title: 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.
authors.affiliation: Department of Mechanical Engineering and Center of advanced Material, University of Malaya , 50603, Kuala Lumpur, Malaysia.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mehrali
authors.forename: Ehsan
authors.initials: E
authors.lastname: Moghaddam
authors.forename: Seyed Farid Seyed
authors.initials: SF
authors.lastname: Shirazi
authors.forename: Saeid
authors.initials: S
authors.lastname: Baradaran
authors.forename: Mohammad
authors.initials: M
authors.lastname: Mehrali
authors.forename: Sara Tahan
authors.initials: ST
authors.lastname: Latibari
authors.forename: Hendrik Simon Cornelis
authors.initials: HS
authors.lastname: Metselaar
authors.forename: Nahrizul Adib
authors.initials: NA
authors.lastname: Kadri
authors.forename: Keivan
authors.initials: K
authors.lastname: Zandi
authors.forename: Noor Azuan Abu
authors.initials: NA
authors.lastname: Osman
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D001696:Biomechanical Phenomena; D017610:Calcium Compounds / Q000737:chemistry*; D002448:Cell Adhesion; D002460:Cell Line; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D010006:Osteoblasts / Q000166:cytology*; D010087:Oxides / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D023822:Tissue Engineering / Q000295:instrumentation*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D017610:Calcium Compounds; D010087:Oxides; D011108:Polymers; D017640:Silicates; D006108:Graphite; C031293:calcium silicate