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1、ELISAEnzyme-linkedimmunosorbentassay(ELISA),alsoknownasanenzymeimmunoassay(EIA),isabiochemicaltechniqueusedmainlyinimmunologytodetectthepresenceofanantibodyoranantigeninasample.TheELISAhasbeenusedasadiagnostictoolinmedicineandplantpathology,aswellasaquality-contr
2、olcheckinvariousindustries.Insimpleterms,inELISA,anunknownamountofantigenisaffixedtoasurface,andthenaspecificantibodyisappliedoverthesurfacesothatitcanbindtotheantigen.Thisantibodyislinkedtoanenzyme,andinthefinalstepasubstanceisaddedthattheenzymecanconverttosomed
3、etectablesignal,mostcommonlyacolourchangeinachemicalsubstrate.PerforminganELISAinvolvesatleastoneantibodywithspecificityforaparticularantigen.Thesamplewithanunknownamountofantigenisimmobilizedonasolidsupport(usuallyapolystyrenemicrotiterplate)eithernon-specifical
4、ly(viaadsorptiontothesurface)orspecifically(viacapturebyanotherantibodyspecifictothesameantigen,ina"sandwich"ELISA).Aftertheantigenisimmobilized,thedetectionantibodyisadded,formingacomplexwiththeantigen.Thedetectionantibodycanbecovalentlylinkedtoanenzyme,orcanits
5、elfbedetectedbyasecondaryantibodythatislinkedtoanenzymethroughbioconjugation.Betweeneachstep,theplateistypicallywashedwithamilddetergentsolutiontoremoveanyproteinsorantibodiesthatarenotspecificallybound.Afterthefinalwashstep,theplateisdevelopedbyaddinganenzymatic
6、substratetoproduceavisiblesignal,whichindicatesthequantityofantigeninthesample.TraditionalELISAtypicallyinvolveschromogenicreportersandsubstratesthatproducesomekindofobservablecolorchangetoindicatethepresenceofantigenoranalyte.NewerELISA-liketechniquesutilizefluo
7、rogenic,electrochemiluminescent,andreal-timePCRreporterstocreatequantifiablesignals.Thesenewreporterscanhavevariousadvantagesincludinghighersensitivitiesandmultiplexing.[1][2]Intechnicalterms,newerassaysofthistypearenotstrictlyELISAs,astheyarenot"enzyme-linked"bu
8、tareinsteadlinkedtosomenon-enzymaticreporter.However,giventhatthegeneralprinciplesintheseassaysarelargelysimilar,theyareoftengroupedinthesamecategoryasELISAs.C