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 π-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 × 10⁻⁶ to 6 × 10⁻⁵ M. The detection limit was determined to be 1.5 × 10⁻⁶ M.