Abstract:
Over the last few years, an all- bre uorescence spectroscopic system, called the optrode, has been developed by the Department of Physics at the University of Auckland. The optrode is used amongst other applications to monitor bacteria in situ. Prior to this study, only a single bre optic probe was used to excite and collect uorescence signal from uorescently tagged bacteria. This thesis focuses on increasing the detection limit of the optrode by exploiting the use of dual bre optic probes. In a dual bre optic probe, one bre is used to excite the uorescent sample whilst a second bre is used to collect the uorescence signal from the uorescent sample. For this study, several dual optic probe designs were developed and the sensitivity as well as the detection limit of each design was investigated. The dual bre optic probe designs were developed to maximise the overlapping of the illumination and collection volumes provided by the two bres. Previously, many attempts had been made to use the optrode to measure the bacterial growth in real time. Various trials failed to show the expected trend. In this study, we successfully optimised a protocol to use the optrode for real time bacterial growth measurements. This research also investigated the applicability of the optrode for bioremediation monitoring. A bench-scale column was used in conjunction with the optrode to monitor bacterial distribution and transport in sand. The research carried out for this thesis resulted in improvement of the current optrode system and its applicability for biological applications.
