2011-Synthesis of novel Fe3O4@SiO2@CeO2 microspheres with me

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SynthesisofnovelFe3O4@SiO2@CeO2microsphereswithmesoporousshellforphosphopeptidecapturingandlabelingw

GongCheng,adJi-LinZhang,*aYan-LinLiu,adDe-HuiSunbandJia-ZuanNiac

Received27thJanuary2011,Accepted30thMarch2011DOI:10.1039/c1cc10533g

Fe3O4@SiO2@CeO2microsphereswithmagneticcoreandmesoporousshellweresynthesized,andthemultifunctionalmaterialswereutilizedtocapturephosphopeptidesandcatalyzethedephosphorylationsimultaneously,therebylabelingthephosphopeptidesforrapididenti cation.

Itisvitaltoidentifyphosphorylatedproteinsandtodeterminethephosphorylationsitesbecauseproteinphosphorylationisafrequentpost-translatedmodi cationregulatingvariouscellularprocessessuchasmetabolism,signaling,cellgrowthandpision.1Unfortunately,duetothesmallquantityofphosphoproteins,thelowstoichiometryofphosphorylationandthesuppressione ectbynonphosphorylatedpeptides,itremainsamajorchallengetodetectthembymassspectro-metrywhichisthemostimportantandpowerfultoolfortheanalysisofproteinphosphorylation.

Inrecentyears,signi cante ortshavebeenexpendedtothedevelopmentofa nitymaterialsthatcanrapidlyande ectivelyenrichorisolatephosphopeptides.Thesematerialsmainlyincludeimmobilizedmetal-ionandmetaloxidea nitymaterials.MetalionssuchasFe3+,Ti4+,Zr4+andGa3+wereimmobilizedonchromatographicpackingmaterialsandfunctionalmagneticmicrosphereswereutilizedasa nityprobesforselectiveenrichmentofphosphopeptides.2,3TiO2,ZrO2,Ga2O3andZnOhavebeenreportedtotrapphospho-peptidesandshowmorereproducibleresultsthanmetaliona nitymaterials.Especially,themesoporousmetaloxidea nitymaterialswithmagneticcoresnotonlypossesshighselectivity,butalsocansimplyandrapidlyenrichandseparatephosphopeptidesfromcomplexsamples.4Thus,a nitymetaloxideprobeswithmagneticcoresandmesoporousshellshavebecomeoneofthekeyresearchtoolsfortherapidseparationandselectiveenrichmentofphosphopeptidesandphospho-proteins.However,mostofthereportedmetalionsandmetaloxidematerialsshownonspeci cbinding,whichwouldhinder

a

thee ciencyoftheenrichmentstepandsubsequentlythenumberofphosphopeptidesidenti edviaMS/MS.5Inaddition,usefullabellinginformationfromsomeneutrallossesfromdephosphorylationwhichcanbedetectedinthemassspectrum,complicatestheidenti cationofphosphopeptides,becausetheselossesareunreliable.6Therefore,itisessentialtodevelopnewa nitymaterialsthatcansimultaneouslycapturetargetpeptidesandlabelthemfromthehighlycomplicatedproteolyticmixturefordirectidenti cationinthemassspectrumbyusingthedephosphorylationinformation.

Recently,ceriumoxide,whichhasbeenwidelyappliedincatalysis,sensingandfuelcells,7hasbeendevelopedasanexcellentcatalystforthedephosphorylationofphosphopeptides.8Herein,wesynthesizednovelFe3O4@SiO2@mCeO2micro-sphereswithamesoporousCeO2shellandappliedthemtorapidlyidentifyphosphopeptidesbycombiningtheira nityandcatalysisproperties.

AsillustratedinScheme1a,thesynthesisstrategyofFe3O4@SiO2@mCeO2microspheresinvolvesthepreparationofca.500mmsizedmagnetitemicrospheresbysolvothermalreaction,coatingwithaSiO2layerusingaStobermethod,andtheformationofamesoporousCeO2shellviaachemicalprecipitationandsubsequentcalcinationprocess.ItshouldbenotedthattheintroductionofadensesilicacoatingonthemagnetiteparticlesisessentialforthepreparationandapplicationoftheFe3O4@SiO2@mCeO2microspheres.ThisisbecausetheSiO2layernotonlycontributestostabilizationoftheFe3O4magneticcores,butalsoprovidesanactivesurfaceforfurthermodi cation.TheseFe3O4@SiO2@mCeO2microsphereshavethefollowingadvantages: rst,asan

StateKeyLaboratoryofRareEarthResourceUtilization,

ChangchunInstituteofAppliedChemistry,ChineseAcademyofSciences,Changchun130022,China.E-mail:zjl@http://b

ChangchunInstituteTechnology,Changchun130012,Chinac

CollegeofLifeScience,ShenzhenUniversity,Shenzhen518060,Chinad

GraduateUniversityoftheChineseAcademyofSciences,Beijing100049,PRChina

wElectronicsupplementaryinformation(ESI)available:Experimentaldetailsandfurthercharacterizationdata.SeeDOI:10.1039/c1cc10533g

Scheme1SchematicillustrationofthesynthesisstrategyofFe3O4@SiO2@mCeO2(a)andthecaptureandlabelingmechanismoftheFe3O4@SiO2@mCeO2microspheres(b).

a nityprobe,theycanenrichphosphopeptidesfrommixedpeptides,therebyproducingclearphosphopeptidesignalsinmassspectra;second,theycanalsocatalyzethedephosphory-lationprocessleadingtocharacteristicmassdecreasesof80nDainthemassspectrum;third,themagneticcorefacilitatesrapidenrichmentandisolation,whilethemeso-porousCeO2shellcanimprovetheselectivityande ciencyforidenti cationofthetargetphosphopeptides.

Mostreportedmetaloxidesaresynthesizedbyhydrolysisofalkoxides5butthisoftenresultsinirregularandaggregatedparticles.Incontrast,theas-preparedFe3O4@SiO2@mCeO2microsphereswithmesoporousshellarealmostuniformandmonodisperse.Scanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM)images(Fig.1aandb)revealthatthemicrosphereshavearelativelyroughsurfaceandadistinctsandwichstructure.Thesandwichstructureconsistsofamagneticcore(ca.500nm),aSiO2middlelayer(ca.70nm)andamesoporousCeO2shell(ca.20nm).Apparently,thisthina nityshellcanavoidthe‘‘shadowe ect’’whichwouldhamperthereleaseofphospho-peptides.9Accordingtohigh-resolutionTEM(HRTEM)images(Fig.1candd),theroughshellisporousandconsistsofnumerousCeO2nanocrystallitesofsizeofabout8.0nm.Thedspacingsofthesingle-crystallineCeO2nanoparticles(i.e.0.19,0.27and0.31nm)canbeindexedtothe(220),(200)and(111)crystalplanesofCeO2,respectively.TheCeO2shellcanbefurthercon rmedfromtheenergy-dispersiveX-rayspectrum(EDX)(Fig.1e)sincetheFe3O4@SiO2@mCeO2microspheresareseentobecomposedofFe,Si,CeandO(CuarisingfromthesamplecarrierandCfromtheadhesive

Fig.1(a)SEM,(b)TEM,(c,d)HRTEMimagesoftheas-synthesizedFe3O4@SiO2@mCeO2microspheresand(e)EDXspectrumoftheobtainedFe3O4@SiO2@mCeO2core–shellmicrospheres.

usedforsamplepreparationarediscounted).SuchstructuralCeO2a nitymaterialisbene cialfore ect …… 此处隐藏：10696字，全部文档内容请下载后查看。喜欢就下载吧 ……