Visualisation of H₂O₂ penetration through skin indicates importance to develop pathway-specific epidermal sensing

Area of Science:

• Dermatology
• Biomedical Engineering
• Oxidative Stress Research

Background:

• Elevated reactive oxygen species (ROS), including hydrogen peroxide (H2O2), are implicated in various skin disorders.
• Epidermal sensing of H2O2 offers a potential method for monitoring skin disease progression.

Purpose of the Study:

• To evaluate in vitro epidermal sensing of H2O2 by visualizing its permeation through skin.
• To identify the primary pathways for H2O2 transdermal penetration.

Main Methods:

• Skin membranes were mounted in Franz cells.
• Prussian white microparticles were applied to the stratum corneum.
• H2O2 permeation was visualized by the oxidation of Prussian white to Prussian blue, forming blue dots.
• Skin surface images were compared with dot patterns.

Main Results:

• Approximately 74% of the blue dots, indicating H2O2 permeation, were localized around hair shafts.
• The extent of Prussian white to Prussian blue conversion correlated with skin membrane resistance.
• Hair follicles were identified as the predominant routes for H2O2 transdermal penetration.

Conclusions:

• Hair follicles serve as the main pathways for hydrogen peroxide (H2O2) transdermal penetration.
• Future H2O2 monitoring on skin should focus on pathway-specific epidermal sensing with micrometer resolution at hair follicles.
• This approach can aid in detecting and quantifying H2O2 as a biomarker for skin pathologies.