Electrical Impedance Spectroscopy Quantifies Skin Barrier Function in Organotypic In Vitro Epidermis Models

Area of Science:

• Dermatology
• Toxicology
• Biophysics

Background:

• 3D human epidermal equivalents (HEEs) are advanced models for pre-clinical research in dermatology and toxicology.
• Assessing epidermal barrier function is crucial for understanding skin health and disease.
• Non-invasive methods are needed for continuous monitoring of HEEs.

Approach:

• Developed a custom electrical impedance spectroscopy (EIS) setup with a 12-electrode pair lid for 24-transwell systems.
• Performed serial EIS measurements over seven days on HEEs, assessing impact on morphology and barrier function.
• Correlated impedance spectra features (EIS ^diff and EIS ^SC) with specific epidermal characteristics like differentiation and stratum corneum thickness.

Key Points:

• EIS measurements did not affect HEE morphology and showed consistent trends over time.
• EIS ^diff correlated with keratinocyte terminal differentiation, while EIS ^SC correlated with stratum corneum thickness.
• Genetic modifications (CRISPR/Cas9) and cytokine exposure confirmed EIS ^diff's sensitivity to differentiation and barrier defects.

Conclusions:

• EIS offers a non-invasive, quantitative method for assessing HEE epidermal barrier function.
• This technique can consecutively monitor barrier development, defects, and repair in HEE models.
• EIS provides objective readouts for evaluating therapeutic molecule efficacy in restoring barrier function.