Oxygen concentration has been measured using fluorescence quenching in solid polymer hosts. The feasibility of generalizing these oxygen transducers to a wider class of chemical sensors through coupling to other chemistries is proposed. An example of such coupling is given in a glucose/oxygen transducer. The glucose transducer is produced by entrapping an enzyme, glucose oxidase, in' the composite matrix of a hydrophilic oxygen transducer. Glucose oxidase catalyzes a reaction between glucose and oxygen, thereby lowering the local oxygen concentration. This transducer yields a glucose modified optical oxygen signal.
The specific focus of this research is the development of a theoretical model that describes the coupling of glucose concentration to relative fluorescence intensity, the experimental measurement of the key parameters in this model, and the evaluation of the sensitivity of the variation in relative fluorescence intensity with changes in glucose concentration. The experimental parameters include the diffusivity of oxygen in PHEMA (1.36 x 10-7 cm2/s), the solubility ofoglucose in PHEMA (0.24 g in PHEMA/g in buffer), and the diffusivity of glucose in PHEMA (8.25 x 10-8 cm2/s). When these experimental parameters are incorporated, the model developed predicts critical design requirements of the transducer.