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Membrane&MembraneFilter---MembraneSolutions

ContentAboutMembraneCheckMembrane&MembraneFiltersbyYourselfTerminologyMembraneMaterialsCompetitiveAnalysisStudyMaterials(MainCompetitors)Attachment:CrossReference

AboutMembrane--What’sMembraneMembraneisaselectivebarrierbetweentwophases,theterm"selective"beinginherenttoamembraneoramembraneprocess.

Itshouldbenotedthisisamacroscopicdefinitionwhileseparationshouldbeconsideredatthemicroscopiclevel.

Membranescansimplybeclassifiedbynatureintotwocategories:biologicalandsyntheticmembranes.

Amembranefilterisathin,polymericfilmorfilamentmadeupofmillionsofmicroscopicpores.Membraneshavemanydifferentpropertiesthataffecttheperformanceofthefilterinapplications.membranefiltersareclassifiedaccordingtotheirstructuresintoseveralcategoriesintermsof"poresize"(listedfromsmallesttothelargest);namely,gasseparation,nanofiltration,reverseosmosis,ultrafiltration,andmicroporousmembranesAboutMembrane---TypesofMembranesTypesofmembranesmostcommonlyusedinclude:Microfiltration(MF)(0.05µm--10µm)Ultrafiltration(UF)(1-20nm)Nanofiltration(NF)(>1nm)ReverseOsmosis(RO)(0.1-1nm)ApplicationSamplePreparation实验室样品的制备SterilizationFiltration除菌过滤EnvironmentalMonitoringandAnalysis环境监测与分析Tissueculturemediasterilization细胞培养介质的过滤Proteinandenzymefiltration蛋白质和酶的过滤AboutMembrane--CustomersLabFiltrationProducts&LabWareDistributorBiology&LifeScienceCompanyandLaboratoryChemistryCompanyandLaboratoryUniversity&ResearchInstituteCheckMembranesbyYourselfMembraneFilter(DiscMembrane)MembraneinRollsTerminologyHydrophilic&HydrophobicForliquidfiltration,amembranemustbewettablewiththefluidbeingfiltered.Thewettabilityofamembraneistiedtothechemicalpropertiesofthemembranesurface.Mostpolymersusedtomanufacturemicroporousmembranesarenaturallyhydrophobic,meaningtheywillnotwetoutwithwater.Someexceptionsarenylonandcellulosewhicharenaturallyhydrophilicandwillwetoutwithwater.

HydrophilicHydrophobicTheporesize,usuallystatedinmicrometers(µm),offiltermediaisdefinedbythediameterofparticlesretainedbythefiltermatrix.Poresizeratings,whichcanbeeithernominalorabsolute,refertothesizeoforganismsorparticlesretainedbythefiltermedia.

AbsoluteRating:Anabsoluteporesizeratingspecifiestheporesizeatwhichachallengeorganismofaparticularsizewillberetainedwith100%efficiencyunderstrictlydefinedtestconditions.Amongtheconditionsthatmustbespecifiedare:testorganism(orparticlesize),challengepressure,concentrationanddetectionmethodusedtoidentifythecontaminant.

NominalRating:Measurementofthesmallestparticleafilterretainstypicallyata90-98%efficiencyleveldependingonmanufacturer'sclaim.

PoreSizeBubblePoint

BubblePointisapractical,nondestructivetestusedforestimatingtheporesizeofmicroporousfiltersandconfirmingtheintegrityofsterilizingmembranefiltersandfiltersystems.Itisthemostwidelyusednon-destructiveintegritytest.

Bubblepointisbasedonthefactthatliquidisheldintheporesofthefilterbysurfacetensionandcapillaryforces.Theminimumpressurerequiredtoforceliquidoutoftheporesisameasureoftheporediameter.Thepressurerequiredtoforceliquidoutofaliquid-filledcapillarymustbesufficienttoovercomesurfacetensionandisadirectmeasureofeffectivetubediameter.

FormulaforBubblePointTest

Where:

P=bubblepointpressure

d=porediameter

k=shapecorrectionfactor

cosθ=liquid-solidcontactangle

ó=surfacetensionFlowRateFlowreferstothetimeittakesforaparticularflowstreamtopassthroughthefilter.Flowratedifferencescanbecausedbydifferencesinthickness,porosity,materialsandporearchitecture.Hydrophilicfiltersareusuallytestedwithwater.Hydrophobicmembranesareusuallytestedwithanalcohol.Membranestobeusedforairfiltrationcanbetestedwithdryairordrynitrogen.

ChemicalCompatibilityFiltermaterialmustbecompatiblewiththechemicalnatureofthesamplestreamundertheconditionsthatthefiltrationwillbeperformed.Thiswillminimizetheriskofstructuralfailureduringfiltration.

BindingProperties

Sincemanycellculturemediacomponentsareheat-sensitiveandchemicalsterilizationmethodsmayleaveunwantedby-products,membranefiltrationisoftenthemethodofchoiceforsterilizinghighvaluebiotechnologyproducts,suchastissueculturemediaandexpensiveproteinadditives.

Researchersmustbeconfidentthatwhenthesesolutionsarefiltered,eithertoensuresterilityortoremoveparticulates,theproteinsarenotlost.

Becausetheinternalsurfaceareaofpolymericmicroporousmembranesis100–600timesasgreatasthefrontalsurfacearea,thereisavastinternalsurfaceareaaccessibletoproteins.Sincethenonspecificbinding(NSB)ofproteinsmayaffecttherecoveryofexpensivefinalproduct,selectingthe“best”membranefilterisatoppriority.

ThicknessDependingonthefiltertype,thethicknessofmembranefiltersrangesfrom10to170µm.Conversely,depthfilterscanrangebetween100and500µminthickness.

Thicknessofmembranesismeasuredusinggaugeswitharesolutionof1to2microns.Careistakentoensurethatthemembraneisnotcrushedduringthemeasurement.

PyrogenicityPyrogensarefragmentsofbacterialcellwalls.Wheninjectedintothebody,pyrogenscanelicitafeverresponseinhumans.Pyrogensresultfrombacterialcontaminationinthemanufacturingprocess,thepost-manufacturingprocess,orfrompackaging.Becausetheydonotrepresentfunctionalcells,pyrogenscannotbeidentifiedinacontaminationtestforbacteria.Rather,theyarecompoundsthatsitonthefiltersurfaceandcanbereleasedasthefiltratestreampassesthroughthefilter.

Extractables

Extractablesarecontaminantspresentinthefinalfiltratethatoriginateinthefilterordevice.Extractablesfromthesefilterscanbeofthreetypes:Fromthesheddingoffiltermaterials,suchaspolymerparticlesfrommembranesorfibersfromnonwovensResidualchemicalscarriedoverfromthemanufacturingprocessSecondarychemistrieswashedoffthefilter

Oneofthefinalstepsinthemanufactureofmembranesisextensivewashingwithwatertoremoveallresidualchemicals.Extractablestestingisconductedbecausethechemicalsusedinprimarymanufactureofthemembraneandadditionofsecondarychemistriesareincompatiblewithbiologicalmaterialsandtoxictohumansandanimals.Providingassurancethatthesechemicalshavebeenremovedisveryimportant.MembraneMaterialsNylon（Polyamide)MembraneFilter：NyloniscommonlyusedforgenerallaboratoryfiltrationandfiltrationofHPLCsamplespriortoinjection.

Nylon

bindsproteinandshouldnotbeusedwhenmaximumproteinrecoveryisimportant.

尼龙膜是亲水性膜，适宜于普通水溶液和有机溶液过滤，由于其高蛋白结合力，不宜用于蛋白质的过滤·PTFE（

Polytetrafluoroethylene）Membraneishydrophobicandchemicallyresistanttoallsolvents,acidsandbases.TheMembraneisverylowinextractablesandhasanexcellentthermalstability.PTFE是疏水性膜，耐强酸，强碱并耐高温，适宜于强腐蚀性溶液和有机溶液以及气体的过滤

我们也可以提供亲水性的PTFE膜

Mixedcelluloseester（MCE)membranefiltersarecomposedofcelluloseacetateandcellulosenitrate.BecauseMCEmembraneisbiologicallyinert,it’soneofthemostwidelyusedmembranesinanalyticalandresearchapplications.混合纤维素膜是醋酸纤维素和硝酸纤维素的混合物，是分析和研究中应用最最广泛的膜之一。PES（Polyethersulfone)MembraneFilter：PESisahydrophilicmembranethathasverylowproteinbindingandhighflowcharacteristicsmembrane.PES是亲水性膜，低蛋白质结合力，高流速

CAmembrane：CelluloseAcetateisaverylowproteinbindingmembranethatisidealforaqueousbasedsamples.

CAmembranesarean

excellentchoicewhenmaximumproteinrecoveryinthefiltrat