Electrochemical laccase sensor based on 3-methylthiophene/3-thiopheneacetic acid/bis(3,4-ethylenedioxythiophene)-N-nonylacridone as a new polymer support

• Enzymatic electrode for detection of phenolic compounds.
• Modification of platinum electrodes with conducting copolymer.
• Optimization of copolymer synthesis.
• Stable and active sensing device was obtained.

An amperometric biosensing electrode was constructed by immobilization of laccase in an electrochemically synthesized copolymer based on N-alkylacridone derivative on a Pt electrode. Laccase from Cerrena unicolor has been successfully immobilized (electrolytic deposition) on the surface of thin film built of 3-methylthiophene/3-thiopheneacetic acid/2,7-bis[2-(3,4-etylenedioxythiophene)]-N-nonylacridone. A clearly defined reduction current according to the phenolic compound presence was observed in cyclic voltammetry, which attributed to the reduction of enzymatically produced quinone on the electrode surface. The immersion of the laccase-coated electrode in solution with substrate generated large catalytic currents easily recorded by cyclic voltammetry at low potential scan rates. The response of the biosensing platform is evaluated in the presence of hydroquinone (HQ) and syringaldazine, used as phenolic enzymatic substrates. The system exhibits a clear electrocatalytic activity and the substrates can be amperometrically determined at −0.10 V vs. SCE. Considering the fact, that the immobilization strategy showed high efficiency, obtained results suggest that the method for phenoloxidase immobilization has a great potential of enabling high throughput fabrication of bioelectronic devices.