A nano-sandwich construct built with graphene nanosheets and carbon nanotubes enhances mechanical properties of hydroxyapatite–polyetheretherketone scaffolds

Abstract

A nano-sandwich construct was built by combining two-dimensional graphene nanosheets (GNSs) and one-dimensional carbon nanotubes (CNTs) to improve the mechanical properties of hydroxyapatite–polyetheretherketone (HAP–PEEK) scaffolds for bone tissue engineering. In this nano-sandwich construct, the long tubular CNTs penetrated the interlayers of graphene and prevented their aggregation, increasing the effective contact area between the construct and matrix. The combination of GNSs and CNTs in a weight ratio of 2:8 facilitated the dispersion of each other and provided a synergetic effect in enhancing the mechanical properties. The compressive strength and modulus of the scaffolds were increased by 63.58% and 56.54% at this time compared with those of HAP–PEEK scaffolds, respectively. The carbon-based fillers, pulling out and bridging, were also clearly observed in the matrix. Moreover, the dangling of CNTs and their entangling with GNSs further reinforced the mechanical properties. Furthermore, apatite layer formed on the scaffold surface after immersing in simulated body fluid, and the cells attached and spread well on the surface of the scaffolds and displayed good viability, proliferation, and differentiation. These evidence indicate that the HAP–PEEK scaffolds enhanced by GNSs and CNTs are a promising alternative for bone tissue engineering.

In vitro effect of graphene structures as an osteoinductive factor in bone tissue engineering: A systematic review

“…Five articles 13, 83-86 used osteoblasts. Immortalized mouse embryonic fibroblasts (iMEFs), immortalized mouse adipose-derived cells (iMADs), immortalized mouse calvarial cells (iCALs)87 and human osteosarcoma cell line hMG63 34,[88][89][90][91][92] were other types of the cells used.…”

“…Different types of graphene used in the included studies were pristine graphene, 19 36 GFs, 33 GNSs, 34 GQDs, 94 and nanosized graphene 18 (NGO).…”

“…141 In order to overcome these limitations, graphene and its derivatives can be incorporated into polymers through different methods to produce composites exhibiting synergistic effects over the two individual components with improved properties. 34,36,37,46,52,61,63,66,68,70,73,75,78,91 Recently, graphene-polymer composites have been used for orthopedic applications. 142,143 For example, GO in Ct matrix was shown to affect interactions between cells and scaffold leading to improved cell proliferation.…”

“…148 Additionally, in recent studies, incorporation of CNTs and GNSs to promote the mechanical properties of polymer has attracted attention of researchers. [149][150][151][152] Feng et al 34 displayed the synergetic effect of CNTs and GNSs on enhancement of mechanical properties, as well as cellular behavior. They showed that a scaffold constructed by combination of HAP-PEEK with GNSs at 0.2 wt % and CNTs at 0.8 wt % had positive influence on cell proliferation with significantly more optical density than other treatment groups.…”

“…,38,50,67,73,74 energy dispersive spectrometer (EDS),4,13,34,44,76,80 porosity measurement,4,35,61,75,78 electrical tests,25,35,70 protein adsorption test,20,22,42,43,48,63,68,75,81,91 ultraviolet-visible (UV-Vis) spectroscopy,49,69 calcium absorption test,70 dynamic light scattering (DLS),18,30,36,66,82 zeta potential (ZP) measurement,18,29,38,40,42,47,66 degradation rate measurement,48,71,75,91 water absorption,…”