Atomic force microscopy is an advanced imaging technique for viewing biological structures and dynamic biological mechanisms at the nanometre scale. This thesis describes a high-resolution atomic force microscope designed for imaging biological samples in physiological solution. This microscope includes a highly sensitive interferometric cantilever detector, along with a home-built frequency/phase and amplitude detector. The initial chapters of this thesis begin with a description of the experimental set-up, as well as various tests carried out to characterise the fast frequency detector. Following this is a description of the interferometric cantilever detector, which possess a noise floor at a mere 5 fm/√Hz, making it particularly suited for detecting cantilevers in liquids. Results chapters then go on to demonstrate the capability of this instrument to image at nanometre and atomic-scale resolution. Images of the atomic structure of muscovite mica in buffer solution are presented. Images of chaperonin protein GroEL were also acquired, which contain features of the protein's apical domain. Most importantly, for the first time AFM was used to track the pore-formation of pore forming protein pneumolysin in buffer solution. Supported lipid bilayers were prepared and images were captured of the proteins oligomerising on their surface. The initial stage of pore-formation was investigated by comparing the height of pneumolysin before and after pores were formed. Details of the monomers making up the structure of the protein were also imaged, as well as pores created within the supported lipid bilayers.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:626278 |
| Date | January 2013 |
| Creators | Khan, Z. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1399519/ |
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