1、Designation: F 2258 05Standard Test Method forStrength Properties of Tissue Adhesives in Tension1This standard is issued under the fixed designation F 2258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is intended to provide a means forcomparison of the adhesive strengths of tissue adhesivesintended for use as surg
3、ical adhesives or sealants, or both, onsoft tissue. With the appropriate choice of substrate, it may alsobe used for purposes of quality control in the manufacture oftissue adhesive based medical devices.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not p
4、urport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2
5、D 907 Terminology of AdhesivesE4 Practices for Force Verification of Testing Machines2.2 American Association of Tissue Banks Standards:3Standards for Tissue Banking3. Terminology3.1 DefinitionsMany terms in this test method are definedin Terminology D 907.3.2 Definitions:3.2.1 tissue adhesivefor th
6、e purposes of this test method,tissue adhesive is defined as a compound or system intendedfor use in closing wounds (surgical or traumatic) or for sealingagainst leakage of body fluids.3.2.2 tissue sealanta surface coating with adequate adhe-sive strength to prevent leakage of body fluids.4. Signifi
7、cance and Use4.1 The utility, range, and efficacy of adhesives in clinicalmedicine are well documented in the literature. Whether beingused as an adhesive, hemostatic, sealant, or carrier for drugs orgrowth factors, or both, the scope of adhesive use in clinicalmedicine continues to expand. There ar
8、e several factors whichare vital to the success and efficacy of a medical tissue adhesiveincluding, (1) adequate tissue bonding strength, (2) tissuecompatibility, (3) acceptable biodegradable properties whenthe adhesive is used internally, (4) availability, (5) ease ofapplication, and (6) cost.4.2 M
9、edical adhesives are currently used for a variety ofapplications and tissue types. Applications range from fixationof external tissues to internal application for use with eithersimilar or dissimilar opposing surfaces. While the biological orchemical makeup, or both, of the adhesive may define itsch
10、aracteristics, additional mechanical factors including adhe-sive volume or method of application, or both, may alsocontribute significantly toward the performance of the adhe-sive. In an effort to fairly and adequately quantify adhesivebonding strength for medical adhesives, it is important todevelo
11、p a consistent, reproducible testing standard for evalua-tive and comparative purposes. Due to the fact that theadhesives will be used on or in living tissues, a readilyavailable biological testing surface is preferred.4.3 The data generated from a standardized testing methodon biologic tissue may v
12、ary from that found in vivo, however,testing results should offer valuable information on the poten-tial bonding capacity and for the preparation of subsequent invivo experiments.4.4 The complexity and variety of individual applicationsfor tissue adhesive devices, even within a single indicated use(
13、surgical procedure), is such that the results of a tensile test arenot suitable for determining allowable design stresses withoutthorough analysis and understanding of the application andadhesive behaviors.1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Mater
14、ials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Mar. 1, 2005. Published March 2005. Originallyapproved in 2003. Last previous edition approved in 2003 as F 2258 03.2For referenced ASTM standards, visit the ASTM website, www.as
15、tm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the American Association of Tissue Banks (AATB), 1350Beverly Rd., Suite 220-A, McLean, VA 22101.1Copyright
16、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.5 This test method may be used for comparing adhesivesor bonding processes for susceptibility to fatigue and environ-mental changes, but such comparisons must be made with greatcaution since dif
17、ferent adhesives may respond differently tovarying conditions.5. Apparatus5.1 Testing Machine, of the constant-rate-of-crosshead-movement type and comprising essentially the following:5.1.1 Fixed Member, a fixed or essentially stationary mem-ber carrying one grip.5.1.2 Movable Member, a movable memb
18、er carrying asecond grip.5.1.3 Grips, for holding the test specimen between the fixedmember and the movable member of the testing machine canbe either the fixed or self-aligning type.5.1.3.1 Fixed Grips are rigidly attached to the fixed andmovable members of the testing machine. When this type ofgri
19、p is used, extreme care should be taken to ensure that the testspecimen is inserted and clamped so that the long axis of thetest specimen coincides with the direction of pull through thecenterline of the grip assembly.5.1.3.2 Self-aligning Grips are attached to the fixed andmovable members of the te
20、sting machine in such a manner thatthey will move freely into alignment as soon as any load isapplied so that the long axis of the test specimen will coincidewith the direction of the applied pull through the center line ofthe grip assembly. The specimens should be aligned as per-fectly as possible
21、with the direction of pull so that no rotarymotion that may induce slippage or damage to the sample willoccur in the grips; there is a limit to the amount of misalign-ment self-aligning grips will accommodate.5.1.4 Drive Mechanism, for imparting to the movable mem-ber a uniform, controlled velocity
22、with respect to the stationarymember, with this velocity to be regulated as specified in 9.3.5.1.5 Load Indicator, a suitable load-indicating mechanismcapable of showing the total tensile load carried by the testspecimen when held by the grips. This mechanism shall beessentially free of inertia lag
23、at the specified rate of testing andshall indicate the load with an accuracy of 61 % of theindicated value, or better. The accuracy of the testing machineshall be verified in accordance with Practices E4.5.2 Temperature-controlling Equipment, capable of main-taining the test temperature to 62C. If a
24、mbient laboratoryconditions are employed, the same degree of control is re-quired. A water bath or environmental chamber capable ofmaintaining 37C is required for testing on tissue substrates.6. Test Substrate6.1 For comparative testing, either fresh or frozen splitthickness porcine skin graft may b
25、e used.6.1.1 Frozen split thickness porcine skin that has beenaseptically prepared is available commercially and is preferreddue to ease of use and the potential for more consistentproperties. It should be thawed according to the manufacturersinstructions prior to use. Unused graft may be kept at 2
26、to 8Cfor up to two weeks after thawing.6.1.2 If fresh skin is chosen, it should be prepared accordingthe method in Appendix X1.6.2 Application Specific Testing:6.2.1 The strength of any adhesive is highly dependent onthe test substrate, or adherend. For a specific application, thepreferred substrate
27、 is freshly harvested tissue from the targetorgan of a domestic food animal. Tissue from bovine, porcine,or ovine origin is preferred due to wide availability and the factthat relatively large samples of tissue can be harvested from asingle source. Ideally, the tissue should be used within 24 h ofha
28、rvest, and should be kept between 5 and 10C prior to testingif it cannot be used immediately after harvesting. Storage andhandling of tissue samples should be carried out according tothe guidelines set forth in Standards for Tissue Banking by theAmerican Association of Tissue Banks. The specimens sh
29、ouldbe brought to the test temperature or other prescribed tempera-ture (such as body temperature) prior to application of theadhesive.6.2.2 Fixed tissue should not be used since it has beendemonstrated that fixatives cause large alterations in themechanical properties of the tissue and it is probab
30、le that theadhesive strength would be affected as well.6.2.3 If the target organ is of a size or geometry, or both, thatdoes not allow fabrication of test samples as shown in Fig. 1,a tissue of similar origin but larger size should be used. Forexample, if the intended indication is for anastomosis o
31、f smallblood vessels, a larger vessel should be substituted.6.2.4 The thickness of the tissue sample should be mini-mized and should not exceed 5 mm. Thicker samples will leadto distortion of the substrate and mixed loading (shear andtension). It is also important that the thickness be as uniform as
32、possible.6.3 Substrates for Quality Control Testing:6.3.1 For testing that is undertaken as part of a qualitycontrol process in the manufacturing of a tissue adhesivedevice, the use of freshly harvested tissue is highly inconve-nient and may also lead to unacceptable variation in the testresults, es
33、pecially if the failure occurs in the adherend (sub-strate failure). Since the purpose of quality control testing is todemonstrate consistency in the device, substitution of a modelsubstrate is preferred so long as it is demonstrated that theadhesive does bond to the adherand. For devices that requi
34、reFIG. 1 Test FixturesF2258052contact with tissues to cure, Mediskin XenoGraft should beused for quality control testing as well as comparative testing.7. Test Specimen7.1 Specimens with Soft-tissue Substrates shall conform tothe form shown in Fig. 1. The only critical dimension is thebonding surfac
35、e, which shall be 2.5 6 0.005 cm2. The tissuecan be bonded to the specimen holder with any suitableadhesive. Gel-type cyanoacrylate adhesives have been found tobe convenient for this purpose since they adhere well to moisttissues and cure quickly. In cases where the test adhesive isbased on cyanoacr
36、ylates, this test method may not work withall tissue types since the tissue may pull off of the fixtureinstead of failing at the test adhesive interface. In this case,alternative means of securing the tissue to the test fixture mayneed to be employed or an alternative test configuration such asT-Pee
37、l or Lap-Shear can be chosen.7.2 Specimens with Polymer or Metal Substrates shallconform to the form and dimensions shown in Fig. 1.7.3 Number of Test SpecimensTest at least 10 specimensof each type. Discard results if failure occurs between the testfixture and the tissue sample and test additional
38、samples toobtain a total of 10 valid tests. Tissue substrates tend to givehigher variances and may require more samples to attain areasonable estimate of the mean strength.8. Sample Preparation8.1 Tissue Preparation:8.1.1 Tissue substrate materials should be kept moist at alltimes with phosphate buf
39、fered saline (PBS).8.1.2 The substrate will be placed face down on gauzesoaked in PBS, and the back side will be patted dry with freshgauze.8.1.3 The back-side of the tissue sample will be glued to thetest fixture using a suitable adhesive. When Mediskin Xe-nograft is used, the epidermal surface wil
40、l be glued to thefixture, leaving the dermal surface for test adhesive bonding.Gel-type cyanoacrylate adhesives have been found to be usefulfor this purpose since they set quickly and adhere to mostmaterials.8.1.4 After the adhesive has cured (approximately 10 minfor cyanoacrylate adhesives), place
41、the fixtures on a cuttingboard and trim the excess tissue away from the fixture using asharp scalpel. The scalpel must be held perpendicular to theboard to ensure that the tissue sample has the same dimensionsas the fixture.8.1.5 Wrap the tissue with gauze soaked in PBS, place thefixtures in a plast
42、ic bag, and place them in a water bath orenvironmental chamber at 37C.8.2 Preparation of the Adhesive Bond:8.2.1 Prepare the test adhesive according to the manufac-turers directions or by other prescribed procedure.8.2.2 Remove the test fixtures from the plastic bag and patthe surface of the tissue
43、dry with fresh gauze.8.2.3 Apply sufficient adhesive to uniformly coat the over-lap area without significant overflow. Excess adhesive couldrun over the edge of the substrate, causing artificially high testvalues. The amount required will have to be determinedexperimentally. For adhesives that are d
44、elivered with a spraydevice, controlling the amount and distribution of the materialwill be difficult. It may be necessary to use a template toprevent overspray. Alternatively, petroleum jelly may appliedto the portion of the tissue outside of the overlap area toprevent bonding.8.2.4 Bond the two si
45、des of the test fixture together, takingcare to keep the fixtures aligned and to maintain the prescribedoverlap.8.2.5 Apply a force of approximately 1 to2Ntothebondarea until the adhesive sets. For slow-curing adhesives, it maybe necessary to use a clamping device that can be left in placewhile the
46、fixture is returned to the environmental chamber orwater bath.8.3 Measure and record the width and length of the adhesivebond to within 0.05 cm.8.4 Re-cover the tissue with gauze soaked in PBS, replacethe sample in a plastic bag, and return it to the constanttemperature environment.9. Test Procedure
47、9.1 Condition the test specimens for definite periods of timeunder specified, controlled conditions before testing if desired.For comparative testing, the conditioning time should be 1 h 615 min. Recommended conditions for tissue adhesives in-tended for internal applications are 37 6 1C in phosphate
48、buffered saline. For adhesives intended for external topical use,recommended conditions are 30 6 1C and 50 6 5 % relativehumidity. For quality control testing with metal or polymersubstrates, the recommended conditions are 23 6 1C and 506 5 % relative humidity.9.2 After conditioning, it is recommend
49、ed that all speci-mens be stabilized at the test temperature for 15 min beforetesting if the test temperature is different from the conditioningtemperature. Tissue samples must be kept moist throughout theprocess to prevent shrinkage due to drying. For comparativetesting, the test conditions should be 23 6 1C and 50 6 5%relative humidity (see Annex A1).9.3 Place the test specimens in the grips of the testingmachine so that the applied load coincides with the long axis ofthe specimen. Load the specimen to failure at a constantcross-head speed of 2 mm/min.9.4 Record the l
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