毕业论文外文翻译-壳聚糖-茶多酚纳米颗粒的合成和性质及细胞毒性的研究

毕业论文外文翻译-壳聚糖-茶多酚纳米颗粒的合成和性质及细胞毒性的研究SynthesisandCharacterizationofChitosan-TeaPolyphenolNanoparticlesandTheirCytotoxicityStudyAbstractInthisstudy,chitosan-teapolyphenolnanoparticlesweresynthesizedusingasimpleandgreenmethod.Thephysicalandchemicalpropertiesofthenanoparticleswerecharacterizedbyvarioustechniquesincludingdynamiclightscattering,Fouriertransforminfraredspectroscopy,andtransmissionelectronmicroscopy.ThecytotoxicityofthenanoparticleswasevaluatedusingMTTassayandcellmorphologicalobservation.Theresultsshowedthatthesynthesizednanoparticleshadadiameterof183.6nm,apositivesurfacechargeof27.54mV,andapolydispersityindexof0.22.Thenanoparticlesexhibitedgoodbiocompatibilitywithcellsandlowcytotoxicity,indicatingtheirpotentialapplicationindrugdelivery.Keywords:chitosan,teapolyphenol,nanoparticles,cytotoxicity,drugdeliveryIntroductionNanoparticleshavebeenextensivelystudiedinthefieldofdrugdeliveryduetotheiruniquepropertiessuchashighsurfacearea,highreactivity,andenhancedpermeationandretentioneffect.Amongvariousmaterials,chitosanhasattractedgreatattentionasadrugdeliverycarrierduetoitsbiocompatibility,biodegradability,andlowtoxicity(1).However,chitosannanoparticlesoftensufferfromlowstabilityandpoorsolubility,whichlimittheirapplicationindrugdelivery.Toovercometheselimitations,variousmethodshavebeendevelopedtoimprovethestabilityandsolubilityofchitosannanoparticles,suchascrosslinking,coating,andblendingwithothermaterials(2).Teapolyphenolsarenaturalplantextractswithvariousbiologicalactivitiessuchasantioxidation,anticancer,andanti-inflammatoryeffects(3).Therefore,teapolyphenolshavebeenwidelyusedasfunctionalfoodingredientsandnutraceuticals.Inaddition,teapolyphenolshavealsobeeninvestigatedaspotentialanticanceragentsduetotheirabilitytoinduceapoptosisandinhibitcellproliferation(4).However,teapolyphenolssufferfromlowbioavailabilityandpoorstability,whichlimittheirtherapeuticefficacy(5).Toimprovethestabilityandsolubilityofchitosannanoparticlesandenhancethetherapeuticefficacyofteapolyphenols,wesynthesizedchitosan-teapolyphenolnanoparticlesusingasimpleandgreenmethod.Thephysicalandchemicalpropertiesofthenanoparticleswerecharacterized,andthecytotoxicityofthenanoparticleswasevaluated.MaterialsandMethodsMaterialsChitosan(degreeofdeacetylation>85%,molecularweight300,000-400,000g/mol)waspurchasedfromSigma-Aldrich(USA).Teapolyphenolswereextractedfromgreentealeavesandpurifiedusingethanolprecipitationaccordingtoapreviousmethod(6).Dulbecco'smodifiedeaglemedium(DMEM),fetalbovineserum(FBS),andpenicillin/streptomycinsolutionwereobtainedfromGibco(USA).3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide(MTT)anddimethylsulfoxide(DMSO)werepurchasedfromSigma-Aldrich(USA).Allreagentswereofanalyticalgradeandusedwithoutfurtherpurification.SynthesisofChitosan-TeaPolyphenolNanoparticlesChitosan-teapolyphenolnanoparticleswerepreparedusingasimpleandgreenmethod.Briefly,chitosan(50mg)wasdissolvedin5mlofaceticacid(1%,v/v),andteapolyphenol(5mg)wasdissolvedin5mlofdistilledwater.Theteapolyphenolsolutionwasaddeddropwiseintothechitosansolutionundermagneticstirringatroomtemperature.Themixturewasstirredforanother30mintoobtainahomogeneoussolution.Thesolutionwasthenaddeddropwiseto20mlof0.1Msodiumhydroxidesolutionundermagneticstirringtoinducenanoparticleformation.Themixturewasstirredfor60minandthencentrifugedat10,000rpmfor10mintoremoveunreactedmaterials.Thenanoparticleswerewashedthreetimeswithdistilledwaterandfreeze-driedforfurtheruse.CharacterizationofChitosan-TeaPolyphenolNanoparticlesThephysicalandchemicalpropertiesofchitosan-teapolyphenolnanoparticleswerecharacterizedbyvarioustechniques.Thenanoparticlesizeandzetapotentialweremeasuredusingadynamiclightscatteringinstrument(Malvern,UK).Theparticlemorphologywasobservedusingatransmissionelectronmicroscope(TEM,JEOL,Japan)afternegativestainingwithuranylacetate.ThechemicalstructureofthenanoparticleswasanalyzedbyFouriertransforminfraredspectroscopy(FTIR,PerkinElmer,USA)usingKBrpellets.CytotoxicityStudyThecytotoxicityofchitosan-teapolyphenolnanoparticleswasevaluatedusingMTTassayandcellmorphologicalobservation.Humangastriccancercells(SGC-7901)wereseededina96-wellplateatadensityof5×103cellsperwellinDMEMsupplementedwith10%FBSand1%penicillin/streptomycinsolution.After24h,thecellsweretreatedwithdifferentconcentrationsofchitosan-teapolyphenolnanoparticles(0,12.5,25,50,100,and200μg/ml)for24h.Then,theMTTsolution(5mg/ml)wasaddedtoeachwellandincubatedforanother4h.Thesupernatantwasdiscarded,andDMSOwasaddedtodissolvetheformazancrystals.Theabsorbancewasmeasuredat490nmusingamicroplatereader(BioTek,USA).Cellviabilitywascalculatedasapercentageofthecontrolgroup.Forcellmorphologicalobservation,thecellsweretreatedwithchitosan-teapolyphenolnanoparticles(50μg/ml)for24handthenobservedunderaninvertedmicroscope(Olympus,Japan).ResultsandDiscussionsCharacterizationofChitosan-TeaPolyphenolNanoparticlesChitosan-teapolyphenolnanoparticlesweresynthesizedusingasimpleandgreenmethod,andthephysicalandchemicalpropertiesofthenanoparticleswerecharacterizedbyvarioustechniques.AsshowninFigure1AandB,thenanoparticleshadadiameterof183.6nmandapositivesurfacechargeof27.54mV,indicatinggoodstabilityandlowaggregation.Thenanoparticlesexhibitedanarrowsizedistributionwithapolydispersityindexof0.22,indicatinggoodhomogeneity.TheTEMimageofthenanoparticlesshowedasphericalshapewithasmoothsurface,andthesizeobservedbyTEMwasconsistentwiththeDLSmeasurement(Figure1C).FTIRspectroscopywasusedtoinvestigatethechemicalstructureofthenanoparticles.Thecharacteristicabsorptionpeaksofchitosanat1658cm-1(amideI)and1569cm-1(amideII)wereobservedinthespectrumofchitosan-teapolyphenolnanoparticles,indicatingthesuccessfulformationofnanoparticles(Figure1D).CytotoxicityStudyThecytotoxicityofchitosan-teapolyphenolnanoparticleswasevaluatedusingMTTassayandcellmorphologicalobservation.AsshowninFigure2A,thecellviabilityofSGC-7901cellstreatedwithchitosan-teapolyphenolnanoparticleswasabove90%atconcentrationsupto200μg/ml,indicatinggoodbiocompatibilitywithcellsandlowcytotoxicity.Themorphologicalobservationofcellstreatedwithchitosan-teapolyphenolnanoparticles(50μg/ml)showednoobviouschangescomparedwiththecontrolgroup(Figure2B).ConclusionInthisstudy,wesuccessfullysynthesizedchitosan-teapolyphenolnanoparticlesusingasimpleandgreenmethod.Thenanoparticleshadadiameterof183.6nm,apositivesurfacechargeof27.54mV,andapolydispersityindexof0.22,indicatinggoodstabilityandlowaggregation.Thenanoparticlesexhibitedgoodbiocompatibilitywithcellsandlowcytotoxicity,indicatingtheirpotentialapplicationindrugdelivery.Furtherstudiesareneededtoinvestigatetheinvivoefficacyandsafetyofthesenanoparticles.Figure1Characterizationofchitosan-teapolyphenolnanoparticles.(A)Sizedistributionofnanoparticlesmeasuredbydynamiclightscattering;(B)Zetapotentialofnanoparticles;(C)Transmissionelectronmicroscopyimageofnanoparticles;(D)Fouriertransforminfraredspectroscopyspectraofchitosanandchitosan-teapolyphenolnanoparticles.Figure2Cytotoxicityevaluationofchitosan-teapolyphenolnanoparticles.(A)MTTassayofSGC-7901cellstreatedwithdifferentconcentrationsofnanoparticles(n=3,*p<0.05comparedwithcontrol);(B)MorphologicalobservationofSGC-7901cellstreatedwithchitosan-teapolyphenolnanoparticles(50μg/ml)andcontrolgroup.AcknowledgmentsThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(No.81673508).References1.QiL,XuZ,JiangX,HuC,ZouX,Preparationandantibacterialactivityofchitosannanoparticles.CarbohydrRes.2004;339:2693-2700.2