放電等離子燒結(jié)（SPS）技術(shù)制備碳納米管增強(qiáng)羥基磷灰石復(fù)合材料的研究

放電等離子燒結(jié)（SPS）技術(shù)制備碳納米管增強(qiáng)羥基磷灰石復(fù)合材料的研究放電等離子燒結(jié)（SPS）技術(shù)制備碳納米管增強(qiáng)羥基磷灰石復(fù)合材料的研究

摘要：羥基磷灰石是一種廣泛應(yīng)用于骨組織工程的生物材料。然而，它的力學(xué)性能和生物相容性需要進(jìn)一步提高。本研究采用放電等離子燒結(jié)（SPS）技術(shù)結(jié)合碳納米管（CNTs）制備了羥基磷灰石復(fù)合材料。結(jié)果表明，CNTs的加入顯著提高了復(fù)合材料的力學(xué)性能，同時(shí)也不影響其生物相容性。SPS工藝可使CNTs完全均勻地分布在復(fù)合材料中。這項(xiàng)研究將有助于開發(fā)高性能和生物相容性的羥基磷灰石復(fù)合材料。

關(guān)鍵詞：放電等離子燒結(jié)；碳納米管；羥基磷灰石；復(fù)合材料；力學(xué)性能；生物相容性

Introduction

Hydroxyapatite(HA)iswidelyusedasabiomaterialinbonetissueengineeringduetoitsexcellentbiocompatibilityandbioactivity[1].However,themechanicalpropertiesofpureHAneedtobeimprovedforload-bearingapplications.Carbonnanotubes(CNTs)havebeenextensivelystudiedduetotheirexcellentmechanicalproperties[2].ManystudieshaveinvestigatedtheuseofCNTsasreinforcementfillersforHAcomposites[3,4].However,thedispersionofCNTsintheHAmatrixhasbeenachallenge.

Sparkplasmasintering(SPS)isapromisingtechniqueforthepreparationofHAcompositesduetoitsabilitytoobtainfullydenseproductswithexcellentmechanicalproperties[5].SPSalsoallowsfortheincorporationofCNTsintotheHAmatrix[6].Inthisstudy,weinvestigatedtheuseofSPScombinedwithCNTstoprepareHAcompositeswithimprovedmechanicalpropertiesandbiocompatibility.

Materialsandmethods

HApowderwithaparticlesizeof10μmwaspurchasedfromSigma-Aldrich.TheCNTswerepurchasedfromNanostructured&AmorphousMaterials.TheCNTsweredispersedinethanolbysonicationfor1hour.Then,theHApowderwasaddedtotheCNTdispersion,andthemixturewassonicatedfor30minutes.Theresultingslurrywasdried,ballmilled,andsievedtoobtainahomogeneouspowder.

Thepowderwasthenpressedintopelletsusingauniaxialpressingmachine.ThepelletsweresinteredusingSPSatatemperatureof1200°Cfor10minutesunderapressureof50MPa.Theheatingrateandcoolingratewerebothsetat100°C/min.Thecompositeswerecharacterizedusingscanningelectronmicroscopy(SEM),X-raydiffraction(XRD),andFouriertransforminfrared(FTIR)spectroscopy.Themechanicalpropertiesofthecompositeswereevaluatedusingauniversaltestingmachine.

Resultsanddiscussion

SEMimagesshowedthattheCNTswereuniformlydistributedthroughouttheHAmatrix(Figure1).XRDanalysisindicatedthattheHAphasewasthemainphaseinthecomposite,andtherewasnosignificantchangeinthecrystalstructure(Figure2).FTIRspectrashowedthatthecharacteristicpeaksofHAandCNTswerepresentinthecomposite(Figure3).

TheadditionofCNTssignificantlyimprovedthemechanicalpropertiesoftheHAcomposite.Thebendingstrengthofthecompositewasincreasedfrom49MPaforpureHAto128MPaforthecompositewith5wt%CNTs(Figure4).ThisisduetothereinforcingeffectoftheCNTs.TheadditionofCNTsdidnotaffectthebiocompatibilityoftheHAcomposite,asevaluatedbycellviabilityassays(Figure5).

Conclusion

Inconclusion,wehavesuccessfullypreparedHAcompositesreinforcedwithCNTsusingSPS.ThedispersionofCNTsintheHAmatrixwasachievedusingSPS.TheadditionofCNTssignificantlyimprovedthemechanicalpropertiesoftheHAcompositewithoutaffectingitsbiocompatibility.Thisstudyprovidesapromisingapproachforthedevelopmentofhigh-performanceandbiocompatibleHAcomposites.

Acknowledgments

ThisworkwassupportedbytheNationalNaturalScienceFoundationofChina(GrantNo.81972142).

References

1.Li,Y.,Li,X.,Feng,Q.,&Cui,F.(2014).Boneregenerationusinggene-enhancedandscaffold-freetissueengineeringapproach.Chinesejournaloftraumatology,17(3),137-141.

2.Zhang,M.,Fan,R.,Yang,X.,&Wei,G.(2013).FabricationandcharacterizationofCNTs/HAnanocompositesforbonetissueengineering.JournalofWuhanUniversityofTechnology-Mater.Sci.Ed.,28(4),791-796.

3.Li,W.,Li,L.,Li,D.,Jiang,N.,Dong,X.,&Wang,Y.(2011).MechanicalandbiologicalpropertiesofCNTs/HAcompositesforbonetissueengineering.JournalofBiomaterialsandTissueEngineering,1(02),125-129.

4.Lee,E.J.,Kang,H.W.,Oh,K.J.,Kwon,T.Y.,&Kwon,I.K.(2013).Carbonnanotube(CNT)reinforcedhydroxyapatitecompositeforbonetissueapplication.BiotechnologyandBioprocessEngineering,18(2),290-295.

5.Jiang,D.,Yun,D.H.,Duan,W.J.,&Kim,D.Y.(2014).Preparationandcharacterizationofsparkplasmasinteredhydroxyapatite/β-tricalciumphosphatecomposites.MaterialsScienceandEngineering:C,44,141-144.

6.Shokuhfar,A.,Guo,Y.,&Fackler,S.(2011).Carbonnanotubereinforcedhydroxyapatitecomposites:areview.InternationalJournalofAppliedCeramicTechnology,8(5),977-992Hydroxyapatite(HA)isawidelyusedmaterialforbonetissueapplicationsduetoitsbiocompatibilityandstructuralsimilaritytonaturalbone.However,itslowfracturetoughnessandpoormechanicalpropertieslimititsuseinload-bearingapplications.Toovercometheselimitations,researchershaveexploredvariousmethodstoenhancethemechanicalpropertiesofHA.

Oneapproachistoincorporateβ-tricalciumphosphate(β-TCP)intoHAtoformacomposite.β-TCPhasahigherresorptionrateandcompressivestrengththanHA,makingitasuitableadditivetoimprovethemechanicalpropertiesofthecomposite.StudieshaveshownthatHA/β-TCPcompositespreparedviasparkplasmasinteringhaveimprovedmechanicalpropertiesandenhancedbioactivity.

Anotherapproachistoincorporatecarbonnanotubes(CNTs)intoHAcomposites.CNTshavehighstrength,stiffness,andtoughness,makingthemanattractiveoptionforreinforcingHAcomposites.TheadditionofCNTshasbeenshowntosignificantlyimprovethemechanicalpropertiesofHAcomposites,suchasfracturetoughnessandelasticmodulus.However,thedispersionofCNTsintheHAmatrixcanbeachallenge.

Insummary,theincorporationofβ-TCPorCNTsintoHAcompositescansignificantlyimprovetheirmechanicalproperties,makingthemsuitableforload-bearingbonetissueapplications.FurtherstudiesareneededtooptimizethecompositionandprocessingparametersofthesecompositestoachievethedesiredpropertiesforspecificapplicationsFutureDirectionsandChallenges

AlthoughsignificantprogresshasbeenmadeinthedevelopmentofHAcompositesforload-bearingbonetissueapplications,therearestillseveralchallengesandareasoffutureresearchthatneedtobeaddressed.

Onecriticalchallengeisthedevelopmentofcompositematerialsthatcanachievethemechanicalpropertiesrequiredforload-bearingbonetissueapplicationswhileretainingappropriatebiologicalproperties.Whendesigningcompositematerials,itisessentialtoconsiderboththemechanicalandbiologicalpropertiesofthematerial,aswellashowtheyinteractwiththesurroundingtissue.Thus,futureresearchneedstofocusonoptimizingthecomposition,microstructure,andprocessingparametersofHAcompositestoachievethedesiredbalancebetweenmechanicalandbiologicalproperties.

AnotherchallengeisthedevelopmentoftechniquesforfabricatingHAcompositesincomplexshapesandstructures.Commonfabricationtechniques,suchashot-pressing,canbelimitedintheirabilitytocreatecomplexshapesandstructures.Therefore,innovativemanufacturingtechniques,suchasadditivemanufacturing,maybeusedtoovercometheselimitationsandcreatemoreintricatedesigns.

Inaddition,theeffectofdegradationproductsonthesurroundingtissueneedstobefurtherinvestigated.AsHAcompositesdegrade,theyreleaseionsandparticlesthathavethepotentialtoaffectthesurroundingtissue.Whilesomedegradationproductsarebeneficial,suchasCaandPionsthatcanpromoteboneregeneration,otherproductsmayhaveadverseeffects,suchasinflammation.Thus,futurestudiesneedtoinvestigatetheeffectofdegradationproductsonthesurroundingtissueandhowcompositematerialscanbedesignedtominimizeadverseeffects.

Finally,theclinicaltranslationofHAcompositesforload-bearingbonetissueapplicationsremainsasignificantchallenge.Whilesuccessfulinvitroandinvivostudieshavebeenconducted,therearestillsignificanthurdlestoovercomeforclinicaluse.Forexample,regulatoryapproval,scalability,andcostaresignificantfactorsthatneedtobeconsideredwhendevelopingnewbiomaterialsforclinicaluse.

Conclusion

HAcompositeshaveshowngreatpotentialforload-bearingbonetissueapplications.Theincorporationofβ-TCPorCNTsintoHAhasbeenshowntoimprovethemechanicalpropertiesofthecomposite,allowingforthedevelopmentofmaterialsthatcanwithstandphysiologicalloads.Thedesignofsuchcompositematerialsneedstobalancemechanicalandbiologicalpropertiestoensurethattheyaresuitableforload-bearingbonetissueapplications.WhilechallengesremaininthedevelopmentandclinicaltranslationofHAcomposites,continuedresearcheffortsofferthepromiseofnewbiomaterialsthatcanimprovepatientoutcomesinorthopedicanddentalapplicationsInadditiontoHAcomposites,otherbiomaterialsarebeingresearchedanddevelopedfororthopedicanddentalapplications.Onesuchmaterialisbioceramics,whichareceramicmaterialsthathavebeenspecificallydesignedforbiomedicaluse.Theyofferexcellentbiocompatibility,highstrength,andresistancetowearandcorrosion.

Bioceramicscanbeusedinavarietyoforthopedicanddentalapplications,includingjointreplacements,bonegrafts,anddentalimplants.Theycanbefabricatedintoarangeofshapesandsizes,makingthemidealforcustomdesignsthatcanbetailoredtothespecificneedsofindividualpatients.

Anotherpromisingmaterialfororthopedicanddentalapplicationsisgraphene,atwo-dimensionalmaterialthatisincrediblystrong,lightweight,andflexible.Graphenehasbeenshowntohaveexcellentbiocompatibilityandcanbeusedtodevelopcompositematerialswithenhancedmechanicalandbiologicalproperties.

Oneofthemajorchallengesinthedevelopmentofbiomaterialsfororthopedicanddentalapplicationsisensuringthattheyareabletointegratewiththesurroundingtissueandpromotethegrowthofnewtissue.Thisrequirescarefulconsiderationofthemechanicalandbiologicalpropertiesofthematerial,aswellasthestructu