An Amperometric Biosensor Based on Cytochrome C Immobilized on a Gold Electrode for Detection of Dissolved Hydrogen Sulfide

Cytochrome C biosensor for dissolved H₂S Detection

Abstract

Background and aims: Cytochrome C, a metalloprotein, can play the role of electron transporter electrochemically. In the present work, an amperometric biosensor for the detection of hydrogen sulfide in aqueous media has been fabricated by immobilizing Cytochrome C on the surface of gold electrode.

Materials and Methods: The surface was modified by nanoparticle and self-assemble monolayer of 3- mercaptopropionic acid. 1-(3-DimethylAminoPropyl)-3-EthylCarboDiimide Methiodide (EDC) and N-hydroxysuccinimide (NHS) were applied as coupling reagents for covalent attachment of Cytochrome C on modified gold electrode surface.

Results and Conclusion: Experimental design based on Central Composite Design (CCD) method revealed the optimal condition for current peak at pH 6, 5 mM phosphate buffer and 20 °C. In the presence of hydrogen sulfide in electrolyte, oxidation and reduction peaks reduced and over time were completely vanished. Under the investigated aqueous conditions, the lowest tested H₂S concentration was 0.001 ppm, and a rapid amperometric response was observed. The electrode response remained observable during the investigated 15-day period.