Pt-Decorated MWCNTs-Ionic Liquid Composite-Based Hydrogen Peroxide Sensor To Study Microbial Metabolism Using...

Area of Science:

• Electrochemistry
• Biosensing
• Microbiology

Background:

• Hydrogen peroxide (H2O2) is a key metabolite in biological processes, including the oral microbiome.
• Accurate detection of H2O2 in complex matrices is challenging due to low concentrations and interfering substances.

Purpose of the Study:

• To develop a highly sensitive, nonenzymatic H2O2 sensor for biological applications.
• To miniaturize the sensor for use in scanning electrochemical microscopy (SECM).
• To detect H2O2 produced by oral bacteria in simulated biofilms.

Main Methods:

• Fabrication of a 25 μm diameter H2O2 sensor using Pt nanoparticles on multiwalled carbon nanotubes and a conducting ionic liquid.
• Coupling the sensor with a Pt electrode for dual SECM probe.
• Detection of H2O2 produced by Streptococcus gordonii in a simulated biofilm under physiological conditions.

Main Results:

• The sensor exhibited a low detection limit (250 nM) and a broad linear range (250 nM to 7 mM).
• Successfully detected H2O2 (65 ± 10 μM) produced by S. gordonii in a simulated biofilm.
• Detected lower H2O2 concentrations (30 μM) in the presence of salivary enzymes, overcoming limitations of existing assays.

Conclusions:

• The developed H2O2 sensor is highly sensitive, stable, and suitable for detecting H2O2 in complex biological samples.
• Miniaturization and SECM compatibility enable spatial mapping of H2O2 production in biofilms.
• The sensor holds potential for studying biological processes in challenging environments requiring high sensitivity and compact detection.