In vivo measuring of skin softness using the Gas Bearing Electrodynamometer

Area of Science:

• Dermatology
• Bioengineering
• Materials Science

Background:

• The stratum corneum's biomechanical properties influence skin condition perception and function.
• Objective measurement of skin viscoelasticity is crucial for evaluating topical product efficacy.

Purpose of the Study:

• To objectively measure stratum corneum viscoelastic properties in vivo using a Gas Bearing Electrodynamometer.
• To evaluate the effects of emollients and water on skin softness.
• To assess the reproducibility and influencing factors of the measurement technique.

Main Methods:

• Utilized a Gas Bearing Electrodynamometer to measure in vivo viscoelastic properties of the stratum corneum.
• Analyzed changes in skin surface relief during probe movement.
• Studied the effects of water and various emollient formulations (o/w and w/o emulsions) on skin softness.
• Assessed measurement reproducibility and sources of variation.

Main Results:

• The Gas Bearing Electrodynamometer demonstrated good reproducibility (CV ~3%).
• Skin softness was significantly affected by water, with short-term effects.
• Water-in-oil (w/o) and oil-in-water (o/w) emulsions improved skin softness, with o/w emulsions showing a more pronounced and longer-lasting effect (up to 6 hours).
• The non-volatile components of emollients, particularly the oil phase, are critical for the softening effect.

Conclusions:

• The Gas Bearing Electrodynamometer is a promising tool for objective assessment of skin softness.
• This technique can effectively evaluate the impact of topical applications, including new formulations and specific ingredients.
• Understanding the biomechanical properties of the stratum corneum is key to developing effective skincare products.