Thesis

Size-dependent mechanical properties of single polyurethane nanofibres

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Awarding institution
  • University of Strathclyde
Date of award
  • 2012
Thesis identifier
  • T13246
Qualification Level
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Department, School or Faculty
Abstract
  • Electrospinning is a process in which a high-voltage electric field is used to create a fibre that is nanometres in diameter and meters in length. These nanofibres are then collected onto a target to create a non-woven, fibrous structure of variable fibre diameter and morphology. These electrospun nanofibre mats have a broad range of applications including being used as chemical sensors, filtration, electrode materials and drug delivery systems. They are also an excellent candidate for engineered tissue scaffolds since the fabricated structure mimics that of an extracellular matrix. When cells are seeded onto a fabricated mesh, their behaviour strongly depends on the biomaterial's properties. Various studies have already confirmed the role of micro-topography, the surface chemistry and treatment of a scaffold, on cell viability, attachment and signal transduction. The strong dependency of cell behaviour on the material properties further complicates the study of mechanotransduction, which is essential for cellular processes such as cell differentiation, growth, survival and the maintenance of cellular homeostasis [1]. With the development of newer technologies, namely atomic force microscopy, we are now able to visualise and characterise the properties of single nanofibres. In this study, the mechanical properties of single electrospun polyurethane nanofibres are investigated using atomic force microscopy. It was found that the elastic modulus varies significantly with a change in fibre diameter and multiple experiments were performed to confirm this observation. An attempt was also made to explain this change in fibre modulus by using nanoindentation and we hypothesise that a shallow, hard surface layer forms on the nanofibres caused by a change in the crystal structure of the polymer. The implications that these observations have on cellular mechanotransduction were then discussed and suggestions were given on how these can be limited.
Resource Type
DOI
Date Created
  • 2012
Former identifier
  • 948093

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