Incorporating silica‐coated graphene in bioceramic nanocomposites to simultaneously enhance mechanical and biological performance

Abstract

The applications of a variety of bioactive ceramics such as hydroxyapatite (HA) in orthopedics are limited by their insufficient mechanical properties, especially poor fracture toughness. Thus, further extending the clinical applications of these materials warrants the enhancement of their mechanical properties. Although the reinforcement of ceramics by 2D nanomaterials has been well recognized, integrated structural, mechanical, and functional considerations have been neglected in the design and synthesis of such composite materials. Herein, we report the first use of silica-coated reduced graphene oxide (S-rGO) hybrid nanosheets to create bioceramic-based composites with simultaneously enhanced mechanical and biological properties. In the representative HA-based bioceramic systems prepared by spark plasma sintering, S-rGO incorporation was found to be more effective for increasing the Young's modulus, hardness, and fracture toughness than the incorporation of uncoated reduced GO (rGO). Furthermore, when assessed with osteoblast-like MG-63 cells, such novel materials led to faster cell proliferation and higher cell viability and alkaline phosphatase activity than are generally observed with pure HA; additionally, cells demonstrate stronger affinity to S-rGO/HA than to rGO/HA composites.The S-rGO/bioceramic composites are therefore promising for applications in orthopedic tissue engineering, and this research provides valuable insights into the fabrication of silica-coated hybrid nanosheet-reinforced ceramics. K E Y W O R D Scytocompatibility, fracture toughness, hybrid 2D nanomaterial, hydroxyapatite, spark plasma sintering

Applications of Ceramic/Graphene Composites and Hybrids

“…The surface modifications of graphene may also improve the mechanical performance, for example, Unnithan et al developed CS/HA/GO scaffolds containing simvastatin (SV) crosslinked with GO, which showed enhanced osteogenic and biomineralization performances [ 252 ]. Recently, silica-coated rGO nanosheets, developed by a sol-gel method, were mixed with HA nanorods and densified by SPS [ 253 ]. These composites showed enhanced mechanical properties (Young’s modulus, hardness, and fracture toughness) and better biological properties (faster osteoblast-like MG-63 cells proliferation and alkaline phosphatase activity) than materials fabricated using uncoated rGO sheets.…”

Leveraging the Recent Advancements in GelMA Scaffolds for Bone Tissue Engineering: An Assessment of Challenges and Opportunities

“…The results showed a significant increase in mineralization and osteogenesis in the graphene oxide and silica-coated graphene oxide groups compared with the control group. This increase was attributed to the large surface area of the graphene oxide and the ability of the nanoparticles to increase the adsorption and preservation of endogenous BMPs within the matrix . In addition, in vivo bone regeneration capacity of the hydrogels was also examined, with the results showing a significant increase in bone formation in the graphene oxide and silica-coated graphene oxide groups compared to the control group (Figure B) …”

Friction and Wear Behaviors of Reduced Graphene Oxide- and Carbon Nanotube-Reinforced Hydroxyapatite Bioceramics

“…The mixed powders were densified using an SPS system (Dr. Sinter 1050, Sumitomo Coal Mining, Japan). According to our previous experiments, the optimal sintering conditions for HA nanorods are 1,050°C dwell temperature, 100°C/min heating and cooling rates, and 3 min dwell time (Li Z. et al, 2020). Briefly, 0.6 g mixed powder was wrapped in a graphite foil and loaded in a cylindrical graphite die with an inner diameter of 10 mm.…”