Solutions For Biomedical Testing
Solutions for Biomedical TestingSolutions for Biomedical Testing TM
ContentsSolutions for Biomedical TestingLonger life expectancy, an increasingly active populationand scientific advances are fueling a tremendous demandfor new and improved biomedical devices and materials. Astechnology evolves, researchers and manufacturers face theenduring task of delivering biomaterials and products thatcombine high quality with life-long performance.Biomedical testing allows the performance and compatibilityof new materials and medical devices to be proven in vitro,without putting patients at risk, and for the evaluation ofcritical and complex issues in a controlled and repeatablemanner. In addition to helping new products meet essentialregulations, such as Food and Drug Administration (FDA)compliance, biomedical testing allows the quality of medicalproducts to be verified in a production line, and thedevelopment of new and innovative solutions in thelaboratory.This brochure outlines some of the testing challenges facingdifferent sectors of the biomedical community and howthey are successfully addressed using Instron ’s BioPulssolutions. As you read further, you’ll get a sense of howInstron can help you with your research and bring your ownproducts to market and improve the quality of life for thepeople who use them.TM2KPa neege Tes 2 st6 ing-27HPa ip Tge ess 2 tin3 g-25BPa iomge ates 2 ri0 als-21BPa iologe gics 1 al6 Ti- 1 ss9 ueMPa edige cas6 lD- 1 evi5 cessContents
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BioPulsToday, Instron ’s unmatched knowledge and experience are reflected in our BioPuls range of application-centric solutionsfor the biomedical testing industry. These unique testing innovations advance the understanding of material properties andperformance across a vast spectrum of biomaterials and medical products.TMInstron has engineered the BioPuls range to be the most advanced solution for biomedical testing challenges. With demands asdiverse as low force testing on native tissues to complex multi-axial simulation of spinal segments, we have ensured that ourproducts best fit the needs of individual customers and provide many years of superior performance. With no compromises onquality or performance, the BioPuls designs of equipment and accessories reflect Instron’s leading product design philosophy,where data integrity, safety and protection of investment are paramount. Whether you are engaged in cutting-edge research orcritical quality assurance on the production floor, there is a BioPuls testing solution available from Instron.Testing LeadershipSince 1946, Instron has been the leading provider of testing equipment for every kind of material and structure.For decades, our experience and global perspective has enabled us to be at the forefront of biomedical testing.Global Support and ServiceToday, Instron has offices in 17 countries and a staff of more than 1200 dedicated professionals who speak more than 20languages. Instron offers an extensive range of calibration and verification services and is supported by a vast network offield service engineers.4
BioPulsApplication ExcellenceThe Instron global team of biomedical applications specialists and professional engineers delivers an array of BioPuls turnkey solutions for biomaterials, orthopaedics, biomechanics, medical devices and dental testing. Our dedicated BiomedicalApplications Team continues to advance their application knowledge and experience through strong customer relationships,active participation on standards committees and conference attendance. www.instron.com5
Medical DevicesMedical DevicesRegulatory agencies worldwide have set stringent performancestandards for nearly every category of medical device. Today,bringing a new medical device to market requires in-depthknowledge of all of its characteristics, from properties of theraw materials to long-term performance under complex serviceconditions. The testing required to meet the wide variety ofstandards spans nearly every type of mechanical test, includingtension, compression, impact, fatigue and hardness.For single-use products, testing is particularly importantduring material selection to maximize the trade-off betweenperformance and cost. For implantable devices, testingprotocols ensure that the materials and design will stand upto prolonged use in vivo.This section provides a glimpse into some of the applicationsolutions Instron has provided to its medical device customers.You will see how our engineers have addressed a variety ofapplications, including needles, syringes, tubing and packaging.Needle Insertion ForceThe ChallengeNeedle insertion force measurementis a critical parameter for needledevelopers, as well as in quality controlto ensure patient safety. In recentyears, researchers and manufacturershave invested significant resources indeveloping surgical simulation andpreoperative planning tools, whichrequire parameters such as needleinsertion force. Insertion force is alsoa key value in characterizing needlegeometry and sharpness, and inunderstanding the effects of velocity,viscosity and frictional force along theneedle axis during insertion intosoft tissues.6Our SolutionWith a wide variety of needles available,fixturing is unique to the objective andapplication of the tests and results.Test configurations, such as the BioPulsmultineedle test fixture, reduce testing timein needle production and quality controlprocesses. Instron also offers a robustsingle needle fixture that provides significantadvantages for research and development.TMGThe BioPuls curved needle tester is used toensure that the needle is sharp enough to puncturetissue and strong enough to retain its shape duringuse.GGThe BioPuls multineedle test fixture (upper)and rotational membrane holder (lower)increase the rate of testing on up to eightneedles at multiple penetration points.A single straight needle fixture (upper) andvariable angle membrane holder (lower) are oftenused in research and development processes forcharacterizing needle sharpness.
Medical DevicesPlunger Force for Needles and SyringesThe ChallengeNeedles and syringes must be tested toensure the forces necessary to move theplunger and eject fluid from the barrelare not too high or too low. These forcesdepend on many factors, including thedevice materials, viscosity of the liquid,radiation processes used for sterilization,and instrument design. When testingneedles, the host tissue (into whichthe fluid is injected) is another factorinfluencing device performance.Our SolutionFixturing specific to the nature and application of the test is usually required. The lower grip istypically designed to hold the barrel, and an upper unit is designed to either eject liquid from thebarrel in a compression test or inspire liquid into the barrel in a tensile test.Instron universal testing systems can be configured in either an upright or horizontal positionto utilize these fixturing options. In some cases, the horizontal configuration is advantageousbecause it allows accurate simulation of the instrument in its functional position. Thisconfiguration may also prevent any sediment in the liquid from clogging the barrel or needle tipduring the test.GGA horizontal 5544 universal testing system with fixturing is used to compare the effect of variousmedication viscosities on the breakout and sustaining forces required to eject liquid from the barrel.The fixture shown above is used to measurethe ejection forces of fluids from the barrel of asyringe. The fixture uses plastic inserts to holda variety of different syringe sizes and diameters.G55MT MicroTorsion system for torsion testing conical lock fittings with luer taper for syringes.GA 5544 universal testing system with standardcompression platens can be used to evaluatebreakout and sustaining forces required to movethe needle plunger.www.instron.com7
Medical DevicesSuturesThe ChallengeTypical tests include a ‘straight-pull’ test that evaluates the tensile strength and elongation of thesuture material itself, and a ‘knot-pull’ test that evaluates the tensile strength of specific knottingtechniques used during surgery. Tests can be conducted in a saline bath to evaluate the strengthof suture material under physiological conditions. The fluid environment and body temperaturecan change material properties, and such changes must be understood before the materials areused in surgery.The BioPuls pneumatically activated cord and yarn grips, as well as manual capstan grips, areideal for gripping suture material. Wrapping the material around the mandrel head of the clampeliminates high stress points that lead to premature failure.Typical test set ups use a universal testing system. For on-site and quality control testing, theInstron 3300 Series mechanical testing systems combine low cost and ease of use with the precisionrequired for low-force suture testing.GSutures are manufactured from avariety of resorbable and non-resorbablematerials, and may be a single filamentor braided with or without coating.Tensile strength and strain are criticalmeasures of performance during andafter surgical procedures. The strengthof different knotting techniques mustalso be evaluated. The test methodmust determine breaking strength andcorresponding percent elongation,accurately measure strain withoutdamaging the material, and adhere toFDA guidelines.Our SolutionA 3345 universal testing system, configured withpneumatic cord and yarn grips, is used to performa knot-pull test on suture material.GGThe challenge in measuring strain in a bath witha video extensometer is finding appropriate gaugelength marks. In this sutures application, smallround pieces of adhesive putty were successful inallowing us to track strain through break.GThe BioPuls Bath, Submersible Pneumatic Grips and SVE are a unique testing solution for evaluating thetensile properties of sutures under physiological conditions. A close up of the specimen with video markersis shown above.8
Medical DevicesMetallic Wire and TubingOur SolutionThe ChallengeThe primary objective for characterizing most metallic wires and tubes is determining tensilestrength and strain at break. For accurate strain measurement, a non-contacting videoextensometer is preferred and is the only feasible choice when wire samples will not supportthe weight of conventional clip-on style strain devices. The video extensometer also preventspremature failure of the wire associated with the knife-edges of clip-on extensometers.Metallic wires and tubing are usedin the manufacture of a wide varietyof medical devices, including stents,needles and guide wires. The engineersdeveloping the materials used for theseproducts or designing the product itself,need to know the strength, stiffnessand flexibility of these wires and tubes.For example, in the design of a stent,measuring strain at a particular stressis critical. Too little strain and thestent will not be sufficiently flexible; toomuch strain and it will not maintain itsfunctional shape.GA close-up of the stainless steel tubing specimenshown above. The gripped ends of the tubing arefilled with inserts to maintain the tubing geometryand prevent jaw breaks. The 25.4 mm (1 in) gaugelength is marked with 2 mm wide black tapewrapped around the diameter of the specimen.Pneumatic side action grips or screw grips with serrated faces are proven BioPuls solutions forgripping this material. When testing metallic tubing, inserts should be used to plug the specimenends before they are put into the grips. This is helpful in preventing the specimen from collapsing,allowing tensile failure to occur in the gauge area.GA 5569 universal testing system, 5 kN pneumaticside action grips with serrated faces and a videoextensometer are ideal for testing stainlesssteel tubing in tension with high precision strainmeasurement.GCord and yarn grips are a unique solution fortesting thin wire specimens in tension. The designof the grip prevents jaw breaks that commonly canoccur with side acting grips.GElectroPuls E1000 performs a high-frequencyfatigue test on 300 micron-diamater wire usinglightweight collet grips.www.instron.com9
Medical DevicesDrug Eluting StentsThe ChallengeDrug eluting stents (DES) are usedin procedures where major arterialblockage is present in coronary arteries.DES are metal stents coated with adrug that elutes over 30-90 days todramatically reduce restenosis thatcan occur with bare metal stents.One critical factor in the successfuldeployment/placement is to make surethe DES is expanded fully to the arterialwall. Under expansion can result ingaps between the stent and wall thatcould lead to blood clots or sub-acutethrombosis (SAT).Our SolutionRadial force specifications are critical tothe proper selection of DES for particularinterventional procedures. The Instron RX550 can provide highly accurate andrepeatable results for radial stiffness andstrength for DES. The proprietary segmentalcompression mechanism of the fixture meansthat external compliance issues, often foundin other radial force measurement techniques,will not be an issue. Also, with stent sizesshrinking to address neural blockages,lower-force load cells can be used to provideresults for these sensitive tests. Bluehill software provides a wide variety of automatedcalculations for standard results like peakloads, but also more complex measurementslike energy.GInstron 5544 RX550 System testing a DES.GSequence of a DES being deployed in a clogged artery.Embolic FiltersThe ChallengeEmbolic filters are used within a varietyof interventional procedures to capturedebris resulting from the deploymentof a medical device, like a stent. Thestent is used to open arterial pathsthat may be occluded by plaque. Uponplacement of the stent, dislodged plaque(or embolic material) can potentiallybe responsible for heart attacks, strokes,kidney failure or death. Firm placementof the embolic filter is a criticalrequirement for successful procedures.Our SolutionOne of the most critical parameters for proper utilization of the filter is the radial forces it impartson the arterial wall. This fit ensures that all material is captured before heading further downthe arterial pathways. The Instron RX550 system has the fidelity to measure the small radialexpansion forces of the embolic filter. The small frictional forces of the fixture means that yourdata will present clean results from the radial tests. Additionally, tensile tests can be performedto evaluate resistance to tearing properties during deployment. Bluehill software will generatestandard reports that can be submitted for regulatory submissions.GInstron 5542 RX550 System testing embolic filter at 37 C.10
Medical DevicesStent GraftsThe ChallengeStent grafts are used to treat a widevariety of peripheral arterial issues, aswell as abdominal and thoracic aorticpathologic conditions like abdominalaortic aneurysms (AAA). The success ofendovascular stent grafts for AAA’s hasprovided motivation to adapt similartechnology for descending thoracicaortic aneurysms (TAA’s). Survival ratesfor untreated and traditionally treated(through complex thoracic surgeries)aneurysms are typically quite poor.Advantages of the stent grafts includeshorter operative time, avoidance ofmajor thoracic or thoracoabdominalincisions, and significant reductions inmorbidity and mortality. For success,the stent graft must be accuratelyplaced and must not move, especially inupper descending thoracic aorta cases.Our SolutionTypical secure placement for stent grafts are a strong function of the proper selection and sizingsince the physiological movements of the aorta can be significant. Additionally, stent grafts havemuch larger diameters than coronary stents (30 mm versus 2-3 mm). The Instron RX650can accommodate stent grafts that are more than 40 mm in diameter and more than 200 mm inlength. Custom sizes can be provided for special specimen types and provide radial strength andstiffness over the entire graft or the securing graft ends. Although room temperature testing canprovide excellent comparative results, the system can be configured with a heating chamber toprovide body temperature results as well.GInstron 5544 RX650 System testing a stent graft.Bioabsorbable Drug-Coated Medical DevicesThe ChallengeBioabsorbable drug-coated devicesare used to deliver an acute dosage ofdrugs to specific treatment sites in amanner that prevents systemic drugdelivery. This enables clinicians totreat a lesion site with specific drugsthat may cause an adverse reaction ifdelivered systemically. Additionally, thebioabsorbable drug-coated device mayspeed healing due to more localizedhigh concentration of the drugs.Because the device typically dissolveswithin 12-18 months, restenosis andclotting could be greatly reduced. Thisdevice also eliminates the metal stentinterference problem for heart imagingpost procedure.Our SolutionThe Instron RX is used to ensure the radial strength of the bioabsorbable devices is great enoughto expand and properly seat against the treatment site. In that way, drugs are eluted throughthe tissue and not the bloodstream. Additionally, data can be generated to determine the lengthof time the device can maintain its radial strength since this is a critical device requirement. Aswith all tests on the Instron RX systems, Bluehill software generates standard reports that can besubmitted for regulatory submissions to simplify approval processes.GLoading of a Bioabsorbable stent into a RX550 fixture.www.instron.com11
Medical DevicesMedical GlovesThe ChallengeMedical gloves can be manufacturedfrom materials, such as latex, nitrileand vinyl; all of which must adhereto performance levels specifiedby the FDA, as well as internationalstandards (ASTM D6319-00ae3,ASTM D5250-00e4, EN 455-2,ISO 11193-1, ISO/AWI 11193-2).The aging effects of the materialmust be evaluated to ensure thatcross-contamination of the examinerand the patient does not occur.Testing should examine the strengthand elongation of the material atbreak to ensure that measured valuesfall within normal ranges of use. Themain testing difficulty usually involvesmeasuring strain, since traditionalstrain measurement devices riskdamaging the material andcausing unwanted failures at theattachment points.Medical PackagingThe ChallengeThe medical device industry is movingtoward prepackaged disposable devices,such as surgical instruments andsyringes. The tensile strength of theadhesives used for such packaging mustbe assessed according to ASTM F 88to ensure sterilization of instrumentsduring shipment and during storage atthe customer site.12Our SolutionBioPuls pneumatic grips are ideal forgripping delicate materials without tearingor causing slippage. The grips allow foradjustable gripping pressure and a choice offace dimensions and surfaces, such asrubber-coated, serrated, wave-profile or flatmetallic. Instron ’s long travel extensometerand video extensometers are well suited forproviding accurate measures of strain in thesetypically high-elongation materials. Whilethe long travel extensometer was designedspecifically for this type of application,providing a cost-effective easy to use solution,the video extensometer utilizes the mostadvanced technology for tracking markson the specimen that eliminate pre-maturefailure, which may result from contact points.GA 5544 universal testing system configured withside action screw grips and rubber-coated facescan be used for evaluating the tensile strength ofmedical gloves.Our SolutionTear, Peel, Friction (TPF) software modulecontains preconfigured methods forconducting three different peel tests: T-peel,90 peel and 180 peel. Using a high dataacquisition rate to ensure the peel profile isaccurately characterized, the strength of theadhesive bond is evaluated using the basiccalculation of maximum force on an absolutepeak, or using more advanced calculationssuch as the average of a specific number ofpeaks, troughs or combination of both. Usershave great flexibility in specifying wheremeasurement begins and ends, enabling thesoftware to calculate a broad range of results.GA 3342 universal testing system with 250 Ncapacity pneumatic side action grips and linecontact faces is used to grip disposable syringepackaging in a T-peel test. Such tests allowquality personnel to investigate the seal strength oftheir packaging methods and to ensure the sterilityof the devices after delivery.
Medical DevicesSurgical Tubing, Fittings and CathetersThe ChallengeSurgical tubing is used in a widerange of applications, such as drains,feeding tubes, irrigation and surgicalprocedures. The tubing comes inmany shapes and sizes with dozensof possible interconnections andfittings. The mechanical performanceof these items is critical, as failurecould seriously endanger patients.Testing requirements include failureof the material, failure at joints, andsimulation of physiological parameters.In more advanced cases, tortuosity testsmay be used to evaluate frictional forcesexperienced within catheters as they arefed through arterial vessels.Our SolutionIn all testing applications, whether evaluating the mechanical properties of the tubing itself- orassessing the strength of the connection between the tubing and the fittings, correct gripping ofthe tubing is essential to obtaining accurate measurements. BioPuls pneumatically activatedcord and yarn grips or manual capstan grips are designed to securely grip surgical tubing whileensuring that test specimens fall within the gauge area.For modulus and yield calculations, a non-contacting strain measurement device is necessary toaccurately measure elongation and prevent failures due to knife-edges or clip-on extensometers.Our video extensometer enables precise strain measurement without damaging the tubing.An Instron universal testing system is ideal for these testing requirements. For more advancedapplications, such as evaluating the frictional force of surgical tubing in tortuosity tests, ahorizontal test configuration may be necessary. Using the horizontal testing frame, tubingdevelopers and quality control specialists design their own test method for measuring variousfrictional, insertion and removal forces of all types of tubing. For both the upright and horizontaltest frames, an environmental bath can easily be added to the test space to ensure measurementsare taken under physiological conditions.GGA 5545 universal testing system configured withside action screw grips and serrated faces isused to compare the strength of a fitting with theultimate strength of the tubing material.Tensile strength, strain at break and elasticmodulus measurements are acquired for thin-walltubing specimens using a 3345 universal testingsystem, pneumatic side action grips and a longtravel extensometer.G55MT MicroTorsion system with micro grip chucks for multi-turn torsion testing of surgical tubing.www.instron.com13
Medical DevicesBreast ImplantsThe ChallengeBreast augmentation and reconstructionare common operations for womenwho have undergone a mastectomyor for cosmetic purposes. Implantsare manufactured with an outer shell,usually made of an elastomer (likesilicone) and filled with either siliconeor saline. The shape and size of theimplant designs vary to accommodatepatient preferences. The mechanicalcharacteristics of these devices must beevaluated, following standardsEN 12180 and ISO 14607, to ensurepatient safety over time.Our SolutionBreast implant testing is conducted to evaluate the performance of the design or material of aspecific implant, and also for comparison with others on the market. A compression-fatiguetest is used to evaluate the strength and life of the implant over time. With the implant mountedbetween compression platens, the testing system must allow for cyclic compression of the implantfor 2 million cycles at 200 cycles per minute. An Instron fatigue testing systems providesexcellent accuracy and waveform fidelity when performing such fatigue tests in either load orposition control. WaveMatrix software allows easy set up of these straightforward cyclic tests,with variable data collection rates to optimize data storage and ensure that important datafrom events, such as yield or failure, is collected. Fatigue testing systems can be run at higherfrequencies to reduce test time without compromising the integrity of the test.An impact resistance test is performed to ensure that the implant does not fail under suddenforce. This test involves dropping a specified mass vertically onto the implant. In order toaccurately control velocity and acceleration of the mass, as well as collect maximum impactload and deformation values, a Dynatup drop tower is highly recommended. The 9250HV withImpulse machine control and data acquisition system accurately delivers a repeatable impactto the specimen while collecting load, time and energy data.GAn 8872 fatigue testing system with compression platens evaluates the fatigue properties of a breastimplant.GThe Dynatup 9250HV drop tower isused to evaluate the strength of theimplant under impact.1 4
Medical DevicesBandagesThe ChallengeBandages are a commonly usedproduct whose materials and designsare characterized by their ability tocarry a tensile load - i.e., how muchforce they can withstand before failureoccurs in tension. Measurementof mechanical properties allowsevaluation of bandage performancewhile providing insight formanufacturing processes andquality control.Our SolutionA standard tensile test is used to evaluate tensile strength and elongation at break, two importantparameters in product development and quality control. However, special consideration must begiven to testing these materials without causing unwanted failures. BioPuls elastomeric gripsand pneumatic grips are suitable for testing multi-stranded woven materials used in bandageswithout causing premature failure at the jaw faces.GElastomeric grips are used to evaluate the strengthof bandages in tension.Disability Aids: Hip ProtectorOur SolutionThe ChallengeAccidental falls are a leading causeof injury among elderly people.Specifically, hip fractures are thelargest single injury resulting fromfalls in patients aged 65 to 74 years.Biomechanical analysis shows that themaximum force on the hip when fallingapproaches three times the body weight.This can be reduced by about a thirdusing a protective device. The devicemust be able to absorb and dissipateimpact energy and be comfortableenough to wear on a daily basis.Evaluation of the performance of a hipprotector is conducted by simulating a fallusing an impact testing system. By specifyingcrosshead weight, drop height, velocity andacceleration, test configurations are designedto accurately reproduce forces producedduring a fall.The Dynatup 9250HV impact testing systemallows for all of these configurations, andthe Impulse machine control and dataacquisition system simplifies measurementsof maximum load, time to max load, time tofailure, total time, impact energy and energyto max load. Results from such tests assistresearchers and engineers in the designof protective devices, and help physiciansproperly prescribe these devices to preventpatient injury.GThe impact resistance of a hip protector is evaluatedusing a Dynatup 9250HV impact testing system.www.instron.com15
Biological TissuesBiological TissuesInjury, the aging process, and disease are contributing factorsto the irreversible changes in human tissue that lead to pain,discomfort and immobility in a person over time. Asresearchers and engineers work to develop replacementtissues, perfect surgical techniques, and learn to accuratelydiagnose these changes in tissue physiology and mechanics,a crucial step is to evaluate the natural tissues they areattempting to simulate. Further, mechanical understanding ofhealthy tissue is used to diagnose diseased or damaged tissueduring the procedure or in the surgeon’s office.The following section provides for an overview of the mostcommon tissue testing applications. Not only do the Instron biomedical applications specialists have a selection of standardproducts and accessories, but also the experience and breadthof knowledge to help create a customized solution that meetsyour individual testing requirements.Soft Tissues: Low ForceThe ChallengeMany soft tissues, such as skin orcollagen, are delicate specimens withlow ultimate strength values.An ensuring system should be highlysensitive to low force measurementsand small displacements in tension,compression, flexure and fatigue.The in vivo conditions must also bepreserved, ensuring the mechanicalproperties of natural tissues aremaintained and that bio-engineeredtissues are tested in their workingenvironment.GGMicro three-point bend fixture with saline tank.16Our SolutionInstron ’s ElectroPuls and MicroTester systems offer the precision necessary forlow-force testing of tissues and biomaterialsin tension, compression, flexure and fatigue.With the correct selection of a load cell andlightweight grips, these systems have anexceptional capability to run verylow-force tests.Each system features a twin-column designand an all-electric actuator, making it ideallysuitable for clean room environments. TheMicroTester and the ElectroPuls E1000 canbe configured vertically or horizontally tofit on any laboratory workbench and foreasy mounting of a temperature-controlledenvironmental bath and optical instruments.GThe MicroTester is extremely versatile for a varietyof low-force tissue tests in both vertical andhorizontal configurations.ElectroPuls systems are capable of runningslow-speed static tests through to highfrequency dynamic tests, and the MicroTesterprovides a much higher resolution formeasuring extremely
55MT MicroTorsion system for torsion testing conical lock fittings with luer taper for syringes. www.instron.com 7 Medical Devices G The fixture shown above is used to measure the ejection forces of fluids from the barrel of a syringe. The fixture uses plastic inserts to hol
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