Synthesis, Mechanical Properties, and in Vitro Biocompatibility with Osteoblasts of Calcium Silicate–Reduced Graphene Oxide Composites

Abstract

Calcium silicate (CaSiO3, CS) ceramics are promising bioactive materials for bone tissue engineering, particularly for bone repair. However, the low toughness of CS limits its application in load-bearing conditions. Recent findings indicating the promising biocompatibility of graphene imply that graphene can be used as an additive to improve the mechanical properties of composites. Here, we report a simple method for the synthesis of calcium silicate/reduced graphene oxide (CS/rGO) composites using a hydrothermal approach followed by hot isostatic pressing (HIP). Adding rGO to pure CS increased the hardness of the material by ∼40%, the elastic modulus by ∼52%, and the fracture toughness by ∼123%. Different toughening mechanisms were observed including crack bridging, crack branching, crack deflection, and rGO pull-out, thus increasing the resistance to crack propagation and leading to a considerable improvement in the fracture toughness of the composites. The formation of bone-like apatite on a range of CS/rGO composites with rGO weight percentages ranging from 0 to 1.5 has been investigated in simulated body fluid (SBF). The presence of a bone-like apatite layer on the composite surface after soaking in SBF was demonstrated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The biocompatibility of the CS/rGO composites was characterized using methyl thiazole tetrazolium (MTT) assays in vitro. The cell adhesion results showed that human osteoblast cells (hFOB) can adhere to and develop on the CS/rGO composites. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of cells on the CS/rGO composites were improved compared with the pure CS ceramics. These results suggest that calcium silicate/reduced graphene oxide composites are promising materials for biomedical applications.

Synergistic effects of reduced graphene oxide and hydroxyapatite on osteogenic differentiation of MC3T3-E1 preosteoblasts

“…These results show good consistency with those of ARS and von Kossa staining, other markers for late osteogenic differentiation. These results are supported by recent evidence showing that rGO/ calcium silicate and GO/calcium phosphate composites have a synergistic effect in accelerating the osteogenesis of osteoblasts and MSCs by significantly increasing calcium deposition [67,68], underscoring the need for such hybrid composites for bone tissue engineering. Moreover, it has been revealed that gelatinfunctionalized GO can be efficiently used for the biomimetic mineralization of HAp, leading to promote the osteogenic differentiation of MC3T3-E1 cells [61].…”

Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite

“…Note that different observations among the apatite layer growth on the surface of samples are relevant to their morphologies which are also in agreement with the observations made by several research groups [33,34].The results showed that the apatite morphology varied among bioceramics. This morphological difference was attributed to changes in the ion concentrations and pH in SBF after the soaking of different bioceramics [35]. Moreover, EDS spectra shown in Fig.…”

Experimental and numerical investigation of the effective electrical conductivity of nitrogen-doped graphene nanofluids

“…A simplified Hummers' method was used to synthesize graphene oxide (GO) (Mehrali et al 2013a(Mehrali et al , 2014a and the NDG was prepared by a hydrothermal process with GO as raw material in an ammonia solution. As shown in Fig.…”