Standard 25 mm
Pneumatic Vice Action Grip
Light grips holding a soft, wet substrate. Whatever holds the substrate must not crush it, and on tissue or a tissue analogue that window is narrow.
SpecificationsTesting standard
ASTM F2458
Standard Test Method for Wound Closure Strength of Tissue Adhesives and Sealants
Written and technically reviewed by Dak System Inc. engineeringLast reviewed
ASTM F2458 provides a means of comparing the wound closure strength of tissue adhesives used to hold soft tissue in apposition. With an appropriate substrate it can also serve as a quality-control test in the manufacture of medical devices used as tissue adhesives.
At a glance
- Test type
- Tensile — the specimen is pulled apart
- Published by
- ASTM
- Edition
- F2458-05(2024)
- Material
- Adhesives, tapes & bonded joints
- Runs on
- Series 7200 and Series 9000
What the test does
A substrate is selected and kept in the moisture condition that represents its use, then cut to create the wound to be closed. The adhesive or sealant is applied exactly as the product's instructions direct and allowed its specified cure time. The two halves are gripped without crushing the substrate and separated at a constant rate until the closure fails. The failure force is recorded along with the failure mode — adhesive, cohesive or substrate — and the substrate and its condition are reported alongside every value.
What it measures, and why it matters
How much force it takes to pull a glued wound open, as a comparison between products. Tissue adhesives are increasingly used as adjuncts to sutures and staples or as replacements for them, and while the forces a real wound sees vary enormously with the indication and with the patient, all such uses depend on the material resisting mechanical force — so the adhesive properties are central to judging fitness for use. The standard is explicit that it provides a means of comparison, and with an appropriate substrate a quality-control tool, rather than a clinical prediction.
Comparison, with the substrate as the variable
The method is written for comparing products. What it is compared on is chosen, and that choice governs the number.
- Purpose
- Comparison of wound closure strength between tissue adhesivesA comparative method, stated as such.
- Secondary use
- Quality control in manufacture, with an appropriate substrate
- Principle
- Two substrate halves joined across a cut by the adhesive, then pulled apart
- Substrate
- Chosen, and decisiveA tissue analogue and real tissue do not give the same answer, and neither does one tissue against another.
- Context
- Adjunct to sutures and staples, or a replacement for them
- Record the substrate, its source and its condition
- DakWithout it the number cannot be compared with anybody else's, including your own last batch.
The standard notes that the forces involved vary greatly with the indication and with patient-specific circumstances. It compares products under one defined condition; it does not predict clinical holding strength.
Test speed
- Rate
- A constant rate of grip separation as specified
- Reported
- The force at which the closure failed
- Failure mode
- Adhesive, cohesive or substrateA substrate tear means the adhesive outlasted the tissue — good news, and not a wound closure strength.
- Keep the substrate wet if that is its service condition
- DakMost tissue adhesives are used on moist tissue, and drying the substrate changes the bond fundamentally.
Calculations
Wound closure strength—
The force at which the joined substrate separates
Reported as a force, normalised by the bonded dimension where the specification requires it.
Why the substrate governs—
Adhesion depends on the surface it is made to
A tissue adhesive bonds by wetting and interacting with a specific surface chemistry. Change the substrate and you change the mechanism, not just the magnitude.
How the test runs
- 01Select the substrate and record its source, preparation and condition.
- 02Keep it in the moisture state that represents its use.
- 03Cut the substrate to create the wound to be closed.
- 04Apply the adhesive or sealant exactly as the product's instructions direct.
- 05Allow the specified cure or set time.
- 06Select a load cell suited to a bond failing at a few newtons.
- 07Verify the load cell class at that working load.
- 08Grip the two halves without crushing the substrate.
- 09Separate at the specified constant rate.
- 10Record the failure force and the failure mode.
- 11Report the substrate and its condition alongside every value.
Grips and fixtures for this method
Self-identifying
Load Cells
A cell matched to a bond that fails at a few newtons, verified at that load rather than at frame capacity.
SpecificationsWhat the report has to contain
- Reference to ASTM F2458 and the edition
- Adhesive or sealant identification and lot
- Substrate type, source, preparation and moisture condition
- Application method, quantity and cure time
- Conditioning and test temperature
- Load cell capacity and its verified class at the working load
- Rate of grip separation
- Failure force for each specimen
- Failure mode — adhesive, cohesive or substrate
- A statement that the result is comparative
What the machine must be capable of
Very small forces, measured traceably. Wound closure strengths are commonly a few newtons, and an accuracy class applies only down to a stated fraction of a load cell's capacity, so a frame's own cell is almost certainly working outside the range its certificate covers — the same constraint that governs catheter, closure and label testing. Grips must hold a soft and often wet substrate without crushing it, which is a narrow window, and a substrate that slips makes the bond look weaker than it is.
What goes wrong in practice
Reporting a value without the substrate, its source and its condition, which makes it incomparable with anyone else's result and with your own previous batch. Drying a substrate that is used wet. Averaging in substrate tears, which describe the tissue's tear resistance rather than the bond. Oversized load cells. And presenting a comparative figure as a clinical holding strength, which is exactly the reading the standard's own framing is written to prevent, since the forces a real wound sees vary enormously with the indication, the site and the patient.
ASTM F2458 or ASTM F2255 / F2256
| F2458 — wound closure | F2255 / F2256 | |
|---|---|---|
| Geometry | Tension across a closed cut | Lap shear and T-peel |
| Question | Does the wound stay shut? | How strong is the bond in shear or peel? |
| Substrate dependence | High | High |
| Together | Describe the adhesive's behaviour | Describe the adhesive's behaviour |
Three geometries for the same family of products, because a tissue adhesive is loaded in all of them. A wound gapes, slides and peels, and no single test covers the three.
Questions we are asked about this test
What is ASTM F2458?
It is the ASTM method for comparing the wound closure strength of tissue adhesives and sealants — the materials used to hold soft tissue in apposition, either alongside sutures and staples or in place of them. Two substrate halves are joined across a cut by the adhesive and then pulled apart. The current designation is ASTM F2458-05(2024).
Why does the substrate matter so much?
Because a tissue adhesive bonds by wetting and interacting with a particular surface, so changing the substrate changes the bonding mechanism rather than just the magnitude. A tissue analogue and real tissue give different answers, and one tissue gives a different answer from another. The substrate, its source, its preparation and its moisture condition therefore belong in the report — without them a result cannot be compared even with your own previous batch.
Is this a prediction of clinical performance?
No, and the standard is careful about it. It notes that the nature and magnitude of the forces involved vary greatly with the indication and with patient-specific circumstances. What the method provides is a comparison between products under one defined condition, and with an appropriate substrate a quality-control tool for manufacture. Presenting it as a clinical holding strength claims more than it supports.
What does a substrate tear mean?
That the adhesive was stronger than the tissue or analogue it was applied to. Commercially that is a good outcome, but it is not a wound closure strength — the number obtained describes the substrate's tear resistance. It should be recorded as a substrate failure rather than averaged in, and if the intention was to characterise the adhesive, a stronger substrate is needed.
Why keep the substrate wet?
Because most tissue adhesives are applied to moist tissue, and moisture is not incidental to how they work — several cure in response to it, and all of them have to displace or tolerate it to reach the surface. A dried substrate presents a different surface chemistry and a different wetting problem, so the bond formed on it is not the bond formed in use.
What load cell does this need?
A small one, verified at the working load. Wound closure strengths are commonly a few newtons, and an accuracy class applies only down to a stated fraction of capacity, so a frame's own cell is almost certainly outside the range its certificate describes. This is the same constraint that governs catheter, closure and label testing, and it is the commonest measurement error in low-force medical work.
How does it relate to the other tissue adhesive methods?
They cover the three ways a wound loads an adhesive. F2458 pulls the closure apart in tension, which is a wound gaping. ASTM F2255 measures lap shear, which is tissue sliding. ASTM F2256 measures T-peel, which is an edge lifting. A real wound does all three, so a product is characterised across the set rather than by any one of them.
Running ASTM F2458 on the Series 7200 and Series 9000
Dak verifies against whichever standard the method names, and where a class applies our frames sit a class tighter than it asks.
| The method asks for | Dak supplies | |
|---|---|---|
| Capacity | Very low — wound closure strengths are commonly a few newtons | Load cells from 1 kg to 60 ton on the Series 7200, and 0.5 to 100 kN on the Series 9000 |
| Force accuracy | Verified at the actual working load, which is very small | ISO 7500-1 Class 0.5, verified to ASTM E4, DIN 51221 and BS 1610 |
| Gripping | Grips holding two substrate halves that the adhesive has joined across a cut | Wedge, vice-action, pneumatic and hydraulic grips, built to the specimen |
| Environment | 23 ± 2 °C standard laboratory atmosphere | 3009 series chambers, −150 °C to +400 °C — temperature only |
This page describes the method as practised. The governing text is the current edition from the issuing body. Tell us what you are testing and we will answer with the machine, the fixture and a quotation.