Amperometric sensor for hydrogen peroxide based on immobilized cytochrome c on binary self-assembled monolayers

Area of Science:

• Electrochemistry
• Biosensors
• Nanomaterials

Background:

• Hydrogen peroxide (H(2)O(2)) is a crucial biomarker in various biological and environmental processes.
• Sensitive and selective detection of H(2)O(2) is essential for diagnostics and monitoring.
• Developing efficient biosensors requires robust immobilization strategies and electrocatalytic materials.

Purpose of the Study:

• To fabricate a sensitive electrochemical sensor for H(2)O(2) determination.
• To investigate the electrochemical properties of immobilized cytochrome c (cyt c).
• To evaluate the performance of the sensor in terms of sensitivity, linearity, and response time.

Main Methods:

• Immobilization of cytochrome c (cyt c) on gold electrodes using binary self-assembled monolayers (SAMs) of thioctic acid (T-COOH) and thioctic acid amide (T-NH(2)).
• Electrochemical characterization using cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry.
• Assessing electrocatalytic activity towards H(2)O(2) reduction.

Main Results:

• The modified electrode exhibited significant electrocatalytic activity for H(2)O(2) reduction.
• A linear relationship was observed between catalytic current and H(2)O(2) concentration (10.0–300 microM) with R(2) = 0.9996.
• The sensor demonstrated high sensitivity (1.7 nA microM(-1) cm(-2)) and a fast response time (95% steady-state current within 10 s).
• The apparent Michaelis-Menten constant (K(m)(app)) was determined to be 619 microM.

Conclusions:

• The developed biosensor based on immobilized cyt c on SAMs-modified gold electrodes is highly sensitive and efficient for H(2)O(2) detection.
• The binary SAMs provide a suitable platform for cyt c immobilization and enhance electrocatalytic performance.
• This sensor holds promise for practical applications in H(2)O(2) determination due to its rapid response and high sensitivity.