生物醫(yī)用材料的發(fā)展與應(yīng)用

生物醫(yī)用材料的發(fā)展與應(yīng)用

家禽數(shù)據(jù)和存儲數(shù)據(jù)丟失內(nèi)皮細(xì)胞和外皮細(xì)胞qui灘產(chǎn)品系統(tǒng)polict.4.3incicib.coh-pcrsicicicicicicicicidicidicidicidicidicidicicidicicicicidicidicib內(nèi)插民事訴訟。AccordingtoInternationalOrganizationforStandardization,biomedicalmaterialisdefinedaslifelessmaterialsthatinteractwithbiologicalsystems,withbiocompatibilityorbiodegradation.Thematerialscanbeclassifiedintobiomedicalinorganicmaterial,biomedicalsyntheticmaterial,andnaturalpolymermaterial.Thebiomedicalmaterialsdirectlycontactinternalenvironmentofhumanbody,andsometimesareimplantedinvivo.Therefore,theyshouldhavebiocompatibility,chemicalstability,suitablephysicalmechanicalfunctionandsimpleprocessingandmolding,buthavenotoxicity.Importantly,goodbiocompatibilityiscrucialforapplicationofbiomedicalpolymermaterials.Biocompatibilityincludeshistocompatibilityandbloodcompatibility.Histocompatibilityreferstothatmaterialsinteractwithorganismandbodyfluidanddonotinducecellmutation,distortion,cancerationorrejection;bloodcompatibilityreferstothatmaterialscontactwithbloodanddonotinduceproteindenaturationinplasma,destroyeffectivecomponentsofblood,bloodcoagulationorthrombosis.Duetothespecialandcomplicatedclottingmechanismoforganism,developmentandapplicationofbloodcontactingbiomaterialshasbecomethefocusinthefieldofbiomedicalpolymermaterials.MaterialsurfacemodificationhasbeenfrequentlyusedtoobtainmaterialswithgoodbloodcompatibilityCurrentsurfacemodificationmethodscommonlyutilizegrouporgiantmoleculesthatcanhinderclottingmechanismactivationorinhibitdirectcontactbetweenbloodcoagulationfactorandmaterialsurface.Combinationofnaturalsubstanceswithanticoagulationpropertycanalsobeused.Recently,surfacedeactivatedwithalbumincansuppressbloodcoagulationandhasbloodcompatibility.Therefore,materialsthatassemblesalbumintoobtainbloodcompatibility(antithrombogenicitymaterials)havebecomearesearchfocus.Acomputer-basedonlinesearchofPubMedandWanfangdatabasewasperformedforrelatedarticlespublishedbetween1969and2010withkeywords“Biocompatibility,Bloodcompatibility,Bio-inertsurface,Bio-activesurface”inEnglishandChinese,respectively.Inclusioncriteria:articlesregardingpreparationandmechanismofbiomedicalpolymeranticoagulantmaterials;articlespublishedrecentlyinauthoritativejournalsinthesamefiled.Exclusioncriteria:repetitivestudies.patibut模型Atotalof54articleswerecollected.Followingreadingthetitlesandabstracts,24unrelatedorrepetitivearticleswereexcluded,finally,30articleswereincluded.The30articleswerefurtheranalyzed.References1-9discussedmaterialswithbiocompatibilityandbloodcompatibility;references10-15discussedbioinertsurfacematerials,andreferences16-30introducedbioactivesurfacematerials.Generally,thebloodcompatibilityofmaterialsisimprovedbytwoways:reducinginteractionbetweenpolymermaterialssurfaceandcompositionsinblood,thatis,preparingbioinertmaterialswithminimalinteractionwithbloodcompositions;controllinginteractionbetweenpolymermaterialssurfaceandblood.Forexample,thebiologicalrecognitionmechanismofproteininbloodwassimulated,andbioactivesubstanceswereloadedonthesurfaceofmaterialstoimplementsimulationofinteractionbetweenmaterialsandbloodtoobtaingoodbloodcompatibility,whichwasalsotermed“bioactivesurfacematerials”.Accordingtotheabovefindings,materialswithbloodcompatibilityhavebeenprepared.u2004范圍PEOisaflexiblepolymerpolyether.Inwater,itssegment,CH2CH2O,canbindthreehydronestoformPEOhydrate,whichhasgoodwatersolubility.Insolid/waterinterface,PEOextendstowaterphasetoformhydratedPEOlayer,whichcaneffectivelyhindergiantmolecularadsorption.Otherpolymers,suchashydroxyethylmethacrylateandpoly(acrylicacid),canalsoformhydrophiliasurfacetohindergiantmolecularadsorption,butPEOisthebetter.StudiesregardinginteractionbetweenPEOandbloodconstituenthaveshownthatPEOrarelyinteractswithbloodconstituents,exhibitinggoodbioinert,andhasbeenregardedasidealmaterialtohinderproteinabsorptionandplateletattachment.Avarietyofmethods,suchassurfacefilmcoatingmodification,surfacecovalentbondlinkage,andsurfaceionsedimentationandabsorption,havebeenusedtoreactwithvariouspolymerstopreparepolymermaterialsforsurfacemodification.Testingof1H-NMRofgraftcopolymerwithPEOofdifferentchainlengthsshowsthatwaterbindingPEOpresentshighmotilityat-60°C.Inaddition,Testingof13C-NMRofthelinewidthofpolyethyleneglycolsegmentCsignalisdecreasedwithincreasingpolyethyleneglycolchainlength,indicatingpolyethyleneglycolchainmotilityisincreasedwithchainlength,butamountofproteinabsorptionandplateletattachmentisrapidlydecreasedwithincreasingpolyethyleneglycolchainmotility.Whenthedegreeofpolymerizationofpolyethyleneglycolreaches100,plateletattachmentisnotobserved,indicatingpolyethyleneglycolmovementonmaterialsurfaceishighlycorrelatedwithPEOinhibitiontobloodconstituentadherenceonthesurface.NaaaokaproposedseveralhypothesesregardinganticoagulantmechanismsofPEOgraftchain.PEOisakindofmoleculechainwithhighhydrophilicityandcompliance.Therefore,PEOcanbindwatertoformhydratedPEOchaintohinderbloodconstituentadherenceinadose-dependentmanner.MoreoverrapidmovementofhydratedPEOchaininfluencesfluidmechanicsinmaterial/bloodinterface.Thatis,watermicrostreambindingtoPEOinhibitsproteindetention,adherenceanddegenerationonmaterialsurface.u3000yrs.siphityposed.u-roincipatictssiciviphsu3000.....分析Cellmembraneinbloodvesselsisanunevenstructureoflipidhydrophobicregionandproteinhydrophilicregion.Thelipidarrangesinliquidcrystallinestatewithdimoleculetoformbiomembraneskeleton;theproteininlayslipiddimolecularlayers.Simulationofthisstructureisveryimportanttoimprovebloodcompatibility.A“covercontrolmodel”hasbeenproposed.Microphaseseparationmaterialsimmediatelyadhereplasmaproteinwhencontactingwithbloodandthisadherenceiscontrolledbymicrophasestructuresofthematerials.Thatis,proteinswithdifferenthydrophilicityareselectivelyabsorbedindifferentregions.Asthisabsorptiondoesnotactivateglycoproteinonplateletsurface,bloodcoagulationishindered.Inaddition,thesizeofmicrophaserangesfrom10to100nm;promoterofbloodcoagulationonsurfaceisacompositecomprisingthreeproteins,withasizeof10-20nm.Therefore,itisdifficulttoadherethesurface,therebyobstructingbloodcoagulation.u2004anion-rowellblot.u2004Manybloodconstituents,suchashemoglobin,platelet,andsomeplasmaprotein,areofelectronegativityinblood,soisinnerwallofbloodvessels.Therefore,itisproposedthattheelectrostaticrepulsionbetweeninnerwallofbloodvesselsandsomebloodconstituentsbenefitanticoagulation.Therefore,anion-modifiedpolyurethanehasbeenwidelyusedtoimproveanticoagulation.Furtherstudiesshowedthatcarboxylicacid,sulfonicgroupandsulfanilamidoradicalgroup-modifiedpolyurethanematerialsexhibitgoodpropertyofanticoagulation.Thesegroupsareimportantcomponentsofthenaturalanticoagulationsubstance,heparin.Inblood,theseanion-modifiedsurfacespresentsimilaranticoagulationeffectsasheparin.Therefore,thesematerialshavebeencalledheparinoidanticoagulantmaterials.非價(jià)值主義醫(yī)學(xué)srain回收方式Duetospecificpropertiesofpolymermaterials,suchasunbalancedthermodynamics(ageneralflabbystate),theirbioinertsurfacepresentsgoodanticoagulationeffectsinvitroorinashortperiodoftime.However,the“bioinert”propertycannotbemaintainedforalongperiodoftime.Therefore,idealpolymermaterialsshouldnotactivateanycoagulationmechanism,andpreparationofanticoagulantmaterialswithbioactivityhasbecomeresearchfocus.Infact,bloodcoagulationandanticoagulationisabalancesystem.Theanticoagulantmaterialsaretherebydividedintotwocategories:bioactivematerialswithfibrinolyticfunction(thrombolysis)andbioactivematerialswithanticoagulantproperty(inhibitingthrombosis).polictority雙價(jià).3.3indexhombo姐生物.vhnkensp.....inrewelle-.........3.3.3日性別教育思想面臨的挑戰(zhàn)Topreparebioactivematerialswithfibrinolyticfunction,bioactivesubstances,suchasplasmase,urokinase,streptokinase,arefixedonthesurfaceofpolymermaterials.TheurokinaseandstreptokinaseareclinicallyusedthrombolyticdrugsCurrently,theroleoffibrinolyticeffectinanti-thrombosishasarousedincreasingattention.TerumoandSalemCompanyadheredfibrinolysinsubstancetopolyesterelasticfiber-weavedtube-shapedinnerwallanddevelopedanovelartificialbloodvesselswithfineanti-thrombosisproperty.加入抗混養(yǎng)類型的創(chuàng)建Heparinizedandheparinoidsurface:heparinisanaturalmucopolysaccharide,andcancombineavarietyofbloodcoagulationfactorstoformcompositetoneutralizetheiractivities.Anumberofstudiesofheparinizedpolyurethanesurfacehavebeenconducted.Heparinmoleculecontains-COOH,-OH,-NH2groups,whichallowheparintoadherematerialsurfacethroughsomereagentsasintermediatematerials.Studieshaveshownthatcovalentlinkedheparinonthematerialsurfacethatmaintainsoriginalconfigurationandconformation,aswellasmobilityexhibitsgoodanticoagulantproperty.Thatis,comparedwithfreeheparinizedgiantmolecules,whenheparindirectlycontactswithmaterialsurface,heparinizedgiantmoleculescansignificantlyreduceanticoagulantpropertyduetomotioninhibition,structuralalteration.Therefore,heparinhasbeencombinedwithmaterialsurfacethroughaspacebridge:long-chainaldylorhydrophilicchainsegments.PEOhasbeenconsideredabetter“spacebridge”.DuetothehydrophilicityandcomplianceofPEOchains,whenmaterialscontacttobloodcontainingwater>50%,heparingiantmoleculesextendtoblood,andtheoriginalconfigurationandconformationofheparinarewellmaintained.Somesimplefunctionalgroupshaveshownspecificeffectswithbloodconstituentsandcanbeusedtoprepareanticoagulantmaterialswithbioactivity.Carboxylicacid,sulfonicgroupandsulfanilamidoradicalgroupsareimportantcomponentsofthenaturalanticoagulationsubstance,heparinandexhibitanticoagulanteffectsasheparinizedsurface.Therefore,Carboxylicacid,sulfonicgroupandsulfanilamidoradicalgroups-modifiedmaterialsalsopresentwithanticoagulantproperties,andarecalledheparin-likeanticoagulantmaterials.Basedonmodelofpolyurethane-graftedPEOatoneend,theterminalendofPEOchainwasgraftedoneanionsulfonicgroup,andpolyurethanematerialwithmolecularstructureofPEU-g-PEO-S03ˉwasprepared.BloodcompatibilityevaluationshowedthatthismaterialpresentedlessplateletadherenceandactivationbutprolongedanticoagulanteffectscomparedwithPEO-g-PEO.Itislikelythattheelectronegativityandheparinoidactivityofsulfonicgroupbenefitsanticoagulanteffects.非價(jià)值學(xué)和雙標(biāo)性政策,主要包括雙環(huán)目數(shù)和雙發(fā)酵劑和雙發(fā)生專利信息技術(shù)Infact,humanbloodvesselendotheliumistheonlymaterialwithbloodcompatibility.Simulationofendotheliumprovidesanewoptionforpreparationofmaterialswithbloodcompatibility.Urokinaseandheparinhavebeenintroducedtopolymersurface,whichsimulateendothelialfunction.Someresearchersalsoproposethathydrophobicporousmaterialsurfacecanfacilitateformationoffibrinnetwork,allowingendothelialcellstopreventbloodcoagulationandthrombosis.Currently,ultrathinweavedfibershavebeenused.Inaddition,growthandlong-termsurvivalofendothelialcellsonpolymermaterialsurfacemaybealsoagoodthoughtPseudo-intimasurfaceformedintheinnerwallofartificialbloodvesselsmainlycomprisesproteinandbloodcellsinblood,andthecomponentandthicknessofproteinlayercannotbewellcontrolled.Despitesomeimprovementmeasures,thesurfaceofpseudo-intimahasnosufficientcompatibility.Anti-thrombosisfunctionofvascularendotheliumdependsonsubstancesproducedorretainedbyendothelialcellsasreceptororproteinabsorber.Theypresentlocalactivity.Forexample,theycaninhibitenlargementofbloodcoagulationchainreaction,therebypreventingthrombosisonendotheliumsurface.Alargenumberofstudieshavefocusonendothelialcellscoveringpolymermaterialssurface.Endothelializationiscrucialforbloodcompatibilityofsmall-boreartificialbloodvessels.ItisfirstlyproposedbyHerring.Endothelialcellshavebeenimplantedonthesurfaceofpolyurethanevessels,whichgrewwellandwithstoodshort-temperfusionofculturemedia,buttheimplantedcellsonexpandedPTFEmaterialsurfacewererarelysurvived.whichporene-g-stearylpeoLessplateletwerefoundtoadhereonsurfacewithalbumincomparedwiththatwithfibrinogenandγ-globulin.Thisindicatesthatmaterialsurfacewithalbumincansuppressfibrinogenandγ-globulinfunctionandplayanticoagulanteffects.Studiesonpolystyrene-g-stearylPEO(PS-g-SPEO)graftedcopolymersurfaceshowedthatsurfacewithgreatestSPEOcontentabsorbedalargeamountofalbumin,whichpotentiallycorrelatedwithoctadecylattheterminalendofSPEO.Theoctadecylselectivelyabsorbedalbumin,formedareal-timealbumindeactivation,andreducedplateletabsorption.Formationofalayerofalkylchainsegmenthasbeenfrequentlyused.Longalkylchain,s