Mechanical and structural properties of collagen fibrils.
Doctoral thesis, UCL (University College London).
There is a fundamental need for techniques that are capable of determining the mechanical properties of biological fibrils at the nanoscale. This is because of the direct relationship between structure and function of an organism and the mechanical properties of its building blocks. Collagen, for example, which is the most abundant protein in mammals, is best known as the principal tensile element providing the mechanical structure to our bodies. Although collagen has been investigated intensively in the last decades, relatively little is known about its mechanics and inner structure. In this thesis, atomic force microscopy (AFM) based methods were employed to probe the mechanical properties of the nanometer-sized type I collagen fibrils from rat tail tendon (diameter 50 - 300 nm). AFM-based nanoindentation was performed to determine the elasticity of individual fibrils under both physiological conditions and in the dehydrated state. To gain insight into the fibril interior structure a novel AFM-based scraping technique was developed that can dislocate parts of the outer layer of delicate biological specimens. Applied to individual collagen fibrils, the technique led to a successful exposure of the fibril core. Nanoindentation measurements of fibril shell and core indicated no significant differences in the mechanical properties. Further, the longitudinal stretching behaviour of single fibrils was studied in novel nanoscale strain experiments. This provided additional insight into the internal structure of fibrils as it is the molecular arrangement which determines the stretching behaviour. The outcome of this thesis promises a better understanding of the structural and mechanical properties of collagen fibrils and provides novel techniques and tools for advanced mechanical characterisation at the nanoscale.
|Title:||Mechanical and structural properties of collagen fibrils|
|Additional information:||Authorisation for digitisation not received|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology|
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