Description
Numeroustechniqueshavebeendevelopedtoprepareimmunoliposomesbasedonthenucleophilicreactivityoffreeaminegroupsofproteinsorpeptides.However,themostcommon,versatileandstraightforwardactivationchemistryforcreatingreactiveacylatingreagentsandlabelingpeptides/proteinsistoformNHSesterwithprimaryamines.AsinglestepnucleophilicsubstitutionreactionbetweenNHSesterderivativeandalphaaminesattheNterminalorthebetaaminesoflysinesidechainsleadstotheformationofastableamidebond.
N-Hydroxysuccinimide(NHS)estersofDSPE-PEG-NHSliposomesreactwiththeprimaryaminegroupsonthepeptides,proteins,antibodiesorotherfunctionalligandsfortargeteddrugdeliveryapplications.ThenucleophilicattackoftheaminegroupsontheNHS-activatedcarbonylgroupoftheDSPE-PEG-NHSresultsintheeliminationoftheNHSgroupandformationofamidelinkage.
Immunodox®-NHSisaPEGylatedproduct.Forotheraminereactive(PEGylatedandnon-PEGyalatedproducts)andalsoImmunodox®productssuitableforothertypesconjugationmethodsseehere.
FORMULATIONINFORMATION
Immunodox®-NHS(PEGylated)(Post-insertion)
| PostInsertionKit(3Vials) | Specification |
|---|---|
| Vial1 | PreformedDoxorubicinLiposomescomposedofHSPCandCholesterol(60:40molarratio) |
| Vial2 | DSPE-PEG(2000)-NHSlipid(reactivePEGylatedlipid)inpowderform |
| Vial3 | DSPE-PEG(2000)lipid(non-reactivePEGylatedlipid)inpowderform |
| LipidCompositionforVial1* | Concentration(mg/ml) | Concentration(mM) | MolarRatioPercentage |
|---|---|---|---|
| HydrogenatedSoyPC | 11.5 | 14.66 | 60 |
| Cholesterol | 3.83 | 9.9 | 40 |
| Total | 15.33mg/ml | 24.56mM | 100 |
| *Forthe5-mlkit,thevolumeofvial1is4ml.1mlofmicellesolutionthatareformedusingvials2and3willbeaddedtothisvialtomakethefinalvolumeof5mlinthefinalproduct.Forthe2-mlkit,thevolumeofvial1is1.6ml.0.4mlofmicellesolutionthatisformedusingvials2and3willbeaddedtothisvialtomakethefinalvolumeof2mlinthefinalproduct. | |||
| Buffers,LiposomeSizeandEncapsulatedDrugConcentrationforVial1 | Specification |
|---|---|
| InsideBuffer | AmmoniumSulfate |
| OutsideBuffer | PhosphateBufferedSaline |
| pH | 7.4 |
| LiposomeSize | 100nm |
| EncapsulatedDoxorubicin | 2mg/ml(3.45mM) |
| Vial2* | Specification |
|---|---|
| DSPE-PEG(2000)-NHSLipid | ThisvialcontainsreactiveDSPE-PEG(2000)-NHSlipidinpowderform.Thislipidisconjugatedtoareactiveprotein,peptideorligandcontainingamineandthenmixedwithnon-reactiveDSPE-PEG(2000)lipidinaqueoussolutiontoformmicelles.ThePEGylatedlipidmicellesareincubatedwithpreformedliposomesinvial1andPEGlipidswillpost-insertthemselvesintotheliposomes. |
| *TheamountofthepowderedPEG(2000)-NHSlipidforthe2-mlkitis1.34mgandforthe5-mlkitis3.34mg. | |
| Vial3* | Specification |
|---|---|
| DSPE-PEG(2000)Lipid | Thisvialcontainsnon-reactiveDSPE-PEG(2000)lipidinpowderform.ThislipidinmixedwithDSPE-PEG(2000)-NHSlipidwhichisalreadyconjugatedtoaligand(protein,peptide,etc.)inaqueoussolutiontoformmicelles.ThePEGylatedlipidmicellesareincubatedwithpreformedliposomesinvial1andPEGlipidswillpost-insertthemselvesintotheliposomes. |
| *TheamountofthepowderedPEG(2000)-DSPElipidforthe2-mlkitis5mgandforthe5-mlkitis12.5mg. | |
ConjugationProtocol
MaterialsandEquipment
The3-vialpost-insertionkitcontainspreformedliposomes(vial1),non-reactivePEGylatedlipidinpowderform(vial2)andDSPE-PEG(2000)-NHSlipidinpowderform(vial3). Inordertousethepost-insertionkit,youwillneed:
- Laboratoryvortexmixerisrecommendedtohave.
- Laboratorymagneticstirrerisneededfordialysis.
- Twosmall10mlroundbottomflasksortwosmallglassvials.
- Arotaryevaporator. Weunderstandthatmanylabsmightnothavearotovap.Alternatively,youcanuseanitrogentankconnectedtoathinhoseforcreatingastreamofnitrogenflowtodrythelipidandmakeathinfilm.
- Asmallamountofasolventsuchachloroformormethylenechloride(youwillonlyneedafewmilliliters).
- Phosphatebufferedsaline(PBS).
- ASonicator.Itisbettertohaveabathsonicator.Ifyoudonot,thatisfine.Youstillcanfollowtheprotocol.Youmayalsouseavortexinsteadofthesonicatorforagitationofthesolutionaswell.
- Float-A-Lyzer®withaproperMWCOthateasilyallowsthecleanupofyourliposomeconjugatedligandfromfreeandnon-conjugatedprotein,peptideorantibody.YouneedtomakesurethattheMWCOisbelow1,000,000dalton.At1,000,000daltontheporesizeonthedialysismembranegetscloseto100nmandthereforeyourliposomescanbedialyzedout.Youcannotusedialysiscassettesblindly.Pleaseunderstandthetechniquebeforeusingeitherspincolumnordialysiscassette.IfyoudonotusethecorrectMWCOyoucanloseyourentireprep.ForthisprotocolwerecommendMWCOof300,000dalton.
PreparationMethod
- Thepost-insertionkitscomeintwosizes;2mland5ml.Forthe2mlkitsize,dissolvethecontentofvial3in100µlofchloroformormethylenechloride.Forthe5mlkitsize,thecontentofvial3shouldbedissolvedin250µlofchloroformormethylenechloride.Transferthesolutiontoa10mlroundbottomflask.Drythechloroformusingarotaryevaporatororunderastreamofnitrogenandmakeadriedlipidfilm.
- Forthe2mlkit,add100µlofPBSbuffertothedriedlipidfilm.Forthe5mlkit,theamountoftheaddedbufferis250µl.Itispreferredtosonicatethehydratedlipidfilmusingabathsonicatorandsonicatethemicellesolutionfor5minutes.IfyoudonothaveabathsonicatorthenhydratethedriedlipidfilmwithPBSforatleast1hourandconstantlyrotatethesolutionintheroundbottomflaskusingarotavap(notconnectedtovacuum)orbyhandtomakesurethatallthedriedlipidonthewalloftheroundbottomflaskwillgotothesolutionandformmicelles.Alternatively,youcanuseavortextoagitatethesolution.Thegoalistohaveallthedriedlipidonthewalloftheroundbottomglasstogothemicellesolution.CoverthemouthoftheroundbottomflaskwithParafilm.Refrigeratethemicellesolutionofnon-reactivePEGlipidsuntilitisreadytobemixedwithmicellesformedinstep4.
- For2mlpost-insertionkit,theamountofDSPE-PEG-NHSis1.34mg(0.22µmol)andfor5mlofpost-insertionkittheamountofDSPE-PEG-NHSis3.34mg(0.55µmol).Forthe2mlkitsize,dissolvethecontentofvial2in100µlofchloroformormethylenechloride.Forthe5mlkitsize,thecontentofvial2shouldbedissolvedin250µlofchloroformormethylenechloride.Transferthesolutiontoa10mlroundbottomflask.Drythechloroformusingarotaryevaporatororunderastreamofnitrogen.
- Addthewater-solubleprotein,peptideorligandat1:2molarratioofligandtodriedfilmofDSPE-PEG-NHS.For2mlkitadd300µlofwater-solublesolutionofproteinofligandinPBS(pH7.4)tothedriedlipidfilmandfor5mlkitadd750ulofwater-solublesolutionofproteinofligandinPBS(pH7.4)tothedriedlipidfilm.Itispreferredtosonicatethehydratedlipidfilmusingabathsonicatorandsonicatethemicellesolutionfor5minutes.IfyoudonothaveabathsonicatorthenhydratethedriedlipidfilmwithPBSforatleast1hourandconstantlyrotatethesolutionintheroundbottomflaskusingarotavap(notconnectedtovacuum)orbyhandtomakesurethatallthedriedlipidonthewalloftheroundbottomflaskwillgotothesolutionandformmicelles.Alternatively,youcanuseavortextoagitatethesolution.Thegoalistohaveallthedriedlipidonthewalloftheroundbottomglasstogothemicellesolution.Thesolutionisincubatedatroomtemperaturefor6hoursandinrefrigeratorfor24hours.ThereactionispHsensitive.Readthetechnicalnotebelowformoreinformation.
- Mixthemicellesinstep2tothemicellesinstep4.Thetotalvolumeofmicellesfor2mlkitshouldbe400µlandfor5mlkitshouldbe1000µl.
- Toconductpost-insertion,themicellardispersionisthenco-incubatedwithpreformedplainliposomesat60℃for30min.
- Removethenon-conjugatedprotein,peptideorantibodyfromtheimmunoliposomesbydialysis.Wepreferdialysistosizeexclusioncolumns.Dialysisisamuchslowerprocessbuttherewillbeminimumlossofimmunoliposomesaftertheprepiscleanedfromnon-conjugatedprotein/peptide/ligand.Spincolumnsaremuchfaster;however,youcaneasilyloseover50%oftheliposomesonthespincolumn.WerecommendusingFloat-A-Lyzer® dialysiscassettefromSpectrumLabs.YouwillneedtochooseacassettewithproperMWCOdependingontheMWofyourprotein,peptide,antibodyorantibodyfragment.NOTE:Ifyoudecidetouseadialysiscassette,youwillneedtomakesurethattheMWCOisbelow1,000,000dalton.At1,000,000dalton,theporesizeonthedialysismembranegetscloseto100nmandtherefore,yourliposomescanbedialyzedout.Youcannotusedialysiscassettesandspincolumnsblindly.Theycomeinvarioussizesandyouneedtochoosethecorrectsizewisely.Dialyzetheimmunoliposomesolutionin1literofPBSatpH7.4for8hours.Changethedialysisbufferwithafresh1literofPBSandletisdialyzeforanother8hours.Afterthisstep,yourcleanedupimmunoliposomeisreadytobeused.
LiposomeParticleCalculator
Immunodox®liposomesareunilamellarandsizedto100nm.Themolarconcentrationofliposomeis24.56mM.Byhaving liposomediameter(nm)andlipidconcentration(µM),youcancalculatethetotalnumberofthelipidsinoneliposomeandthenumberoftheliposomesinonemilliliteroftheliposomesolution.Tousethecalculatorclick here.
TechnicalNotes
- Doxorubicinisafluorescentmoleculewithλex470nmandλem585nm.Ifyouareusingafluorescenttagonyourantibodyorligand,thenyouneedtomakesurethattheywillnotinterferewitheachother.
- HydrolysisofDSPE-PEG-NHSinaqueoussolutionscompeteswiththeprimaryaminereaction,resultingintheeliminationoftheNHSgroup,whichcanconsequentlydecreasethecouplingyieldpriortothereactionwiththeprotein/antibody.InordertominimizetheimpactofthehydrolysisofNHSester,useahighconcentrationofprotein/antibodytoincreasetheefficiencyofthecross-linking.
- ThereactionofNHSesterswithaminesisstronglypH-dependent:atlowpH,theaminogroupisprotonated,andnomodificationtakesplace.Athigher-than-optimalpH,hydrolysisofNHSesterisquick,andmodificationyielddiminishes.Thehalf-lifeofNHSestersatpH7and8is4-5hoursand1hour,respectively.WhilstNHSestershaveahalf-lifeofonly10minutesatpH8.6.Therefore,toavoidthehydrolysisofNHSester,DSPE-PEG-NHSlipidshouldbeusedimmediatelyforconjugationtoantibodies,proteinsorpeptidescontainingfreeamines.NHSesterreactionsareconductedincommonbuffersatpH7-8.
- PrimaryaminebufferssuchasTrisshouldNOTbeusedbecausetheycompeteforreaction;however,insomeprocedures,itisusefultoaddTrisorglycinebufferattheendofaconjugationproceduretoquench(stop)thereaction.
- IfyouareusingaligandorpeptidethatishydrophobicthenitisrecommendedtosolubilizeitinDMSOorDMFandthenaddthebuffertoit.Itisrecommendednottousemorethan5%volumeofDMSOorDMFinthesolution.DMFandDMSOarebothcompatIBLewithliposomesandtheyarealsomiscibleinwater.Otherorganicsolventsuchasethanolandchloroformarenotcompatiblewithliposomesandwillcausetheliposomestolyse.IfyouendupusingDMSOorDMFthenaftertheconjugationreactionisdone,youneedtoremoveDMSOandDMFfromtheliposomes.InordertodothatyouneedtouseadialysiscassettethatismadefromREGENERATEDCELLULOSEMEMBRANE.NOTE:NotallmembranesarecompatiblewithDMFandDMSO.WerecommendusingaSlide-A-Lyzer™MINIDialysisDevicewithMWCOof2KmadefromregeneratedcellulosemembranemanufacturedbyThermofisher.AfterDMSOorDMFisremovedyoucanuseFloat-A-Lyzer®dialysisdeviceforthefinalstepofcleaninguptheprep.
- Liposomesshouldbekeptat4°CandNEVERbefrozen.
Database
Directlinktothedatabasepageforeasynavigation:ImmunoliposomesConjugationDatabase
Appearance
Immunodox®-NHS(PEGylated)post-insertionkitcomesinthreevials:vial1isaredtranslucentliquidmadeofnanosizeunilamellarliposomeswhichdoesnotcontainanyreactiveofnon-reactivePEGylatedlipid. Usuallyduetothesmallsizeofliposomesnosettlingwilloccurinthebottomofthevial.Vial2containsreactiveDSPE-PEG(2000)-NHSlipidinwhitepowderform.Vial3containsnon-reactiveDSPE-PEG(2000)lipidinwhitepowderform.
EducationalVideo
Ordering/ShippingInformation
- Allliposomebasedformulationsareshippedonblueiceat4°Cininsulatedpackagesusingovernightshippingorinternationalexpressshipping.
- LiposomesshouldNEVERbefrozen.Icecrystalsthatforminthelipidmembranecanrupturethemembrane,changethesizeoftheliposomesandcausetheencapsulateddrugtoleakout.Liposomesinliquidformshouldalwaysbekeptintherefrigerator.
- ClientswhoorderfromoutsideoftheUnitedStatesofAmericaareresponsiblefortheirgovernmentimporttaxesandcustomspaperwork.EncapsulaNanoSciencesisNOTresponsibleforimportationfeestocountriesoutsideoftheUnitedStatesofAmerica.
- WestronglyencouragetheclientsinJapan,Korea,TaiwanandChinatoorderviaadistributor.Toughcustomsclearanceregulationsinthesecountrieswillcausedelayincustomclearanceoftheseperishableformulationsifordereddirectlythroughus.Distributorscaneasilyclearthepackagesfromcustoms.Toseethelistofthedistributorsclickhere.
- ClientsorderingfromuniversitiesandresearchinstitutesinAustraliashouldkeepinmindthattheliposomeformulationsaremadefromsyntheticmaterialandtheformulationsdonotrequirea“permittoimportquarantinematerial”.LiposomesareNOTBIOLOGicalproducts.
- Ifyouwouldlikeyourinstitute’sFedExorDHLaccounttobechargedforshipping,thenpleaseprovidetheaccountnumberatthetimeofordering.
- EncapsulaNanoScienceshasnocontroloverdelaysduetoinclementweatherorcustomsclearancedelays.YouwillreceiveaFedExorDHLtrackingnumberonceyourorderisconfirmed.ContactFedExorDHLinadvanceandmakesurethatthepaperworkforcustomsisdoneontime. AllsubsequentshippinginquiriesshouldbedirectedtoFederalExpressorDHL.
StorageandShelfLife
Storage
Immunodox®productsshouldalwaysbestoredatinthedarkat4°C,exceptwhenbroughttoroomtemperatureforbriefperiodspriortoanimaldosing.DONOTFREEZE.IfthesUSPensionisfrozen,theencapsulateddrugcanbereleasedfromtheliposomesthuslimitingitseffectiveness.Inaddition,thesizeoftheliposomeswillalsochangeuponfreezingandthawing.
ShelfLife
Immunodox®-NHSismadeondailybasis.Thebatchthatisshippedismanufacturedonthesameday.Itisadvisedtousetheproductswithin4monthsofthemanufacturingdate.
ReferencesandbackgroundreADIng
1.NaK,LeeSA,JungSH,HyunJ,ShinBC.Elastin-likepolypeptidemodifiedliposomesforenhancingcellularuptakeintotumorcells.ColloidsandSurfacesB:Biointerfaces.2012Mar1;91:130-6.
2.DaiW,FanY,ZhangH,WangX,ZhangQ,WangX.AcomprehensivestudyofiRGD-modifiedliposomeswithimprovedchemotherapeuticefficacyonB16melanoma.Drugdelivery.2015Jan2;22(1):10-20.
3.FerreiraDdosS,FariaSD,deAraújoLopesSC,TeixeiraCS,MalachiasA,Magalhães-PaniagoR,deSouzaFilhoJD,OliveiraBL,GuimarãesAR,CaravanP,FerreiraLA.Developmentofabone-targetedpH-sensitiveLiposomalformulationcontainingdoxorubicin:physicochemicalcharacterization,cytotoxicity,andbiodistributionevaluationinamousemodelofbonemetastasis.Internationaljournalofnanomedicine.2016;11:3737-51.
4.WangD,FuJ,ShiY,PengD,YuanL,HeB,DaiW,ZhangH,WangX,TianJ,ZhangQ.ThemodulationoftumorvesselpermeABIlitybythalidomideanditsimpactsondifferenttypesoftargeteddrugdeliverysystemsinasarcomamousemodel.JournalofControlledRelease.2016Sep28;238:186-96.
5.FeiW,ZhangY,HanS,TaoJ,ZhengH,WeiY,ZhuJ,LiF,WangX.RGDconjugatedliposome-hollowsilicahybridnanovehiclesfortargetedandcontrolleddeliveryofarsenictrioxideagainsthepaticcarcinoma.Internationaljournalofpharmaceutics.2017Mar15;519(1):250-62.
6.AbuchowskiA,KazoGM,VerhoestJrCR,VanEsT,KafkewitzD,NucciML,ViauAT,DavisFF.Cancertherapywithchemicallymodifiedenzymes.I.Antitumorpropertiesofpolyethyleneglycol-asparaginaseconjugates.Cancerbiochemistrybiophysics.1984Jun;7(2):175-86.
7. SartoreL,CalicetiP,SchiavonO,VeroneseFM.EnzymemodificationbyMPEGwithanaminoacidorpeptideasspacerarms.Appliedbiochemistryandbiotechnology.1991Jan1;27(1):45-54.
8. ShahinM,SoudyR,El-SikhryH,SeubertJM,KaurK,LavasanifarA.Engineeredpeptidesforthedevelopmentofactivelytumortargetedliposomalcarriersofdoxorubicin.Cancerletters.2013Jul1;334(2):284-92.
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现在国内最差也是用3代试剂，有些地方会用4代试剂。
4代试剂（检查抗原+抗体）——窗口期为4周。因为抗原于3-4周达到复制的峰值，此时通过4代试剂检查，如果感染了HIV，抗原/抗体至少有一个为阳性，如果都是阴就排除了。
3代试剂（只查抗体）——窗口期为6周。
以上为理论分析+临床经验的结果，可以说是99.9%的准确度。
但是目前FDA、CDC和试剂生产商统一达成的共识，也就是针对普通人，最保守的窗口期是3个月。无论什么试剂，3个月都100%排除。
需要的仪器有：酶标仪、恒温箱、枪、枪头、烧杯、滤纸.当然有自动洗板机最好.
复习了很多文献在测定方法里面均提到了CV
例如：
Theintra-assaycoefficientofvariationfortheassaywas4-6%.
Theanalyticcoefficientofvariationwas10.2%
问题是：
我是否可以直接使用说明书里的CV值？
如果不可以，我该如何操作进行计算
ELISA的基础是抗原或抗体的固相化及抗原或抗体的酶标记。结合在固相载体表面的抗原或抗体仍保持其免疫学活性，酶标记的抗原或抗体既保留其免疫学活性，又保留酶的活性。在测定时，受检标本（测定其中的抗体或抗原）与固相载体表面的抗原或抗体起反应。用洗涤的方法使固相载体上形成的抗原抗体复合物与液体中的其他物质分开。再加入酶标记的抗原或抗体，也通过反应而结合在固相载体上。此时固相上的酶量与标本中受检物质的量呈一定的比例。加入酶反应的底物后，底物被酶催化成为有色产物，产物的量与标本中受检物质的量直接相关，故可根据呈色的深浅进行定性或定量分析。由于酶的催化效率很高，间接地放大了免疫反应的结果，使测定方法达到很高的敏感度。
1．取出试剂盒室温平衡30min，取出血样放至室温。
2．配标准品：取150uL标准品加入150uL标准品稀释液稀释，依次稀释5次。
3．加样：分别于各反应孔中加入标准品50uL，样品40UL，标准品做复孔，样品做3孔。
4．分别于样品孔中加入10UL抗体。
5．标准品和样品孔中分别加入50uL链酶亲和素-HRP，盖上封板膜,轻轻震荡混匀，37℃温育60min。
6．配洗涤液：将30倍浓缩洗涤液用蒸馏水30倍稀释后备用。
7．洗涤：小心揭开封板膜，弃去液体，甩干，每孔加200uL洗涤液，静置30s后弃去，如此重复5次，拍干。
8．显色：每孔先加入显色剂A 50uL，再加显色剂B 50uL，轻轻震荡混匀，37℃避光显色6min。
9． 终止：每孔加入终止液50uL，终止反应（此时蓝色立即转为黄色）。
10．测定：以空白孔调零，450nm波长依序测量各孔的吸光度。测定应在加终止液10min之内进行。
11．保存结果，收拾桌面。
12．分析处理数据
注意事项
1. 取出板条前恢复到室温后再打开外包装袋，实验中不用的板条立即放回包装中，密闭封口，其余不用试剂应盖好。
2. 实验操作中请使用一次性的吸头，避免交叉污染。
3．实验板孔加入试剂的顺序应一致，以保证所有反应孔的孵育时间一致。
4．洗涤过程中反应孔中残留的洗涤液应在滤纸上充分拍干，勿将滤纸直接放入反应孔中吸水。
5．试剂盒内试剂请在保质期内使用，不同批号试剂不要混用。
6．1000pg/ml以上的结果为非线性的，根据此标准曲线无法得到精确的结果。大于1000pg/ml 的样品应以标准稀释缓冲液稀释后重做。在结果分析时，结合考虑相应的稀释度。
