Amperometric hydrogen peroxide biosensor based on covalently immobilizing thionine as a mediator

Area of Science:

• Electrochemistry
• Biosensor Technology
• Nanomaterials

Background:

• Hydrogen peroxide (H2O2) is a crucial analyte in various biological and chemical processes.
• Development of sensitive and selective biosensors is essential for accurate H2O2 detection.
• Novel immobilization strategies are needed to enhance biosensor performance.

Purpose of the Study:

• To fabricate a novel amperometric biosensor for hydrogen peroxide detection.
• To utilize hemoglobin immobilized on a composite material for enhanced sensing capabilities.
• To characterize the electrochemical properties and analytical performance of the developed biosensor.

Main Methods:

• Fabrication of a modified electrode using 2,6-pyridinedicarboxylic acid (PDC) polymer, thionine, and nano-Au.
• Immobilization of hemoglobin onto the nano-Au surface.
• Characterization using electrochemical impedance spectroscopy and atomic force microscopy.
• Performance evaluation via cyclic voltammetry and chronoamperometry.

Main Results:

• Successful fabrication of a hemoglobin-based biosensor on a nano-Au/thionine/PDC modified electrode.
• Fast amperometric response time (within 6 s) for hydrogen peroxide detection.
• Linear detection range from 9.1 µM to 5.0 mM with a low detection limit of 2.6 µM.
• Apparent Michaelis-Menten constant (K(M)(app)) of 3.2 mM.
• Demonstrated good stability and reproducibility of the biosensor.

Conclusions:

• The developed amperometric biosensor demonstrates efficient immobilization of hemoglobin.
• The biosensor exhibits excellent analytical performance for hydrogen peroxide detection.
• The novel composite material offers a promising platform for biosensor development.