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Nrog rau kev tsim cov khoom siv tshiab uas mos heev rau cov khoom siv kho mob thiab cov ntawv thov biomedical, kev piav qhia txog lawv cov khoom siv lub cev thiab cov khoom siv kho tshuab yog qhov tseem ceeb thiab nyuaj. Ib txoj kev hloov kho atomic force microscopy (AFM) nanoindentation tau siv los piav qhia txog qhov modulus qis heev ntawm lub lens tshiab lehfilcon A biomimetic silicone hydrogel uas tau coated nrog ib txheej ntawm cov qauv txhuam polymer branched. Txoj kev no tso cai rau kev txiav txim siab meej ntawm cov ntsiab lus sib cuag yam tsis muaj cov teebmeem ntawm viscous extrusion thaum mus txog cov polymers branched. Tsis tas li ntawd, nws ua rau nws muaj peev xwm txiav txim siab cov yam ntxwv kho tshuab ntawm cov txhuam ib leeg yam tsis muaj cov teebmeem ntawm poroelasticity. Qhov no yog ua tiav los ntawm kev xaiv AFM probe nrog tus qauv tsim (qhov loj me ntawm lub taub hau, geometry thiab lub caij nplooj ntoos hlav) uas yog qhov tshwj xeeb tshaj yog rau kev ntsuas cov khoom ntawm cov khoom siv mos thiab cov qauv biomedical. Txoj kev no txhim kho qhov rhiab heev thiab qhov tseeb rau kev ntsuas qhov tseeb ntawm cov khoom siv mos heev lehfilcon A, uas muaj qhov modulus qis heev ntawm elasticity ntawm thaj chaw saum npoo (txog li 2 kPa) thiab qhov elasticity siab heev hauv sab hauv (yuav luag 100%) ib puag ncig dej. Cov txiaj ntsig ntawm kev tshawb nrhiav qhov chaw tsis yog tsuas yog qhia txog cov khoom ntawm qhov chaw mos heev ntawm lub lens lehfilcon A, tab sis kuj qhia tau tias cov modulus ntawm cov txhuam polymer branched zoo ib yam li cov ntawm silicon-hydrogen substrate. Cov txheej txheem piav qhia txog qhov chaw no tuaj yeem siv rau lwm cov ntaub ntawv mos heev thiab cov khoom siv kho mob.
Cov khoom siv kho tshuab ntawm cov ntaub ntawv tsim los rau kev sib cuag ncaj qha nrog cov ntaub so ntswg uas muaj sia nyob feem ntau txiav txim siab los ntawm ib puag ncig biological. Qhov sib phim zoo meej ntawm cov khoom siv no pab kom ua tiav cov yam ntxwv kho mob xav tau ntawm cov khoom siv yam tsis ua rau muaj kev tsis zoo ntawm cov cellular1,2,3. Rau cov ntaub ntawv homogeneous ntau, kev piav qhia txog cov khoom siv kho tshuab yog qhov yooj yim vim muaj cov txheej txheem txheem thiab cov txheej txheem sim (piv txwv li, microindentation4,5,6). Txawm li cas los xij, rau cov ntaub ntawv mos mos xws li gels, hydrogels, biopolymers, cov cell uas muaj sia nyob, thiab lwm yam, cov txheej txheem sim no feem ntau tsis siv tau vim muaj kev txwv kev ntsuas thiab qhov tsis sib xws ntawm qee cov ntaub ntawv7. Tau ntau xyoo, cov txheej txheem indentation ib txwm muaj tau hloov kho thiab hloov kho kom piav qhia txog ntau yam khoom siv mos mos, tab sis ntau txoj kev tseem raug kev txom nyem los ntawm qhov tsis txaus ntseeg uas txwv lawv siv8,9,10,11,12,13. Qhov tsis muaj cov txheej txheem sim tshwj xeeb uas tuaj yeem piav qhia txog cov khoom siv kho tshuab ntawm cov ntaub ntawv supersoft thiab cov txheej saum npoo av txwv lawv siv ntau yam kev siv.
Hauv peb txoj haujlwm yav dhau los, peb tau qhia txog lub lens sib cuag lehfilcon A (CL), ib yam khoom mos mos heterogeneous nrog txhua yam khoom siv ultra-mos uas tau los ntawm cov qauv tsim biomimetic uas tau tshoov siab los ntawm qhov chaw ntawm lub qhov muag cornea. Cov khoom siv biomimetic no tau tsim los ntawm kev sib txuas ib txheej polymer branched, cross-linked ntawm poly (2-methacryloyloxyethylphosphorylcholine (MPC)) (PMPC) rau ntawm silicone hydrogel (SiHy) 15 tsim rau cov khoom siv kho mob raws li. Cov txheej txheem grafting no tsim ib txheej ntawm qhov chaw uas muaj cov qauv txhuam polymeric branched mos mos thiab elastic heev. Peb txoj haujlwm yav dhau los tau lees paub tias cov qauv biomimetic ntawm lehfilcon A CL muab cov khoom zoo dua ntawm qhov chaw xws li kev txhim kho kev tiv thaiv kev ntub dej thiab kev ua qias tuaj, kev nce ntxiv ntawm lubricity, thiab txo cov cell thiab cov kab mob adhesion15,16. Tsis tas li ntawd, kev siv thiab kev txhim kho ntawm cov khoom siv biomimetic no kuj qhia txog kev nthuav dav ntxiv rau lwm cov khoom siv biomedical. Yog li ntawd, nws yog ib qho tseem ceeb heev uas yuav tsum piav qhia txog cov khoom ntawm qhov chaw ntawm cov khoom siv ultra-mos no thiab nkag siab txog nws txoj kev sib cuam tshuam nrog lub qhov muag kom tsim tau lub hauv paus kev paub dav dav los txhawb kev txhim kho thiab kev siv yav tom ntej. Feem ntau cov iav sib cuag SiHy muaj nyob hauv khw yog tsim los ntawm kev sib xyaw ua ke ntawm cov polymers hydrophilic thiab hydrophobic uas tsim cov qauv khoom sib xws17. Ntau txoj kev tshawb fawb tau ua los tshawb nrhiav lawv cov khoom siv kho tshuab siv cov txheej txheem kev sib txuas lus, tensile thiab microindentation test18,19,20,21. Txawm li cas los xij, tus qauv tsim biomimetic tshiab ntawm lehfilcon A CL ua rau nws yog cov khoom siv heterogeneous tshwj xeeb uas cov khoom siv kho tshuab ntawm cov qauv txhuam polymer branched txawv ntawm cov ntawm SiHy lub hauv paus substrate. Yog li ntawd, nws nyuaj heev rau kev ntsuas cov khoom no siv cov txheej txheem ib txwm muaj thiab indentation. Ib txoj kev cog lus siv txoj kev sim nanoindentation siv rau hauv atomic force microscopy (AFM), ib txoj kev uas tau siv los txiav txim siab cov khoom siv kho tshuab ntawm cov khoom siv viscoelastic mos xws li cov hlwb biological thiab cov ntaub so ntswg, nrog rau cov polymers mos22,23,24,25. ,26,27,28,29,30. Hauv AFM nanoindentation, cov hauv paus ntawm kev sim nanoindentation tau ua ke nrog cov kev nce qib tshiab hauv AFM thev naus laus zis los muab kev ntsuas ntau dua thiab kev sim ntawm ntau yam khoom siv supersoft31,32,33,34,35,36. Tsis tas li ntawd, cov thev naus laus zis muab lwm yam txiaj ntsig tseem ceeb los ntawm kev siv cov qauv sib txawv. indenter thiab probe thiab qhov ua tau ntawm kev sim hauv ntau yam kua xov xwm.
AFM nanoindentation tuaj yeem muab faib ua peb yam tseem ceeb: (1) cov khoom siv (sensors, detectors, probes, thiab lwm yam); (2) cov kev ntsuas ntsuas (xws li lub zog, kev hloov chaw, qhov ceev, qhov loj ntawm lub ramp, thiab lwm yam); (3) Kev ua cov ntaub ntawv (kev kho qhov pib, kev kwv yees qhov kov, kev sib haum xeeb ntawm cov ntaub ntawv, kev ua qauv, thiab lwm yam). Ib qho teeb meem tseem ceeb nrog txoj kev no yog tias ntau txoj kev tshawb fawb hauv cov ntaub ntawv siv AFM nanoindentation tshaj tawm cov txiaj ntsig sib txawv heev rau tib yam qauv / cell / khoom siv hom 37,38,39,40,41. Piv txwv li, Lekka et al. Kev cuam tshuam ntawm AFM probe geometry ntawm Young's modulus ntawm cov qauv ntawm cov khoom siv hydrogel homogeneous thiab heterogeneous cells tau kawm thiab piv. Lawv tshaj tawm tias cov nqi modulus yog nyob ntawm kev xaiv cantilever thiab lub taub hau, nrog rau tus nqi siab tshaj plaws rau lub pyramid-puab probe thiab tus nqi qis tshaj plaws ntawm 42 rau lub spherical probe. Ib yam li ntawd, Selhuber-Unkel et al. Nws tau pom tias qhov ceev ntawm qhov indenter, qhov loj ntawm qhov indenter thiab tuab ntawm cov qauv polyacrylamide (PAAM) cuam tshuam li cas rau Young's modulus ntsuas los ntawm ACM43 nanoindentation. Lwm qhov ua rau muaj teeb meem yog qhov tsis muaj cov ntaub ntawv xeem modulus qis heev thiab cov txheej txheem xeem dawb. Qhov no ua rau nws nyuaj heev kom tau txais cov txiaj ntsig tseeb nrog kev ntseeg siab. Txawm li cas los xij, txoj kev no muaj txiaj ntsig zoo rau kev ntsuas thiab kev sib piv ntawm cov qauv zoo sib xws, piv txwv li siv AFM nanoindentation los sib txawv cov hlwb ib txwm los ntawm cov hlwb mob qog noj ntshav 44, 45.
Thaum kuaj cov ntaub mos mos nrog AFM nanoindentation, txoj cai dav dav yog siv lub probe nrog lub caij nplooj ntoos hlav qis tsis tu ncua (k) uas phim cov qauv modulus thiab lub taub hau hemispherical / puag ncig kom thawj qhov probe tsis tho qhov chaw ntawm cov qauv thaum thawj zaug kov nrog cov ntaub mos mos. Nws tseem ceeb heev uas lub teeb liab deflection tsim los ntawm lub probe yuav muaj zog txaus kom pom los ntawm lub laser detector system24,34,46,47. Hauv cov ntaub ntawv ntawm cov hlwb heterogeneous ultra-mos, cov ntaub so ntswg thiab gels, lwm qhov kev sib tw yog kom kov yeej lub zog nplaum ntawm lub probe thiab qhov chaw ntawm cov qauv kom ntseeg tau tias muaj kev ntsuas rov ua dua thiab txhim khu kev qha48,49,50. Txog thaum tsis ntev los no, feem ntau cov haujlwm ntawm AFM nanoindentation tau tsom mus rau kev kawm txog tus cwj pwm kho tshuab ntawm cov hlwb biological, cov ntaub so ntswg, gels, hydrogels, thiab biomolecules siv cov probes spherical loj, feem ntau hu ua colloidal probes (CPs). , 47, 51, 52, 53, 54, 55. Cov lus qhia no muaj lub vojvoog ntawm 1 txog 50 µm thiab feem ntau yog ua los ntawm borosilicate iav, polymethyl methacrylate (PMMA), polystyrene (PS), silicon dioxide (SiO2) thiab pob zeb diamond-zoo li carbon (DLC). Txawm hais tias CP-AFM nanoindentation feem ntau yog thawj qhov kev xaiv rau kev piav qhia txog cov qauv mos mos, nws muaj nws cov teeb meem thiab kev txwv. Kev siv cov lus qhia loj, micron-sized spherical ua rau thaj chaw sib cuag ntawm lub taub hau nrog cov qauv thiab ua rau poob qhov kev daws teeb meem loj. Rau cov qauv mos mos, tsis sib xws, qhov twg cov khoom siv kho tshuab ntawm cov ntsiab lus hauv zos yuav txawv ntawm qhov nruab nrab hla thaj chaw dav dua, CP indentation tuaj yeem zais txhua qhov tsis sib xws hauv cov khoom ntawm qhov ntsuas hauv zos 52. Colloidal probes feem ntau yog ua los ntawm kev txuas cov micron-sized colloidal spheres rau tipless cantilevers siv cov nplaum epoxy. Cov txheej txheem tsim khoom nws tus kheej muaj ntau yam teeb meem thiab tuaj yeem ua rau muaj kev tsis sib xws hauv cov txheej txheem calibration probe. Tsis tas li ntawd, qhov loj me thiab qhov hnyav ntawm cov khoom colloidal cuam tshuam ncaj qha rau cov txheej txheem calibration tseem ceeb ntawm cantilever, xws li resonant zaus, lub caij nplooj ntoos hlav stiffness, thiab deflection rhiab heev56,57,58. Yog li, cov txheej txheem siv feem ntau rau cov probes AFM ib txwm muaj, xws li kev ntsuas kub, yuav tsis muab qhov calibration raug rau CP, thiab lwm txoj hauv kev yuav tsum tau ua cov kev kho no57, 59, 60, 61. Cov kev sim CP indentation ib txwm siv cov kev hloov pauv loj cantilever los kawm cov khoom ntawm cov qauv mos, uas tsim lwm qhov teeb meem thaum calibrating tus cwj pwm tsis-linear ntawm cantilever ntawm qhov sib txawv loj62,63,64. Cov txheej txheem niaj hnub colloidal probe indentation feem ntau coj mus rau hauv tus account geometry ntawm cantilever siv los calibrate lub probe, tab sis tsis quav ntsej txog kev cuam tshuam ntawm cov khoom colloidal, uas tsim kev tsis paub meej ntxiv hauv qhov tseeb ntawm txoj kev38,61. Ib yam li ntawd, cov qauv elastic uas xam los ntawm kev sib cuag qauv sib haum yog nyob ntawm qhov geometry ntawm qhov indentation probe, thiab qhov tsis sib xws ntawm qhov taub thiab qhov chaw ntawm cov qauv tuaj yeem ua rau muaj qhov tsis raug27, 65, 66, 67, 68. Qee qhov haujlwm tsis ntev los no los ntawm Spencer et al. Cov yam ntxwv uas yuav tsum tau coj mus rau hauv tus account thaum piav qhia txog cov txhuam polymer mos siv CP-AFM nanoindentation txoj kev tau hais txog. Lawv tau tshaj tawm tias kev khaws cia ntawm cov kua dej viscous hauv cov txhuam polymer ua haujlwm ntawm qhov ceev ua rau muaj kev nce hauv lub taub hau load thiab yog li ntawd kev ntsuas sib txawv ntawm cov khoom nyob ntawm qhov ceev30,69,70,71.
Hauv kev tshawb fawb no, peb tau piav qhia txog qhov modulus ntawm cov khoom siv ultra-soft heev lehfilcon A CL siv txoj kev hloov kho AFM nanoindentation. Muab cov khoom thiab cov qauv tshiab ntawm cov khoom siv no, qhov rhiab heev ntawm txoj kev indentation ib txwm tsis txaus los piav qhia txog modulus ntawm cov khoom siv mos heev no, yog li nws yog qhov tsim nyog los siv txoj kev AFM nanoindentation nrog kev rhiab heev dua thiab qis dua. theem. Tom qab tshuaj xyuas qhov tsis txaus thiab teeb meem ntawm cov txheej txheem colloidal AFM probe nanoindentation uas twb muaj lawm, peb qhia vim li cas peb thiaj xaiv qhov me dua, tsim tshwj xeeb AFM probe los tshem tawm kev rhiab heev, suab nrov tom qab, taw tes taw tes, ntsuas qhov ceev modulus ntawm cov khoom siv mos heterogeneous xws li kev cia kua dej. thiab kev ntsuas qhov tseeb. Tsis tas li ntawd, peb tau ntsuas qhov zoo thiab qhov ntev ntawm lub taub hau indentation, tso cai rau peb siv cov qauv haum cone-sphere los txiav txim siab modulus ntawm elasticity yam tsis tau ntsuas thaj chaw sib cuag ntawm lub taub hau nrog cov khoom siv. Ob qho kev xav tsis meej uas tau ntsuas hauv txoj haujlwm no yog cov khoom siv elastic tag nrho thiab qhov tob indentation-independent modulus. Siv txoj kev no, peb xub sim cov qauv ultra-soft nrog lub modulus paub los ntsuas qhov txheej txheem, thiab tom qab ntawd siv txoj kev no los piav qhia txog qhov chaw ntawm ob lub lens sib txawv. Txoj kev no ntawm kev piav qhia txog AFM nanoindentation surfaces nrog kev nkag siab ntau dua yuav siv tau rau ntau yam biomimetic heterogeneous ultrasoft cov ntaub ntawv nrog kev siv tau zoo hauv cov khoom siv kho mob thiab cov ntawv thov biomedical.
Cov tsom iav sib cuag Lehfilcon A (Alcon, Fort Worth, Texas, Tebchaws Meskas) thiab lawv cov silicone hydrogel substrates tau raug xaiv rau kev sim nanoindentation. Ib lub lens mount tsim tshwj xeeb tau siv rau hauv kev sim. Txhawm rau teeb tsa lub lens rau kev sim, nws tau muab tso rau ntawm lub dome-puab sawv ntsug, xyuas kom meej tias tsis muaj cua npuas nkag mus rau hauv, thiab tom qab ntawd kho nrog cov npoo. Ib lub qhov hauv lub fixture ntawm sab saum toj ntawm lub lens tuav muab kev nkag mus rau qhov chaw nruab nrab ntawm lub lens rau kev sim nanoindentation thaum tuav cov kua hauv qhov chaw. Qhov no ua rau cov tsom iav hydrated tag nrho. 500 μl ntawm cov kua ntim khoom sib cuag lens tau siv ua cov kua sim. Txhawm rau txheeb xyuas cov txiaj ntsig ntau, cov polyacrylamide (PAAM) hydrogels uas tsis ua haujlwm muaj nyob hauv khw tau npaj los ntawm cov khoom sib xyaw polyacrylamide-co-methylene-bisacrylamide (100 mm Petrisoft Petri tais diav, Matrigen, Irvine, CA, Tebchaws Meskas), ib qho elastic modulus paub ntawm 1 kPa. Siv 4-5 tee (kwv yees li 125 µl) ntawm phosphate buffered saline (PBS los ntawm Corning Life Sciences, Tewkesbury, MA, USA) thiab 1 tee ntawm OPTI-FREE Puremoist contact lens solution (Alcon, Vaud, TX, USA). ) ntawm AFM hydrogel-probe interface.
Cov qauv ntawm Lehfilcon A CL thiab SiHy substrates tau pom siv FEI Quanta 250 Field Emission Scanning Electron Microscope (FEG SEM) system nruab nrog Scanning Transmission Electron Microscope (STEM) detector. Txhawm rau npaj cov qauv, cov lens tau ntxuav ua ntej nrog dej thiab txiav ua cov wedges zoo li lub ncuav mog qab zib. Txhawm rau kom ua tiav qhov sib txawv ntawm cov khoom hydrophilic thiab hydrophobic ntawm cov qauv, 0.10% stabilized solution ntawm RuO4 tau siv ua xim, uas cov qauv tau raus rau 30 feeb. Lub lehfilcon A CL RuO4 staining yog qhov tseem ceeb tsis yog tsuas yog ua tiav qhov sib txawv zoo dua, tab sis kuj pab khaws cov qauv ntawm cov txhuam polymer branched hauv lawv daim ntawv qub, uas tom qab ntawd pom ntawm cov duab STEM. Tom qab ntawd lawv tau ntxuav thiab qhuav hauv cov khoom sib xyaw ethanol / dej nrog kev nce ntxiv ethanol concentration. Cov qauv tom qab ntawd tau pov nrog EMBed 812 / Araldite epoxy, uas kho thaum hmo ntuj ntawm 70 ° C. Cov qauv blocks tau los ntawm resin polymerization tau txiav nrog ultramicrotome, thiab cov seem nyias nyias tau pom nrog STEM detector hauv hom nqus tsev qis ntawm qhov hluav taws xob nrawm ntawm 30 kV. Tib lub SEM system tau siv rau kev piav qhia ntxaws ntxaws ntawm PFQNM-LC-A-CAL AFM probe (Bruker Nano, Santa Barbara, CA, USA). Cov duab SEM ntawm AFM probe tau txais hauv hom nqus tsev siab nrog qhov hluav taws xob nrawm ntawm 30 kV. Tau txais cov duab ntawm ntau lub kaum sab xis thiab magnifications los sau txhua qhov ntsiab lus ntawm cov duab thiab qhov loj ntawm AFM probe tip. Txhua qhov ntev ntawm cov duab tau ntsuas digitally.
Ib lub Dimension FastScan Bio Icon atomic force microscope (Bruker Nano, Santa Barbara, CA, USA) nrog hom "PeakForce QNM hauv Fluid" tau siv los pom thiab nanoindentate lehfilcon A CL, SiHy substrate, thiab PAAm hydrogel qauv. Rau kev sim duab, PEAKFORCE-HIRS-FA probe (Bruker) nrog lub nominal tip radius ntawm 1 nm tau siv los ntes cov duab siab daws teeb meem ntawm cov qauv ntawm tus nqi scan ntawm 0.50 Hz. Tag nrho cov duab tau raug thaij hauv cov kua dej.
Cov kev sim AFM nanoindentation tau ua tiav los ntawm kev siv PFQNM-LC-A-CAL probe (Bruker). Lub AFM probe muaj lub taub hau silicon ntawm lub nitride cantilever 345 nm tuab, 54 µm ntev thiab 4.5 µm dav nrog lub zaus resonant ntawm 45 kHz. Nws yog tsim tshwj xeeb los piav qhia thiab ua cov kev ntsuas nanomechanical ntawm cov qauv mos mos. Cov sensors tau calibrated ib tus zuj zus ntawm lub Hoobkas nrog cov chaw teeb tsa ua ntej calibrated. Lub caij nplooj ntoos hlav constants ntawm cov probes siv hauv kev tshawb fawb no yog nyob rau hauv qhov ntau ntawm 0.05–0.1 N / m. Txhawm rau txiav txim siab qhov zoo li cas thiab qhov loj ntawm lub taub hau, lub probe tau piav qhia meej siv SEM. Hauv daim duab 1a qhia txog qhov kev daws teeb meem siab, qhov loj me me scanning electron micrograph ntawm PFQNM-LC-A-CAL probe, muab kev pom holistic ntawm kev tsim probe. Hauv daim duab 1b qhia txog qhov pom loj dua ntawm sab saum toj ntawm lub taub hau probe, muab cov ntaub ntawv hais txog cov duab thiab qhov loj ntawm lub taub hau. Ntawm qhov kawg kawg, lub koob yog ib lub hemisphere li ntawm 140 nm hauv txoj kab uas hla (Daim Duab 1c). Hauv qab no, lub taub hau tapers mus rau hauv ib lub conical zoo li, ncav cuag qhov ntev ntsuas ntawm kwv yees li 500 nm. Sab nraum thaj tsam tapering, lub taub hau yog cylindrical thiab xaus rau hauv tag nrho qhov ntev ntawm 1.18 µm. Qhov no yog qhov tseem ceeb ua haujlwm ntawm lub taub hau probe. Tsis tas li ntawd, ib lub spherical polystyrene (PS) probe loj (Novascan Technologies, Inc., Boone, Iowa, USA) nrog lub taub hau txoj kab uas hla ntawm 45 µm thiab lub caij nplooj ntoos hlav tas li ntawm 2 N / m kuj tau siv rau kev sim ua ib qho colloidal probe. nrog PFQNM-LC-A-CAL 140 nm probe rau kev sib piv.
Tau muaj kev tshaj tawm tias cov kua dej tuaj yeem raug ntes ntawm AFM probe thiab cov qauv txhuam polymer thaum lub sijhawm nanoindentation, uas yuav siv lub zog rau sab saud ntawm AFM probe ua ntej nws kov qhov chaw 69. Qhov kev cuam tshuam viscous extrusion no vim yog kev khaws cia kua dej tuaj yeem hloov qhov pom tseeb ntawm kev sib cuag, yog li cuam tshuam rau kev ntsuas qhov modulus ntawm qhov chaw. Txhawm rau kawm txog cov nyhuv ntawm probe geometry thiab indentation ceev ntawm kev khaws cia kua dej, cov kab nkhaus indentation tau plotted rau lehfilcon A CL qauv siv 140 nm txoj kab uas hla probe ntawm qhov hloov pauv tas li ntawm 1 µm / s thiab 2 µm / s. probe txoj kab uas hla 45 µm, qhov chaw teeb tsa zog ruaj khov 6 nN ua tiav ntawm 1 µm / s. Kev sim nrog probe 140 nm hauv txoj kab uas hla tau ua tiav ntawm qhov ceev indentation ntawm 1 µm / s thiab lub zog teeb tsa ntawm 300 pN, xaiv los tsim lub siab sib cuag hauv qhov ntau ntawm lub cev (1-8 kPa) ntawm lub qhov muag sab saud. siab 72. Cov qauv mos mos uas tau npaj tiav ntawm PAA hydrogel nrog lub siab ntawm 1 kPa tau raug sim rau lub zog indentation ntawm 50 pN ntawm qhov ceev ntawm 1 μm / s siv lub probe nrog lub cheeb ntawm 140 nm.
Vim tias qhov ntev ntawm lub conical ib feem ntawm lub hau ntawm PFQNM-LC-A-CAL probe yog kwv yees li 500 nm, rau txhua qhov tob ntawm qhov indentation <500 nm nws tuaj yeem xav tias qhov geometry ntawm lub probe thaum lub sijhawm indentation yuav tseem yog qhov tseeb rau nws cov duab cone. Tsis tas li ntawd, nws xav tias qhov chaw ntawm cov khoom siv hauv kev sim yuav ua rau pom qhov kev teb rov qab elastic, uas kuj yuav raug lees paub hauv cov ntu hauv qab no. Yog li ntawd, nyob ntawm cov duab thiab qhov loj ntawm lub hau, peb tau xaiv lub qauv cone-sphere fitting tsim los ntawm Briscoe, Sebastian thiab Adams, uas muaj nyob rau hauv tus muag khoom software, los ua peb cov kev sim AFM nanoindentation (NanoScope). Kev sib cais cov ntaub ntawv tshuaj xyuas software, Bruker) 73. Tus qauv piav qhia txog kev sib raug zoo ntawm lub zog-kev hloov chaw F (δ) rau lub cone nrog lub spherical apex defect. Ntawm daim duab. Daim Duab 2 qhia txog qhov geometry ntawm kev sib cuag thaum lub sijhawm sib cuam tshuam ntawm lub khob khov kho nrog lub taub hau kheej kheej, qhov twg R yog lub vojvoog ntawm lub taub hau kheej kheej, a yog lub vojvoog sib cuag, b yog lub vojvoog sib cuag ntawm qhov kawg ntawm lub taub hau kheej kheej, δ yog lub vojvoog sib cuag. qhov tob ntawm qhov nkag, θ yog ib nrab lub kaum ntawm lub khob. Daim duab SEM ntawm qhov kev soj ntsuam no qhia meej meej tias lub taub hau kheej kheej 140 nm txoj kab uas hla sib koom ua ke rau hauv lub khob, yog li ntawm no b tsuas yog txhais los ntawm R, piv txwv li b = R cos θ. Cov software uas tus neeg muag khoom muab muab kev sib raug zoo ntawm lub khob-lub vojvoog los xam Young's modulus (E) tus nqi los ntawm cov ntaub ntawv sib cais quab yuam xav tias a > b. Kev sib raug zoo:
qhov twg F yog lub zog indentation, E yog Young's modulus, ν yog Poisson's ratio. Lub vojvoog sib cuag a tuaj yeem kwv yees siv:
Daim duab ntawm cov qauv sib cuag ntawm lub khob khov kho nrog lub taub hau kheej kheej nias rau hauv cov khoom siv ntawm Lefilcon lub lens sib cuag nrog ib txheej saum npoo ntawm cov txhuam polymer branched.
Yog tias a ≤ b, qhov kev sib raug zoo txo ​​qis rau qhov sib npaug rau lub tshuab indenter spherical ib txwm muaj;
Peb ntseeg tias qhov kev sib cuam tshuam ntawm qhov kev soj ntsuam indenting nrog cov qauv branched ntawm PMPC polymer txhuam yuav ua rau lub vojvoog sib cuag a loj dua li lub vojvoog sib cuag kheej kheej b. Yog li ntawd, rau txhua qhov kev ntsuas ntau ntawm cov modulus elastic ua nyob rau hauv txoj kev tshawb fawb no, peb siv qhov kev vam khom tau txais rau rooj plaub a> b.
Cov ntaub ntawv biomimetic ultrasoft uas tau kawm hauv txoj kev tshawb fawb no tau raug thaij duab tag nrho siv scanning transmission electron microscopy (STEM) ntawm qhov seem ntawm cov qauv thiab atomic force microscopy (AFM) ntawm qhov chaw. Qhov kev piav qhia ntxaws ntxaws no tau ua tiav los ntawm peb cov haujlwm uas tau luam tawm yav dhau los, uas peb tau txiav txim siab tias cov qauv txhuam polymeric dynamically branched ntawm qhov chaw PMPC-modified lehfilcon A CL tau pom cov khoom siv kho tshuab zoo sib xws rau cov ntaub so ntswg corneal 14. Vim li no, peb xa mus rau cov chaw sib cuag lens ua cov ntaub ntawv biomimetic14. Ntawm daim duab 3a, b qhia cov seem ntawm cov qauv txhuam polymer PMPC branched ntawm qhov chaw ntawm lehfilcon A CL substrate thiab cov khoom SiHy tsis kho, raws li. Cov chaw ntawm ob qho qauv tau raug tshuaj xyuas ntxiv siv cov duab AFM siab daws teeb meem, uas tau lees paub ntxiv txog cov txiaj ntsig ntawm STEM kev tshuaj xyuas (Daim duab 3c, d). Thaum muab ua ke, cov duab no muab qhov ntev kwv yees ntawm cov qauv txhuam polymer PMPC branched ntawm 300–400 nm, uas yog qhov tseem ceeb rau kev txhais cov kev ntsuas AFM nanoindentation. Lwm qhov kev soj ntsuam tseem ceeb uas tau los ntawm cov duab yog tias qhov qauv ntawm CL biomimetic khoom siv yog morphologically txawv ntawm SiHy substrate khoom siv. Qhov sib txawv no hauv lawv cov morphology ntawm qhov chaw tuaj yeem pom tseeb thaum lawv sib cuam tshuam nrog lub indenting AFM probe thiab tom qab ntawd hauv cov nqi modulus ntsuas.
Cov duab STEM hla ntawm (a) lehfilcon A CL thiab (b) SiHy substrate. Scale bar, 500 nm. Cov duab AFM ntawm qhov chaw ntawm lehfilcon A CL substrate (c) thiab lub hauv paus SiHy substrate (d) (3 µm × 3 µm).
Cov polymers bioinspired thiab cov qauv txhuam polymer yog cov mos mos thiab tau kawm dav thiab siv rau hauv ntau yam kev siv biomedical74,75,76,77. Yog li ntawd, nws yog ib qho tseem ceeb uas yuav tsum siv txoj kev AFM nanoindentation, uas tuaj yeem ntsuas lawv cov khoom siv kho tshuab kom raug thiab ntseeg tau. Tab sis tib lub sijhawm, cov khoom tshwj xeeb ntawm cov ntaub ntawv mos mos no, xws li cov modulus elastic qis heev, cov kua dej ntau thiab elasticity siab, feem ntau ua rau nws nyuaj rau xaiv cov khoom siv, cov duab thiab cov duab ntawm qhov indenting probe. Qhov loj. Qhov no yog qhov tseem ceeb kom tus indenter tsis tho qhov chaw mos ntawm cov qauv, uas yuav ua rau muaj qhov yuam kev hauv kev txiav txim siab qhov chaw sib cuag nrog qhov chaw thiab thaj chaw sib cuag.
Rau qhov no, kev nkag siab txog cov qauv ntawm cov khoom siv biomimetic ultra-soft (lehfilcon A CL) yog qhov tseem ceeb. Cov ntaub ntawv hais txog qhov loj me thiab cov qauv ntawm cov txhuam polymer branched tau los ntawm kev siv txoj kev thaij duab muab lub hauv paus rau kev ua haujlwm ntawm qhov chaw siv cov txheej txheem AFM nanoindentation. Hloov chaw ntawm micron-sized spherical colloidal probes, peb tau xaiv PFQNM-LC-A-CAL silicon nitride probe (Bruker) nrog lub taub hau ntawm 140 nm, tsim tshwj xeeb rau kev ntsuas ntau ntawm cov khoom siv kho tshuab ntawm cov qauv biological 78, 79, 80, 81, 82, 83, 84. Lub laj thawj rau kev siv cov probes ntse dua piv rau cov probes colloidal ib txwm muaj tuaj yeem piav qhia los ntawm cov yam ntxwv ntawm cov khoom siv. Piv rau qhov loj ntawm lub taub hau probe (~140 nm) nrog cov txhuam polymer branched ntawm qhov chaw ntawm CL lehfilcon A, qhia nyob rau hauv daim duab 3a, nws tuaj yeem xaus lus tias lub taub hau loj txaus los kov ncaj qha rau cov qauv txhuam no, uas txo qhov muaj feem ntawm lub taub hau tho los ntawm lawv. Txhawm rau piav qhia txog qhov no, hauv daim duab 4 yog daim duab STEM ntawm lehfilcon A CL thiab lub taub hau indenting ntawm AFM probe (kos rau qhov ntsuas).
Daim duab qhia txog STEM duab ntawm lehfilcon A CL thiab ACM indentation probe (kos rau qhov ntsuas).
Ntxiv mus, qhov loj ntawm 140 nm yog me txaus kom tsis txhob muaj kev pheej hmoo ntawm cov teebmeem nplaum extrusion uas tau tshaj tawm yav dhau los rau cov txhuam polymer tsim los ntawm CP-AFM nanoindentation method69,71. Peb xav tias vim yog lub duab tshwj xeeb cone-spherical thiab qhov me me ntawm AFM tip no (Daim duab 1), qhov xwm txheej ntawm cov nkhaus quab yuam tsim los ntawm lehfilcon A CL nanoindentation yuav tsis nyob ntawm qhov ceev indentation lossis qhov ceev loading / unloading. Yog li ntawd, nws tsis cuam tshuam los ntawm cov teebmeem poroelastic. Txhawm rau sim qhov kev xav no, cov qauv lehfilcon A CL tau indented ntawm lub zog siab tshaj plaws siv PFQNM-LC-A-CAL probe, tab sis ntawm ob qhov ceev sib txawv, thiab cov kab tensile thiab retract force tau siv los plot lub zog (nN) hauv kev sib cais (µm) tau qhia hauv Daim Duab 5a. Nws yog qhov tseeb tias cov kab nkhaus thaum lub sijhawm thauj khoom thiab tshem tawm tag nrho sib tshooj, thiab tsis muaj pov thawj tseeb tias lub zog shear ntawm xoom qhov tob indentation nce nrog qhov ceev indentation hauv daim duab, qhia tias cov txhuam txhuam ib leeg tau piav qhia tsis muaj poroelastic effect. Qhov sib piv, cov teebmeem khaws cia kua (viscous extrusion thiab poroelasticity effects) yog qhov pom tseeb rau 45 µm txoj kab uas hla AFM probe ntawm tib qhov ceev indentation thiab tau hais txog los ntawm hysteresis ntawm cov kab ncab thiab retract, raws li pom hauv Daim Duab 5b. Cov txiaj ntsig no txhawb nqa qhov kev xav thiab qhia tias 140 nm txoj kab uas hla probes yog qhov kev xaiv zoo rau kev piav qhia cov chaw mos mos zoo li no.
lehfilcon A CL indentation force curves siv ACM; (a) siv lub probe nrog lub cheeb ntawm 140 nm ntawm ob qhov loading rates, qhia txog qhov tsis muaj poroelastic effect thaum lub sijhawm indentation ntawm qhov chaw; (b) siv cov probes nrog lub cheeb ntawm 45 µm thiab 140 nm. s qhia txog cov teebmeem ntawm viscous extrusion thiab poroelasticity rau cov probes loj piv rau cov probes me dua.
Yuav kom paub txog cov nplaim ultrasoft, cov txheej txheem AFM nanoindentation yuav tsum muaj qhov probe zoo tshaj plaws los kawm cov khoom ntawm cov khoom siv hauv kev kawm. Ntxiv rau qhov zoo li thiab qhov loj ntawm lub taub hau, qhov rhiab heev ntawm AFM detector system, qhov rhiab heev rau qhov ntxeev ntawm lub taub hau hauv qhov chaw sim, thiab qhov tawv ntawm cantilever ua lub luag haujlwm tseem ceeb hauv kev txiav txim siab qhov tseeb thiab kev ntseeg tau ntawm nanoindentation. Kev ntsuas. Rau peb lub kaw lus AFM, qhov txwv ntawm kev ntes ntawm Position Sensitive Detector (PSD) yog kwv yees li 0.5 mV thiab yog raws li qhov nrawm ntawm lub caij nplooj ntoos hlav uas tau calibrated thiab qhov rhiab heev ntawm cov kua dej deflection ntawm PFQNM-LC-A-CAL probe, uas sib raug rau qhov rhiab heev ntawm theoretical load. yog tsawg dua 0.1 pN. Yog li ntawd, txoj kev no tso cai rau kev ntsuas qhov tsawg kawg nkaus indentation force ≤ 0.1 pN yam tsis muaj ib qho peripheral noise component. Txawm li cas los xij, nws yuav luag tsis yooj yim sua rau lub kaw lus AFM kom txo qhov nrov peripheral rau qib no vim muaj cov yam xws li kev co tshuab thiab cov kua dej dynamics. Cov yam no txwv tsis pub qhov rhiab heev ntawm AFM nanoindentation txoj kev thiab ua rau muaj lub suab nrov tom qab ntawm kwv yees li ≤ 10 pN. Rau qhov kev piav qhia ntawm qhov chaw, lehfilcon A CL thiab SiHy substrate cov qauv tau raug ntxig rau hauv qab cov xwm txheej uas muaj dej txaus siv 140 nm probe rau SEM kev piav qhia, thiab cov kab nkhaus zog tau muab tso rau ntawm lub zog (pN) thiab siab. Daim phiaj sib cais (µm) tau pom hauv Daim Duab 6a. Piv rau SiHy lub hauv paus substrate, lehfilcon A CL force curve qhia meej meej txog theem hloov pauv pib ntawm qhov chaw sib cuag nrog txhuam polymer forked thiab xaus nrog kev hloov pauv ntawm qhov chaw sib cuag ntawm lub taub hau nrog cov khoom hauv qab. Qhov kev hloov pauv ntawm cov kab nkhaus zog no qhia txog tus cwj pwm elastic tiag tiag ntawm txhuam polymer branched ntawm qhov chaw, raws li pov thawj los ntawm cov kab nkhaus compression ze ze tom qab cov kab nkhaus nruj thiab qhov sib piv hauv cov khoom siv kho tshuab ntawm cov qauv txhuam thiab cov khoom siv SiHy loj. Thaum piv lefilcon. Kev sib cais ntawm qhov nruab nrab ntev ntawm txhuam polymer branched hauv daim duab STEM ntawm PCS (Daim Duab 3a) thiab nws cov kab nkhaus raws abscissa hauv Daim Duab 3a. 6a qhia tau hais tias txoj kev no muaj peev xwm ntes tau lub taub hau thiab cov polymer branched ncav cuag sab saum toj ntawm qhov chaw. Kev sib cuag ntawm cov qauv txhuam. Tsis tas li ntawd, qhov sib tshooj ze ntawm cov kab nkhaus qhia tias tsis muaj cov nyhuv khaws cia kua. Hauv qhov no, tsis muaj kev sib txuas ntawm rab koob thiab qhov chaw ntawm cov qauv. Cov seem sab saud ntawm cov kab nkhaus rau ob qho qauv sib tshooj, qhia txog qhov zoo sib xws ntawm cov khoom siv kho tshuab ntawm cov ntaub ntawv substrate.
(a) AFM nanoindentation force curves rau lehfilcon A CL substrates thiab SiHy substrates, (b) force curves qhia txog kev kwv yees qhov chaw sib cuag siv txoj kev suab nrov tom qab.
Yuav kom kawm tau cov ntsiab lus zoo dua ntawm cov kab nkhaus zog, cov kab nkhaus nruj ntawm lehfilcon A CL qauv raug rov tsim dua hauv daim duab 6b nrog lub zog siab tshaj plaws ntawm 50 pN raws y-axis. Daim duab no muab cov ntaub ntawv tseem ceeb txog lub suab nrov keeb kwm yav dhau los. Lub suab nrov yog nyob rau hauv qhov ntau ntawm ± 10 pN, uas yog siv los txiav txim siab qhov chaw sib cuag thiab xam qhov tob ntawm qhov nkag. Raws li tau tshaj tawm hauv cov ntaub ntawv, kev txheeb xyuas cov ntsiab lus sib cuag yog qhov tseem ceeb rau kev ntsuas cov khoom siv xws li modulus85. Ib txoj hauv kev uas muaj kev ua tiav ntawm cov ntaub ntawv nkhaus zog tau qhia txog kev sib haum xeeb zoo dua ntawm cov ntaub ntawv sib haum xeeb thiab kev ntsuas ntau rau cov ntaub ntawv mos86. Hauv txoj haujlwm no, peb xaiv cov ntsiab lus sib cuag yog qhov yooj yim thiab lub hom phiaj, tab sis nws muaj nws cov kev txwv. Peb txoj hauv kev txuag kom txiav txim siab qhov chaw sib cuag yuav ua rau muaj cov nqi modulus ntau dhau rau qhov tob me me (< 100 nm). Kev siv cov algorithm-based touchpoint detection thiab automated data processing yuav yog kev txuas ntxiv ntawm txoj haujlwm no yav tom ntej los txhim kho peb txoj kev. Yog li, rau lub suab nrov tom qab ntawm qhov kev txiav txim ntawm ± 10 pN, peb txhais qhov chaw sib cuag ua thawj qhov chaw ntawm x-axis hauv Daim Duab 6b nrog tus nqi ntawm ≥10 pN. Tom qab ntawd, raws li lub suab nrov ntawm 10 pN, ib txoj kab ntsug ntawm qib ~ 0.27 µm cim qhov chaw sib cuag nrog qhov chaw, tom qab ntawd qhov nkhaus ncab txuas ntxiv mus txog thaum lub substrate ntsib qhov tob ntawm ~ 270 nm. Nthuav, raws li qhov loj ntawm cov yam ntxwv ntawm cov txhuam polymer branched (300–400 nm) ntsuas siv txoj kev thaij duab, qhov tob ntawm CL lehfilcon A qauv pom siv txoj kev suab nrov tom qab yog li 270 nm, uas ze heev rau qhov loj me ntawm kev ntsuas nrog STEM. Cov txiaj ntsig no ntxiv lees paub qhov sib xws thiab kev siv tau ntawm cov duab thiab qhov loj ntawm AFM probe tip rau kev nkag mus ntawm cov qauv txhuam polymer branched mos thiab elastic heev no. Cov ntaub ntawv no kuj muab pov thawj muaj zog los txhawb peb txoj kev siv suab nrov tom qab ua qhov chaw rau kev taw qhia cov ntsiab lus sib cuag. Yog li ntawd, txhua qhov txiaj ntsig ntawm kev suav lej thiab kev sib txuas ntawm cov quab yuam yuav tsum yog qhov tseeb.
Kev ntsuas ntau los ntawm AFM nanoindentation txoj kev yog nyob ntawm cov qauv lej siv rau kev xaiv cov ntaub ntawv thiab kev tshuaj xyuas tom qab. Yog li ntawd, nws yog ib qho tseem ceeb uas yuav tsum xav txog txhua yam uas cuam tshuam nrog kev xaiv ntawm indenter, cov khoom siv thiab cov txheej txheem ntawm lawv kev sib cuam tshuam ua ntej xaiv ib tus qauv tshwj xeeb. Hauv qhov no, lub taub hau geometry tau ua tib zoo piav qhia siv SEM micrographs (Daim Duab 1), thiab raws li cov txiaj ntsig, 140 nm txoj kab uas hla AFM nanoindenting probe nrog lub khob tawv thiab lub taub hau spherical geometry yog qhov kev xaiv zoo rau kev piav qhia lehfilcon A CL79 cov qauv. Lwm qhov tseem ceeb uas yuav tsum tau soj ntsuam zoo yog qhov elasticity ntawm cov khoom siv polymer uas raug sim. Txawm hais tias cov ntaub ntawv pib ntawm nanoindentation (Daim Duab 5a thiab 6a) qhia meej txog cov yam ntxwv ntawm kev sib tshooj ntawm cov kab nruj thiab kev sib txuas, piv txwv li, kev rov qab elastic tag nrho ntawm cov khoom siv, nws yog ib qho tseem ceeb heev kom paub meej tias qhov xwm txheej elastic ntawm cov neeg sib cuag. Txog qhov kawg no, ob qhov kev sib tshuam sib law liag tau ua tiav ntawm tib qho chaw ntawm qhov chaw ntawm lehfilcon A CL qauv ntawm tus nqi indentation ntawm 1 µm / s nyob rau hauv cov xwm txheej hydration tag nrho. Cov ntaub ntawv nkhaus zog tau pom hauv daim duab 7 thiab, raws li xav tau, cov kab nthuav dav thiab kev sib txuas ntawm ob daim ntawv luam tawm yuav luag zoo ib yam, qhia txog qhov siab elasticity ntawm cov qauv txhuam polymer branched.
Ob lub zog indentation force curves ntawm tib qhov chaw ntawm qhov chaw ntawm lehfilcon A CL qhia txog qhov elasticity zoo tagnrho ntawm qhov chaw lens.
Raws li cov ntaub ntawv tau los ntawm SEM thiab STEM cov duab ntawm lub taub hau probe thiab lehfilcon A CL nto, feem, tus qauv cone-sphere yog qhov sawv cev lej tsim nyog ntawm kev sib cuam tshuam ntawm AFM probe tip thiab cov khoom siv polymer mos mos uas raug sim. Tsis tas li ntawd, rau tus qauv cone-sphere no, cov kev xav tseem ceeb txog cov khoom elastic ntawm cov khoom luam tawm tuav qhov tseeb rau cov khoom siv biomimetic tshiab no thiab siv los ntsuas qhov elastic modulus.
Tom qab kev ntsuam xyuas tag nrho ntawm txoj kev AFM nanoindentation thiab nws cov khoom, suav nrog cov khoom indentation probe (puab, qhov loj me, thiab lub caij nplooj ntoos hlav nruj), qhov rhiab heev (suab nrov tom qab thiab kev kwv yees qhov chaw sib cuag), thiab cov qauv sib xws ntawm cov ntaub ntawv (kev ntsuas modulus ntau), txoj kev tau siv. piav qhia txog cov qauv ultra-soft muaj nyob hauv khw kom paub tseeb cov txiaj ntsig ntau. Ib qho polyacrylamide hydrogel lag luam (PAAM) hydrogel nrog cov modulus elastic ntawm 1 kPa tau sim nyob rau hauv cov xwm txheej hydrated siv 140 nm probe. Cov ntsiab lus ntawm kev sim module thiab kev xam tau muab rau hauv Cov Ntaub Ntawv Ntxiv. Cov txiaj ntsig tau qhia tias qhov nruab nrab modulus ntsuas yog 0.92 kPa, thiab qhov sib txawv %RSD thiab feem pua ​​(%) ntawm qhov paub modulus tsawg dua 10%. Cov txiaj ntsig no lees paub qhov tseeb thiab kev rov ua dua ntawm txoj kev AFM nanoindentation siv hauv txoj haujlwm no los ntsuas moduli ntawm cov ntaub ntawv ultrasoft. Cov nplaim ntawm cov qauv lehfilcon A CL thiab SiHy lub hauv paus substrate tau ntxiv tus cwj pwm siv tib txoj kev AFM nanoindentation los kawm txog qhov pom tseeb ntawm qhov chaw ultrasoft ua haujlwm ntawm qhov tob indentation. Cov kab sib cais ntawm lub zog indentation tau tsim rau peb cov qauv ntawm txhua hom (n = 3; ib qho indentation rau ib qho qauv) ntawm lub zog ntawm 300 pN, qhov ceev ntawm 1 µm / s, thiab tag nrho hydration. Cov kab sib koom ntawm lub zog indentation tau kwv yees siv tus qauv cone-sphere. Txhawm rau kom tau txais modulus nyob ntawm qhov tob indentation, ib feem dav 40 nm ntawm cov kab nkhaus tau teeb tsa ntawm txhua qhov nce ntawm 20 nm pib los ntawm qhov chaw sib cuag, thiab ntsuas cov nqi ntawm modulus ntawm txhua kauj ruam ntawm cov kab nkhaus. Spin Cy et al. Ib txoj hauv kev zoo sib xws tau siv los piav qhia txog qhov sib txawv ntawm modulus ntawm poly (lauryl methacrylate) (P12MA) polymer txhuam siv colloidal AFM probe nanoindentation, thiab lawv sib xws nrog cov ntaub ntawv siv tus qauv sib cuag Hertz. Txoj kev no muab ib daim duab ntawm qhov pom tseeb modulus (kPa) piv rau qhov tob ntawm qhov nkag (nm), raws li pom hauv Daim Duab 8, uas qhia txog qhov pom tseeb modulus / qhov tob gradient. Lub elastic modulus xam ntawm CL lehfilcon A qauv yog nyob rau hauv qhov ntau ntawm 2-3 kPa hauv 100 nm sab saud ntawm cov qauv, dhau qhov ntawd nws pib nce nrog qhov tob. Ntawm qhov tod tes, thaum kuaj SiHy lub hauv paus substrate tsis muaj zaj duab xis zoo li txhuam ntawm qhov chaw, qhov siab tshaj plaws indentation tob ua tiav ntawm lub zog ntawm 300 pN yog tsawg dua 50 nm, thiab tus nqi modulus tau los ntawm cov ntaub ntawv yog li 400 kPa, uas yog sib piv rau cov nqi ntawm Young's modulus rau cov ntaub ntawv loj.
Qhov pom tseeb modulus (kPa) vs. qhov tob ntawm qhov nkag (nm) rau lehfilcon A CL thiab SiHy substrates siv AFM nanoindentation method nrog cone-sphere geometry los ntsuas modulus.
Qhov saum npoo ntawm qhov tshiab biomimetic branched polymer txhuam qauv qhia txog qhov modulus qis heev ntawm elasticity (2–3 kPa). Qhov no yuav phim qhov kawg dai dawb ntawm lub forked polymer txhuam raws li pom hauv daim duab STEM. Txawm hais tias muaj qee qhov pov thawj ntawm qhov modulus gradient ntawm ntug sab nraud ntawm CL, lub ntsiab modulus siab substrate muaj feem cuam tshuam ntau dua. Txawm li cas los xij, sab saum toj 100 nm ntawm qhov chaw yog nyob rau hauv 20% ntawm tag nrho qhov ntev ntawm branched polymer txhuam, yog li nws yog qhov tsim nyog los xav tias cov nqi ntsuas ntawm modulus hauv qhov tob indentation no yog qhov tseeb thiab tsis nyob ntawm qhov cuam tshuam ntawm cov khoom hauv qab.
Vim yog qhov tsim tshwj xeeb biomimetic ntawm lehfilcon A contact lens, uas muaj cov qauv txhuam polymer PMPC branched grafted rau ntawm qhov chaw ntawm SiHy substrates, nws nyuaj heev rau kev txheeb xyuas cov khoom siv kho tshuab ntawm lawv cov qauv nto siv cov txheej txheem ntsuas ib txwm muaj. Ntawm no peb nthuav qhia ib txoj kev AFM nanoindentation siab heev rau kev txheeb xyuas cov ntaub ntawv ultra-mos xws li lefilcon A nrog cov dej ntau thiab elasticity siab heev. Txoj kev no yog raws li kev siv AFM probe uas nws qhov loj me thiab geometry raug xaiv kom zoo kom phim cov qauv ntawm cov yam ntxwv ntawm ultra-mos nto uas yuav tsum tau luam tawm. Qhov kev sib xyaw ua ke ntawm qhov ntev ntawm probe thiab cov qauv muab kev nkag siab ntau dua, tso cai rau peb ntsuas qhov modulus qis thiab cov khoom elastic ntawm cov khoom txhuam polymer branched, tsis hais txog cov teebmeem poroelastic. Cov txiaj ntsig tau qhia tias cov txhuam polymer branched PMPC tshwj xeeb ntawm qhov chaw lens muaj qhov modulus elastic qis heev (txog li 2 kPa) thiab elasticity siab heev (yuav luag 100%) thaum sim hauv ib puag ncig aqueous. Cov txiaj ntsig ntawm AFM nanoindentation kuj tso cai rau peb los piav qhia txog qhov pom tseeb ntawm kev sib cuag modulus / qhov tob gradient (30 kPa / 200 nm) ntawm qhov chaw biomimetic lens. Qhov gradient no yuav yog vim qhov sib txawv modulus ntawm cov txhuam polymer branched thiab SiHy substrate, lossis cov qauv branched / qhov ceev ntawm cov txhuam polymer, lossis kev sib xyaw ua ke. Txawm li cas los xij, kev tshawb fawb tob ntxiv yog qhov xav tau kom nkag siab tag nrho txog kev sib raug zoo ntawm cov qauv thiab cov khoom, tshwj xeeb tshaj yog cov nyhuv ntawm txhuam branching rau cov khoom siv kho tshuab. Cov kev ntsuas zoo sib xws tuaj yeem pab piav qhia txog cov khoom siv kho tshuab ntawm qhov chaw ntawm lwm cov ntaub ntawv mos mos thiab cov khoom siv kho mob.
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