ASTM F2256-05(2010)
(Test Method)Standard Test Method for Strength Properties of Tissue Adhesives in T-Peel by Tension Loading
Standard Test Method for Strength Properties of Tissue Adhesives in T-Peel by Tension Loading
SIGNIFICANCE AND USE
Materials and devices that function at least in part by adhering to living tissues are finding increasing use in surgical procedures either as adjuncts to sutures and staples, or as frank replacements for those devices in a wide variety of medical procedures. While the nature and magnitude of the forces involved varies greatly with indication and with patient specific circumstances, all uses involve to some extent the ability of the material to resist imposed mechanical forces. Therefore, the mechanical properties of the materials, and in particular the adhesive properties, are important parameters in evaluating their fitness for use. In addition, the mechanical properties of a given adhesive composition can provide a useful means of determining product consistency for quality control, or as a means for determining the effects of various surface treatments on the substrate prior to use of the device.
The complexity and variety of individual applications for tissue adhesive devices, even within a single indicated use (surgical procedure) is such that the results of a T-Peel test are not suitable for determining allowable design stresses without thorough analysis and understanding of the application and adhesive behaviors.
This test method may be used for comparing adhesives or bonding processes for susceptibility to fatigue and environmental changes, but such comparisons must be made with great caution since different adhesives may respond differently to varying conditions.
SCOPE
1.1 This test method is intended to provide a means for comparison of the adhesive strengths of tissue adhesives intended for use as surgical adhesives or sealants, or both, on soft tissue. With the appropriate choice of substrate, it may also be used for purposes of quality control in the manufacture of tissue adhesive based medical devices.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:F2256 −05(Reapproved 2010)
Standard Test Method for
Strength Properties of Tissue Adhesives in T-Peel by
Tension Loading
This standard is issued under the fixed designation F2256; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.2 tissue adhesive—for the purposes of this test method,
tissue adhesive is defined as a compound or system intended
1.1 This test method is intended to provide a means for
for use in closing wounds (surgical or traumatic) or for sealing
comparison of the adhesive strengths of tissue adhesives
against leakage of body fluids.
intended for use as surgical adhesives or sealants, or both, on
3.2.3 tissue sealant—a surface coating with adequate adhe-
softtissue.Withtheappropriatechoiceofsubstrate,itmayalso
sive strength to prevent leakage of body fluids.
be used for purposes of quality control in the manufacture of
tissue adhesive based medical devices.
3.2.4 T-peel strength—the average load per unit width of
bond line required to produce progressive separation of two
1.2 The values stated in SI units are to be regarded as
bonded flexible adherends, under conditions designated in this
standard. No other units of measurement are included in this
method.
standard.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 Materials and devices that function at least in part by
responsibility of the user of this standard to establish appro-
adhering to living tissues are finding increasing use in surgical
priate safety and health practices and determine the applica-
procedureseitherasadjunctstosuturesandstaples,orasfrank
bility of regulatory limitations prior to use.
replacements for those devices in a wide variety of medical
procedures. While the nature and magnitude of the forces
2. Referenced Documents
involvedvariesgreatlywithindicationandwithpatientspecific
2.1 ASTM Standards:
circumstances,allusesinvolvetosomeextenttheabilityofthe
D907Terminology of Adhesives
material to resist imposed mechanical forces. Therefore, the
E4Practices for Force Verification of Testing Machines
mechanical properties of the materials, and in particular the
2.2 American Association of Tissue Banks Standards:
adhesive properties, are important parameters in evaluating
Standards for Tissue Banking
their fitness for use. In addition, the mechanical properties of a
given adhesive composition can provide a useful means of
3. Terminology
determining product consistency for quality control, or as a
3.1 Definitions—Many terms in this test method are defined
meansfordeterminingtheeffectsofvarioussurfacetreatments
in Terminology D907.
on the substrate prior to use of the device.
3.2 Definitions:
4.2 The complexity and variety of individual applications
3.2.1 flexible—as used in this test method, indicates that the
for tissue adhesive devices, even within a single indicated use
adherends shall have such dimensions and physical properties
(surgical procedure) is such that the results of a T-Peel test are
astopermitbendingthemthroughanyangleupto90°without
not suitable for determining allowable design stresses without
breaking or cracking.
thorough analysis and understanding of the application and
adhesive behaviors.
ThistestmethodisunderthejurisdictionofASTMCommitteeF04onMedical
andSurgicalMaterialsandDevicesandisthedirectresponsibilityofSubcommittee 4.3 This test method may be used for comparing adhesives
F04.15 on Material Test Methods.
or bonding processes for susceptibility to fatigue and environ-
Current edition approved June 1, 2010. Published September 2010. Originally
mentalchanges,butsuchcomparisonsmustbemadewithgreat
approved in 2003. Last previous edition approved in 2005 as F2256–05. DOI:
caution since different adhesives may respond differently to
10.1520/F2256-05R10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
varying conditions.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on 5. Apparatus
the ASTM website.
3 5.1 Testing Machine, of the constant-rate-of-crosshead-
Available from the American Association of Tissue Banks (AATB), 1350
Beverly Rd., Suite 220-A, McLean, VA 22101. movement type and comprising essentially the following:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2256−05 (2010)
5.1.1 Fixed Member, a fixed or essentially stationary mem- that relatively large samples of tissue can be harvested from a
ber carrying one grip. single source. Ideally, the tissue should be used within 24 h of
5.1.2 Movable Member, a movable member carrying a harvest,andshouldbekeptbetween5and10°Cpriortotesting
second grip. if it cannot be used immediately after harvesting. Storage and
5.1.3 Grips,forholdingthetestspecimenbetweenthefixed handling of tissue samples should be carried out according to
member and the movable member of the testing machine can the guidelines set forth in Standards forTissue Banking by the
be either the fixed or self-aligning type. AmericanAssociation of Tissue Banks. The specimens should
5.1.3.1 Fixed Grips are rigidly attached to the fixed and be brought to the test temperature or other prescribed tempera-
movable members of the testing machine. When this type of ture (such as body temperature) prior to application of the
gripisusedextremecareshouldbetakentoensurethatthetest adhesive.
specimen is inserted and clamped so that the long axis of the 6.2.2 Fixed tissue should not be used since it has been
test specimen coincides with the direction of pull through the demonstrated that fixatives cause large alterations in the
centerline of the grip assembly. mechanical properties of the tissue and it is probable that the
5.1.3.2 Self-Aligning Grips are attached to the fixed and adhesive strength would be affected as well.
movablemembersofthetestingmachineinsuchamannerthat 6.2.3 Ifthetargetorganisofasizeorgeometry,orboth,that
they will move freely into alignment as soon as any load is does not allow fabrication of test samples as shown in Fig. 1,
applied so that the long axis of the test specimen will coincide a tissue of similar origin but larger size should be used. For
with the direction of the applied pull through the center line of example, if the intended indication is for anastomosis of small
the grip assembly. The specimens should be aligned as per- blood vessels, a larger vessel should be substituted (see 6.2).
fectly as possible with the direction of pull so that no rotary 6.2.4 The thickness of the tissue sample should be mini-
motion that may induce slippage or damage to the sample will mized and should not exceed 5 mm.Thicker samples will lead
occur in the grips; there is a limit to the amount of misalign- to distortion of the substrate and mixed loading (shear and
ment self-aligning grips will accommodate. tension).Itisalsoimportantthatthethicknessbeasuniformas
5.1.4 Drive Mechanism,forimpartingtothemovablemem- possible.
berauniform,controlledvelocitywithrespecttothestationary
6.3 Substrates for Quality Control Testing:
member, with this velocity to be regulated as specified in 9.3.
6.3.1 For testing that is undertaken as part of a quality
5.1.5 Load Indicator, a suitable load-indicating mechanism
control process in the manufacturing of a tissue adhesive
capable of showing the total tensile load carried by the test
device, the use of freshly harvested tissue is highly inconve-
specimen when held by the grips. This mechanism shall be
nient and may also lead to unacceptable variation in the test
essentially free of inertia lag at the specified rate of testing and
results, especially if the failure occurs in the adherend (sub-
shall indicate the load with an accuracy of 61% of the
strate failure). Since the purpose of quality control testing is to
indicated value, or better. The accuracy of the testing machine
demonstrate consistency in the device, substitution of a model
shall be verified in accordance with Practices E4.
substrate is preferred so long as it is demonstrated that the
5.2 Temperature-controlling Equipment, capable of main- adhesive does bond to the adherand. Due to the nature of the
taining the test temperature to 62°C. If ambient laboratory
conditionsareemployedthesamedegreeofcontrolisrequired.
Awaterbathorenvironmentalchambercapableofmaintaining
37°C is required for testing on tissue substrates.
6. Test Substrate
6.1 For comparative testing, either fresh or frozen split
thickness porcine skin graft may be used.
6.1.1 Frozen split thickness porcine skin that has been
aseptically prepared is available commercially and is preferred
due to ease of use and the potential for more consistent
properties.Itshouldbethawedaccordingtothemanufacturer’s
instructions prior to use. Unused graft may be kept at 2 to 8°C
for up to two weeks after thawing.
6.1.2 Iffreshskinischosen,itshouldbepreparedaccording
the method in Appendix X1.
6.2 Application Specific Testing—Due to the size of the
T-Peeltestspecimens,manytissueswillnotbesuitableforthis
test.
6.2.1 The strength of any adhesive is highly dependent on
the test substrate, or adherend. For a specific application, the
preferred substrate is freshly harvested tissue from the target
organ of a domestic food animal. Tissue from bovine, porcine,
orovineoriginispreferredduetowideavailabilityandthefact FIG. 1T-Peel Sample Configuration (Side View)
F2256−05 (2010)
T-Peel test, the substrate must be flexible and should have 8.4 Re-cover the tissue with gauze soaked in PBS, replace
sufficient stiffness to minimize substrate distortion during the the sample in a plastic bag, and return it to the constant
test. temperature environment.
6.3.2 For devices that require contact with tissues to cure,
9. Test Procedure
Mediskin XenoGraft should be used for quality control testing
as well as comparative testing.
9.1 Conditionthetestspecimensfordefiniteperiodsoftime
under specified, controlled conditions before testing if desired.
7. Test Specimen
Forcomparativetesting,theconditioningtimeshouldbe1h 6
15 min. Recommended conditions for tissue adhesives in-
7.1 The T-Peel test specimen is shown in Fig. 1.Two
tended for internal applications are 37 6 1°C in phosphate
substrate samples are required for each test.
bufferedsaline.Foradhesivesintendedforexternal
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