Researchers at the University of Arkansas, Marco Fielder and Arun Nair, have investigated the nanoscale effects of water and mineral content on the deformation mechanisms and thermal properties of collagen. The scientists compared the results to the same properties of non-mineralized collagen reinforced with carbon nanotubes and has demonstrated efficacy as a reinforcing material for bio-composites.
Researchers Nair and Fielder examined the mechanics and thermal properties of collagen-based bio-composites containing different weight percentages of minerals, water and carbon nanotubes when subjected to external loads. Their study suggested that variations of water and mineral content had a strong impact on the mechanical behavior and properties of the bio-composites, the structure of which mimics nanoscale bone composition. With increased hydration, the bio-composites increased their vulnerability to stress. The researchers also found that the presence of carbon nanotubes in non-mineralized collagen reduced the deformation of the gap regions.
Stiffness was also assessed to analyze the material's resistance to deformation. Both mineralized and non-mineralized collagen bio-composites showed less stability with greater water content. Composites with 40% mineralization were twice as strong as those without minerals, regardless of the amount of water content. Stiffness of composites with carbon nanotubes was similar to that of the mineralized collagen.
"As the degree of mineralization or carbon nanotube content of the collagenous bio-composites increased, the effect of water to change the magnitude of deformation decreased," Fielder said.
"Though several studies have characterized the mechanics of fibrils, the effects of variation and distribution of water and mineral content in fibril gap and overlap regions are unexplored," stated Nair, an associate professor of mechanical engineering. "Exploring these regions builds an understanding of the structure of bone, which is important for uncovering its material properties. If we understand these properties, we can design and build better bio-inspired materials and bio-composites."