Biosensor based on laccase immobilized on plasma polymerized allylamine/carbon electrode

Area of Science:

• Biomaterials Science
• Electrochemistry
• Enzyme Immobilization

Background:

• Biosensors require efficient enzyme immobilization for optimal performance.
• Carbon electrodes are versatile platforms for biosensor development.
• Plasma functionalization offers a controlled method for surface modification.

Purpose of the Study:

• To develop a simple and rapid method for functionalizing carbon electrodes for laccase immobilization.
• To investigate the effect of allylamine plasma deposition on carbon surface properties.
• To compare the performance of physisorbed versus covalently immobilized laccase for biosensor applications.

Main Methods:

• Allylamine coating deposition on carbon electrodes using RF tubular plasma reactor.
• Surface characterization to determine amine group density (N/C ratio).
• Immobilization of laccase (Trametes versicolor) via physisorption and covalent bonding.
• Electrochemical measurements of enzyme activity and current output using ABTS substrate.

Main Results:

• High density of amine groups (N/C ratio up to 0.18) achieved on carbon surfaces.
• Optimal plasma deposition time of 30 minutes for enhanced laccase immobilization efficiency.
• Covalently immobilized laccase exhibited twice the activity and current output compared to physisorbed laccase.
• High sensitivity for oxygen reduction with ABTS (4.8 μA mg⁻¹L) and DMP (2.7 μA mg⁻¹L).
• Excellent biosensor stability observed over 6 months.

Conclusions:

• Plasma-based allylamine functionalization is an effective method for immobilizing laccase on carbon electrodes.
• Covalent immobilization significantly enhances biosensor performance (activity, current output).
• The developed laccase biosensor demonstrates high sensitivity, stability, and biocompatibility for various applications.