Application Note | ElastoSens™ Bio
Measuring mechanical properties of stomach tissue using ElastoSens™ Bio
Introduction
The stomach is a hollow, muscular organ whose function depends closely on its mechanical behavior. Properties such as elasticity, compliance, stiffness, and viscoelasticity govern how it expands to receive food, mixes contents, and regulates emptying into the intestine. These mechanical features also reflect the layered organization of gastric tissue, with smooth muscle, connective tissue, and mucosa each contributing to overall function. By studying them, scientists and clinicians can better understand how a healthy stomach functions, detect early signs of disease, and design therapies that restore or preserve performance.
Key mechanical properties of stomach
Elasticity
Elasticity describes the stomach’s ability to return to its resting shape after being stretched by ingested food or liquid. This property is central to maintaining gastric tone and ensuring efficient emptying.
Compliance
Compliance refers to the ease with which the stomach wall can expand in response to increasing volume. High compliance allows the stomach to accommodate meals without large increases in pressure, which is essential for comfort and normal digestion.
Stiffness
Stiffness reflects the resistance of gastric tissue to deformation under pressure. Regional differences in stiffness between the fundus, corpus, and antrum influence motility patterns and the mechanical coordination of gastric function.
Viscoelasticity
Viscoelasticity combines elastic recoil with time-dependent deformation. This property enables the stomach wall to adapt gradually during prolonged filling, while also providing resistance during rapid distension.
Relationship between diseases and mechanical properties of stomach tissue
Functional dyspepsia
Altered compliance and sensitivity in the stomach wall are linked to discomfort and impaired accommodation. Changes in these mechanical responses contribute to early satiety and postprandial distress.
Gastric cancer
Cancerous remodeling of stomach tissue can change stiffness and viscoelastic behavior, affecting motility and wall mechanics. These changes can compromise normal digestion and gastric emptying.
Gastroparesis
In gastroparesis, abnormal mechanical properties of the stomach wall, such as impaired elasticity and altered compliance, interfere with coordinated contractions. This leads to delayed emptying and persistent digestive symptoms.
Post-surgical remodeling
After surgical procedures such as partial gastrectomy or bariatric surgery, the stomach undergoes significant structural and mechanical adaptation. Scar tissue formation increases stiffness at surgical margins, while altered geometry changes the distribution of stress and compliance during filling. These remodeling processes can impact long-term gastric function and patient outcomes.
How stomach tissue mechanics are assessed
In Vivo techniques (Clinics)
To study the stomach’s mechanical behavior within the body, instruments are designed to capture how the tissue responds under physiological conditions. Approaches such as robotic indentation systems, laparoscopic tools fitted with force and position sensors, and non-invasive imaging-based elastography methods allow measurement of tissue stiffness, compliance, and viscoelasticity directly in situ. These tools provide valuable insights into the stomach’s ability to deform and recover, supporting both diagnostic evaluation and the development of realistic surgical training systems.
Ex Vivo techniques (Research)
In laboratory settings, gastric tissues are examined outside the body using controlled mechanical testing devices. Uniaxial tensile testers are used to stretch samples and measure elasticity, while radial compression and indentation setups assess stiffness and viscoelasticity under localized loading. Inflation chambers may also be employed to replicate physiological pressure changes. By testing intact walls as well as separated layers, researchers can build a detailed picture of the structural and functional contributions of each gastric region, which is essential for developing computational models and guiding medical device design.
Case study: Stomach tissue mechanical characterization with ElastoSens™ Bio
ElastoSens™ Bio: a contactless tool for Ex Vivo tissue testing
In the field of stomach biomechanics, the ElastoSens™ Bio offers an innovative solution for ex vivo testing. This instrument enables continuous, non-destructive measurement of viscoelastic properties, maintaining the structural integrity of gastric tissue during experimentation. Its technology allows precise characterization of soft samples and supports repeated assessments over time under controlled environmental conditions, complementing the insights obtained from traditional mechanical tests.
To demonstrate the capabilities of the ElastoSens™ Bio, we performed an ex vivo study on stomach tissue specimens. The following section outlines the materials and methods applied in this experiment, followed by the results, providing a practical example of the instrument’s use.
Material and methods
Sheep stomach tissue was obtained from a local farm. Specimens with an approximate thickness of 3.2 mm were excised using a biopsy-like punch, resulting in cylindrical samples (23 mm internal diameter, variable height). 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 37 °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 gastric regions of the same organ (n = 3).
Figure 1. Sheep stomach tissue prepared and loaded into the ElastoSens™ Bio macro holders for non-destructive viscoelastic characterization. The top panel shows the intact stomach sample prior to sectioning, and the bottom panel shows representative spleen portions placed in the holders for testing.
Results and discussion
The viscoelastic properties of sheep stomach tissue were evaluated using the ElastoSens™ Bio non-destructive testing system (Figure 2). The shear storage modulus (G′) and shear loss modulus (G″) were measured as 9.7 ± 2.0 kPa and 4.3 ± 2.4 kPa, respectively (n = 3). These values characterize the small-strain viscoelastic response of stomach tissue, consistent with its functional role in accommodating and mixing ingested food.
Waite et al. (2016) characterized ovine rumen using uniaxial tensile and stress-relaxation tests, reporting equilibrium tensile moduli of ~5–15 kPa. Assuming near-incompressibility (E ≈ 3G), this corresponds to shear moduli of ~1.5–5 kPa, which are of the same order of magnitude but somewhat lower than our 37 °C, PBS-hydrated shear results. These differences likely arise from the distinct testing modalities: Waite et al. focused on equilibrium tensile properties, whereas oscillatory shear emphasizes dynamic viscoelastic behavior. In addition, mechanical testing of biological soft tissues is highly sensitive to experimental conditions, and variations in hydration, temperature, and regional architecture (e.g., papillae orientation and layer composition) can influence the measured properties.
Figure 2: Viscoelastic properties of sheep stomach tissue: 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 stomach tissue—defined by elasticity, viscoelasticity, and structural anisotropy—are fundamental to understanding its physiological roles in food storage, mixing, and controlled emptying. The present study demonstrates that non-destructive viscoelastic testing with the ElastoSens™ Bio enables reliable quantification of stomach wall 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 gastroenterology studies.
Beyond these findings, the ElastoSens™ Bio offers unique advantages for stomach and gastrointestinal tissue research:
- Simple preparation and setup minimize handling and preserve tissue hydration and structural integrity.
- High sensitivity and repeatability allow consistent measurements across different gastric regions (fundus, body, antrum), capturing intra-organ variability.
- Cross-species benchmarking facilitates translational research by directly comparing stomach mechanics in animal models and humans.
- Platform versatility supports testing of diverse soft tissues and biomaterials under identical conditions, useful for developing gastric implants, scaffolds, or adhesives.
- Engineered tissue applications benefit from non-destructive, repeated measurements that reflect the dynamic evolution of bioengineered gastric constructs.
- Controlled incubation and repeated testing make it possible to monitor changes in viscoelastic properties over time, whether due to digestion-related processes, pharmacological treatment, or disease progression.
Taken together, these capabilities position the ElastoSens™ Bio as a powerful tool for advancing our understanding of stomach biomechanics, supporting comparative physiology, and guiding the design of biomaterials and therapies intended to restore or modulate gastric function.
References
Friis, S. J., Hansen, T. S., Poulsen, M., Gregersen, H., Brüel, A., & Nygaard, J. V. (2023). Biomechanical properties of the stomach: A comprehensive comparative analysis of human and porcine gastric tissue. Journal of the Mechanical Behavior of Biomedical Materials, 138, 105614.
Lim, Y. J., Deo, D., Singh, T. P., Jones, D. B., & De, S. (2009). In situ measurement and modeling of biomechanical response of human cadaveric soft tissues for physics-based surgical simulation. Surgical endoscopy, 23(6), 1298-1307.
Waite, S. J., Cater, J. E., Walker, C. G., Amirapu, S., Waghorn, G. C., & Suresh, V. (2016). Passive mechanical properties of ovine rumen tissue. International Journal for Computational Methods in Engineering Science and Mechanics, 17(3), 156–164.
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