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Graphene, a Novel and Promising Biomaterial BY ANDREW VAHRADIAN, MAY 7, 2014
Initially derived from graphite, graphene is a metamaterial (a material artificially engineered to have unique properties not commonly found in nature) composed of a single layer of carbon atoms arranged in a 2-dimensional, regular hexagonal (honeycomb) lattice.
Graphene was first synthetically isolated in 2004, and due to its distinctive optical, thermal, mechanical, electronic, and quantum properties, an increasing amount of scientific research is being conducted on the material as it could catalyze technological innovation in the biomedical field.
A recent study demonstrated that graphene exhibits the greatest mechanical strength ever measured in a natural or artificial material - approximately 10x the strength of titanium. And although graphene is composed of just a single layer of atoms, the intrinsic strength of the material is "extremely remarkable" as its structure presents no defects or grain boundaries within its composition. Additional research has revealed that variable amounts of graphene and its derivatives can be successfully combined with other metals, such as copper or nickel, in order to increase the tensile strength.
Graphene also displays great elasticity, which is attributable to its carbon-carbon bonds displayed in a hexagonal arrangement. Because of its atom monolayer, graphene is very lightweight, weighing only 0.77 mg/m2. To put in perspective, the developers stated that “a 1 square meter graphene hammock would support a 4 kg cat but would weigh only as much as one of the cat's whiskers, at 0.77 mg (about 0.001% of the weight of a 1 square meter sheet of paper)”.
Lastly, it has been recently demonstrated that graphene sheets may have a significant antibacterial effect. Surgical Site Infections (SSIs) are a significant concern with spinal surgery, and graphene's antibacterial properties could potentially help reduce the rates of infection after fusions by being incorporated in spinal hardware. Graphene has the potential to increase the resistance of current spinal implants by either combining graphene with other alloys, or by using layers of graphene as a coating.
In addition to spinal instrumentation, another potential application of graphene technology for spine surgery is the development of new micro/nano-electromechanical systems (MEMS and NEMS), which would enable real-time evaluation of the biomechanics of a patient's anatomy under different real-life situations after receiving a spinal implant (such as an artificial disc or an interbody cage).
While graphene has shown promise as a new biomedical material, further research will need to be conducted on the biocompatibility of graphene with neuronal tissue, the long-term biological effects of graphene implants, the behavior of graphene under electromagnetic fields commonly used in neuroimaging and MRI, issues related to the reported cytotoxicity of graphene derivatives, as well as cellular damage caused by edge irregularities on graphene nanomaterials.