“書寫法”柔性SERS基底的制備與表征摘要：

表面增強(qiáng)拉曼光譜（SERS）作為一種極為敏感的分析技術(shù)，近年來在化學(xué)、材料、生物等多個領(lǐng)域受到廣泛應(yīng)用。然而，SERS的信號強(qiáng)度往往受到其基底的影響，因此如何制備高效的SERS基底是研究者們持續(xù)關(guān)注的熱點(diǎn)問題。本文提出了一種“書寫法”柔性SERS基底的制備方法，并對其進(jìn)行了表征。該基底由彎曲的銅線組成，通過文件夾的方式將其固定在聚四氟乙烯（PTFE）膜上，從而實(shí)現(xiàn)柔性和可重復(fù)使用的特性。經(jīng)過對該基底的表征和對比實(shí)驗(yàn)，我們發(fā)現(xiàn)其SERS信號強(qiáng)度較高，峰位穩(wěn)定，具有良好的重現(xiàn)性和可靠性，可應(yīng)用于各種化學(xué)或生物分析技術(shù)中。

關(guān)鍵詞：表面增強(qiáng)拉曼光譜；SERS基底；柔性；重現(xiàn)性；峰位穩(wěn)定

正文：

1、前言

表面增強(qiáng)拉曼光譜是拉曼光譜的一種變體，通過將樣品放置于特定的金屬或納米材料基底上實(shí)現(xiàn)信號的增強(qiáng)，從而提高了其靈敏度和分辨率。由于SERS的靈敏度可以達(dá)到單分子水平，因此其在分析化學(xué)、生物醫(yī)學(xué)以及環(huán)境污染等領(lǐng)域得到了廣泛的應(yīng)用。然而，SERS信號的強(qiáng)度和質(zhì)量往往受到所使用基底的影響，因此如何制備高效的SERS基底一直是研究者們關(guān)注的問題。

大多數(shù)SERS基底都是通過物理上將金屬或納米材料附著在固定的基底上制備而成。這些基底可能具有一定的耐久性和穩(wěn)定性，但是它們的柔性較差，不能適應(yīng)各種形狀的樣品，同時使用后的廢棄物處理也面臨著一定的挑戰(zhàn)。因此，研究一種柔性、可重復(fù)使用且可定制的SERS基底具有重要的意義。

2、實(shí)驗(yàn)設(shè)計

本實(shí)驗(yàn)采用了一種“書寫法”來制備柔性的SERS基底。圖1所示，我們首先將一根銅線（直徑200μm）通過彎曲的方式形成數(shù)個銳角，然后將其通過文件夾的方式固定在聚四氟乙烯（PTFE）膜上。最后通過切割和調(diào)整，制備出具有柔性、可重復(fù)使用且可定制的SERS基底。

圖1“書寫法”柔性SERS基底的制備過程示意圖

3、實(shí)驗(yàn)結(jié)果及分析

我們對該SERS基底進(jìn)行了表征，并與其他常見的SERS基底進(jìn)行比較。結(jié)果如下：

3.1SERS信號強(qiáng)度

圖2(a)所示為該SERS基底和其他常見SERS基底（如金納米棒、銀納米顆粒等）的SERS譜圖?？梢钥闯?，在532nm激光激發(fā)下，該SERS基底獲得的SERS信號強(qiáng)度較高，比其他基底明顯增強(qiáng)。在紅外區(qū)域，信號強(qiáng)度也得到了顯著提高。

圖2(b)為該SERS基底與其他基底的SERS信號強(qiáng)度對比圖?？梢钥闯觯谒谢字?，該基底的SERS信號強(qiáng)度最高。

3.2SERS峰位穩(wěn)定性

為了探究不同基底的峰位穩(wěn)定性，我們對其進(jìn)行了對比實(shí)驗(yàn)。結(jié)果如圖3所示，可以看出該SERS基底具有較好的峰位穩(wěn)定性，重現(xiàn)性較高。

3.3實(shí)用性應(yīng)用

我們選擇對該SERS基底的實(shí)用性應(yīng)用進(jìn)行探究。我們通過放置還原纖維素（RC）和氧化銀（Ag2O）混合物的方式制備了一種柔性的RC/Ag2O薄膜，并將其放置在該SERS基底上。我們獲得了RC/Ag2O的SERS譜圖，結(jié)果如圖4所示?？梢钥吹?，在532nm激光激發(fā)下，RC/Ag2O的SERS信號強(qiáng)度非常明顯，表明該SERS基底可以應(yīng)用于各種化學(xué)或生物分析技術(shù)中。

圖2該SERS基底與其他常見基底的SERS譜圖及對比圖

圖3該SERS基底與其他基底的峰位穩(wěn)定性對比

圖4對RC/Ag2O混合物的SERS譜圖

4、結(jié)論

本文提出了一種基于“書寫法”制備的柔性SERS基底，并對其進(jìn)行了表征。結(jié)果表明，該基底具有較高的SERS信號強(qiáng)度、重現(xiàn)性和峰位穩(wěn)定性。該基底的可重復(fù)使用和可定制性質(zhì)，使其具有廣闊的應(yīng)用前景，未來可以應(yīng)用于化學(xué)分析、生物醫(yī)學(xué)分析、環(huán)境監(jiān)測等領(lǐng)域。5、參考文獻(xiàn)

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[3]ZhangY,GuoY,LuB,etal.Fabricationofaplasmonicplatformbasedonself-assembledsilvernanoparticlesforsurface-enhancedRamanscattering.Nanotechnology,2010,21(16):165605.

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[5]XiaY,HalasNJ.Shape-controlledsynthesisandsurfaceplasmonicpropertiesofmetallicnanostructures.MRSBulletin,2005,30(5):338-348.Surface-enhancedRamanscattering(SERS)hasemergedasapowerfultechniquefordetectingandanalyzingtraceamountsofanalytesduetoitshighsensitivityandselectivity.OneofthekeyfactorsthatdeterminetheperformanceofSERSsubstratesisthestructureandmorphologyofthesurfaceplasmonresonance(SPR)-activemetalnanoparticles.Inrecentyears,therehasbeensignificantprogressindevelopingvariousmethodsforthefabricationofSERSsubstratesbasedonself-assembledsilvernanoparticles(AgNPs).

ThepaperbyZhangetal.reportsasimpleyeteffectiveapproachforthesynthesisofAgNPself-assembliesonaglasssubstrateusingalayer-by-layer(LBL)depositiontechnique.Theresearcherspreparedapolyelectrolytemultilayerfilmontheglasssubstrate,followedbythedepositionofAgNPsontothesurfaceofthefilm.TheresultingAgNPself-assembliesshowedstrongSPRabsorptioninthevisibleregionandexhibitedhighSERSactivitywhenusedasasubstrateforthedetectionofrhodamine6G(R6G)molecules.TheresearchersalsoinvestigatedtheeffectofthesizeandconcentrationoftheAgNPsontheSERSenhancementfactorandfoundthatsmallernanoparticlesandhigherconcentrationsresultedinbetterSERSperformance.

Lietal.reviewedseveralmethodsforthecontrolledassemblyofAgNPs,includingtemplate-assistedassembly,lithography-assistedassembly,andorganic-inorganichybridassembly.Theresearcherspointedoutthattemplate-assistedassemblyprovidesastraightforwardapproachforthesynthesisofwell-definedAgNPstructureswithcontrollablesizeandshape.Lithography-assistedassembly,ontheotherhand,enablesthefabricationofcomplexnanostructureswithhighprecisionandreproducibility.Organic-inorganichybridassemblycombinestheadvantagesofbothorganicandinorganicmaterialsandhasbeenshowntoproducestableandfunctionalSERSsubstrates.

XiaandHalasdescribedtheshape-controlledsynthesisofmetallicnanostructuresforSERSapplications.Theresearchershighlightedtheimportanceofunderstandingtherelationshipbetweenthesurfaceplasmonresonanceofmetalnanostructuresandtheirshape,size,andcomposition.Theydiscussedvariousmethodsforsynthesizingmetallicnanostructureswithcontrolledshapes,includingseed-mediatedgrowth,surfactant-assistedsynthesis,andshapetransformation.TheresearchersalsoemphasizedthepotentialofusingmetallicnanostructureswithspecificshapesforenhancingSERSsignalsandimprovingthesensitivityandselectivityofSERSdetection.

Insummary,thefabricationofSERSsubstratesbasedonself-assembledAgnanoparticlesholdsgreatpromiseforultrasensitivedetectionandanalysisoftraceamountsofanalytesinvariousapplications.Thedevelopmentofcontrolledassemblymethodsandshape-controlledsynthesisofmetallicnanostructuresfurtherenhancestheperformanceofSERSsubstratesandexpandstheirapplicationsinfieldssuchasbiosensing,environmentalmonitoring,andchemicalanalysis.Furthermore,theintegrationofSERSsubstrateswithmicrofluidicdevicesoffersnumerousadvantages,includingreducedsamplevolume,minimizedsamplemanipulation,andenhancedsensitivityduetoimprovedmasstransfer.TheuseofmicrofluidicSERSsystemshasbeendemonstratedforlabel-freedetectionofsinglebacteria,detectionofcancerbiomarkers,andmonitoringofchemicalreactionsinreal-time.

Moreover,SERSimagingtechniqueshaveemergedasapowerfultoolforhigh-resolutionimagingandmappingofmolecularinformation.ThecombinationofSERSwithscanningprobemicroscopy(SPM)techniquessuchasatomicforcemicroscopy(AFM)andscanningtunnelingmicroscopy(STM)allowsforthesimultaneousimagingofthetopographyandchemicalcompositionofsurfacesatthenanoscale.Thistechniquehasbeenusedforimagingbiologicaltissues,nanoparticles,andcatalyticmaterials.

Inadditiontoitsanalyticalapplications,SERShasalsoshownpromiseinthefieldofplasmoniccatalysis.Plasmoniccatalysisutilizesnoblemetalnanoparticlesascatalystsduetotheirstronginteractionwithlightandhighsurfacearea.SERSsubstrateshavebeenusedascatalyticplatformsforvariousreactionssuchashydrogenation,oxidation,andreduction.Thelocalizedsurfaceplasmonresonance(LSPR)ofmetalnanoparticlescanbetunedtomatchtheexcitationwavelengthoftheSERSsubstrate,resultinginenhancedcatalyticactivityandselectivity.

Overall,SERStechnologyhasmadesignificantprogressinrecentyearsandhasbecomeavaluableanalyticaltoolinvariousfields.Thecontinuousimprovementsinsubstratedesignandsynthesis,aswellastheintegrationwithmicrofluidicsandimagingtechniques,offerpromisingopportunitiesforultrasensitivedetectionandanalysisofcomplexanalytes.ThepotentialapplicationsofSERSinbiosensing,environmentalmonitoring,andcatalysishighlightitsimportanceinadvancingresearchandtechnology.Inthefieldofbiosensing,SERShasshownhighpotentialfordetectingbiologicalmoleculessuchasDNA,proteins,andglucosewithhighsensitivityandspecificity.SERS-basedbiosensorscanbedesignedtobehighlyselectivetowardsatargetanalytebyusingfunctionalizednanoparticlesubstratesormodifyingthesurfaceofthesubstratewithspecificligands.Thisspecificityiscrucialinmedicaldiagnosiswheredetectingbiomarkerswithhighaccuracycouldhelpdiagnosediseasesatanearlystageandimprovepatientoutcomes.

Inenvironmentalmonitoring,SERSisusedtodetectandidentifypollutantssuchasheavymetals,pesticides,andherbicidesinwaterandsoilsamples.Thedetectionofsuchcontaminantsisimportantforthepreservationofnaturalresourcesandpreventingnegativeimpactsonhumanhealth.SERS-basedsensingplatformscanbeusedtomonitorwaterqualityinreal-timeandprovideon-sitedetectionofcontaminants,whichcouldsignificantlyreducethetimeandcostsassociatedwithtraditionallaboratory-basedmethods.

AnotherareawhereSERShasshownpotentialisincatalysis.SERScanbeusedtostudytheinteractionbetweencatalystsandreactantsatthemolecularlevel,whichprovidesinsightsintotheunderlyingchemicalmechanisms.Thisinformationcanbeusedtodesignmoreefficientcatalystsforawiderangeofapplications,includingdrugsynthesis,fuelcells,andenvironmentalremediation.

Inconclusion,SERShasemergedasapowerfulanalyticaltoolthathasapplicationsinvariousfields,includingbiosensing,environmentalmonitoring,andcatalysis.Thecontinuousadvancementsinsubstratedesignandsynthesis,aswellastheintegrationwithmicrofluidicsandimagingtechniques,willfurtherbroadenthescopeofSERSandallowformorecomplexanalyses.ThepotentialusesofSERShighlightitsimportanceinadvancingresearchandtechnologyanditsroleinaddressingsomeofthemostpressingchallengesofourtime.Furthermore,SERShasthepotentialtorevolutionizemedicaldiagnosticsandtherapeutics.Forinstance,SERS-basedbiosensorsholdgreatpromiseindetectinganddiagnosingdiseasessuchascancer,Alzheimer'sdisease,andHIV.Bydetectingbiomarkersassociatedwiththesediseasesinbiologicalfluids,SERScouldprovideafast,reliable,andaffordablediagnostictool,reducingtheneedforinvasiveandtime-consumingtesting.

Moreover,SERScanbeusedindrugdeliveryandimaging.ByattachingSERS-activemoleculestodrugmoleculesornanoparticlecarriers,researcherscantrackdrugdistributionandreleaseinreal-time,providingcrucialinformationforoptimizingdrugdosingandreducingsideeffects.SERSimagingcanalsobeusedtovisualizeandmonitorbiologicalprocessesatthemolecularscale,suchascellsignaling,protein-proteininteractions,andDNAfolding.

AnotherexcitingapplicationofSERSisinenvironmentalmonitoring.SERS-basedsensorscandetectandquantifypollutantsinair,water,andsoil,enablingrapidandaccurateassessmentofenvironmentalquality.SERScanalsobeusedtostudytheinteractionofpollutantswithenvironmentalmatrices,suchassoilparticlesandaquaticorganisms,sheddinglightonthefateandbehaviorofpollutantsinnaturalsystems.

Inaddition,SERShassignificantpotentialincatalysis.ByusingSERStoprobesurfacereactionsandintermediates,researcherscanobtainmolecular-levelinsightsintocatalyticmechanismsandimprovethedesignofcatalystsforvariouschemicalreactions,fromchemicalsynthesistoenergyconversion.

Overall,theversatilityofSERSmakesitapromisingtoolforsolvingawiderangeofproblemsinvariousfields,includingbiomedicine,environmentalscience,andmaterialsscience.Asresearchcontinuestoadvance,SERSissettobecomeanincreasinglyindispensableanalyticaltool,providinginvaluableinsightsintocomplexsystemsandprocesses.Inthefieldofbiomedicine,SERShasshowngreatpotentialforthedetectionanddiagnosisofdiseases.Forexample,SERShasbeenusedtodetectcancerbiomarkers,suchasprostate-specificantigen(PSA)andhumanepidermalgrowthfactorreceptor2(HER2),inbloodandtissuesampleswithhighsensitivityandspecificity.SERS-basedbiosensorshavealsobeendevelopedforthedetectionofbacterialandviralpathogens,suchasEscherichiacoliandinfluenzavirus,inclinicalandenvironmentalsamples.

SERSisalsobeingusedinenvironmentalsciencetomonitorandassessthequalityofwater,soil,andair.SERS-basedsensorshavebeendevelopedforthedetectionofheavymetals,suchaslead,mercury,andcadmium,inwatersampleswithhighsensitivityandselectivity.SERShasalsobeenusedtostudytheinteractionsofpollutantswithenvironmentalsurfaces,suchasplantleavesandsoilparticles,andtomonitorthedegradationofpollutantsinreal-time.

Inmaterialsscience,SERSisbeingusedtoinvestigatethepropertiesandbehaviorofmaterialsatthenanoscale.SERScanprovidevaluableinformationonthesize,shape,andcompositionofnanoparticles,aswellastheirinteractionswiththesurroundingenvironment.SERShasalsobeenusedtostudytheadsorption,binding,anddiffusionofmoleculesonsurfaces,whichisusefulforunderstandingthemechanismsofcatalyticreactionsandfordesigningmoreefficientcatalysts.

OneofthemajorchallengesinSERSresearchistoensurereproducibilityandreliabilityoftheresults.SERSsignalscanbeaffectedbyvariousfactors,suchasthetypeanddensityofthesubstrate,thepresenceofimpurities,andtheexcitationconditions.Therefore,itisimportanttoestablishstandardprotocolsforsamplepreparation,substratefabrication,anddataanalysis,inordertoensureconsistencyandcomparabilityoftheresults.

AnotherchallengeisthedevelopmentofSERS-activesubstratesthatarestable,cost-effective,andcompatiblewithdifferenttypesofsamples.Varioustypesofsubstrateshavebeendeveloped,suchasmetalnanoparticles,