Application Note | ElastoSens™ Bio
Measuring mechanical properties of skin using ElastoSens™ Bio
Introduction
The skin is not only the body’s largest organ but also a dynamic mechanical barrier that protects against environmental stress, regulates water balance, and contributes to sensory perception. Its function depends heavily on the structural organization of collagen, elastin, and other dermal components, which together give rise to unique mechanical behaviors such as elasticity, stiffness, and viscoelasticity. Measuring these properties provides insight into how skin responds to forces in daily life, from stretching and compression to shear. By studying them, scientists and clinicians can better understand how healthy skin functions, detect early signs of disease, and design therapies that restore or preserve performance.
Key mechanical properties of skin
Elasticity
Elasticity reflects the skin’s ability to return to its original shape after being deformed. It is primarily governed by the elastic fiber network, which allows skin to recoil following stretching or suction loading. Clinical studies show that elasticity declines significantly with age, affecting firmness and the visible appearance of the skin.
Stiffness
Stiffness describes how resistant the skin is to deformation under load. It is strongly influenced by collagen organization in the dermis, with anatomical site and age being important determinants. Research demonstrates that deeper layers, like the reticular dermis, are generally stiffer than superficial papillary layers, and that stiffness progressively decreases over the lifespan.
Viscoelasticity
Skin exhibits both viscous and elastic responses when subjected to stress, meaning that part of the deformation recovers immediately while another part recovers slowly over time. This viscoelastic behavior reflects the interplay of collagen, elastin, and the extracellular matrix, and is essential for skin’s ability to withstand continuous or repetitive mechanical loads.
Anisotropy
The skin’s mechanical response varies depending on the direction of applied force, a property known as anisotropy. This directional dependence is linked to the orientation of collagen fibers (e.g., along Langer’s lines) and affects how skin stretches or resists tearing in different regions of the body.
Relationship between diseases and mechanical properties of skin
Systemic sclerosis
In systemic sclerosis, skin becomes markedly stiffer and less elastic due to excessive collagen deposition and fibrosis. Measuring mechanical parameters such as reduced elasticity or increased hardness helps in assessing disease progression and treatment outcomes.
Morphea and localized scleroderma
Localized fibrotic diseases like morphea alter skin stiffness and thickness. Mechanical testing methods, particularly suction and indentation, can quantify these changes, supporting both diagnosis and therapeutic monitoring.
Photoaging
Chronic UV exposure accelerates the breakdown of collagen and elastic fibers, leading to reduced elasticity and increased laxity. Mechanical measurements reveal that photoaged skin recovers less effectively after deformation, explaining the clinical appearance of wrinkles and sagging.
Burn scars and fibrosis
Scar tissue and fibrotic remodeling after burns significantly alter the skin’s viscoelastic properties, often resulting in excessive stiffness and reduced compliance. Objective measurement of these properties is increasingly used to track scar maturation and evaluate therapeutic interventions.
How skin tissue mechanics are assessed
In Vivo Techniques (Clinics)
In clinical practice, the mechanical properties of skin are usually assessed with non-invasive techniques such as suction testing, indentation, or torsional loading. These methods apply a gentle mechanical force directly to the skin surface and track how the tissue deforms and recovers. Because they can be performed safely and quickly on patients, they are widely used to evaluate elasticity, firmness, and viscoelasticity in relation to aging, disease, or treatment response. Their value lies in providing standardized, reproducible measurements that translate the skin’s “feel” into objective data, supporting dermatology, plastic surgery, and cosmetic science.
Ex Vivo Techniques (Research)
In research settings, mechanical testing of excised skin samples allows for a deeper exploration of the tissue’s structural behavior. Tensile testing can stretch the skin until it fails, revealing stress–strain relationships; indentation can probe localized stiffness; torsion can assess resistance to twisting; and rheological approaches can capture viscoelastic properties. Because samples can be studied layer by layer, researchers can connect structural features such as collagen and elastin networks to the skin’s macroscopic mechanical performance. These ex vivo methods provide a detailed picture of skin biomechanics that cannot be achieved in vivo, helping to advance fields like regenerative medicine, biomaterials design, and the development of therapies that target age-related or pathological changes.
Case study: Skin tissue mechanical characterization with ElastoSens™ Bio
ElastoSens™ Bio: a Contactless Tool for Ex Vivo Tissue Testing
In the field of skin biomechanics, the ElastoSens™ Bio offers an advanced method for ex vivo testing. This instrument measures the viscoelastic properties of skin continuously and non-destructively, ensuring that sample integrity is maintained throughout the experiment. Its technology enables precise characterization of soft biological tissues and supports repeated measurements over time under controlled environmental conditions, thereby complementing and extending the information provided by conventional mechanical assays.
To demonstrate the potential of the ElastoSens™ Bio, we conducted an ex vivo study on skin samples. The following section presents the materials and methods used in this experiment, followed by the results, offering a practical example of the instrument’s application.
Material and Methods
Sheep and cow skin were obtained fresh from a local farm. Samples were trimmed to approximately 1.8 mm thickness, corresponding to epidermis and dermis without underlying hypodermis, and cut into circular punches for loading into ElastoSens™ Bio membrane holders (Figure 1). To prevent drying, samples were immersed in phosphate-buffered saline (PBS) overnight at 4 °C prior to testing. Each specimen was then placed in the ElastoSens™ Bio instrument at 25 °C for 1 hour to equilibrate. Excess PBS was gently removed before measurement.
The instrument provided real-time viscoelastic parameters, including the shear storage modulus (G′) and the shear loss modulus (G″). For each condition, results were expressed as mean values obtained from three samples, collected from different regions of the same skin layer (n = 3).
Figure 1. Sheep and cow skin tissue prepared and loaded into the ElastoSens™ Bio membrane holders for non-destructive viscoelastic characterization. The top panel shows the intact skin sample prior to sectioning, and the bottom panel shows representative skin portions gripped in the holders for testing.
Results and Discussion
The viscoelastic properties of sheep and cow skin were evaluated using the ElastoSens™ Bio testing system (Figure 2). For sheep skin, the shear storage modulus (G′) averaged 6.11 ± 1.62 kPa (n = 3), while cow skin showed a slightly lower value of 4.92 ± 0.24 kPa (n = 3). Manan et al. (2015) measured bovine skin from the butt-bend region (~3 mm thick, epidermis + dermis with hypodermis removed) using uniaxial tension, reporting an average Young’s modulus of 12.57 MPa, corresponding to a small-strain shear modulus of approximately 94 kPa.
Differences between our values and those reported in the mentioned reference can be attributed to variations in testing technology and conditions, including deformation mode (tension versus shear), strain level, temperature, and testing time, as well as sample preparation and measurement direction. Overall, the ElastoSens™ Bio evaluates hydrated samples under small-strain oscillatory shear, conditions that capture the tissue’s compliant response and preserve its structure. This kPa-range modulus therefore provides a physiologically relevant representation of skin in its native role as a protective and load-bearing barrier.
Figure 2: Viscoelastic properties of skin tissue for sheep and cow: shear storage modulus (G′) obtained with the ElastoSens™ Bio non-destructive testing system (mean ± SD, n=3).
Conclusions and Perspectives
The mechanical properties of skin tissue—defined by elasticity, viscoelasticity, and structural anisotropy—are fundamental to understanding its physiological roles in protection, barrier function, and sensory perception. Non-destructive viscoelastic testing with the ElastoSens™ Bio enables reliable quantification of skin mechanics, capturing key parameters such as shear storage modulus (G′) and shear loss modulus (G″). This approach provides precise and reproducible data, offering a robust baseline for both biomedical research and translational dermatology studies. Beyond these findings, the ElastoSens™ Bio offers unique advantages for skin and soft tissue research:
- Simple preparation and setup minimize handling while preserving hydration and structural integrity.
- High sensitivity and repeatability allow consistent measurements across different anatomical sites, capturing regional variability.
- Cross-species benchmarking facilitates translational research by directly comparing skin mechanics in animal models and humans.
- Platform versatility supports testing of diverse soft tissues and biomaterials under identical conditions, making it useful for developing skin substitutes, scaffolds, or wound-healing materials.
- Controlled incubation and repeated testing enable monitoring of viscoelastic changes over time, whether due to aging, UV exposure, pharmacological treatment, or pathological conditions.
- Engineered tissue applications also benefit from non-destructive, repeated measurements that reflect the dynamic evolution of bioengineered skin constructs.
Taken together, these capabilities position the ElastoSens™ Bio as a powerful tool for advancing our understanding of skin biomechanics, supporting comparative physiology, and guiding the design of biomaterials and therapies intended to restore or enhance skin function.
References
Kalra, A., Lowe, A., & Al-Jumaily, A. M. (2016). Mechanical behaviour of skin: a review. J. Mater. Sci. Eng, 5(4), 1000254.
Lynch, B., Pageon, H., Le Blay, H., Brizion, S., Bastien, P., Bornschlögl, T., & Domanov, Y. (2022). A mechanistic view on the aging human skin through ex vivo layer-by-layer analysis of mechanics and microstructure of facial and mammary dermis. Scientific reports, 12(1), 849.
Junker, H. J., Thumm, B., Halvachizadeh, S., & Mazza, E. (2023). A quantitative comparison of devices for in vivo biomechanical characterization of human skin. Mechanics of soft materials, 5(1), 5.
Luebberding, S., Krueger, N., & Kerscher, M. (2014). Mechanical properties of human skin in vivo: a comparative evaluation in 300 men and women. Skin Research and Technology, 20(2), 127-135.
Manan, N. F. A., Mahmud, J., & Jumahat, A. (2015). Biomechanical behaviour of bovine skin: An experiment-theory integration and finite element simulation. Jurnal Teknologi, 76(10), 103–111.
Discover how our technology non-destructively measures the viscoelastic properties of soft biomaterials and tissues using micro-volumes of samples
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