The first part of the study focused on the preparation and assessment of healthy and viable cell cultures of primary rat cortical neurons for the study of network behaviour. Cultures were grown on silicon surfaces of varying composition and roughness to test the feasibility of integrating these cultures on silicon-based electronic devices. Also, the health and viability of neurons growing on non-transparent silicon substrates have been assessed by detailed histological analysis and cell counting using standard immunofluorescence techniques. Neurons extracted from various ganglia of the pond snail <i>Lymnaea stagnalis </i>have been prepared for patch-clamping using established dissection, isolation and enzymatic digestion protocols. The second part of the project concentrated on formulating a theory of gigaseal formation during patch-clamping by a critical review of the literature. The critical factors for highly resistive seal formation were identified and realised on prototype devices, including the patch aperture length and physical nature of the aperture surface. The physical natures of SiO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> (and modifications by boron deposition) were investigated by wettability experimentation. A relationship between interactive molecular surface energy and the wetting angle was obtained from an established theoretical wetting model. The third part of this study focused on the geometric properties of microfabricated apertures. Apertures were modified by deposition techniques to increase the radius of curvature of the edge profile, thereby mimicking a rounded glass pipette opening. An image analysis algorithm was developed to quantify the radius of curvature of the cross-section profile from atomic force microscopy (AFM) data. A second algorithm was developed to quantify the circularity error of the aperture top-view by analysis of the profile texture. The profile was exacted after the application of contrast enhancement and edge-detection filters from scanning electron microscopy (SEM) image data. Lastly, patch-clamp electrodes have been successfully integrated into planar silicon-based devices. This work presents the first patch-clamp microstructure capable of being scaled to a 100-μm inter-nodal spacing for construction of MEA designs.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:649832 |
| Date | January 2005 |
| Creators | Dworak, Bradley Jay |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13750 |
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