Application Note | ElastoSens™ Bio
Measuring mechanical properties of aorta tissue using ElastoSens™ Bio
Introduction
The aorta is a highly specialized elastic artery designed to buffer the pulsatile output of the heart and maintain smooth, continuous blood flow throughout the body. Its wall is composed of elastin, collagen, smooth muscle cells, and connective tissue arranged in a layered structure that gives rise to complex mechanical behavior. These mechanical properties—how the aorta stretches, stiffens, and recoils—directly influence how effectively it can withstand blood pressure, store elastic energy, and distribute load across its layers. By studying them, scientists and clinicians can better understand how a healthy aorta functions, detect early signs of disease, and design therapies that restore or preserve performance.
Key mechanical properties of aorta tissue
Elasticity
Elasticity describes the aorta’s ability to stretch during systole and recoil during diastole, enabling it to store and release energy with each heartbeat. This property is largely attributed to elastin in the arterial wall, which provides the distensibility necessary for the aorta to act as an effective buffer. As pressure rises, collagen fibers progressively engage, modifying the elastic response.
Stiffness
Stiffness refers to how resistant the aorta is to deformation when exposed to pressure. It increases when the vessel loses elastin integrity, when collagen fibers dominate load-bearing, or when structural remodeling occurs. Clinically, stiffness is commonly assessed through pulse wave velocity, which reflects how quickly pressure waves travel along the artery.
Compliance
Compliance reflects how much the aortic diameter or area changes in response to pressure. A compliant aorta accommodates blood ejected from the heart with minimal pressure elevation. As compliance decreases, systolic pressures rise, altering hemodynamic load and reducing the vessel’s ability to moderate pulsatility.
Anisotropy
Anisotropy captures the fact that the aortic wall behaves differently depending on the direction of loading. Its layered architecture—with fibers arranged helically or circumferentially—creates distinct mechanical responses in the circumferential and longitudinal directions. This directional dependence is especially important in experimental testing, where uniaxial and biaxial methods reveal how load is shared across the wall.
Viscoelasticity
Viscoelasticity describes the time-dependent behavior of the aorta, where deformation and recoil depend not only on the magnitude of load but also on the rate at which it is applied. This property influences how the vessel adapts to pulsatile flow, pressure changes, and continuous cyclic loading.
Relationship between diseases and mechanical properties of aorta tissue
Aging
With aging, the aorta naturally loses elastin functionality while collagen becomes more prominent in bearing load. This shift increases stiffness, reduces compliance, and alters the vessel’s ability to dampen pulsatile energy. Age-associated changes form the basis for early vascular aging and contribute to higher cardiovascular risk.
Hypertension
Chronic high blood pressure exposes the aortic wall to sustained mechanical stress, accelerating structural remodeling. Increased stiffness, reduced distensibility, and collagen engagement become more pronounced, making the vessel less capable of absorbing pressure fluctuations and further elevating hemodynamic load.
Atherosclerosis
Structural and compositional changes associated with plaque development alter local mechanical behavior of the aortic wall. Regions affected by atherosclerosis may stiffen, lose compliant motion, and become mechanically heterogeneous, disrupting normal pressure–diameter dynamics and increasing vulnerability to further complications.
Aortic Aneurysm (degenerative remodeling)
Although not deeply discussed in your sources as a standalone disease, degenerative remodeling mechanisms described—including fiber reorganization and loss of elastin—are consistent with the mechanical deterioration seen in aneurysmal tissue. Reduced elasticity, compromised strength, and altered anisotropy influence how the wall responds to pressure and contribute to progressive dilation.
How aorta tissue mechanics are assessed
In Vivo techniques (Clinics)
In clinical settings, the mechanical behavior of the aorta is evaluated using non-invasive tools that observe how the artery expands, contracts, and conducts pressure waves. Techniques such as carotid–femoral pulse wave velocity, applanation tonometry, and Doppler ultrasound measure the speed at which the pulse travels along the aorta, offering insight into arterial stiffness. Imaging methods, particularly MRI, can capture both anatomical structure and dynamic changes in diameter and flow throughout the cardiac cycle. These instruments help healthcare professionals build a clear picture of the aorta’s elasticity and its role in cardiovascular health.
Ex Vivo techniques (Research)
In research environments, excised aortic tissues are characterized using mechanical testing systems that apply controlled loads and measure the resulting deformation. Common instruments include uniaxial tensile testers, planar biaxial testing devices, and inflation–extension setups, which stretch or pressurize the tissue to reveal its structural and mechanical behavior. Many of these systems incorporate optical or digital tracking to accurately capture local strain patterns. By replicating physiological conditions in a controlled setting, these tools help researchers understand how the aorta responds to stress and support the development of better models, materials, and technologies for vascular applications.
Case study: Aorta tissue mechanical characterization with ElastoSens™ Bio
ElastoSens™ Bio: a contactless tool for Ex Vivo tissue testing
In the field of aorta biomechanics, the ElastoSens™ Bio offers a modern and non-destructive approach to ex vivo mechanical characterization. This instrument measures viscoelastic properties continuously while preserving the structural integrity of delicate vascular tissues. Its technology enables detailed evaluation of soft samples and supports repeated measurements over extended periods, even under controlled changes in temperature or hydration. This approach complements traditional mechanical tests by providing additional insights into time-dependent behavior and physiological responses.
To demonstrate the capabilities of the ElastoSens™ Bio, we performed an ex vivo experiment using aorta tissue samples. The following section describes the materials and methods employed in this study, followed by the resulting data, illustrating the instrument’s practical application in vascular research.
Material and methods
Porcine aorta was obtained from Sustainable Swine Resources (SSR). Samples were cut into circular punches for loading into ElastoSens™ Bio membrane holders (Figure 1). The average thickness of the samples is 1.93 mm. 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″). Results were expressed as mean values obtained from three samples, collected from different regions of the same aorta (n = 3).
Figure 1. Porcine aorta tissue prepared and loaded into the ElastoSens™ Bio membrane holders for non-destructive viscoelastic characterization. The top panel shows the intact aorta sample prior to sectioning, and the bottom panel shows representative aorta punches in the membrane grips for testing.
Results and discussion
The viscoelastic properties of porcine aorta were evaluated using the ElastoSens™ Bio testing system (Figure 2). The shear storage modulus (G′) averaged 24 ± 1.9 kPa (n = 3), consistent with the aorta’s relatively stiff, elastin- and collagen-rich wall.
For comparison, Widman et al. (2016) used shear-wave elastography on ex vivo porcine aortic segments and reported arterial wall shear moduli ranging from ~41 ± 5 kPa to ~97 ± 10 kPa as intraluminal pressure increased from 20 to 120 mmHg. Although these values are higher, their measurements were performed under pressurization and pre-stretch, which increase apparent stiffness via fiber recruitment. By contrast, ElastoSens™ Bio quantifies non-destructive, viscoelasticity on intact, unloaded tissue, providing a complementary baseline modulus and enabling repeat measurements on the same specimen.
Figure 2: Viscoelastic properties of porcine aorta tissue: shear storage modulus (G′) obtained with the ElastoSens™ Bio non-destructive testing system (mean ± SD, n=3).
Conclusions and perspectives
The mechanical properties of aortic tissue—defined by elasticity, stiffness, viscoelasticity, and anisotropy—play a central role in how the vessel accommodates pulsatile blood flow, buffers cardiac pressure, and maintains vascular homeostasis. The present study demonstrates that non-destructive viscoelastic testing with the ElastoSens™ Bio enables reliable quantification of aortic wall mechanics, capturing key parameters such as shear storage modulus (G′) and shear loss modulus (G″). This approach provides precise and reproducible measurements, offering a robust baseline for cardiovascular research, vascular biomechanics, and translational studies focused on arterial function. Beyond these findings, the ElastoSens™ Bio offers unique advantages for aorta-focused investigations:
- Simple sample preparation supports gentle handling of aortic segments and helps preserve hydration, lamellar structure, and natural fiber organization during testing.
- High sensitivity and repeatability enable consistent measurements across different aortic regions (ascending, arch, thoracic, abdominal), capturing physiologically relevant intra-vessel variability.
- Cross-species benchmarking allows direct comparison of aortic mechanical properties in animal models and humans, supporting translational cardiovascular research and model validation.
- Platform versatility accommodates native vascular tissues, engineered constructs, and biomaterials under identical conditions—valuable for developing grafts, vascular patches, and compliance-matched implants.
- Controlled incubation and repeated measurements make it possible to track temporal changes in viscoelastic behavior due to enzymatic digestion, pharmacological treatment, or simulated disease progression.
- Engineered tissue applications benefit from non-destructive, repeated testing that monitors the evolving mechanical maturation of bioengineered aortic scaffolds or vascular tissue constructs.
Taken together, these capabilities position the ElastoSens™ Bio as a powerful tool for advancing our understanding of aortic biomechanics, supporting comparative physiology, and guiding the design of vascular biomaterials and therapeutic strategies aimed at restoring or enhancing arterial function.
References
Macrae, R. A., Miller, K., & Doyle, B. J. (2016). Methods in mechanical testing of arterial tissue: a review. Strain, 52(5), 380-399.
Segers, P., Rietzschel, E. R., & Chirinos, J. A. (2020). How to measure arterial stiffness in humans. Arteriosclerosis, thrombosis, and vascular biology, 40(5), 1034-1043.
Widman, E., Maksuti, E., Amador, C., Urban, M. W., Caidahl, K., & Larsson, M. (2016). Shear wave elastography quantifies stiffness in ex vivo porcine artery with stiffened arterial region. Ultrasound in Medicine and Biology, 42(10), 2423–2435.
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