Carbon Fiber Biocompatibility for Implants

Abstract

Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA) to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8) and 0.8 mm at 41.6% vs. 19.5% (p < 10−4), respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

A Review on the Use of Hydroxyapatite-Carbonaceous Structure Composites in Bone Replacement Materials for Strengthening Purposes

“…Mild toxicity was also reported for CNTs mainly due to oxidative stress and inflammation [ 175 ]. Peterson [ 176 ] conducted an animal study on epoxy/carbon fibre-composite and reported that carbon fibres can undergo osseointegration with live bone.…”

Functionalization of Carbon Nanomaterials for Biomedical Applications

“…As a consequence, they show outstanding mechanical properties along the axis direction but poor mechanical properties in the transverse direction due to the weak van der Waals forces between the layers typical of graphite [360]. Carbon fibers display rather different mechanical properties: tensile strengths from 5.65 to 1.5 GPa and specific modulus from 407 to 106 GPa [360] which may exceed the strength and modulus of steel, 2.39 and 26.6 GPa, respectively [361]. Different types of thermal and stretching treatments can be applied to improve the CF orientation thus increasing the Yang modulus [361].…”

“…Carbon fibers display rather different mechanical properties: tensile strengths from 5.65 to 1.5 GPa and specific modulus from 407 to 106 GPa [360] which may exceed the strength and modulus of steel, 2.39 and 26.6 GPa, respectively [361]. Different types of thermal and stretching treatments can be applied to improve the CF orientation thus increasing the Yang modulus [361]. However, because they are more expensive when compared with other competitors such as glass fibers or plastic fibers, they are used in high performance specialized materials.…”

Comparative In Vitro Study of the Bond Strength of Composite to Carbon Fiber Versus Ceramic to Cobalt–Chromium Alloys Frameworks for Fixed Dental Prostheses

“…This composition provides excellent mechanical properties, such as high resistance to fatigue, fracture, abrasion and temperature. Moreover, it presents a low specific weight, thermal expansion coefficient, electrical conductivity and a good buffering of vibration forces [ 1 , 2 , 3 , 4 , 5 , 6 ]. CFRC has been mainly used in fixed dental prostheses (FDPs) and framework manufacturing [ 7 , 8 ].…”