Characterization of different diamond-like carbon electrodes for biosensor design

Area of Science:

• Electrochemistry
• Materials Science
• Biosensors

Background:

• Diamond-like carbon (DLC) films are increasingly utilized in electrochemical research due to their unique properties.
• DLC electrodes can be fabricated with varying sp(3)/sp(2) carbon hybridization ratios or doped with metals like nickel.
• These characteristics make DLC a versatile material for developing sensitive electrochemical transducers.

Purpose of the Study:

• To investigate the electrochemical performance of DLC electrodes for hydrogen peroxide detection.
• To develop and compare amperometric glucose biosensors based on two distinct DLC electrode formulations: SiCAr1 and SiCNi5%.
• To evaluate the sensitivity, detection limits, and operational stability of the developed glucose biosensors.

Main Methods:

• Electrochemical characterization using cyclic voltammetry and amperometric measurements.
• Fabrication of amperometric glucose biosensors by immobilizing glucose oxidase onto SiCAr1 and SiCNi5% electrodes using glutaraldehyde cross-linking.
• Performance evaluation of biosensors at a fixed potential of +1.0V in a phosphate buffer (40mM, pH 7.4).

Main Results:

• SiCAr1 electrodes exhibited higher sensitivity to glucose (0.6875 μA/mM) compared to SiCNi5% electrodes (0.3654 μA/mM).
• Detection limits for glucose were determined to be 20 μM for SiCAr1 and 30 μM for SiCNi5%.
• Both biosensors showed good operational stability, retaining 48% (SiCAr1) and 79% (SiCNi5%) of their initial response after 10 days.

Conclusions:

• DLC electrodes, particularly the SiCAr1 formulation, are effective and sensitive transducers for amperometric glucose biosensors.
• The SiCAr1-based glucose biosensor offers superior sensitivity and stability compared to the nickel-doped SiCNi5% counterpart.
• These findings highlight the potential of tailored DLC materials for advanced biosensing applications.