核壳结构四氧化三铁二氧化硅作为荧光剂

HindawiPublishingCorporationJournalofNanomaterialsVolume2013,ArticleID178138,7pages@SiO2NanoparticlesYaohuiXu,1,2YangZhou,1,2WenhuiMa,1,2andShixingWang11FacultyofMetallurgicalandEnergyEngineering,KunmingUniversityofScienceandTechnology,Kunming650093,China2NationalEngineeringLaboratoryforVacuumMetallurgy,KunmingUniversityofScienceandTechnology,Kunming650093,ChinaCorrespondenceshouldbeaddressedtoYangZhou;[e-mail]11December2012;Accepted5January2013AcademicEditor:TaoChenCopyright©2013YaohuiXuetal.ThisisanopenaccessarticledistributedundertheCreativeCommonsAttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperlycited.ThemagneticFe3O4@SiO2nanoparticles(NPs)functionalizedwith8-chloroacetylaminoquinolineasafluorescentsensorfordetectionandremovalofZn2+havebeensynthesized.Thecore-shellstructuresofthenanoparticlesandchemicalcompositionhavebeenconfirmedbyTEM,XRD,FTIR,andXPStechniques.TheadditionoffunctionalizedFe3O4@SiO2NPsintotheacetonitrilesolutionofZn2+hadaneffectofvisualcolorchangeaswellassignificantfluorescentenhancement.High-saturatedmagnetizations(24.7emu/g)[e-mail]edhighremovalefficiencytowardsZn2+(92.37%).Inthiswork,weprovidedaneasyandefficientroutetodetectZn2+andsimultaneouslyremoveZn2+.1.IntroductionZincion,asbiologicallyimportantmetalions,playsavitalbiologicalroleinvariouspathophysiologicprocesses,suchasgeneexpression,cellapoptosis,enzymaticadjustment,andneurotransmission,becauseofitsstructuralproperties[1–3].Toxicinexcessorabsence,thebreak-upofzincionhomeostasismaycausepathologyofintellectualdevelop-mentandotherneurologicalproblemssuchasAlzheimer’sandParkinson’sdiseases[4,5].Therefore,theanalyticalapproachestodetectZn2+havebeenstudiedintensively.Sofar,manyselectivesmart-molecularfluorescentprobestargetingZn2+havebeenreported,thataremostlybasedonquinoline,fluorescein,benzazole,orfluorophores[6–10].Forexample,Lietal.[11]reporteda“switchingon”fluorescentchemodosimeterofselectivitytoZn2+anditsapplicationtoMCF-7cells.Leeetal.[12]alsosynthesizedandeval-uatedtwonewratiometricchemosensorsforthequan-tificationofpotentiallytoxicfreeZn2+ionsinaqueoussolutions.Recently,ChenandLietal.[13]synthesizedanewfluorescentchemosensorbasedonahelicalimideasfluorophoreandacyclenmoietyasionophore,whichnotonlyshowedenhancedfluorescentresponsesinthepresenceofZn2+,Cd2+,andHg2+,butalsocouldsimultaneouslyandselectivelydistinguishthethreecationsinasimulatedphysiologicalconditionwiththehelpofcysteineasanauxiliaryreagent.Moreover,Dingetal.[14]investigatedselectiveandsensitive“turn-on”fluorescentZn2+sensorsbasedondi-andtripyrrinswithreadilymodulatedemissionwavelengths.However,theirchemosensorswereunsuitableorinconvenientfortheseparation,removal,andenrichmentoftargetspeciesorinrapidscreeningapplications.Overthepastdecade,themodificationofsmallmolecularfluorescentprobesonthesurfaceofnanostructuredmaterialshasbeenattractingsignificantattention[15–18].Amongthesenanostructuredmaterials,core-shellFe3O4@SiO2NPshavebeenwidelyfavoredinbiologicalandenvironmentalapplications[19–21].Firstofall,themagneticFe3O4NPsascoreintheFe3O4@SiO2NPswouldfacilitatethemag-neticseparationandrecuperationfromthedetectionsystemwithinthemagneticfield.Moreover,thecoatingofsilicawouldnotonlystabilizethemagneticnanocorecompletely,butalsoprovidesitesgreatlyforsurfacemodification[22–24].Inaddition,duetomoreadvantagesofsilica,suchasnontox-icity,biocompatibilitychemicalinertness,noswelling,andtransparency,itisapossibleoptiontodevelopthenontoxic,2JournalofNanomaterialsCH2CH2CNNOHHNHNClNNH2OHSilanizationNCOOOOOOOCOSiSi(CH2)3NH2CAAQFe3O4@SiO2Fe3O4@SiO2-APTESFe3O4@SiO2-CAAQClClScheme1:[e-mail],[e-mail],8-chloroacetylaminoquinoline(CAAQ)wassynthesizedandcovalentlylinkedtoFe3O4@SiO2NPssurfacetoestablishanefficientsystemforthedetectionandremovalofZn2+(labeledasFe3O4@SiO2-CAAQ)[e-mail]e(FeCl3⋅6H2O,98%),ferrouschloridetetrahydrate(FeCl2⋅4H2O,99%),dichloromethane(DCM),ammoniumhydroxide(28wt%),tetraethylorthosilicate(TEOS),andpotassiumcarbonatewereobtainedfromSinopharmChemicalReagentTianjinCo.Ltd.8-Aminoquinoline,chloroacetylchloride,triethy-lamine(TEA),and3-aminopropyltriethoxysilane(APTES)werepurchasedfromAlfaAesarandAladdinCo.Ltd.2.2.Synthesis.Thesynthesisof8-chloroacetylaminoquino-line(CAAQ)wasbasedontheperviousreport[25].8-Aminoquinoline(0.95g,6.6mmol)and1mLTEAweremixedin50mLDCMinanicebathfor30min.Then,chloroacetylchloride(0.6mL,7.5mmol)wasaddeddrop-wise.Themixturewaskeptindarknesswithcontinuousmagneticstirr