Nanotexturisation of gold surfaces and its application to neural implants

Frommhold, Andreas (2011). Nanotexturisation of gold surfaces and its application to neural implants. University of Birmingham. Ph.D.

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Abstract

The objective of this thesis was to develop a new methodology for the improvement of the interface properties of gold electrodes for neural implants. The goal was to increase the surface area without a change in geometrical footprint of the electrode with nano-fabrication tools. A process has been created that uses Nanosphere Lithography for masking layer deposition and anisotropic etching to fabricate nanostructures on the surface of the electrodes. Optimisation of the process parameters led to a control of structure shape, which allowed to produce a variety of shapes. The effect of the nano-structures on the interface was investigated by impedance spectroscopy and complementary electrochemical measurements. It showed that the interface impedance could be decreased significantly by up to a magnitude of scale with the surface modifications. In addition a porous columnar form of sputtered gold was found that also showed decreased interface impedance compared to standard gold films. A set of neural implants was designed and fabricated to test the effect of surface modification in vitro in neurological tissue. The surface modification process was successfully implemented in the device fabrication. The in-vitro assessment showed signs of improved interface performance compared to unmodified devices.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):