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Skin viscoelasticity displays site- and age-dependent angular anisotropy
E C Ruvolo1, G N Stamatas, N Kollias
1Methods and Models Development, CPPW, Johnson & Johnson Consumer Co., Skillman, NJ 08558, USA. eruvolo@cpcus.jnj.com
Skin Pharmacology and Physiology
|September 14, 2007
Summary
Skin elasticity changes with age, becoming more anisotropic and less dispersed. A new method using acoustic shear waves accurately measures these directional changes, revealing a link between skin structure and function.
Area of Science:
- Biophysics
- Dermatology
- Materials Science
Background:
- Skin aging is characterized by significant loss of elasticity.
- Objective measurements have not fully captured the magnitude of age-related mechanical property changes.
- Skin's mechanical properties exhibit directional non-uniformity (anisotropy) that requires investigation.
Purpose of the Study:
- To present a sensitive methodology for quantifying the angular anisotropy of skin elasticity.
- To investigate age-dependent changes in skin mechanical properties.
- To explore the relationship between skin anisotropy and structural parameters.
Main Methods:
- Utilized the Reviscometer RVM 600 to measure directional dependence of acoustic shear wave speed.
- Determined anisotropy and angular dispersion width based on angular distribution of resonance running time at 3-degree intervals.
- Correlated anisotropy direction with Langer's dermal cleavage lines.
Main Results:
- Anisotropy increases with age, while angular dispersion width decreases.
- A ratio of anisotropy to dispersion width provides a sensitive parameter for skin viscoelasticity assessment across a wide age range (infants to 75 years).
- The direction of anisotropy aligns with Langer's lines, indicating a structural basis for mechanical properties.
Conclusions:
- The proposed methodology accurately captures age-dependent changes in skin mechanical properties.
- Demonstrated a clear structure-function relationship in skin's anisotropic mechanical behavior.
- The method offers high sensitivity and a large dynamic range for assessing skin viscoelasticity.
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