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Nekuvandudzwa kwezvinhu zvitsva zve-ultra-soft zvezvishandiso zvekurapa uye biomedical application, iwo akazara maratidziro ezvemuviri uye zvemichina zvimiro zvakakosha uye zvinonetsa.Iyo yakagadziridzwa atomic force microscopy (AFM) nanoindentation nzira yakashandiswa kuratidza iyo yakaderera zvakanyanya pamusoro peiyo modulus itsva lehfilcon A biomimetic silicone hydrogel contact lens yakavharwa ne layer yebranched polymer brashi zvimiro.Iyi nzira inobvumira kutsunga chaiko kwemapoinzi ekuonana pasina mhedzisiro ye viscous extrusion kana ichisvika branched polymers.Uye zvakare, zvinoita kuti zvikwanise kuona ma mechanic maitiro ega ega mabrashi zvinhu pasina mhedzisiro yeporoelasticity.Izvi zvinowanikwa nekusarudza AFM probe ine dhizaini (tip size, geometry uye spring rate) iyo inonyanya kukodzera kuyera zvimiro zvezvinhu zvakapfava uye biological samples.Iyi nzira inovandudza kunzwisiswa uye kurongeka kwekuyera kwakaringana kwechinhu chakapfava kwazvo lehfilcon A, ine yakaderera modulus yekunyungudika pamusoro penzvimbo (kusvika 2 kPa) uye yakanyanyisa kunyungudika mukati (inenge 100%) nharaunda ine mvura. .Mhedzisiro yechidzidzo chepamusoro haina kungoburitsa iyo yekupedzisira-yakapfava pamusoro peiyo lehfilcon A lens, asi yakaratidzawo kuti modulus yebranched polymer brushes yakanga yakafanana neyesilicon-hydrogen substrate.Iyi dhizaini yemhando yepamusoro inogona kushandiswa kune mamwe ma-ultra-soft zvinhu uye michina yekurapa.
Iyo mechanical zvimiro zvezvinhu zvakagadzirirwa kutarisana zvakananga nenyama mhenyu zvinowanzotemwa neiyo biological nharaunda.Mutambo wakakwana wezvinhu izvi zvezvinhu zvinobatsira kuzadzisa inodiwa yekiriniki maitiro ezvinyorwa pasina kukonzera yakashata cellular mhinduro1,2,3.Kune akawanda homogeneous zvinhu, hunhu hwemakanika zvivakwa zviri nyore nekuda kwekuwanikwa kweakajairwa maitiro uye nzira dzekuyedza (semuenzaniso, microindentation4,5,6).Nekudaro, kune ekupedzisira-akapfava zvinhu senge gels, hydrogels, biopolymers, mhenyu maseru, nezvimwewo, idzi nzira dzekuyedza hadziwanzo shanda nekuda kwekuyerwa kugadzirisa zvipimo uye inhomogeneity yezvimwe zvinhu7.Nekufamba kwemakore, nzira dzechinyakare dzekudzikisa dzakagadziridzwa uye dzakagadziridzwa kuti dziratidze huwandu hwakawanda hwezvinhu zvakapfava, asi nzira dzakawanda dzichiri kutambura nekukanganisa kwakakomba kunodzikamisa kushandiswa kwavo8,9,10,11,12,13.Kushaikwa kwehunyanzvi nzira dzekuyedza dzinogona kunyatso uye nekuvimbika hunhu hwemakinari ezve supersoft zvinhu uye mazinga epamusoro anomisa zvakanyanya kushandiswa kwavo mukushandisa kwakasiyana.
Mubasa redu rekare, takaunza lehfilcon A (CL) yekuonana lens, yakapfava heterogeneous zvinhu ine ese ekupedzisira-yakapfava pamusoro pezvivakwa zvinobva kune zvingangoita biomimetic dhizaini inofemerwa nepamusoro pe cornea yeziso.Iyi biomaterial yakagadzirwa nekubatanidza branched, cross-linked polymer layer yepoly (2-methacryloyloxyethylphosphorylcholine (MPC)) (PMPC) pasilicone hydrogel (SiHy) 15 yakagadzirirwa michina yezvokurapa inobva.Iyi nzira yekubatanidza inogadzira dhiri pamusoro pepamusoro rine yakapfava uye yakanyanya elastic branched polymeric brashi chimiro.Basa redu rekare rakatsigira kuti biomimetic chimiro che lehfilcon A CL inopa yepamusoro yepamusoro zvinhu zvakadai sekuvandudza kunyorova uye kudzivirira kusvibiswa, kuwedzera kwemafuta, uye kuderedza sero uye kunamatira kwebhakitiriya15,16.Pamusoro pezvo, kushandiswa nekuvandudzwa kweiyi biomimetic zvinhu zvinopawo kumwe kuwedzera kune mamwe ma biomedical zvishandiso.Naizvozvo, zvakakosha kuratidza hunhu hwepamusoro hweiyi ultra-soft material uye kunzwisisa kupindirana kwayo kwemuchina neziso kuitira kuti ugadzire hwaro hweruzivo hwakakwana hwekutsigira budiriro uye mashandisiro emangwana.Yakawanda inotengeswa SiHy contact lenses inoumbwa nehomogeneous musanganiswa wehydrophilic uye hydrophobic polymers anoumba yunifomu yezvinhu chimiro17.Zvidzidzo zvakati wandei zvakaitwa kuti vaongorore mashandiro avo emuchina vachishandisa chinyakare compression, tensile uye microindentation bvunzo nzira18,19,20,21.Nekudaro, iyo novel biomimetic dhizaini yelehfilcon A CL inoita kuti ive yakasarudzika heterogeneous zvinhu umo ma mechanika eiyo branched polymer brashi zvimiro zvinosiyana zvakanyanya kubva kune ayo eSiHy base substrate.Naizvozvo, zvakaoma chaizvo kuverengera zvivakwa izvi uchishandisa zvakajairwa uye indentation nzira.Nzira inovimbisa inoshandisa nanoindentation yekuyedza nzira inoshandiswa muatomic force microscopy (AFM), nzira yakashandiswa kuona ma mechanika ezvakapfava viscoelastic zvinhu senge biological masero uye matishu, pamwe nemapolymer akapfava22,23,24,25 .,26,27,28,29,30.MuAFM nanoindentation, izvo zvakakosha zvekuyedzwa kwenanoindentation zvakasanganiswa nekufambira mberi muhunyanzvi hweAFM kupa kuwedzera kuyerwa kwekuyerwa uye kuyedzwa kweakasiyana ezvakasikwa supersoft zvinhu31,32,33,34,35,36.Uye zvakare, iyo tekinoroji inopa zvimwe zvakakosha zvakakosha kuburikidza nekushandiswa kweakasiyana geometries.indenter uye probe uye mukana wekuyedza mune dzakasiyana siyana media media.
AFM nanoindentation inogona kugoverwa muzvikamu zvitatu zvikuru: (1) midziyo (sensors, detectors, probes, nezvimwewo);(2) zviyero zvekuyera (senge simba, kutama, kumhanya, saizi yerampu, nezvimwewo);(3) Kugadzirisa data (yekutanga kururamisa, yekubata point fungidziro, data kuenderana, modhi, nezvimwewo).Dambudziko rakakosha nenzira iyi nderekuti zvidzidzo zvakati wandei muzvinyorwa zvinoshandisa AFM nanoindentation mushumo wakasiyana kwazvo wehuwandu hwemhedzisiro yakafanana / sero / zvinhu mhando37,38,39,40,41.Somuenzaniso, Lekka et al.Pesvedzero yeAFM probe geometry pane yakayerwa Yechidiki modulus yemasampuli emakanika homogeneous hydrogel uye heterogeneous masero akadzidzwa nekuenzaniswa.Vanoshuma kuti modulus tsika dzinotsamira zvakanyanya pakusarudzwa kwe cantilever uye chimiro chepi, ine kukosha kwepamusoro kwepiramidhi-yakaita probe uye yakaderera kukosha kwe42 kune yakatenderera probe.Saizvozvo, Selhuber-Unkel et al.Izvo zvaratidzwa kuti indenter kumhanya, indenter size uye ukobvu hwepolyacrylamide (PAAM) samples inokanganisa sei Young's modulus yakayerwa neACM43 nanoindentation.Chimwe chinonetsa kushaikwa kweyakajairwa yakaderera modulus bvunzo zvinhu uye yemahara bvunzo maitiro.Izvi zvinoita kuti zviome kwazvo kuwana mhinduro dzakarurama nechivimbo.Zvisinei, nzira yacho inobatsira zvikuru pakuenzanisa zviyero uye kuongororwa kwekuenzanisa pakati pemhando dzemuenzaniso dzakafanana, semuenzaniso kushandisa AFM nanoindentation kusiyanisa masero akaenzana kubva kumasero ekenza 44, 45.
Paunenge uchiyedza zvinyoro zvinyoro zvine AFM nanoindentation, mutemo wakajairwa wechigunwe kushandisa probe ine yakaderera chitubu chisingaperi (k) icho chinonyatso enderana nemuenzaniso modulus uye hemispherical / kutenderera muromo kuitira kuti yekutanga probe isaboye nzvimbo dzemuenzaniso pa. kutanga kusangana nezvinhu zvinyoro.Izvo zvakakoshawo kuti chiratidzo chekutsauka chinogadzirwa neprobe chive chakasimba zvakakwana kuti chionekwe nelaser detector system24,34,46,47.Munyaya ye-ultra-soft heterogeneous cells, tissues uye gels, rimwe dambudziko nderokukunda simba rekunamatira pakati peprobe uye sampuli yepamusoro kuti ive nechokwadi chekubereka uye kuvimbika kuyerwa48,49,50.Kusvika nguva pfupi yadarika, basa rakawanda paAFM nanoindentation rakanangana nekudzidza kwemaitiro emuchina wemasero ezvipenyu, matishu, gels, mahydrogel, uye biomolecules vachishandisa mahombe spherical probes, anowanzo kunzi colloidal probes (CPs)., 47, 51, 52, 53, 54, 55. Aya mazano ane radius ye 1 kusvika ku50 µm uye anowanzogadzirwa kubva ku borosilicate glass, polymethyl methacrylate (PMMA), polystyrene (PS), silicon dioxide (SiO2) uye diamond- kufanana nekabhoni (DLC) .Kunyangwe CP-AFM nanoindentation kazhinji iriyo yekutanga sarudzo yeakapfava sampuli maitiro, ine matambudziko ayo nemiganhu.Kushandiswa kweakakura, micron-saizi spherical matipi anowedzera iyo yakazara yekubatana nzvimbo yetipi nemuenzaniso uye inoguma nekurasikirwa kukuru kwekugadziriswa kwenzvimbo.Kune dzakapfava, inhomogeneous specimens, uko michina yezvimiro zvenzvimbo inogona kusiyanisa zvakanyanya kubva paavhareji pamusoro penzvimbo yakafara, CP indentation inogona kuvanza chero inhomogeneity muzvivakwa pachiyero chenzvimbo52.Colloidal probes anowanzo kugadzirwa nekubatanidza micron-sized colloidal spheres kune tipless cantilevers uchishandisa epoxy adhesives.Iyo nzira yekugadzira pachayo yakazara nematambudziko mazhinji uye inogona kutungamira mukusawirirana muprobe calibration process.Mukuwedzera, ukuru uye huwandu hwezvikamu zvecolloidal zvinokanganisa zvakananga mitsara yekuenzanisa ye cantilever, yakadai seresonant frequency, kuoma kwechitubu, uye deflection senitivity56,57,58.Saka, nzira dzinowanzo shandiswa dzezvakajairwa AFM probes, dzakaita setembiricha calibration, dzingasape kuenzana kwakaringana kweCP, uye dzimwe nzira dzingadikanwa kuita zvigadziriso izvi57, 59, 60, 61. Yechinyakare CP indentation miyedzo inoshandisa misiyano yakakura cantilever dzidza zvimiro zvemasamples akapfava, izvo zvinogadzira rimwe dambudziko pakuenzanisa maitiro asiri emutsara ecantilever pakutsauka kukuru62,63,64.Mazuva ano colloidal probe indentation nzira dzinowanzo funga nezve geometry ye cantilever inoshandiswa kugadzirisa probe, asi kufuratira pesvedzero yecolloidal particles, izvo zvinogadzira kumwe kusava nechokwadi mukururama kwenzira38,61.Saizvozvo, elastic moduli inoverengerwa nekubatanidza modhi yekukodzera inoenderana zvakananga neiyo geometry ye indentation probe, uye kusawirirana pakati petip uye sampuli yepamusoro maitiro anogona kutungamirira kune zvisizvo27, 65, 66, 67, 68. Mamwe achangobva kushanda naSpencer et al.Izvo zvinhu zvinofanirwa kuverengerwa kana uchiratidzira akapfava mabhurashi epolymer uchishandisa CP-AFM nanoindentation nzira inosimbiswa.Vakataura kuti kuchengetwa kweiyo viscous fluid mumabhurashi epolymer sekushanda kwekumhanya kunokonzeresa kuwedzera kwekurodha musoro uye nekudaro kuyerwa kwakasiyana kwekumhanya kunoenderana nezvinhu30,69,70,71.
Muchidzidzo ichi, takaratidza iyo yepamusoro modulus ye-ultra-soft yakanyanya elastic material lehfilcon A CL tichishandisa yakagadziridzwa AFM nanoindentation nzira.Tichifunga nezvezvivakwa uye chimiro chitsva chechinhu ichi, kunzwisiswa kwemaitiro echinyakare indentation nzira iri pachena haina kukwana kuratidza modulus yechinhu ichi chakapfava zvakanyanya, saka zvinodikanwa kushandisa AFM nanoindentation nzira nekunzwa kwepamusoro uye kuderera kwekunzwa.level.Mushure mekuongorora zvikanganiso uye matambudziko eiyo iripo colloidal AFM probe nanoindentation matekiniki, tinoratidza kuti sei takasarudza diki, yakasarudzika-yakagadzirwa AFM probe kubvisa kunzwiwa, ruzha rwekumashure, pinpoint point yekubata, kuyera velocity modulus yezvakapfava heterogeneous zvinhu zvakadai sekuchengetedza mvura. dependency.uye quantification yakarurama.Pamusoro pezvo, isu takakwanisa kuyera nemazvo chimiro uye zviyero zveiyo indentation tip, zvichitibvumira kushandisa iyo cone-sphere fit modhi kuona modulus yekunyungudika pasina kuongorora nzvimbo yekubatana yetipi nezvinhu.Iwo maviri efungidziro akajeka akaverengerwa mubasa iri ndiwo akazara elastic zvinhu zvivakwa uye indentation kudzika-yakazvimirira modulus.Tichishandisa nzira iyi, takatanga kuyedza ma-ultra-soft mazinga ane inozivikanwa modulus kuyera nzira, tobva tashandisa nzira iyi kuratidza nzvimbo dzezvinhu zviviri zvakasiyana zvekusangana lens.Iyi nzira yekuratidza nzvimbo dzeAFM nanoindentation nekuwedzera kunzwisiswa inotarisirwa kushandiswa kune zvakasiyana-siyana zvebiomimetic heterogeneous ultrasoft zvinhu zvinokwanisa kushandiswa mumishonga yezvokurapa uye biomedical applications.
Lehfilcon A contact lenses (Alcon, Fort Worth, Texas, USA) uye yavo silicone hydrogel substrates yakasarudzwa nokuda kwekuedza nanoindentation.Yakagadzirwa lens gomo yakashandiswa mukuyedza.Kuisa lens yekuyedza, yakanyatsoiswa pachigadziko chakaita dome, kuve nechokwadi chekuti hapana mabhubhu emhepo akapinda mukati, obva agadziriswa nemicheto.Gomba riri kumusoro kwechibatiso chelens rinopa mukana wekupinda pakati peiyo lens yekuedza nanoindentation uchibata mvura panzvimbo.Izvi zvinoita kuti ma lenzi agare akazara mvura.500 μl yekubata lens yekurongedza mhinduro yakashandiswa seyebvunzo mhinduro.Kuti uone huwandu hwemhedzisiro, inotengeswa isiri-activated polyacrylamide (PAAM) mahydrogels akagadzirwa kubva ku polyacrylamide-co-methylene-bisacrylamide kuumbwa (100 mm Petrisoft Petri ndiro, Matrigen, Irvine, CA, USA), inozivikanwa elastic modulus ye1. kPa.Shandisa 4-5 madonhwe (inenge 125 µl) yephosphate buffered saline (PBS kubva kuCorning Life Sciences, Tewkesbury, MA, USA) uye 1 donho re OPTI-FREE Puremoist contact lens solution (Alcon, Vaud, TX, USA).) paAFM hydrogel-probe interface.
Mienzaniso yeLehfilcon A CL neSiHy substrates yakaonekwa pachishandiswa FEI Quanta 250 Field Emission Scanning Electron Microscope (FEG SEM) system yakashongedzerwa neScanning Transmission Electron Microscope (STEM) detector.Kugadzirira sampuli, lenzi dzakatanga kushambidzwa nemvura uye dzakachekwa kuita pie-shaped wedges.Kuti uwane kusiyanisa kwakasiyana pakati pezvikamu zve hydrophilic uye hydrophobic yezvienzaniso, 0.10% yakagadzikana mhinduro yeRuO4 yakashandiswa sedhayi, umo mazamu akanyudzwa kwe30 min.Iyo lehfilcon A CL RuO4 staining yakakosha kwete chete kuti iwane yakagadziridzwa musiyano musiyano, asi inobatsirawo kuchengetedza chimiro chebranched polymer mabhurashi muchimiro chavo chepakutanga, icho chinobva chaonekwa pa STEM mifananidzo.Vakazoshambidzwa uye vakapera mvura mumutsara we ethanol / mvura musanganiswa nekuwedzera ethanol concentration.Iwo masampula akabva akandwa neEMBed 812/Araldite epoxy, iyo yakarapa husiku pa70°C.Sample blocks akawanikwa neresin polymerization akachekwa ne ultramicrotome, uye zvakazoitika zvikamu zvitete zvakaonekwa ne STEM detector mune yakaderera vacuum mode pane inomhanyisa voltage ye30 kV.Iyo imwechete SEM sisitimu yakashandiswa kune yakadzama maitiro ePFQNM-LC-A-CAL AFM probe (Bruker Nano, Santa Barbara, CA, USA).SEM mifananidzo yeAFM probe yakawanikwa mune yakajairika high vacuum modhi ine inomhanyisa voltage ye30 kV.Tora mifananidzo pamakona akasiyana uye magnification kuti urekode zvese zvechimiro uye saizi yeAFM probe tip.Ese matipi mativi ekufarira mumifananidzo akayerwa nedigital.
A Dimension FastScan Bio Icon atomic force microscope (Bruker Nano, Santa Barbara, CA, USA) ine “PeakForce QNM in Fluid” mode yakashandiswa kuona uye nanoindentate lehfilcon A CL, SiHy substrate, uye PAAm hydrogel samples.Pakuedza kwekufungidzira, PEAKFORCE-HIRS-FA probe (Bruker) ine zita retip radius ye 1 nm yakashandiswa kutora mifananidzo yepamusoro yemuenzaniso pachiyero che 0.50 Hz.Mifananidzo yese yakatorwa mune aqueous solution.
AFM nanoindentation miedzo yakaitwa uchishandisa PFQNM-LC-A-CAL probe (Bruker).The AFM probe ine silicon tip pane nitride cantilever 345 nm gobvu, 54 µm kureba uye 4.5 µm yakafara ine resonant frequency ye45 kHz.Iyo yakanyatsogadzirirwa kuratidza uye kuita huwandu hwenanomechanical zviyero pane yakapfava biological samples.Iwo ma sensor anoyerwa ega pafekitori ane pre-calibrated spring marongero.Zvisikwa zvechitubu zvemaprobes akashandiswa muchidzidzo ichi zvaive muhuwandu hwe0.05-0.1 N / m.Kuti unyatsoona chimiro uye saizi yetipi, probe yakaratidzirwa zvakadzama uchishandisa SEM.Pamusoro pemuonde.Mufananidzo 1a unoratidza kukwidziridzwa kwepamusoro, kudzika kwakadzika kutarisisa erekitironi micrograph yePFQNM-LC-A-CAL probe, ichipa maonero akazara ekugadzirwa kweprobe.Pamusoro pemuonde.1b inoratidza maonero akawedzerwa epamusoro petipi yeprobe, ichipa ruzivo nezve chimiro uye saizi yetip.Pakupera kwakanyanyisa, tsono ihemisphere inenge 140 nm muhupamhi (Fig. 1c).Pazasi peizvi, iyo muromo inonyungudika kuita conical chimiro, inosvika kureba yakayerwa ingangoita 500 nm.Kunze kwenzvimbo inotsvedza, muromo une cylindrical uye unopera muhurefu hwetipi hwe1.18 µm.Ichi ndicho chikuru chinoshanda chikamu cheprobe tip.Pamusoro pezvo, spherical spherical polystyrene (PS) probe (Novascan Technologies, Inc., Boone, Iowa, USA) ine dhayamita ye45 µm uye chitubu che2 N/m chakashandiswawo pakuedzwa secolloidal probe.nePFQNM-LC-A-CAL 140 nm probe yekuenzanisa.
Zvinonzi mvura inogona kuvharirwa pakati peAFM probe uye polymer bhurashi chimiro panguva nanoindentation, iyo ichaita simba rinokwira kumusoro paAFM probe isati yanyatsobata pamusoro69.Iyi viscous extrusion mhedzisiro nekuda kwekuchengetwa kwemvura inogona kushandura inooneka nzvimbo yekusangana, nekudaro ichikanganisa zviyero zvemodulus.Kuti udzidze mhedzisiro yeprobe geometry uye indentation kumhanya pakuchengetedza mvura, indentation simba macurves akarongerwa lehfilcon A CL samples uchishandisa 140 nm dhayamita probe pazvimiro zvekufamba zve1 µm/s uye 2 µm/s.probe dhayamita 45 µm, simba rakagadziriswa kuseta 6 nN rinowanikwa pa 1 µm/s.Maedzo ane probe 140 nm mudhayamita akaitwa nekukasira kumhanya kwe1 µm/s uye seti simba re300 pN, yakasarudzwa kugadzira kudzvanywa kwekubatana mukati meiyo physiological range (1–8 kPa) yekumusoro kweziso.kudzvinyirirwa 72. Zvinyoro zvakagadzirirwa zvakagadzirirwa zvePAA hydrogel zvine simba re 1 kPa zvakaedzwa kune simba rekudzivirira re 50 pN pakukurumidza kwe 1 μm / s uchishandisa probe nehupamhi hwe140 nm.
Sezvo kureba kweiyo conical chikamu chepipi yePFQNM-LC-A-CAL probe ingangoita mazana mashanu nm, kune chero indentation yakadzika <500 nm inogona kufungidzirwa zvakachengeteka kuti iyo geometry yeiyi probe panguva yekumisikidzwa icharamba ichokwadi kune yayo. koni chimiro.Uye zvakare, zvinofungidzirwa kuti pamusoro pechinhu chiri pasi pekuyedzwa chinoratidza inodzoreredzwa elastic mhinduro, iyo inozosimbiswa zvakare muzvikamu zvinotevera.Naizvozvo, zvichienderana nechimiro uye saizi yetip, takasarudza iyo cone-sphere yakakodzera modhi yakagadzirwa naBriscoe, Sebastian naAdams, inowanikwa mune software yemutengesi, kuti tigadzirise yedu AFM nanoindentation miedzo (NanoScope).Separation data analysis software, Bruker) 73. Mutevedzeri unotsanangura hukama hwekumanikidza-kubvisa F (δ) yekoni ine spherical apex defect.Pamusoro pemuonde.Mufananidzo 2 unoratidza kusangana geometry panguva yekudyidzana kwekoni yakasimba ine denderedzwa muromo, uko R iri radius ye spherical tip, a inzvimbo yekusangana, b inzvimbo yekusangana pamagumo edenderedzwa muromo, δ ndiyo contact radius.kudzika kwemukati, θ ndiyo hafu-ekona yekoni.Mufananidzo weSEM weiyi probe unoratidza pachena kuti 140 nm dhayamita spherical tip inobatanidza tangentially kuita koni, saka pano b inotsanangurwa chete kuburikidza neR, kureva b = R cos θ.Iyo mutengesi-inopihwa software inopa cone-sphere hukama kuverenga Young's modulus (E) kukosha kubva kusimba rekuparadzanisa data uchitora > b.Hukama:
apo F ndiyo simba rekupinza, E iMudiki modulus, ν ireshiyo yaPoisson.Iyo yekubata radius a inogona kufungidzirwa uchishandisa:
Scheme yeiyo yekubata geometry yekoni yakaoma ine spherical tip yakatsikirirwa mukati mezvinhu zveLefilcon yekubata lens ine pamusoro pedhizaini yemabrashi epolymer.
Kana a ≤ b, hukama hunodzikisira kuequation kune yakajairika spherical indenter;
Isu tinotenda kuti kupindirana kwe indenting probe neiyo branched chimiro chePMPC polymer bhurashi kuchaita kuti iyo yekubata radius a ive yakakura kupfuura spherical contact radius b.Naizvozvo, pazviyero zvese zvehuwandu hweiyo elastic modulus yakaitwa muchidzidzo ichi, takashandisa kutsamira kwakawanikwa kune nyaya a > b.
Iyo ultrasoft biomimetic zvinhu zvakadzidzwa muchidzidzo ichi zvakazara mufananidzo uchishandisa scanning transmission electron microscopy (STEM) yemuenzaniso muchinjiko chikamu uye atomic force microscopy (AFM) pamusoro.Iyi yakadzama yemhando yepamusoro yakaitwa sekuwedzera kwebasa redu rakambodhindwa, umo takaona kuti iyo dynamically branched polymeric brush structure yePMPC-modified lehfilcon A CL surface yakaratidza zvakafanana mechanical properties kune native corneal tissue 14.Nechikonzero ichi, isu tinonongedzera kune yekubata lens nzvimbo sebiomimetic zvinhu14.Pamusoro pemuonde.3a,b ratidza zvikamu zvakachinjika zve branched PMPC polymer brush zvimiro pamusoro pe lehfilcon A CL substrate uye isina kurapwa SiHy substrate, zvichiteerana.Mamiriro ezvienzaniso zvose zvakaongororwa zvakare nekushandiswa kwepamusoro-resolution AFM mifananidzo, iyo yakawedzera kusimbisa migumisiro yekuongorora STEM (Fig. 3c, d).Yakatorwa pamwechete, iyi mifananidzo inopa hurefu hunofungidzirwa hwePMPC branched polymer brashi chimiro pa 300-400 nm, iyo yakakosha pakududzira AFM nanoindentation zviyero.Kumwe kucherechedzwa kwakakosha kunobva pamifananidzo ndeyekuti iyo yakazara pamusoro peiyo CL biomimetic zvinhu zvakasiyana neiyo yeSiHy substrate zvinhu.Uyu mutsauko mune yavo yepasi morphology inogona kuoneka panguva yekudyidzana kwavo kwemuchina neiyo indenting AFM probe uye zvichizotevera mune yakayerwa modulus kukosha.
Cross-sectional STEM mifananidzo ye (a) lehfilcon A CL uye (b) SiHy substrate.Scale bar, 500 nm.AFM mifananidzo yepamusoro yelehfilcon A CL substrate (c) uye nheyo yeSiHy substrate (d) (3 µm × 3 µm).
Bioinspired polymers uye polymer brashi zvimiro zvakapfava uye zvakadzidzwa zvakanyanya uye kushandiswa mune akasiyana biomedical application74,75,76,77.Nokudaro, zvakakosha kushandisa nzira yeAFM nanoindentation, iyo inogona kunyatso uye yakavimbika kuyera maitiro avo emagetsi.Asi panguva imwecheteyo, iyo yakasarudzika midziyo yeaya ekupedzisira-akapfava zvinhu, senge yakaderera yakadzika modulus, yakakwira yemvura yemukati uye yakakwira elasticity, kazhinji inoita kuti zviome kusarudza iyo chaiyo zvinhu, chimiro uye chimiro cheiyo indenting probe.saizi.Izvi zvakakosha kuitira kuti indenter irege kubaya nzvimbo yakapfava yemuenzaniso, izvo zvinozotungamira mukukanganisa pakuona nzvimbo yekubata nepamusoro uye nzvimbo yekubata.
Nokuda kweizvi, kunzwisisa kwakakwana kwe morphology ye-ultra-soft biomimetic zvinhu (lehfilcon A CL) inokosha.Ruzivo nezve saizi uye chimiro chebranched polymer mabhurashi akawanikwa uchishandisa nzira yekufungidzira inopa hwaro hwemakinika maitiro echiso uchishandisa AFM nanoindentation maitiro.Panzvimbo peiyo micron-saizi spherical colloidal probes, isu takasarudza iyo PFQNM-LC-A-CAL silicon nitride probe (Bruker) ine tip dhayamita ye140 nm, yakanyatsogadzirirwa kuwanda kwemepu yemepu yemagetsi ezvinyorwa zvipenyu 78, 79, 80. , 81, 82, 83, 84 Chirevo chekushandisa probes yakapinza kana ichienzaniswa neyakajairwa colloidal probes inogona kutsanangurwa nemaitiro ezvimiro zvezvinhu.Kuenzanisa probe tip size (~ 140 nm) nebranched polymer brushes pamusoro peCL lehfilcon A, inoratidzwa muFig. 3a, zvinogona kugumiswa kuti chidimbu chakakura zvakakwana kuti chibatane zvakananga nemaitiro aya ebhurashi, ayo inoderedza mukana wekuti muromo ubaye mavari.Kuenzanisira pfungwa iyi, muFig. 4 mufananidzo we STEM we lehfilcon A CL uye indenting tip ye AFM probe (yakakweverwa kusvika pachiyero).
Schematic inoratidza STEM mufananidzo welehfilcon A CL uye ACM indentation probe (yakakweverwa kuchiyero).
Pamusoro pezvo, saizi ye140 nm idiki zvakakwana kudzivirira njodzi yechero inonamira extrusion mhedzisiro yakambotaurwa yemabhurashi epolymer anogadzirwa neCP-AFM nanoindentation method69,71.Isu tinofungidzira kuti nekuda kweiyo yakakosha koni-spherical chimiro uye diki saizi yeiyi AFM tip (Fig. 1), chimiro chesimba re curve rinogadzirwa nelehfilcon A CL nanoindentation haizotsamira pakumhanya kweiyo indentation kana kukurumidza kurodha / kurodha. .Naizvozvo, haina kukanganiswa ne poroelastic mhedzisiro.Kuti uedze iyi hypothesis, lehfilcon A CL samples dzakaiswa indents pane yakagadziriswa simba repamusoro uchishandisa PFQNM-LC-A-CAL probe, asi pamavelocities maviri akasiyana, uye mhedzisiro inokonzeresa uye yekudzosa simba curves yakashandiswa kuronga simba (nN) mukuparadzana (µm) inoratidzwa mumufananidzo 5a.Zviri pachena kuti simba rinokombama panguva yekurodha uye kuburitsa zvakazara kupindirana, uye hapana humbowo hwakajeka hwekuti simba rekugera pa zero indentation kudzika rinowedzera nekukasira kumhanyisa mumufananidzo, zvichiratidza kuti mabrashi ega ega akaonekwa pasina poroelastic mhedzisiro.Kusiyana neizvi, zvigadziriso zvekuchengetedza mvura (viscous extrusion uye poroelasticity effects) zvinoonekwa kune 45 µm dhayamita yeAFM probe panguva imwechete yekuisa indentation speed uye inoratidzirwa ne hysteresis pakati pekutambanudza uye kudzorera ma curves, sezvinoratidzwa mumufananidzo 5b.Mhedzisiro iyi inotsigira iyo hypothesis uye inoratidza kuti 140 nm dhayamita probes isarudzo yakanaka yekuratidza nzvimbo dzakapfava dzakadai.
lehfilcon A CL indentation force curves uchishandisa ACM;(a) kushandisa probe ine dhayamita ye140 nm pamatanho maviri ekurodha, kuratidza kusavapo kweporoelastic mhedzisiro panguva yekumisikidzwa kwepamusoro;(b) kushandisa maprobe ane dhayamita ye45 µm uye 140 nm.s inoratidza mhedzisiro ye viscous extrusion uye poroelasticity kune yakakura probes ichienzaniswa nediki probes.
Kuratidzira ultrasoft surfaces, AFM nanoindentation nzira dzinofanirwa kuve neakanakisa probe yekudzidza zvimiro zvezvinhu zviri pasi pekudzidza.Mukuwedzera kune chimiro chepi uye saizi, kunzwisiswa kweiyo AFM detector system, sensitivity kune tip deflection munzvimbo yekuyedza, uye cantilever kuomarara kunoita basa rakakosha pakuona kurongeka uye kuvimbika kwenanoindentation.zviyero.Kune yedu AFM sisitimu, iyo Position Sensitive Detector (PSD) muganho wekuonekwa ingangoita 0.5 mV uye yakavakirwa pane pre-calibrated chitubu mwero uye yakaverengerwa fluid deflection sensitivity yePFQNM-LC-A-CAL probe, inoenderana ne theoretical load sensitivity.iri pasi pe0.1 pN.Nokudaro, iyi nzira inobvumira kuyerwa kwesimba shoma rekupinza ≤ 0.1 pN pasina chero chikamu chemheremhere.Nekudaro, zvinenge zvisingaite kuti AFM system ideredze ruzha rweparipheral kusvika padanho iri nekuda kwezvinhu zvakaita semechanic vibration uye fluid dynamics.Zvinhu izvi zvinodzikamisa kunzwisiswa kwese kweAFM nanoindentation nzira uye zvinokonzeresa kumashure kweruzha chiratidzo cheanenge ≤ 10 pN.Nekutaridzika kwepamusoro, lehfilcon A CL uye SiHy substrate samples dzakaiswa mukati meiyo yakazara hydrated mamiriro uchishandisa 140 nm probe yeSEM ​​maitiro, uye mhedzisiro yesimba curves yakasimudzwa pakati pesimba (pN) nekumanikidza.Mutsara wekuparadzanisa (µm) unoratidzwa mumufananidzo 6a.Kuenzaniswa neSiHy base substrate, iyo lehfilcon A CL force curve inonyatsoratidza chikamu chekuchinja chinotangira pakubata neforogo yepolymer bhurashi uye ichipera nekuchinja kwakapinza kwemateru ekumaka kusangana kwechipi nechinhu chiri pasi.Ichi chinoshanduka chikamu chesimba curve chinosimbisa hunhu hwechokwadi hwebrashi yepolymer bhurasho pamusoro, sezvinoratidzwa neiyo compression curve ichinyatsotevera tension curve uye mutsauko wemakanika zvinhu pakati pebrashi chimiro uye bulky SiHy zvinhu.Kana uchienzanisa lefilcon.Kuparadzaniswa kweavhareji kureba kwebrashi repolymer brashi mu STEM mufananidzo wePCS (Fig. 3a) uye simba rayo curve pamwe neabscissa muFig. 3a.6a inoratidza kuti iyo nzira inokwanisa kuona iyo tip uye iyo branched polymer inosvika kumusoro chaiko kwepamusoro.Kubatana pakati pezvivakwa zvebhurashi.Uye zvakare, kudhumhana kwepedyo kwesimba curves kunoratidza kuti hapana mvura yekuchengetedza maitiro.Muchiitiko ichi, hapana zvachose kunamatira pakati petsono uye pamusoro pemuenzaniso.Zvikamu zvepamusoro-soro zvesimba rema curves emasamples maviri anopindirana, zvichiratidza kufanana kwemagetsi emidziyo ye substrate.
(a) AFM nanoindentation force curves yelehfilcon A CL substrates uye SiHy substrates, (b) manikidzira macurves anoratidza fungidziro yenzvimbo uchishandisa yekumashure ruzha rwechikumbaridzo.
Kuti udzidze ruzivo rwakanyanya rwesimba remagetsi, mutsara wekumanikidzika we lehfilcon A CL sampuli inorongwa zvakare muFig. 6b ine simba guru re 50 pN pamwe ne-y-axis.Iyi girafu inopa ruzivo rwakakosha nezve yekutanga ruzha rwekumashure.Ruzha rwuri muchikamu che ± 10 pN, iyo inoshandiswa kunyatsoona nzvimbo yekusangana uye kuverenga kudzika kwemukati.Sezvakataurwa mumabhuku, kuzivikanwa kwenzvimbo dzekusangana kwakakosha kuti uongorore nemazvo zvinhu zvemukati senge modulus85.Maitiro anosanganisira otomatiki kugadzirisa kwesimba curve data yakaratidza yakagadziridzwa kukwana pakati pe data kuenderana uye chiyero kuyerwa kwezvinhu zvinyoro86.Mubasa iri, sarudzo yedu yemapoinzi ekuonana iri nyore uye ine chinangwa, asi ine painogumira.Maitiro edu ekuchengetedza ekuona nzvimbo yekuonana anogona kukonzera zvishoma overestimated modulus kukosha kune kudiki indentation kudzika (<100 nm).Iko kushandiswa kwealgorithm-based touchpoint yekuona uye otomatiki data kugadzirisa kunogona kuve kuenderera kwebasa iri mune ramangwana kuti tiwedzere kuvandudza nzira yedu.Nokudaro, nokuda kweruzha rwemukati rwemukati pane kurongeka kwe ± 10 pN, tinotsanangura nzvimbo yekubatana seyokutanga data poindi pa x-axis muFigure 6b ine kukosha kwe ≥10 pN.Zvadaro, maererano nechikumbaridzo chemhere che10 pN, mutsara wakatwasuka pamwero we ~ 0.27 µm unoratidza nzvimbo yekubatana nepamusoro, mushure mokunge iyo inotambanudza curve inoenderera mberi kusvikira substrate inosangana nehupamhi hwe ~ 270 nm.Sezvineiwo, zvichibva pahukuru hwemabrashi epolymer brush features (300–400 nm) akayerwa achishandisa nzira yekufungidzira, indentation yakadzika yeCL lehfilcon Sample inocherechedzwa uchishandisa nzira yekumashure ruzha pachikumbaridzo ingangoita 270 nm, iri padyo zvakanyanya saizi yekuyera ne STEM.Mhedzisiro iyi inosimbisa kuenderana uye kushanda kwechimiro uye saizi yeAFM probe tip yekumisikidzwa kweiyi yakapfava uye yakanyanya elastic branched polymer brashi chimiro.Iyi data inopawo humbowo hwakasimba kutsigira nzira yedu yekushandisa ruzha rwekumashure sechikumbaridzo chekunongedza nzvimbo dzekusangana.Nekudaro, chero huwandu hwemhedzisiro inowanikwa kubva kumasvomhu modhi uye yekumanikidza curve fitting inofanira kunge yakaringana.
Zviyero zvehuwandu neAFM nanoindentation nzira dzinoenderana zvachose nemhando dzemasvomhu dzinoshandiswa pakusarudza data uye kuongorora kunotevera.Naizvozvo, zvakakosha kuti titarise zvinhu zvese zvine chekuita nekusarudzwa kweindenter, zvinhu zvemukati uye mechanics ekudyidzana kwavo usati wasarudza imwe modhi.Muchiitiko ichi, iyo tip geometry yakanyatsoratidzwa uchishandisa SEM micrographs (Fig. 1), uye zvichibva pane zvakabuda, iyo 140 nm dhayamita AFM nanoindenting probe ine hard cone uye spherical tip geometry isarudzo yakanaka yekuratidzira lehfilcon A CL79 samples. .Chimwe chinhu chakakosha chinoda kunyatsoongororwa ndeye elasticity ye polymer zvinhu zviri kuedzwa.Kunyangwe iyo yekutanga data ye nanoindentation (Fig. 5a uye 6a) inotsanangura zvakajeka maficha ekupindirana kwemakakatanwa uye compression curves, kureva, kudzoreredza kudzoreredza kwechinhu, zvakakosha zvakanyanya kusimbisa iyo yakasarudzika hunhu hwevanobatika. .Kuti izvi zviitike, maviri akatevedzana indentations akaitwa panzvimbo imwechete pamusoro peiyo lehfilcon A CL sampuli pane indentation rate ye 1 µm / s pasi peyakazara hydration mamiriro.Iyo inokonzeresa simba curve data inoratidzwa mufig.7 uye, sezvaitarisirwa, kukwidziridzwa uye kudzvanya ma curves ezvinyorwa zviviri zvakada kufanana, zvichiratidza kusimba kwepamusoro kwebranched polymer brashi chimiro.
Ma curves maviri ekupinza simba panzvimbo imwe chete pamusoro pe lehfilcon A CL inoratidza kunaka kwakaringana kwenzvimbo ye lens.
Zvichienderana neruzivo rwakawanikwa kubva kuSEM uye STEM mifananidzo yeprobe tip uye lehfilcon A CL pamusoro, zvakateerana, iyo cone-sphere modhi inonzwisisika yemasvomhu inomiririra yekudyidzana pakati peAFM probe tip uye yakapfava polymer zvinhu zviri kuedzwa.Pamusoro pezvo, kune iyi cone-sphere modhi, fungidziro dzakakosha pamusoro pehunyoro hwezvinhu zvakadhindwa zvine chokwadi kune iyi itsva biomimetic material uye inoshandiswa kuyera elastic modulus.
Mushure mekuongorora kwakazara kweAFM nanoindentation nzira uye zvikamu zvayo, kusanganisira indentation probe properties (chimiro, ukuru, uye kuoma kwechirimo), kunzwa (ruzha rwekumashure uye kufungidzira nzvimbo yekuona), uye data fitting models (quantitative modulus zviyero), nzira yacho yaiva. kushandiswa.ratidza anowanikwa mune zvekutengesa e-ultra-soft samples kuti aone mhedzisiro yehuwandu.Yekutengesa polyacrylamide (PAAM) hydrogel ine elastic modulus ye1 kPa yakaedzwa pasi pemvura ine hydrated ichishandisa 140 nm probe.Ruzivo rwekuyedzwa kwemodule uye kuverenga zvinopihwa muRuzivo rwekuwedzera.Mhedzisiro yacho yakaratidza kuti avhareji modulus kuyerwa yaive 0.92 kPa, uye iyo% RSD uye muzana (%) kutsauka kubva kune inozivikanwa modulus yaive isingasviki gumi%.Iyi mhedzisiro inosimbisa kurongeka uye kudzokorora nzira yeAFM nanoindentation inoshandiswa mubasa iri kuyera moduli yezvinhu zve ultrasoft.Nzvimbo dze lehfilcon A CL samples uye SiHy base substrate dzakazoonekwa zvakare dzichishandisa nzira imwechete yeAFM nanoindentation yekudzidza inooneka yekubatanidza modulus ye ultrasoft surface sekushanda kwekudzika kwemukati.Indentation simba rekuparadzanisa macurves akagadzirwa kune matatu emhando yemhando yega yega (n = 3; imwe indentation pamuenzaniso) pane simba re300 pN, kumhanya kwe1 µm/s, uye yakazara hydration.Iyo indentation simba rekugovanisa curve yakafananidzwa uchishandisa cone-sphere modhi.Kuti uwane modulus inotsamira pakudzika kweiyo indentation, 40 nm yakafara chikamu chesimba curve yakaiswa pane imwe neimwe increment ye20 nm kutanga kubva pakubata, uye akayera kukosha kweiyo modulus pane yega yega yesimba curve.Spin Cy et al.Nzira yakafanana yakashandiswa kuratidza iyo modulus gradient yepoly(lauryl methacrylate) (P12MA) mabhurashi epolymer achishandisa colloidal AFM probe nanoindentation, uye anowirirana nedata uchishandisa Hertz yekubata modhi.Iyi nzira inopa zano reinooneka yekubata modulus (kPa) maringe nekudzika kwakadzika (nm), sezvakaratidzwa mumufananidzo 8, iyo inoratidza inooneka yekubata modulus/yakadzika gradient.Iyo yakaverengerwa elastic modulus yeCL lehfilcon A sampuli iri muhuwandu hwe2-3 kPa mukati mepamusoro 100 nm yemuenzaniso, kupfuura iyo inotanga kuwedzera nekudzika.Kune rimwe divi, paunenge uchiyedza SiHy base substrate isina bhurashi-sefirimu riri pamusoro, iyo yakanyanya indentation kudzika yakawanikwa pasimba re300 pN iri pasi pe50 nm, uye kukosha kwemodulus kunowanikwa kubva kune data kunosvika mazana mana kPa. , iyo inofananidzwa nehunhu hweYoung's modulus yezvinhu zvakawanda.
Inooneka contact modulus (kPa) vs. indentation deep (nm) ye lehfilcon A CL uye SiHy substrates inoshandisa AFM nanoindentation nzira ine cone-sphere geometry kuyera modulus.
Iyo yepamusoro yepamusoro yeinoveli biomimetic branched polymer bhurashi chimiro chinoratidza yakanyanya kuderera modulus ye elasticity (2-3 kPa).Izvi zvichaenderana neyemahara yakarembera kupera kweforogo polymer bhurashi sezvakaratidzwa mumufananidzo we STEM.Kunyangwe paine humwe humbowo hwe modulus gradient kumucheto kwekunze kweCL, iyo huru yakakwira modulus substrate ine simba zvakanyanya.Nekudaro, iyo 100 nm yepamusoro yepasi iri mukati me20% yehurefu hwakazara hwebrashi repolymer brashi, saka zvine musoro kufunga kuti zviyero zvakayerwa zvemodulus mune ino indentation yakadzika renji ndeyechokwadi uye haina kusimba. zvinoenderana nemhedzisiro yechinhu chepasi.
Nekuda kweiyo yakasarudzika biomimetic dhizaini yelehfilcon A contact lenses, inosanganisira branched PMPC polymer brashi zvimiro zvakabatanidzwa pamusoro peSiHy substrates, zvakaoma zvikuru kuratidza nekuvimbika ma mechanic properties yezvimiro zvavo zvepamusoro uchishandisa nzira dzekuyera dzechinyakare.Pano tinopa yakakwira AFM nanoindentation nzira yekunyatso ratidza Ultra-yakapfava zvinhu zvakaita selefilcon A ine yakakwira yemvura uye yakanyanya kunyungudika.Iyi nzira yakavakirwa pakushandiswa kweiyo AFM probe ine saizi yepipi uye geometry yakanyatsosarudzwa kuti ienderane nechimiro chechimiro cheiyo ultra-soft surface maficha kuti adhindwe.Uku kusanganiswa kwezviyero pakati pekuferefeta uye chimiro kunopa yakawedzera kunzwa, ichitibvumira kuyera iyo yakaderera modulus uye inherent elastic zvimiro zve branched polymer brashi zvinhu, zvisinei neporoelastic mhedzisiro.Mhedzisiro yacho yakaratidza kuti yakasarudzika branched PMPC polymer mabhurashi hunhu hwelenzi uso hwaive hwakanyanya kuderera elastic modulus (kusvika 2 kPa) uye yakanyanya kunyungudika (inoda kusvika 100%) payakaedzwa munzvimbo ine mvura.Mhedzisiro yeAFM nanoindentation yakatibvumirawo kuratidza iyo inooneka yekubata modulus/yakadzika gradient (30 kPa/200 nm) yebiomimetic lens surface.Iyi gradient inogona kunge yakakonzerwa nemusiyano wemodulus pakati pebrashi repolymer brashi uye SiHy substrate, kana iyo branched chimiro / density yemabhurashi epolymer, kana musanganiswa wayo.Nekudaro, zvimwe zvakadzika zvidzidzo zvinodikanwa kuti unzwisise zvizere hukama pakati pechimiro uye zvivakwa, kunyanya mhedzisiro yebrashi branching pane mechanic properties.Zviyero zvakafanana zvinogona kubatsira kuratidza ma mechanic zvimiro zvepamusoro pezvimwe zvinyoro-zvakapfava zvinhu uye michina yekurapa.
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