Molybdenum disulphide and graphene quantum dots as electrode modifiers for laccase biosensor

Area of Science:

• Electrochemistry
• Materials Science
• Biotechnology

Background:

• Enzyme immobilization is crucial for biosensor development.
• Nanocomposite materials offer enhanced electrochemical properties.
• Molybdenum disulphide (MoS2) and graphene quantum dots (GQDs) are promising nanomaterials.

Purpose of the Study:

• To develop a novel nanocomposite of MoS2 and GQDs for enzyme immobilization.
• To improve the electrochemical performance of screen-printed electrodes.
• To create a sensitive biosensor for caffeic acid and polyphenol determination.

Main Methods:

• Fabrication of MoS2-GQD nanocomposite modified electrodes.
• Enzyme immobilization of laccase onto the modified electrode.
• Electrochemical characterization using cyclic voltammetry and impedance spectroscopy.
• Spectroscopic and microscopic analysis (UV-vis, fluorescence, SEM, TEM, XRD).

Main Results:

• Enhanced conductivity of screen-printed electrodes with MoS2-GQD modification.
• Successful immobilization of laccase on the nanocomposite matrix.
• Development of a laccase biosensor with efficient response to caffeic acid (0.38-100µM).
• Achieved a detection limit of 0.32µM and sensitivity of 17.92nAµM(-1) for caffeic acid.
• Successful application for total polyphenol determination in red wine samples.

Conclusions:

• The MoS2-GQD nanocomposite is a suitable support for enzyme immobilization, enhancing electrochemical properties.
• The developed laccase biosensor demonstrates high sensitivity and efficiency for caffeic acid and polyphenol analysis.
• This analytical tool shows potential for real-world applications, such as in food and beverage analysis.