Tension

Summary

Specimens are typically clamped and pulled at a defined displacement rate while force/displacement data is captured. Force-controlled testing and cyclic testing are also common.

Unique to Biomaterials

Specimens must be fixed to the tester without causing damage at the attachment site. Biomaterials are often soft, slippery, or have irregular shapes and require specialized fixtures to achieve optimal results.
Most biomaterials testing applications require image-based measurement techniques to directly measure specimen geometries and strain values.

Common Applications:

• Muscle, skin, and tendon tissues
• Blood vessels
• Plant structures

Compression Testing

Summary

Parallel plate compression involves crushing a specimen that typically has flat, parallel upper and lower surfaces and a constant cross section. Variations include indentation (spherical or other geometries), puncture, and burst testing.

Unique to Biomaterials

Time-correlated images are helpful to understand test results, especially if the specimen geometries are irregular or material properties are non-homogeneous.  

Very small fixtures and low-force sensors are commonly used with the UniVert to test small delicate materials. The MicroTester is optimized for for even smaller specimens and can achieve force resolutions of 10nN.

Common Applications

• Hydrogels
• Bone
• Cartilage

Bending

Summary

Specimens are typically long and thin and are supported at each end by fixed supports. Load is applied at 1 or 2 points between the fixed supports for 3 or 4 point testing. This is often a test to failure.

Unique to Biomaterials

The irregular shapes and variability in biological structures require appropriate fixtures, protocols, and expertise to ensure reliable data. Time-correlated images are helpful to understand test results, especially if the specimen geometries are irregular or material properties are non-homogeneous.  

For very delicate specimens such as plant fibers or small tissues, the MicroTester highly suitable and can achieve force resolutions of 10nN.

Common Applications

• Rodent long bones
• Orthopaedic devices
• Plant structures

Shear & Peel

Summary

Peel testing is used to characterize the strength of the adhesion of one material to another. Shear testing to characterize a material’s response to shear loads or the adhesion strength of one material to another with a shear load.

Unique to Biomaterials

Biomaterials are often soft, slippery, or have irregular shapes and hence require specialized fixtures to achieve optimal results.

Adhesion is often affected by temperature and humidity. The UniVert can be efficiently equipped with the necessary environmental control accessories. 

Common Applications

• Tapes, glues, and sealants
• Rubbers, gels, and other soft 3-dimensional materials

Fatigue / High Rate

Summary

Fatigue testing involves loading a specimen over many cycles to determine the impact on its mechanical response. Testing modalities include tension, compression, bending, and inflation, among others. High-rate testing involves loading the specimen at velocity to determine how the response of the material varies with strain rate. 

Both fatigue and high strain rate testing benefit from an actuator capable of high accelerations and velocities. The UniVert system can be fitted with an auxiliary actuator to efficiently meet these requirements.

Unique to Biomaterials

This type of testing is necessary musculoskeletal and cardiovascular tissues that would normally be subjected to cyclic loading in vivo. For basic research, the test setup can be easily configured to replicate in vivo conditions. For some orthopaedic materials and applications, established test standards exist.

Common Applications

• Musculoskeletal tissues and synthetic alternatives
• Cardiovascular tissues such as arteries and heart valves

Pressure

Summary

Pressure testing involves controlled inflation of tubular samples, such as arteries, lumens, or other biomaterials. It features a pressure regulator and piston system that allows researchers to inflate samples up to 100 kPa, while recording pressure readings in real time. This setup provides a reliable method for assessing the mechanical response of soft tissues and biomaterials under pressurized conditions.

Unique to Biomaterials

This testing function is particularly useful for studying vascular biomechanics, helping researchers evaluate the strength, compliance, and failure properties of arteries and other tubular structures.

Common Applications

• Inflation of arteries for assessment of cardiovascular implant development
• Disease modeling and tissue engineering

Torsion

Summary

Specimens are typically supported at each end by platens (with compressive load), grips, or jaws similar to a drill chuck. Any protocol specified in terms of axial displacement, axial force, torque, or rotation can be specified.

Unique to Biomaterials

This type of testing is often used to evaluate bones, joints, or similar synthetic materials. The UniVert system can be easily configured to match protocols used in previous research.

Common Applications

• Rodent long bones and/or joints
• Arteries
• Composite materials

Combined Loading

Summary

The UniVert is always equipped with uniaxial linear testing capabilities. In addition, it can support up to 2 additional loading mechanisms. All of these subsystems can be used simultaneously in a single test protocol. Common configurations include:

• torsion-tension (e.g. arteries)
• torsion-compression (e.g. joints)
• tension-pressure (e.g. arteries)
• compression-shear (e.g. muscle)

Less than 0.1N Force Range

Summary

The UniVert systems can be used for testing between 0.1N and 10kN. For testing below 0.1N, the use of the MicroTester system is recommended.

0.1 – 1 N

Summary

The CellScale Eclipse low-force sensors are now available to work with the Univert system! These patent-pending sensors provide unparalleled force sensitivity and overload protection. They are compatible with custom fixtures for tension, compression, indentation, and other test types.

1 – 10 N

Summary

In this force range, the UniVert is typically equipped with a miniature S-beam load cell and plastic fixtures to minimize the offset force. These sensors and fixtures are available for the UniVert S, 1kN, and 10kN models.

Common Applications

• Small animal tissues
• Hydrogels
• Rubbers and other compliant materials

10 – 100 N

Summary

In this force range, the UniVert is typically equipped with a miniature S-beam load cell and plastic fixtures to minimize the offset force. These sensors and fixtures are available for the UniVert S, 1kN, and 10kN models.

Common Applications

• Small animal tissues
• Hydrogels
• Rubbers and other compliant materials

100 – 1000 N

Summary

In this force range, the UniVert is typically equipped with an S-beam load cell and stainless steel fixtures to suitably support the test specimens. These sensors and fixtures can be fitted to the UniVert S (max 200N), 1kN, and 10kN models.

Common Applications

• Small specimens of all types
• Educational labs (particularly UniVert S model)

1000 – 10,000 N

Summary

In this force range, the UniVert is typically equipped with an S-beam load cell and stainless steel fixtures to suitably support the test specimens. These sensors and fixtures can be fitted to the UniVert 10kN models.

Common Applications

• Specimens of all types
• Departmental facilities

Strain Control

Summary

For any given test, the specimen may not deform as expected due to grip slipping, non-uniform material properties, or misalignment. When equipped with an upgraded imaging system, the UniVert software can measure the specimen strain is real-time by tracking features on the specimen surface. This information is used to modulate the cross head motion to achieve the strain profile prescribed in the test method. This ensures that the results of multiple tests can be easily compared and that combined loading protocols are well synchronized. 

Unique to Biomaterials

Biomaterials are often more complex than other engineered materials. Using non-contact strain measurement to achieve true strain control is a powerful tool for materials characterization.

Liquid Baths

Summary

Temperature-controlled fluid liquid baths are used to maintain consistent hydration and temperature conditions when working with certain materials

Unique to Biomaterials

This type of testing is often used in musculoskeletal and cardiovascular tissues that would typically be subjected to cyclic loading in vivo. For basic research, UniVert systems can be easily customized to replicate in vivo conditions. For some orthopaedic materials and applications, established test standards exist

Common Applications

• Musculoskeletal tissues and synthetic alternatives
• Cardiovascular tissues such as arteries and heart valves

Custom Solutions

Summary

Due to the wide variety of applications within the biomaterials space, the UniVert has been carefully designed with a broad range of configurations. Even so, there is often a need for custom fixtures, controls, environmental accommodations, or other functionality. CellScale has a long history of successfully and efficiently collaborating with our customers to achieve successful research outcomes. 

If you have a specialized application, we would be glad to support your research with a custom solution.