5. TOWARDS A LONG-TERM, CONTINUOUS LACTATE SENSOR: IMMOBILIZATION OF LACTATE OXIDASE

Department: Bioengineering
Faculty Advisor(s): David Gough

Primary Student
Name: Adam Louis Strobl
Email: astrobl@ucsd.edu
Phone: 858-534-2713
Grad Year: 2010

Abstract
An accurate, continuous, and long-term lactate sensor would provide clinicians with valuable diagnostic data. Diabetic patients would benefit from the measurement of dynamic metabolic information in order to predict and prevent episodes of diabetic shock. Other patients suffering from pulmonary or cardiac impairment diseases would also benefit from knowledge of lactate levels. The current state of the art in continuous lactate sensors is limited by the short lifespan of these sensors. In comparison to glucose oxidase, the enzyme used most often in glucose sensors, the enzyme lactate oxidase (LOx) utilized here is quite unstable. In order to increase the lifespan of the sensor, we have studied LOx in immobilized form. In particular, the effect of immobilization process parameters on the resulting activity yield and stability of LOx in the immobilized enzyme membrane were studied. An immobilization procedure utilizing the cross-linking agent glutaraldehyde was developed and optimized to give maximum enzymatic yield and stability at physiological conditions. The yield of the process was also measured against the amount of enzyme immobilized to determine if there was a drop in efficiency at large loading levels. This was analyzed through use of a reaction/diffusion model to calculate the effects of substrate diffusion on the spectrophotometric assay. Finally, the loading levels and stabilization achieved in vitro are used to estimate the lifetime of an in vivo sensor. This is accomplished through the use of a model design that was previously determined to be appropriate for a subcutaneous sensor.

« Back to Posters or Search Results