Micro-scale Instruments Applied to a Bovine Nuclear Transfer System
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Manual handling of biological cells is routine in most laboratories. This is gradually changing with the development of robotic cell handling systems, and micro-scale lab-on-chip devices. Attempts were made to develop devices that automate or assist cell handling in the context of a bovine nuclear transfer (NT) system. The system, a zona-free bovine NT cloning system, formed a baseline reference for tool design and performance evaluation. Bovine NT can, as other cell handling procedures, be improved by rapid and precise cell positioning. Improvements in cell handling can increase the quantity of cells processed, and the uniformity of conditions the cells are subject to during processing. Tools were developed for two areas of cell handling: cell fusion and cell transportation. Designs suitable for implementation in microscale lab-on-chip systems were evaluated. Tool development was predominantly experimental, assisted by numerical modelling. The experimental investigation concerned device fabrication and operational performance. A number of cell handling tool designs were built and tested. Coplanar electrodes are not commonly used in bovine NT and reports on their efficacy were not available. These electrodes, which are simple to fabricate, were tested to determine fusion rates achievable in comparison with those of the baseline procedure. A novel fusion device, the micropit, was designed to assist bovine cell pairing and electrofusion. It was initially uncertain whether this device was capable of achieving cell fusion. Tests were conducted; and cell fusion and micro-positioning were demonstrated, as was an increase in biological cell processing throughput. Many miniaturised lab-on-chip systems rely on cell transportation. One illustration in the baseline procedure is the on-chip transport of cells to the cell fusion device. Potential cell transport mechanisms for a miniature cloning system were evaluated by prototype construction and testing. These mechanisms included travelling wave dielectrophoresis and capillary fluid actuation. To facilitate automation of on-chip cell transportation, a low cost electrically isolated cell detection system was developed based on a DVD pick-up unit. Various obstacles that were encountered during the course of device construction are noted, as are the fabrication methods employed.