Asequentialoptimizationmethodofdigitalprojectionvatphotopolymerizationfor3Dmultiscaledevices

Abstract

Digitalprojectionvatphotopolymerization(DPVP)systemsarehelpfuladditivemanufacturingmethodsforsmall-sizeandcustom-madedevices.Inparticular,devicesmadeoftransparentmaterialsareadvantageousfor internalobservationorreal-timemeasurement.However,sincethetransparentphotocurableresintransmitsalargeamountoflight,itisn'teasytocontroltheamountofphotopolymerizationtargetedintheDPVPsystem. Inaddition,thetoxicityofthephotoinitiatorandmediumofthephotocurableresinisoneofthechallengestobesolvedinapplyingtheDPVPsystemtothebiofield.ManystudieshavesuggestedmethodsforcontrollingthephotopolymerizationoftheDPVPsystem.However,themethodofusinganadditiveinthephotocurableresinhasaproblemofloweringthetransparencyofthephotocurableresin.Inaddition,thereareinsufficientstudiestocomprehensivelydealwiththeDPVPsystem'sfabricationissues.ThisstudypresentsasequentialoptimizationmethodofDPVPtodevelop3Dmultiscaledevices.Asatransparentandbiocompatiblephotocurableresinmaterial,biomass-basedisosorbidewasused.Isosorbide-basedphotocurableresin hashightransparencyof89.67%andisabiocompatiblematerialofglucoseleveltoxicity.Asequentialoptimizationmethod(SOM)wasproposedtoapplyisosorbide-basedphotocurableresinstotheDPVPsystem.SOMpresentedasystematicapproachtominimizetrialanderrorconsideringtheDPVP system'sfabricationissues.ThroughthisSOM,thetrialanderroroftheDPVPsystemdecreasedbyhalfcomparedtothepreviousexperimentalmethod. Electrospinningandtwo-photonpolymerizationtechniquesareusedtofabricatemultiscalethree-dimensionaldevices.ThesecomplementthemanufacturinglimitationsoftheDPVPsystem.Liquid-basedexchangeablegradientosmosis(LEGO)chipisdevelopedtobeappliedtocellcultureanddrugdeliveryusingtheDPVPsystemandelectrospinning.ThetransmittanceoftheLEGOchipcanbecontrolledbyadjustingthechannelflowspeedandthediameterofthemembranenanofiber.Inaddition,theLEGOchipcanbeappliedasadynamictranswelldevicethatenablescellcultureinadynamicenvironment.AnotherMultiscale3DdevicewasfabricatedbyintegratingtheDPVPandtheTPPsystems.TheinitialconditionsfortheDPVPprocessto preventdamagetotheTPPstructurewerederivedfromtheproposedSOM.Throughthis,athree-dimensionalstructurewithalevelofseveralμmandathree-dimensionalstructurewithalevelofseveralmmwereintegratedintoonedeviceandfabricated. ThisstudypresentedasystematicapproachofDPVPusingSOMtomakea3Dmultiscaledevice,andintegrationwithotherAMtechnologieswasattempted.Thisresultisappliedtoapplicationsthatrequiremultiscalestructuresinonedevice,suchasLabonachip,organonachip,etc.Inaddition,aresultofhybridtechnologyisexpectedtobroadentheapplicationareaoftheDPVPsystemnotonlyinthebiofieldbutalsoinvariousindustrialfields. |디지털투영방식광중합적층(DPVP)시스템은작은사이즈와맞춤형소자를제작하기에유용한적층제조방법이다.특히,투명한재질의소자개발은내부관찰이나실시간측정에유리하다.하지만DPVP시스템에서투명한광경화성수지는많은양의빛을투과시키기때문에목표한만큼의광중합을제어하기가어렵다.이는DPVP시스템을이용하여투명하고미세한구조물을제작하기어렵다는것을의미한다.또한광경화성수지의광개시제와매질이가지는독성은DPVP시스템을바이오분야에적용하는데해결해야할과제중하나다.기존에많은연구에서DPVP시스템의광중합제어방법들이제시되고있다.하지만광경화성수지에첨가제를사용하는방법은광경화성수지의투명도를떨어뜨리는문제가있다.또한DPVP에서발생할수있는불량을통합적으로다루는연구는부족하다.이연구에서는3Dmultiscale투명소자개발을위한DPVP의순차적최적화방법을제시한다.투명하고생체적합한광경화성수지의재료는biomass기반의isosorbide를사용하였다.Isosorbide기반의광경화성수지는89.67%의높은투명도를가지며,생체적합한물질로포도당수준의독성을가진다.Isosorbide기반광경화성수지를DPVP시스템에적용하기위해순차적최적화방법을제안하였다.순차적최적화방법은DPVP공정에서발생할수있는문제들을고려하여시행착오를최소화할수있도록체계적인접근법을제시하였다.이를통해DPVP시스템의시행착오를기존실험방법에비해절반으로줄였다. Multiscale의3차원소자를제작하기위해electrospinning과two-photonpolymerization기술을융합하여DPVP시스템의제작한계를보완하였다.DPVP시스템과electrospinning을이용하여세포배양및약물전달에응용할수있는Liquid-basedexchangeablegradientosmosis(LEGO)chip을개발하였다.LEGOchip의투과율은채널유속과membrane나노섬유의직경을조절하여제어할수있다.또한LEGOchip은동적인환경에서세포배양을가능하게하는dynamictranswell소자로응용할수있다.또다른Multiscale의3차원소자는DPVP시스템과TPP시스템을통합하여제작되었다.TPP구조물의파손을막기위한DPVP공정초기조건은앞서제안된순차적최적화방법을통해도출되었다.이를통해수μm수준의3차원구조물과수mm수준의3차원구조물을하나의디바이스로통합하여제작하였다. 본연구에서는3Dmultiscale투명소자를만들기위해순차적최적화방법을이용한DPVP의체계적인접근방법을제시하고다른적층제조기술과의통합을시도하였다.이는Labonachip,organonachip등과같이하나의device에서multiscale의구조물을필요로하는application에적용할수있다.또한이러한융합기술은바이오분야뿐아니라다양한산업분야에서도DPVP시스템의응용영역을넓혀줄것으로기대된다.