頭發(fā)再生的微針陣列在可控區(qū)域的3D打印 3D printing of microneedle arrays for hair regeneration in a controllable region

Lietal.MolecularBiomedicine(2023)4:1MolecularBiomedicine

/10.1186/s43556-022-00102-2

RESEARCHOpenAccess

checkfor

updates

3Dprintingofmicroneedlearraysforhairregenerationinacontrollableregion

RongLi1?,XinYuan1,2?,LiZhang1,XuebingJiang1,LiLi1,YiZhang1,LinghongGuo3,4,XideDai1,HaoCheng5,XianJiang3,4andMalingGou1*

Abstract

Hairlossisacommonskindiseasethatcausesintenseemotionalsufering.Hairregenerationinapersonalizedareaishighlydesirableforpatientswithdiferentbaldingconditions.However,theexistingpharmaceuticaltreatmentshavedifcultypreciselyregeneratinghairinadesiredarea.Here,weshowamethodtopreciselycontrolthehair

regenerationusingcustomizedmicroneedlearrays(MNAs).TheMNAwithacustomizedshapeisfastfabricatedbyastaticopticalprojectionlithographyprocessinseconds,whichisa3Dprintingtechnologydevelopedbyourgroup.Inthemousemodel,MNAtreatmentcouldinducehairregrowthinadefnedareacorrespondingtothecustomizedshapeofMNA.AndtheregeneratedhairpromotedbyMNAshadimprovedquality.CellularandmolecularanalysisindicatedthatMNAtreatmentcouldrecruitmacrophagesinsituandtheninitiatetheproliferationofhairfollicle

stemcells,therebyimprovinghairregeneration.Meanwhile,theactivationoftheWnt/β-cateninsignalingpathwaywasobservedinhairfollicles.TheexpressionsofHgf,Igf1andTnf-αwerealsoupregulatedinthetreatedskin,which

mayalsobebenefcialfortheMNA-inducedhairregeneration.Thisstudyprovidesastrategytopreciselycontrolhairregenerationusingcustomizedmicroneedlearraysbyrecruitingmacrophagesinsitu,whichholdsthepromiseforthepersonalizedtreatmentofhairloss.

KeywordsMicroneedles,Hairregeneration,Personalizedtreatment,3Dprinting,Regenerativemedicine

Introduction

Hairlossisacommonskindiseasethatimpactsthebodyimage,socialinteractions,andpsycho-emotionalhealth

[1

,

2

].Inclinicalpractice,alopeciaischaracterizedby

?RongLiandXinYuancontributedequallytothiswork.

*Correspondence:MalingGou

goumaling@

1StateKeyLaboratoryofBiotherapyandCancerCenter,WestChinaHospital,SichuanUniversity,610041Chengdu,China

2DepartmentofPlasticandBurnSurgery,WestChinaHospital,SichuanUniversity,610041Chengdu,China

3DepartmentofDermatology,WestChinaHospital,SichuanUniversity,

610041Chengdu,China

4LaboratoryofDermatology,ClinicalInstituteofInfammation

andImmunology(CIII),FrontiersScienceCenterforDisease-relatedMolecularNetwork,WestChinaHospital,SichuanUniversity,

610041Chengdu,China

5HuahangMicrocreateTechnologyCo.,Ltd,610042Chengdu,China

arangeofpatientcircumstancesandneeds,involvingdiferentsites,degreesofseverityandetiologies

[3

,

4

].Althoughvariousmedicaltreatments(e.g.,minoxidil(MXD),fnasteride,etc.)areefectiveincertainpatients,theyhavenotreachedthedesiredefectforprecisehairregeneration.Terefore,howtopreciselycontrolhairregenerationremainsachallenge.

Microneedlearrays(MNAs)aremicron-scaleclustersofneedlesusedforminimallyinvasiveandpainlesspunc-tureoftheskin.Inadditiontoefcientdrugdelivery,theyhavebeenwidelyusedtoregulatethedermalmicroenvi-ronmentandpromotetissueregenerationviamechanicalstimulationandmicrowounding.Forexample,micronee-dlesalonehavebeenusedforthetreatmentofacne

[5

],keloids[

6

],wrinkles[

7

],etc.Regardinghairlosstreat-ment,somestudieshaveshownthatdrug-freemicronee-dlescanremodeltheperifollicularmicroenvironmentinthebaldingregionandtheninducehairregeneration

springer

?TheAuthor(s)2023.OpenAccessThisarticleislicensedunderaCreativeCommonsAttribution4.0InternationalLicense,which

permitsuse,sharing,adaptation,distributionandreproductioninanymediumorformat,aslongasyougiveappropriatecredittotheoriginalauthor(s)andthesource,providealinktotheCreativeCommonslicence,andindicateifchangesweremade.Theimagesor

otherthirdpartymaterialinthisarticleareincludedinthearticle’sCreativeCommonslicence,unlessindicatedotherwiseinacreditlinetothematerial.Ifmaterialisnotincludedinthearticle’sCreativeCommonslicenceandyourintendeduseisnotpermittedbystatutoryregulationorexceedsthepermitteduse,youwillneedtoobtainpermissiondirectlyfromthecopyrightholder.Toviewacopyofthislicence,visit

/licenses/by/4.0/

.

Lietal.MolecularBiomedicine(2023)4:1

[8

,

9

].Inaddition,thespecifcdistributionofmicronee-dlescandeliversubstancestospecifclocations

[10

,

11

].Basedonthesereports,weproposeahypothesisthatthecustomizedMNAcanlocallymodulatethedermalmicroenvironmentandthenpreciselypromotethehairregenerationinsitu.

3DprintingcanbeusedforthefexiblecustomizationofMNAwithafnestructureandpersonalizedshape

[12

,

13

].Recently,ourgroupdevelopeda3Dprintingtech-nology,staticopticalprojectionlithography(SOPL),forfexiblycustomizingMNA,whichcanrapidlyconstructcustomizedMNAwithinsecondsthroughthespatialpolymerizationofmonomersolutioninducedbystaticprojecteddigitallight

[11

,

14

].Here,SOPLtechnologywasusedtoquicklyfabricateMNAswithdesignedshapes.Next,weinvestigatedthefeasibilityofcustomizedMNAtoinduceprecisehairregenerationinsitu.Itwasfoundthatthetreatmentofround-shapedMNAonthedorsalskinofmiceinducedearlyhairregenerationwitharoundshape.TemechanismswerefoundthatMNAtreat-mentcouldrecruitmacrophagesinsituandtheninitiatetheproliferationofhairfolliclestemcells,thusimprov-inghairregeneration.Inaddition,activationofβ-cateninwasalsoobservedinthetreatedhairfollicles,whichmayinvolveWnt10aandLef1(anuclearresponderofWntsignals).Teupregulationofhepatocytegrowthfactor

Page2of15

(Hgf),insulin-likegrowthfactor1(Igf-1)andtumornecro-sisfactor-α(Tnf-α)wasrecognizedintheMNA-treatedarea,whichmayalsobebenefcialfortheMNA-inducedhairregeneration.Tisstudyprovidesanewstrategyforimprovinghairregenerationinsituandpointstoanewdirectionforfutureregenerativemedicine.

Results

CustomizationofMNAbySOPL

ToquicklyfabricatethecustomizedMNAforprecisehairregeneration,aSOPLtechnologywasemployedinthisstudy[

11

].TeschemeoftheSOPLtechnologyforcus-tomizingtheMNAispresentedinFig.

1

a.AsshowninFig.

1

a,MNAformedthroughthespatialpolymerizationofmonomersolution,whichiscontrolledbythespecifcspatialdistributionoflightintensity.Telightintensitydistributionofamicroneedleinthephotosensitiveresin(Ausbond,A371)canbedescribedasthepointdifusionfunction,whichissimilartotheGaussiandistribution

[15

],whereinthelightintensitygraduallyweakenedfromthecenterofthefocalplanetotheoutside.Whendigitallightpenetratesthephotosensitiveresin,lightisabsorbedwiththegradualincreaseinpenetrationdepth,resultinginthegradualdecreaseinlightintensity[

16

].Accord-ingly,thespecifcspatialdistributionoflightintensityallowsthephotosensitiveresintopreciselypolymerizeto

Fig.1CustomizationofMNAbySOPL.aSchematicdiagramoftheprincipleforcustomizationoftheMNAbySOPL.b2Dgeometricmodelsofamicroneedleatheightsof10,40,100and300μmconstructedinCOMSOL.cThelightintensitydistributionofthemicroneedleatheightsof10,

40,100and300μmsimulatedbyCOMSOL.dPhotographsofround-,annular-,petaloid-,andpentagonalstar-shapedMNAs.(Scalebars:500mm).eSEMimagesofthemicroneedlesandtheMNAs.(Scalebars:500μm)

Lietal.MolecularBiomedicine(2023)4:1

formamicroneedle.Duringthemanufacturingprocess,alightbeamwasmodulatedintoacustomizedpatternbyadigitalmicromirrordevice(DMD)andprojectedtoinducethespatialpolymerizationofthemonomertoformtheMNA.

TovisualizetheformationprocessofmicroneedleintheSOPLtechnology,wesimulatedthelightpropaga-tionandlightintensitydistributionduringmicroneedlefabricationusingfniteelementanalysis.Asimplifed2Dgeometricmodelwithtwoparabolicedgesimitatingthemicroneedleatdesignedheight(H)wasconstructedinCOMSOLsoftware(Fig.

1

b).AsseenfromthenumericalsimulationinFig.

1

c,atthebeginningoflightirradiation,theself-alignedlensefectswereproducedduetothepolymerizationofmonomersolution

[17

].Tenthelightconvergedtothecenter,andthemonomersolutionwaspolymerizedtoformthemicroneedleasaconsequenceofthelightintensitydistributionoftheconicalshape.Tesimulationresultsimpliedthatthemicroneedleisformedinthemannerofgrowth,andthespatialdistribu-tionoflightintensitycanbetheprimaryfactorenablingthefabricationofthemicroneedleviaSOPLtechnology.TisdemonstratedthattheabilityofSOPLtechnologytorapidlycustomizehigh-qualitymicroneedleswithin3s.

Bydesigningprintingpictures,theSOPLtechnologycouldpreparecustomizedMNAwithvariousshapes,suchasround-,annular-,petaloid-,andpentagonalstar-shapedMNAs(Fig.

1

d).Tescanningelectronmicro-scope(SEM)imagesshowedthemorphologiesofthemicroneedlesandtheMNAs(Fig.

1

e).TeobtainedMNAsdidnotshowthelayer-by-layerstructurepresentinthecommon3D-printedproducts,andcouldbefastcustomizedwithin3s.Terefore,SOPLtechnologypro-videstechnicalsupportformanufacturingcustomizedMNAs,whicharethenusedforprecisehairregeneration.

CharacterizationofMNA

TocharacterizetheperformanceofMNAfortreatinghairloss,themechanicalproperties,punctureperfor-mance,andskinhealingwereassessed.TemechanicalstrengthofasinglemicroneedleandMNAweretestedbycompressiontests.Tepicturesofonemicroneedlebeforeandaftercompressiondemonstratedthatthetipofthemicroneedlewasbentaftercompression(Fig.

2

aandb).Teforce-displacementcurvewasalmostlin-earatthebeginning,thenthemicroneedlebentandaturningpointappearedonthecurve,atwhichthecom-pressiondistancewasapproximately280μmandthecompressionforcewasapproximately3.3N(Fig.

2

c).TepicturesoftheMNAbeforeandaftercompression(Fig.

2

dande)showedthattherewasnoobviouschangeinthemicroneedleaftercompression,andtheforce-displacementcurvewasalmostasmoothline(Fig.

2

f).

Page3of15

TediferencesbetweenFig.

2

bandewerepossiblybecauseeachneedleintheMNAreceivedlesspressurethanasinglemicroneedle.Aninsertionforceof0.1–3Nhasbeenreportedtobesufcienttomanuallyinsertthemicroneedleintotheskin

[18

].TisindicatesthattheMNAsaremechanicallystrongenoughforskinpunc-ture.Hematoxylin-eosin(H&E)stainingofskintissueafterMNApunctureindeedshowedthattheMNApen-etratedtheepidermallayer(Fig.

2

g).Inaddition,opti-calcoherencetomography(OCT)demonstratedthattheMNApuncturedintothesuperfcialdermis(Fig.

2

h).Terefore,MNAsfabricatedbySOPLcanbeusedforskinpuncture.AfterconfrmingthecapacityoftheMNAforminimallyinvasiveskinpuncture,theround-shapedMNAwasappliedtothemouseskintoassessthehealingoftheskin.AftertheMNAtreatment,visiblemicroporearrayscorrespondingtotheshapeofMNAformedontheskinsurface,followedbygradualdisappearanceandskinhealingwithin30min(Fig.

2

i).TesedataconfrmedtheminimallyinvasivepunctureofMNAandindicatedrapidskinhealingafterMNApuncture.Inaddition,inprevi-ousstudies

[11

,

14

],wedemonstratedthatmicroneedlematerialshavegoodbiocompatibilityinvitroandinvivo.Collectively,SOPL-customizedMNAscanbeusedforskinpuncture,layingthefoundationfortheregulationoftheskinmicroenvironmentforhairregeneration.

ImprovementofhairregenerationafterMNAtreatment

MNAscanbefexiblycustomizedbySOPLandshowedgoodskinpunctureperformanceinthisstudy.Ithasbeenreportedthatmicroneedletreatmentregulatestheskinmicroenvironmentinthebaldingregionandtheninduceshairregeneration[

8

,

9

].Herein,customizedMNAswerefurtherexploredforpreciselypromotinghairregenerationinsitu.

C57BL/6miceareoneofthemostcommonlyusedanimalmodelsfortheexperimentalevaluationofhairgrowth[

19

],asthehairfolliclesofmiceaged49daysenterthesecondtelogenperiodwhichwilllastfor5weeks

[20

].Inaddition,femalemicehavealongertelo-genperiodthanthemale

[20

,

21

].Terefore,femaleC57BL/6miceagedapproximately7weekswereselectedforthestudy.Inaddition,micewithblackspotsontheskin,thatis,abnormalhaircyclesduetootherreasons,wereexcludedfromthisstudy.TemiceweretreatedasshownintheschematicdiagraminFig.

3

a.TemiceintheMNAgroupreceivedtreatmentwitharound-shapedMNAonthebackfor5seachtime.MiceintheMXDgroupreceivedauniformround-shapedcoatingofMXDonthedorsalskin,whilethemiceinthecontrolgroupreceivednotreatment.Hairgrowthonday28isshowninFig.

3

b.Tisresultdemonstratedthattherewasnoregeneratedhairinthecontrolgroup.Tisisbecauseit

Lietal.MolecularBiomedicine(2023)4:1Page4of15

Fig.2CharacterizationoftheMNA.Picturesofmicroneedletakenwithcamerasaandmicroscopesbshowedthatthetipofthemicroneedlewasbentaftercompressiontests.(Scalebars:500μm).cForce-displacementcurveofasingleMN.Thelargestdeformationoccurredatapproximately3.3Ncompressionforce.dThecamerapicturesoftheMNAindicatednoobviouschangeaftercompressiontests.(Scalebar:500mm).

eMicroscopicimagesofoneneedlefromthearrayshowednoobviousdiferencebetweenbeforeandaftercompressiontests.(Scalebar:500μm).

fTheforce-displacementcurveoftheMNAshowednoobviousturningpoint.H&E-stainedcross-sectiongandOCThrevealedthattheMNAcouldpenetratetheepidermallayeroftheskin.(Scalebars:200μm).iSkinpicturesrecordedthequickskinhealingafterthetreatmentoftheround-shapedMNA.(Scalebar:500mm)

normallytakesapproximately5weekstoenterthenextanagenphaseaftermiceenterthesecondroundofpost-nataltelogen

[20

].TeMXDgroupshowedasparseandmessyhairgrowth,whichdidnotmatchthecircularareaofdrugapplication.Incontrast,theregeneratedhairoftheMNAgroupoccurredinacirculararea,whichcorre-spondedtotheroundshapeofMNA.TisindicatedthattreatmentofMNAwiththedesignedshapeinducedpre-cisehairregenerationinsituinthetargetarea.TeH&Estainingoftreatedskinonday28showedearlyactivehairgrowthinboththeMXDandMNAgroupsandrest-ingtelogenhairfolliclesinthecontrolgroup(Fig.

3

c),confrmingthatMNAtreatmentcaninduceearlyhairregeneration.

Toevaluatethequalityofregeneratedhair,ahairpulltestwasperformed,asshowninFig.

4

a.Teresults

showednosignifcantdiferenceintheamountofoldhairpulledofamongallmice,andnosignifcantdiferencebetweentheamountofoldandregeneratedhairpulledofinthecontrolandMXDgroups(Fig.

4

b).However,intheMNAgroup,reducedregeneratedhairwasfoundtobepulledofwhencomparedwiththeoldhair(Fig.

4

b).BycalculatingthegrayvalueofthephotosinFig.

4

b,thepercentageofhairpulledofwasobtained,andthestatis-ticsconfrmedtheaboveresults(Fig.

4

c).Tisresultindi-catedthattheregeneratedhairpromotedbyMNAshadimprovedquality.

ThepotentialmechanismsofMNAtreatmentinhairregeneration

Afterhairfolliclesarefullydeveloped,theyenterthecycleofcatagen(degeneration),telogen(rest),and

Lietal.MolecularBiomedicine(2023)4:1Page5of15

Fig.3HairregenerationinducedbycustomizedMNA.aSchematicdiagramofMXDandMNAtreatment.bPhotosofmicetakenonday0andday28showedthattherewasnohairregenerationinthecontrolgroup,messyhairregenerationintheMXDgroup,andround-shapedhair

regenerationintheMNAgroup,respectively(n=6).cH&Estainingonday28revealedthatthehairfolliclesinthecontrolgroupwereinthetelogenphase,andthemajorityofhairfolliclesintheMXDandMNAgroupswereintheanagenphase.(Scalebar:200μm)

anagen(growth),duringwhichhairfolliclestemcellacti-vationisacceptedasamarkerofhairfolliclere-entryintoanagen.Cytokeratin15(K15)isacommonhairfolliclestemcellmarkerandiswidelyusedforhairregenerationstudyinmice

[22

–

25

].K15/Ki67double-immunofuores-cencestainingoftheskinsthatreceiveda5-,11-,19-,and28-daytreatmentshowedthathairfolliclestemcellsweregraduallyactivatedbyMNAtreatment,whichdrovehairfolliclestoentertheanagenphase(Fig.

5

).TesedataindicatedthatMNAtreatmentactivatedhairfolliclestemcellsandinitiatedtheirproliferation,realizingprecisehairregenerationinsitu.

Extrinsicinjurycanevokeintrinsicstimulationandsubsequentlyinitiatethephysiologicalrepairprocess

[26

].MNAtreatmenthasmechanicalpressureandmicroinjuryefectsontheskin,butthedetailedmecha-nismofMNA-inducedhairregenerationinsituneedsfurtherexploration.Studieshavereportedthatmechani-calstretch

[22

]andhairplucking

[27

]inducehairregen-erationbymacrophagerecruitmentandsubsequentsecretionofgrowthfactorsorTNF-α.Inaddition,skinmicroinjuries[

26

]andwounds[

28

]alsoreportedlyrecruitmacrophagestoinducehairregeneration.Tere-fore,macrophagesareacceptedasthekeycellsinthe

Lietal.MolecularBiomedicine(2023)4:1Page6of15

Fig.4ImprovedqualityofregeneratedhairafterMNAtreatment.aSketchofthehairpulltest.bHairpulledofonthetapesshowedthatshedhairwasreducedinMNA-inducedregeneratedhair.(Scalebar:0.5cm).cThepercentageofhairpulledofwasobtainedbycalculatingthegrayvalueofthephotos.*P<0.05,**P<0.01,***P<0.001,n=6

regulationofhairregenerationtriggeredbymechanicalstimulationandmicroinjury

[22

,

27

,

28

].Here,theregu-lationofmacrophagesbyMNAsimulationwasinvesti-gated.Aftera1-,3-,5-,and7-dayMNAtreatment(T1,T2,T3,T4),skintissueswereharvestedforpathologicalstaining(Fig.

6

a).TeH&Estainingresultspreliminarily

showedasmallamountofinfammatorycellaccumula-tionafterMNAtreatment(Fig.

6

b).Immunofuores-cencestainingshowedpositiveexpressionofF4/80,amacrophagesurfacemarker,indicatingmacrophageaccumulationafterMNAtreatment.Recruitedmac-rophagesweremainlydistributedintheskindermis(rich

Lietal.MolecularBiomedicine(2023)4:1Page7of15

Fig.5HairfolliclestemcellsactivatedbyMNAtreatment.K15/Ki67double-immunofuorescencestainingondays5,11,19and28revealedthatthehairfolliclestemcellsweregraduallyactivatedandproliferatedafterMNAtreatment.(Scalebar:100μm).*Autofuorescenceofhairshafts

bloodvessels)afterfrstMNAtreatment,andthenmac-rophagesaccumulatedaroundhairfolliclesaftersubse-quent2nd,3rd,and4thtreatments(Fig.

6

c).TesedatasuggestedthatmacrophagesmayberecruitedfromthebloodcirculationtothelocallytreatedskinafterMNAtreatment.

Toinvestigatewhethermacrophagesplayafunc-tionalroleinMNA-inducedhairregeneration,invivomacrophagesweredepletedwithclodronatedisodiumliposomesforreversevalidationasreportedbyotherstudies[

22

,

27

–

30

].First,thephysicalpropertiesofclo-dronatedisodiumliposomesandtheirabilitytodepletemacrophagesinvitrowerecharacterized(Fig.S

1

).Ten,clodronatedisodiumliposomeswereintraperitoneallyinjectedtoinvestigatetheefectofMNA-inducedhairregenerationaftermacrophagedepletion(Fig.

7

a).Onday28,hairregenerationoccurredinthecontrollipo-somegroupbutnotintheclodronatedisodiumgroup(Fig.

7

b).Onday8,F4/80immunofuorescencestainingshowedthatmacrophageswerefoundtoaccumulateinthecontrolliposomegroupbutnotintheclodronatedisodiumgroup(Fig.

7

c).Insummary,MNAtreatmentcouldnotrecruitmacrophagesorinducehairregenera-tionafterinjectionofclodronatedisodiumliposomes,confrmingthatmacrophagesareindispensableinMNA-inducedhairregeneration.

Wnt/β-cateninsignalinghasbeenfoundtoregu-latestemcell-dependenttissuegrowthandthissignal-ingpathwayisessentialintissueregeneration

[31

,

32

].β-cateninisrequiredinbulgestemcellsfortheirprolifer-ation[

33

],andactivationofβ-catenininmousehairfol-liclestemcellsinducesnewhairgrowth[

31

].Terefore,theWnt/β-cateninsignalingpathwayisakeypathwayforhairregeneration

[27

,

34

,

35

].ToinvestigatewhetherMNAtreatmentcouldactivatetheWnt/β-cateninsignal-ingpathway,skintissuescollectedaftera5-,11-,19-,and28-dayMNAtreatmentweresubjectedtoimmunofuo-rescencestainingagainstβ-catenin.Teresultsshowedthattheexpressionofβ-cateningraduallyincreasedwiththecumulativestimulationofMNA,especiallyatthehairbulge,innerrootsheathandouterrootsheathofregen-eratedhairfollicles(Fig.

8

a).TeexpressionofWnt10a,Wnt7b,andLef1,thekeycomponentsoftheWnt/β-cateninpathway

[22

],wastheninvestigatedbyreal-timeqPCR(RT-qPCR)aftera19-dayMNAtreatment.TeresultsshowedenhancedexpressionofWnt10a,Lef1andWnt7b(Fig.

8

b).TeseresultsindicatedthattheWnt/β-cateninsignalingpathwaywasactivatedduringtheprocessofMNA-inducedhairregeneration.

Somestudieshavereportedthatrecruitedmac-rophagescanactivatehairfolliclestemcellstoinducehairregenerationbyreleasingHGF,IGF1andTNF-α

Lietal.MolecularBiomedicine(2023)4:1Page8of15

Fig.6MacrophagesrecruitedinsitubyMNAtreatment.aSchematicdiagramofanimaltreatment.bH&Estainingshowedasmallamountof

infammatorycellaccumulationafter1,2,3and4(T1,T2,T3,T4)MNAtreatments(Scalebar:100μm).cImmunofuorescencestainingdemonstratedtheaccumulationofmacrophagesafterMNAtreatment(Scalebar:100μm)

[22

,

27

,

28

,

36

],whichwassubsequentlyinvestigatedinthisstudy.TeresultsofRT-qPCRafterthreeMNAtreatmentsshowedthattheexpressionlevelsofHgf,Igf1andTnf-αintheMNAgroupweresignifcantlyhigher

thanthoseinthecontrolgroup(Fig.

8

c).Tisresultsug-gestedthatMNAtreatmentcouldupregulatetheexpres-sionofHgf,Igf1andTnf-α,whichmaybeinvolvedinMNA-inducedhairregeneration.

Lietal.MolecularBiomedicine(2023)4:1Page9of15

Fig.7AbrogatedMNA-inducedhairregenerationaftermacrophagedepletion.aSchematicdiagramofanimaltreatment.bRepresentativephotosofmiceonday28showedthatMNA-inducedhairregenerationwasimpededbyintraperitonealinjectionofclodronatedisodiumliposomes.

cF4/80immunofuorescencestainingshowedthatMNA-inducedmacrophagerecruitmentwashinderedafterMNAtreatmentbyintraperitonealinjectionofclodronatedisodiumliposomes.(Scalebar:100μm)

Discussion

Alopeciaisacommondermatologicaldisorderandhas

negativepsychologicalimpactsonpatients

[37

].Cur-rently,precisehairregenerationisurgentlyneededforalopeciapatientssincetheysuferfromdiferentbaldingconditions.However,commonpharmaceuticals,suchasMXDandfnasteride,canhardlyrealizepersonalizedhairregeneration.Terefore,howtopreciselycontrolhairregenerationremainsachallenge.Currently,MNAtreatmentalonehasbeenreportedtohavethepoten-tialtopromotehairregrowth.Herein,wedemonstrateastrategyusingcustomizedMNAstopreciselycontrolhairregenerationinsitu.Inthemousemodel,theround-shapedMNAinducedhairregrowthwitharoundshape

atthesiteofaction.MNAtreatmentshowedimprove-mentofhairqualitywhencomparedwithMXD,indi-catingthathealthierhairfolliclesmaybeobtainedafterMNAtreatment.Collectively,thisworkprovidesanovelmethodtopreciselycontrolhairregenerationusingcus-tomizedMNAs,whichwouldmeettheneedsofdiferentbaldingconditionsandadvancepersonalizedtreatmentsforhairloss.

CustomizedMNAsholdgreatapplicationprospectsinthepersonalizedtreatmentofhairloss.However,theclinicaltranslationofcustomizedMNAisrestrictedbythefabricationmethods.Terapidcustomizationof