Studies in the design and development of miniature optical-fibre in-vivo sensors: With applications in obstructive sleep apnoea syndrome and arterial restenosis.

The current state-of-the-art of in-vivo optical fibre sensors is reviewed. There then follows a review of techniques for pressure measurement and for diagnosis of obstructive sleep apnoea syndrome (OSAS). A catheter containing seven optical fibre pressure transducers for use in the diagnosis of OSAS is described which has been designed, modelled, built and successfully tested both in the laboratory and on six subjects. The transducer has a range of +/-5kPa, a resolution of 10Pa and a potential bandwidth of >1kHz. Oral and nasal breathing, snoring, peristalsis and airway collapse were distinguished using the system. After a review of angioplasty techniques and subsequent healing or arterial restenosis (AR), another optical fibre sensor is described which was designed and built for monitoring the healing of the endothelium and for the detection of AR following percutaneous transluminal coronary angioplasty. The sensor used a fluorescent antibody antigen reaction and its potential was successfully demonstrated both in-vitro and using mammalian models. The resolution was better than 107p Moles of antibody. It was shown that the use of a similar radio-labelled reaction was not feasible for in-vivo use. The study concludes that there is significant scope for development of optical fibre in-vivo physical sensors and biosensors.