Application Note | ElastoSens™ Bio
Measuring mechanical properties of adipose tissue using ElastoSens™ Bio
Introduction
Adipose tissue is more than a passive fat reservoir — it plays structural, protective, metabolic, and endocrine roles in the human body. Its mechanical properties, shaped by the cellular and extracellular matrix components, influence how fat stores expand, protect organs, and interact with surrounding tissues. These properties also affect how adipose tissue responds to external forces, from surgical manipulation to metabolic stress. By studying them, scientists and clinicians can better understand how healthy fat tissue functions, detect early signs of disease, and design therapies that restore or preserve performance.
Key mechanical properties of fat
Elasticity
Elasticity describes adipose tissue’s ability to return to its original shape after being deformed. Subcutaneous and visceral fat exhibit nonlinear elastic behavior, meaning their response depends on the magnitude and type of applied force. This property is critical for functions such as cushioning and mechanical protection, as well as for adapting to changes in body weight and metabolic demand.
Viscoelasticity
Fat tissue shows time-dependent deformation, combining both solid-like and fluid-like behaviors. Viscoelasticity is observed during stress-relaxation and indentation tests, where adipose samples display gradual force relaxation over time. This property ensures that adipose tissue can absorb mechanical loads while also adapting slowly to sustained pressure, which is important for protecting underlying organs and maintaining tissue integrity.
Stiffness
Stiffness reflects resistance to deformation and varies between subcutaneous and visceral adipose depots. Structural differences in extracellular matrix composition, particularly collagen content, contribute to these variations. Increased stiffness has been linked to fibrotic remodeling, reducing tissue flexibility and altering its physiological functions.
Relationship between diseases and mechanical properties of adipose tissue
Obesity
In obesity, adipose tissue undergoes significant mechanical remodeling. Expansion of fat mass is accompanied by changes in extracellular matrix organization, particularly collagen accumulation, which alters tissue stiffness and reduces compliance. These mechanical changes limit adipocyte expansion, promoting metabolic dysfunction and increasing vulnerability to related conditions such as cardiovascular disease.
Diabetes
Type 2 diabetes is associated with distinct alterations in adipose tissue mechanics. Atomic force microscopy studies have shown that diabetic adipose tissue exhibits higher stiffness at the nanoscale, reflecting increased fibrosis and extracellular matrix remodeling. These changes not only impair the tissue’s ability to store lipids efficiently but also contribute to systemic metabolic dysregulation.
Fibrosis
Fibrosis represents an excessive accumulation of extracellular matrix components that increases rigidity in fat tissue. This process reduces the expandability of adipocytes and limits their capacity to adapt during weight gain or loss. Fibrotic stiffening of adipose tissue is closely tied to metabolic disturbances and is recognized as a hallmark of dysfunctional fat in both obesity and diabetes.
How adipose tissue mechanics are assessed
In Vivo Techniques (Clinics)
In clinical practice, non-invasive imaging technologies are used to evaluate the mechanical properties of adipose tissue. Ultrasound elastography is one of the most widely adopted methods, offering real-time visualization of tissue stiffness through either strain or shear-wave techniques. It is portable, safe for repeated use, and particularly useful for examining subcutaneous fat layers in conditions such as obesity or fibrosis. Another advanced method is magnetic resonance elastography (MRE), which uses low-frequency vibrations combined with MRI to generate three-dimensional maps of tissue elasticity. These in vivo techniques provide clinicians with valuable information about fat stiffness and structural changes that are not detectable through anatomy alone, supporting diagnosis, treatment monitoring, and risk assessment.
Ex Vivo Techniques (Research)
In research and experimental settings, a range of methods is employed to study adipose tissue mechanics under controlled conditions. Mechanical testing approaches such as uniaxial tensile testing, compression, indentation, and shear assays are frequently used to characterize stress–strain behavior, viscoelasticity, and energy dissipation in both subcutaneous and visceral fat. These tests help define bulk mechanical properties that are critical for computational modeling, surgical planning, and implant design. At the microscale, atomic force microscopy (AFM) provides nanoscale measurements of tissue elasticity by probing the surface with a fine cantilever tip, revealing local variations in stiffness and their relationship to extracellular matrix remodeling. Together, these ex vivo methods allow researchers to connect structural organization with functional mechanics, advancing our understanding of how fat tissue responds to physiological and pathological changes.
Case study: Adipose tissue mechanical characterization with ElastoSens™ Bio
ElastoSens™ Bio: a Contactless Tool for Ex Vivo Tissue Testing
In the study of adipose tissue biomechanics, advanced ex vivo testing methods provide valuable insights into its complex mechanical behavior. Non-destructive techniques make it possible to monitor viscoelastic properties continuously while preserving the natural structure of the samples. This approach allows for precise characterization of fat tissue under controlled conditions and supports repeated measurements over time, even when environmental factors are varied. By going beyond the limitations of traditional mechanical assays, such methods offer a clearer understanding of how fat responds to load and structural remodeling.
To illustrate these capabilities, we conducted an ex vivo study on adipose tissue samples. The following section describes the materials and methods applied, followed by the results, providing a practical demonstration of the technique’s application.
Material and Methods
Sheep and cow adipose tissue were obtained fresh from a local farm. Sheep samples consisted of subcutaneous back fat, while cow samples consisted of suet fat. For sheep, 3.0 g of tissue was prepared and 1.3 g for cow, and loaded 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 equilibrated in the ElastoSens™ Bio instrument at 37 °C for 1 hour, after which excess PBS was gently removed before measurement.
Figure 1. Sheep fat (left) and cow fat (right) prepared and loaded into the ElastoSens™ Bio macro holders for non-destructive viscoelastic characterization. The top panel shows the intact fat sample prior to sectioning, and the bottom panel shows representative fat portions placed in the holders for testing.
Results and Discussion
The viscoelastic properties of sheep and cow fat were evaluated using the ElastoSens™ Bio non-destructive testing system (Figure 1). Sheep subcutaneous back fat was soft and compliant (G′ = 1.62 ± 0.26 kPa; G″ = 0.68 ± 0.05 kPa), while cow suet fat, a dense visceral depot, was markedly stiffer (G′ = 58.73 ± 5.79 kPa; G″ = 34.16 ± 0.94 kPa). Literature values are in a similar range: Yoo et al. (2011) reported that bovine orbital fat behaves as a compliant tissue under stress-relaxation testing. Variations across studies are expected, as fat mechanics depend strongly on depot origin as well as factors such as age, diet, metabolic state, and the testing technology used. Overall, the ElastoSens™ Bio enables non-destructive testing under controlled temperature and hydration, offering physiologically relevant measurements.
Figure 2: Viscoelastic properties of fat tissue for sheep (left) and cow (right): shear storage modulus (G′) and shear loss modulus (G’’) obtained with the ElastoSens™ Bio non-destructive testing system (mean ± SD, n=3).
Conclusions and Perspectives
The mechanical properties of adipose tissue—shaped by elasticity, viscoelasticity, and matrix organization—are fundamental to understanding its physiological roles in cushioning, energy storage, and metabolic regulation. Non-destructive viscoelastic testing enables reliable quantification of fat 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 studies in metabolism and tissue engineering. Beyond these findings, advanced ex vivo testing platforms offer unique advantages for adipose tissue research:
- Simple preparation and setup minimize sample handling while preserving hydration and native structure.
- High sensitivity and repeatability ensure consistent measurements across different fat depots, capturing variability between subcutaneous and visceral adipose tissue.
- Cross-species benchmarking facilitates translational research by directly comparing adipose mechanics in animal models and humans.
- Versatile platform compatibility supports testing of a wide range of soft tissues and biomaterials, aiding the development of fat-mimicking scaffolds or implants.
- Controlled incubation and repeated testing allow monitoring of viscoelastic changes over time, whether due to obesity-related remodeling, metabolic interventions, or fibrotic progression.
- Engineered tissue applications benefit from non-destructive, repeated measurements that track the evolving properties of bioengineered adipose constructs.
Taken together, these capabilities position modern viscoelastic testing as a powerful tool for advancing our understanding of adipose biomechanics, supporting comparative physiology, and guiding the design of biomaterials and therapies aimed at restoring or improving fat tissue function.
References
Alkhouli, N., Mansfield, J., Green, E., Bell, J., Knight, B., Liversedge, N., … & Winlove, C. P. (2013). The mechanical properties of human adipose tissues and their relationships to the structure and composition of the extracellular matrix. American Journal of Physiology-Endocrinology and Metabolism, 305(12), E1427-E1435.
DeJong, H. M., Abbott, S., Zelesco, M., Kennedy, B. F., Ziman, M. R., & Wood, F. M. (2017). The validity and reliability of using ultrasound elastography to measure cutaneous stiffness, a systematic review. International journal of burns and trauma, 7(7), 124.
Fontanella, C. G., Toniolo, I., Foletto, M., Prevedello, L., & Carniel, E. L. (2022). Mechanical behavior of subcutaneous and visceral abdominal adipose tissue in patients with obesity. Processes, 10(9), 1798.
Wenderott, J. K., Flesher, C. G., Baker, N. A., Neeley, C. K., Varban, O. A., Lumeng, C. N., … & O’Rourke, R. W. (2020). Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy. Scientific reports, 10(1), 20423.
Yoo, L., Gupta, V., Lee, C., Kavehpore, P., & Demer, J. L. (2011). Viscoelastic properties of bovine orbital connective tissue and fat: constitutive models. Biomechanics and Modeling in Mechanobiology, 10(6), 901–914.
Discover how our technology non-destructively measures the viscoelastic properties of soft biomaterials and tissues using micro-volumes of samples
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