Dual-enzyme fiber optic biosensor for pyruvate

In this study, the response characteristics for a dual-enzyme fiber-optic biosensor for pyruvate are presented. An enzyme layer composed of lactate oxidase and lactate dehydrogenase (LDH) was fabricated at the tip of a sensing optrode. The biosensor is based on the luminescence detection of consumed reduced nicotinamide adenine dinucleotide (NADH) and the measured fluorescence intensity is related to the bulk concentration of pyruvate. Such a dual-enzyme optrode can not only retain the merits of fiber-optic biosensors, but can also take advantage of two enzyme-catalyzed reactions. The response sensitivity and detection limit of the proposed dual-enzyme sensors are improved by at least 8 and 5 times, respectively, compared to those of single-enzyme systems.