mechanisms of the improved cell colonization was an increased adsorption of fibronectin, i.e., an important cell-adhesion mediating ECM protein, to these composites, which has been explained by creating a nanoscale surface roughness of the material by the addition of nanotubes, and also by an increased material surface hydrophilia due to the presence of the polymeric component (pure carbon nanotube surfaces were highly hydrophobic, Khang et al, 2007Khang et al, , 2008.…”

Degradation Behavior of Electrospun PLA and PLA/CNT Nanofibres in Aqueous Environment

“…Multiwalled carbon nanotubes (MWCNTs) have the ability to promote stem cells differentiation towards bone cells [28] and enhance bone formation [29][30][31]. They also are used to improve mechanical properties of PLA fibres [32][33][34].…”

PLA-Based Hybrid and Composite Electrospun Fibrous Scaffolds as Potential Materials for Tissue Engineering

“…Multiwalled carbon nanotubes (MWCNTs) have the ability to promote stem cells' differentiation towards bone cells and enhance bone formation [35][36][37]. Due to their nanometer scale size, with a very high strength to weight ratio, they are very attractive as a nanoadditive to improve mechanical properties of polymers, including PLA fibres [38][39][40]. Moreover, CNT have been proven to modify electrical properties of the fibrous structures obtained via ES [24,38,40].…”

“…Due to their nanometer scale size, with a very high strength to weight ratio, they are very attractive as a nanoadditive to improve mechanical properties of polymers, including PLA fibres [38][39][40]. Moreover, CNT have been proven to modify electrical properties of the fibrous structures obtained via ES [24,38,40]. This property is important when stimulating bone tissue formation [41].…”