Biosensing Application of Hybrid Thin-Film Layers-Based Biosensors

Biosensor based on immobilized tyrosinase on Langmuir-Blodgett thin film of arachidic acid and dysprosium bis-phthalocyanine has been developed. The biocomposite thin film has been characterized by UV-Vis spectroscopy, Fourier transformed infrared absorption spectroscopy, atomic force microscopy, and electrochemistry. Enzyme immobilization has been proved, and it maintain well the biocatalytic properties onto solid biocomposite film. The electrochemical detection of biosensor has been performed by measuring the cathodic current due to the reduction of the corresponding quinone at 0.024 V. Under optimum conditions, the performance characteristics of biosensors have been obtained. A linear response range from 5 up to 75 μM of dopamine has been obtained. The detection limit is 7.11 × 10^-7 M for developed biosensors. The biosensor construction is highly reproducible due to use of Langmuir-Blodgett nanotechnology. Finally, the developed biosensor has been applied to the determination of dopamine content in pharmaceutical samples.