Glucose sensor based on glucose oxidase-lipid LB film immobilized in Prussian Blue layer

The structure and dynamic organization of a mixed Langmuir film of glucose oxidase (GOx) and lipid at the air-water interface were studied. The film was transferred onto the Prussian Blue (PB)-modified Pt electrode for biosensor preparation. The PB modified electrode showed well defined redox peaks in 0.1 M PBS electrolyte. The Langmuir film was characterized at the air-water interface by pi-A isotherms. The mixed monolayer was formed by spreading GOx on the LB trough covered with lipid. Time-pressure results show that at least 90 minutes are required to reach the equilibrium state of GOx-lipid film. The monolayer was transferred onto the PB-modified electrode when surface pressure was 40 mN/m. This sensor was characterized by a very low detection limit and a wide linear range. The optimal conditions for both fabricating and response of the sensor were investigated. The proposed biosensor showed a linear calibration range from 5 x 10(-6) to 6 x 10(-5) M. The detection limit was determined to be 1.5 x 10(-6) M.