Collection-Free Express H₂O₂ Detection in Breath Aerosol through Its Capillary Condensation Directly onto the Sensor...

Area of Science:

• Analytical Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Hydrogen peroxide (H₂O₂) is a key biomarker for pulmonary oxidative stress.
• Current methods for H₂O₂ detection in breath aerosol require time-consuming sample collection.
• Developing rapid, non-invasive diagnostic tools for respiratory diseases is crucial.

Purpose of the Study:

• To develop an express method for detecting hydrogen peroxide (H₂O₂) in breath aerosol.
• To enable direct, real-time analysis of H₂O₂ without intermediate sample collection.
• To assess the potential of this method for non-invasive diagnostics of pulmonary disorders.

Main Methods:

• Utilized capillary condensation of breath aerosol onto graphene oxide (GO) and hygroscopic salt (KF) layers.
• Employed Prussian Blue (PB) as an efficient electrocatalyst for H₂O₂ reduction.
• Integrated a sensor for express current peak generation upon aerosol passage.

Main Results:

• Achieved optimal condensing membrane composition (≥30 μg·cm⁻² GO; ∼6 μmol·cm⁻² KF) for efficient PB electroactivity.
• Demonstrated rapid sensor response with redox-peak separation <100 mV within 5 s.
• Generated a current peak within 2 s, proportional to H₂O₂ concentration (0.3–10 µM).
• Successfully distinguished pulmonary oxidative stress in patients with inflammatory diseases and smokers.

Conclusions:

• Express, collection-free detection of H₂O₂ in breath aerosol is feasible using capillary condensation.
• The developed method offers a rapid and non-invasive approach for assessing pulmonary oxidative stress.
• This technique holds promise for advancing non-invasive diagnostics of pulmonary disorders.