Optrodes for Measuring Enzyme Activity and Inhibition

Fiber optics provide a unique means for both invasive and remote detection of chemical and biochemical quantities. Elegant previous work has shown that enzymes are extremely useful “reagents” for (bio)chemical analysis, and we will show here that a combination of enzymatic methods of analysis along with the use of optical fiber sensing schemes can even enlarge the potential of enzyme-based analysis. We will report on how enzyme activities can be measured using optical fibers. In the first approach, a fluorogenic substrate has been immobilized at the tip of the fiber. When brought into contact with an enzyme (such as an esterase), the synthetic substrate undergoes hydrolysis to form a strongly fluorescent fluorophore whose fluorescence intensity is monitored through the optical fiber.