Return to search

Phase Sensitive Estimation Of Fluorescence Lifetime For Fiber Optic Biosensors

Fluorescence lifetime determination and allied studies find application in spectroscopy in general and fiber optic biosensors in particular. Instruments and sensors cited in literature however use open loop, intensity based techniques with sophisticated detectors and components. We propose phase sensitive signal processing schemes to estimate the fluorescence lifetime using simple detectors and components, without compromising on accuracy. The performance of the schemes proposed is analysed and contrasted from a communications (signals and systems) point of view.
The resolution and sensitivity limits imposed in processing the signal, by systematic errors and additive noise, are derived for the schemes suggested. It is found that systematic errors impose a phase resolution limit of about 2°. We then study the suitability of different detectors and channels for application in phase sensitive fluorescence biosensors we analyse the effect of systematic limitations as well as additive noise, in the detection/transmission process, from the point of view of the components used. Certain fundamental limits of operation in terms of excitation intensities are derived for different detector-channel combinations, with a view to obtain a given resolution. A photodiode used with a fiber bundle is found to be sufficient for accurate phase read outs with 10"4 radians resolution. A PMT used in conjunction with a multimode fiber serves as a very good device for microsensing applications
Lastly, the biosensor for oxygen sensing, the ruthenium complex, is studied for standardisation of the sensor. We examine the quenching of fluorescence, the repeatability and reusability of the sensor, the stability of the instrument and such.

Identiferoai:union.ndltd.org:IISc/oai:etd.ncsi.iisc.ernet.in:2005/150
Date06 1900
CreatorsVadde, Venkatesh
ContributorsVivek, Srinivas
PublisherIndian Institute of Science
Source SetsIndia Institute of Science
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis and Dissertation
Format2981919 bytes, application/pdf
RightsI grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.

Page generated in 0.0025 seconds