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Ndi chitukuko cha zipangizo zatsopano zofewa kwambiri pazida zamankhwala ndi ntchito zachipatala, kufotokozera kwathunthu kwa makhalidwe awo akuthupi ndi amakina ndikofunikira komanso kovuta. Njira yosinthidwa ya atomiki ya microscopy (AFM) nanoindentation idagwiritsidwa ntchito pofotokoza modulus yotsika kwambiri ya lehfilcon yatsopano A biomimetic silicone hydrogel contact lens yokutidwa ndi wosanjikiza wa nthambi za polymer burashi. Njirayi imalola kudziwa molondola malo olumikizirana popanda zotsatira za extrusion yokhuthala poyandikira ma polima a nthambi. Kuphatikiza apo, zimapangitsa kuti zikhale zotheka kudziwa mawonekedwe a makina a zinthu za burashi payekha popanda zotsatira za poroelasticity. Izi zimachitika posankha probe ya AFM yokhala ndi kapangidwe (kukula kwa nsonga, geometry ndi liwiro la masika) komwe ndikoyenera kwambiri poyesa makhalidwe a zinthu zofewa ndi zitsanzo zamoyo. Njirayi imawongolera kukhudzika ndi kulondola kuti muyese molondola lehfilcon A yofewa kwambiri, yomwe ili ndi modulus yotsika kwambiri ya elasticity pamalo apamwamba (mpaka 2 kPa) komanso elasticity yayikulu kwambiri m'madzi amkati (pafupifupi 100%). Zotsatira za kafukufuku wa pamwamba sizinangowonetsa kokha momwe lenzi ya lehfilcon A imagwirira ntchito, komanso zinawonetsa kuti modulus ya maburashi a polima opangidwa ndi nthambi inali yofanana ndi ya silicon-hydrogen substrate. Njira yodziwira pamwambayi ingagwiritsidwe ntchito pazinthu zina zofewa kwambiri komanso zida zamankhwala.
Kapangidwe ka makina a zinthu zomwe zimapangidwira kukhudzana mwachindunji ndi minofu yamoyo nthawi zambiri zimatsimikiziridwa ndi chilengedwe cha zamoyo. Kugwirizana bwino kwa zinthuzi kumathandiza kukwaniritsa makhalidwe ofunikira azachipatala a zinthuzo popanda kuyambitsa mayankho oipa a maselo1,2,3. Pazinthu zofanana kwambiri, kufotokozedwa kwa makhalidwe a makina kumakhala kosavuta chifukwa cha kupezeka kwa njira zokhazikika ndi njira zoyesera (monga, microindentation4,5,6). Komabe, pa zinthu zofewa kwambiri monga ma gels, ma hydrogel, ma biopolymers, maselo amoyo, ndi zina zotero, njira zoyesera izi nthawi zambiri sizigwira ntchito chifukwa cha zoletsa zoyezera komanso kusagwirizana kwa zinthu zina7. Kwa zaka zambiri, njira zachikhalidwe zoikira ma indentation zasinthidwa ndikusinthidwa kuti ziwonetse mitundu yosiyanasiyana ya zinthu zofewa, koma njira zambiri zimakumanabe ndi zofooka zazikulu zomwe zimalepheretsa kugwiritsidwa ntchito kwawo8,9,10,11,12,13. Kusowa kwa njira zapadera zoyesera zomwe zingapangitse molondola komanso modalirika mawonekedwe a makina a zinthu zofewa kwambiri ndi zigawo zapamwamba zimalepheretsa kwambiri kugwiritsidwa ntchito kwawo m'njira zosiyanasiyana.
Mu ntchito yathu yapitayi, tinayambitsa lenzi yolumikizirana ya lehfilcon A (CL), chinthu chofewa chosiyana chokhala ndi mawonekedwe ofewa kwambiri ochokera ku mapangidwe omwe angakhale a biomimetic ouziridwa ndi pamwamba pa cornea ya diso. Zinthu zamoyozi zinapangidwa mwa kulumikiza gawo la polima lolumikizidwa ndi nthambi, lolumikizidwa la poly(2-methacryloyloxyethylphosphorylcholine (MPC)) (PMPC) pa silicone hydrogel (SiHy) 15 yopangidwira zida zamankhwala kutengera. Njira yolumikizirayi imapanga gawo pamwamba lomwe lili ndi kapangidwe ka burashi ya polima yofewa kwambiri komanso yotanuka kwambiri. Ntchito yathu yapitayi yatsimikizira kuti kapangidwe ka biomimetic ka lehfilcon A CL kamapereka mawonekedwe apamwamba kwambiri monga kunyowetsa bwino ndi kupewa kuipitsidwa, kukhuthala kwa mafuta, komanso kuchepa kwa kumamatira kwa maselo ndi mabakiteriya15,16. Kuphatikiza apo, kugwiritsa ntchito ndi kupanga zinthu za biomimetic izi kukuwonetsanso kufalikira kwina ku zida zina za biomedical. Chifukwa chake, ndikofunikira kufotokoza mawonekedwe a pamwamba pa chinthu chofewa kwambiri ichi ndikumvetsetsa momwe chimagwirira ntchito ndi diso kuti pakhale chidziwitso chokwanira chothandizira chitukuko ndi ntchito zamtsogolo. Ma lens ambiri olumikizana a SiHy omwe amapezeka pamsika amapangidwa ndi chisakanizo chofanana cha ma polima okonda madzi ndi hydrophobic omwe amapanga kapangidwe kazinthu kofanana17. Kafukufuku wambiri wachitika kuti afufuze mawonekedwe awo a makina pogwiritsa ntchito njira zachikhalidwe zoyesera kupsinjika, kukakamiza ndi kuyika mkati mwa mkati18,19,20,21. Komabe, kapangidwe katsopano ka biomimetic ka lehfilcon A CL kamapangitsa kuti ikhale chinthu chapadera chosiyana momwe mawonekedwe a makina a kapangidwe ka burashi ya polymer yolumikizidwa ndi nthambi amasiyana kwambiri ndi a substrate ya SiHy. Chifukwa chake, n'kovuta kwambiri kuwerengera molondola mawonekedwe awa pogwiritsa ntchito njira zachikhalidwe komanso zoyika mkati. Njira yodalirika imagwiritsa ntchito njira yoyesera ya nanoindentation yomwe imagwiritsidwa ntchito mu atomic force microscopy (AFM), njira yomwe yagwiritsidwa ntchito kudziwa mawonekedwe a makina azinthu zofewa za viscoelastic monga maselo achilengedwe ndi minofu, komanso ma polima ofewa22,23,24,25. ,26,27,28,29,30. Mu AFM nanoindentation, maziko a kuyesa nanoindentation amaphatikizidwa ndi kupita patsogolo kwaposachedwa mu ukadaulo wa AFM kuti apereke kuwunikira kowonjezereka kwa muyeso ndi kuyesa kwa mitundu yosiyanasiyana ya zinthu zofewa kwambiri31,32,33,34,35,36. Kuphatikiza apo, ukadaulowu umapereka zabwino zina zofunika pogwiritsa ntchito ma geometries osiyanasiyana, indenter ndi probe komanso kuthekera koyesa m'malo osiyanasiyana amadzimadzi.
Kuyika kwa nano kwa AFM kungagawidwe m'magulu atatu akuluakulu: (1) zida (ma sensor, ma detector, ma probe, ndi zina zotero); (2) magawo oyezera (monga mphamvu, kusuntha, liwiro, kukula kwa ramp, ndi zina zotero); (3) Kukonza deta (kukonza maziko, kuyerekezera malo olumikizirana, kukonza deta, modeling, ndi zina zotero). Vuto lalikulu ndi njira iyi ndikuti maphunziro angapo m'mabuku ogwiritsa ntchito nano ya AFM akuwonetsa zotsatira zosiyana kwambiri za mtundu womwewo wa chitsanzo/selo/zinthu37,38,39,40,41. Mwachitsanzo, Lekka et al. Mphamvu ya geometry ya probe ya AFM pa modulus yoyesedwa ya Young ya zitsanzo za hydrogel yofanana ndi maselo osiyanasiyana idaphunziridwa ndikuyerekezeredwa. Amanena kuti ma modulus values ​​​​amadalira kwambiri kusankha cantilever ndi mawonekedwe a nsonga, ndi mtengo wapamwamba kwambiri wa probe yooneka ngati piramidi ndi mtengo wotsika kwambiri wa 42 wa probe yozungulira. Mofananamo, Selhuber-Unkel et al. Zawonetsedwa momwe liwiro la indenter, kukula kwa indenter ndi makulidwe a zitsanzo za polyacrylamide (PAAM) zimakhudzira modulus ya Young yomwe imayesedwa ndi nanoindentation ya ACM43. Chinthu china chomwe chimavuta ndi kusowa kwa zida zoyesera za modulus zotsika kwambiri komanso njira zoyesera zaulere. Izi zimapangitsa kuti zikhale zovuta kwambiri kupeza zotsatira zolondola molimba mtima. Komabe, njirayi ndi yothandiza kwambiri pamiyeso yoyerekeza komanso kuwunika koyerekeza pakati pa mitundu yofanana ya zitsanzo, mwachitsanzo kugwiritsa ntchito nanoindentation ya AFM kusiyanitsa maselo abwinobwino ndi maselo a khansa 44, 45.
Poyesa zinthu zofewa pogwiritsa ntchito AFM nanoindentation, lamulo lalikulu ndikugwiritsa ntchito probe yokhala ndi low spring constant (k) yomwe imagwirizana kwambiri ndi sample modulus ndi hemispherical/round tip kuti probe yoyamba isaboole pamwamba pa sample pa nthawi yoyamba yokhudzana ndi zinthu zofewa. Ndikofunikanso kuti chizindikiro cha deflection chomwe chimapangidwa ndi probe chikhale cholimba mokwanira kuti chizindikirike ndi laser detector system24,34,46,47. Pankhani ya maselo, minofu ndi ma gels ofewa kwambiri, vuto lina ndikuthana ndi mphamvu yomatira pakati pa probe ndi pamwamba pa sample kuti zitsimikizire kuti miyeso yoberekanso komanso yodalirika48,49,50. Mpaka posachedwapa, ntchito zambiri pa AFM nanoindentation zakhala zikuyang'ana kwambiri pakuphunzira za machitidwe a makina a maselo achilengedwe, minofu, ma gels, ma hydrogel, ndi ma biomolecule pogwiritsa ntchito ma probes akuluakulu ozungulira, omwe nthawi zambiri amatchedwa colloidal probes (CPs). , 47, 51, 52, 53, 54, 55. Nsonga izi zili ndi utali wa 1 mpaka 50 µm ndipo nthawi zambiri zimapangidwa ndi galasi la borosilicate, polymethyl methacrylate (PMMA), polystyrene (PS), silicon dioxide (SiO2) ndi diamond-like carbon (DLC). Ngakhale kuti CP-AFM nanoindentation nthawi zambiri ndiyo njira yoyamba yofotokozera zitsanzo zofewa, ili ndi mavuto ndi zofooka zake. Kugwiritsa ntchito nsonga zazikulu, zozungulira za micron kumawonjezera malo onse olumikizirana ndi nsonga ndi chitsanzo ndipo kumabweretsa kutayika kwakukulu kwa malo. Pa zitsanzo zofewa, zosafanana, komwe mawonekedwe a makina a zinthu zakomweko amatha kusiyana kwambiri ndi avareji pamalo ambiri, CP indentation imatha kubisa kusafanana kulikonse muzinthu pamlingo wakomweko52. Ma Colloidal probes nthawi zambiri amapangidwa polumikiza ma colloidal spheres a micron-size ku cantilevers zopanda nsonga pogwiritsa ntchito zomatira za epoxy. Njira yopangira yokha ili ndi mavuto ambiri ndipo ingayambitse kusasinthasintha mu njira yowerengera probe. Kuphatikiza apo, kukula ndi kulemera kwa tinthu ta colloidal kumakhudza mwachindunji magawo akuluakulu a calibration a cantilever, monga ma resonant frequency, stiffness ya spring, ndi deflection sensitivity56,57,58. Chifukwa chake, njira zomwe zimagwiritsidwa ntchito kwambiri pa ma probe achikhalidwe a AFM, monga calibration temperature, sizingapereke calibration yolondola ya CP, ndipo njira zina zingafunike kuti zikonzedwe izi57, 59, 60, 61. Mayeso a CP indentation wamba amagwiritsa ntchito large deviations cantilever kuti aphunzire makhalidwe a zitsanzo zofewa, zomwe zimapangitsa vuto lina powerengera khalidwe losakhala la linear la cantilever pa deviations yayikulu62,63,64. Njira zamakono zowerengera probe ya colloidal nthawi zambiri zimaganizira geometry ya cantilever yomwe imagwiritsidwa ntchito powerengera probe, koma zimanyalanyaza mphamvu ya tinthu ta colloidal, zomwe zimapangitsa kusatsimikizika kwina pakulondola kwa njira38,61. Mofananamo, elastic moduli yowerengedwa pogwiritsa ntchito contact model fitting imadalira mwachindunji geometry ya indentation probe, ndipo kusagwirizana pakati pa nsonga ndi makhalidwe a pamwamba pa chitsanzo kungayambitse kusalondola27, 65, 66, 67, 68. Ntchito zina zaposachedwa za Spencer et al. Zinthu zomwe ziyenera kuganiziridwa pofotokoza maburashi ofewa a polymer pogwiritsa ntchito njira ya CP-AFM nanoindentation zawonetsedwa. Iwo adanenanso kuti kusunga madzi okhuthala m'maburashi a polymer monga ntchito ya liwiro kumabweretsa kuwonjezeka kwa katundu pamutu ndipo motero miyeso yosiyanasiyana ya katundu wodalira liwiro30,69,70,71.
Mu phunziroli, tafotokoza za modulus pamwamba pa chinthu chofewa kwambiri chotanuka cha lehfilcon A CL pogwiritsa ntchito njira yosinthidwa ya nanoindentation ya AFM. Popeza tili ndi makhalidwe ndi kapangidwe katsopano ka chinthuchi, kuchuluka kwa chidwi cha njira yachikhalidwe yolowera mkati sikukwanira kufotokoza modulus ya chinthu chofewa kwambirichi, kotero ndikofunikira kugwiritsa ntchito njira ya nanoindentation ya AFM yokhala ndi mphamvu zambiri komanso mphamvu zochepa. Pambuyo powunikira zofooka ndi mavuto a njira zomwe zilipo za colloidal AFM probe nanoindentation, tikuwonetsa chifukwa chake tidasankha probe yaying'ono, yopangidwa mwamakonda ya AFM kuti tichotse mphamvu, phokoso lakumbuyo, malo olumikizirana, kuyeza liwiro la zinthu zofewa zosiyanasiyana monga kudalira madzi osungira. komanso kuchuluka kolondola. Kuphatikiza apo, tidatha kuyeza molondola mawonekedwe ndi miyeso ya nsonga yolowera mkati, zomwe zimatithandiza kugwiritsa ntchito chitsanzo cha cone-sphere fit kuti tidziwe modulus ya elasticity popanda kuwunika dera lolumikizana ndi nsonga ndi chinthucho. Malingaliro awiri osamveka omwe awerengedwa mu ntchitoyi ndi makhalidwe a zinthu zotanuka mokwanira komanso modulus yosadalira kuya kwa indentation. Pogwiritsa ntchito njira iyi, choyamba tinayesa miyezo yofewa kwambiri ndi modulus yodziwika bwino kuti tiwerengere njirayo, kenako tinagwiritsa ntchito njira iyi kuti tifotokoze pamwamba pa zipangizo ziwiri zosiyana za lens yolumikizirana. Njira iyi yofotokozera pamwamba pa AFM nanoindentation yokhala ndi kukhudzidwa kwakukulu ikuyembekezeka kugwiritsidwa ntchito pazinthu zosiyanasiyana za biomimetic heterogeneous ultrasoft zomwe zingagwiritsidwe ntchito muzipangizo zachipatala ndi ntchito zamankhwala.
Lens ya Lehfilcon A (Alcon, Fort Worth, Texas, USA) ndi ma silicone hydrogel substrates awo adasankhidwa kuti ayesedwe ndi nanoindentation. Choyikapo chapadera cha lens chinagwiritsidwa ntchito mu kuyeseraku. Kuti ayike lens kuti ayesere, idayikidwa mosamala pa choyimilira chooneka ngati dome, kuonetsetsa kuti palibe thovu la mpweya lomwe limalowa mkati, kenako limakhazikika ndi m'mbali. Bowo lomwe lili pamwamba pa chogwirira lens limapereka mwayi wopita pakati pa lens kuti ayesere nanoindentation pamene akusunga madziwo pamalo ake. Izi zimasunga ma lenswo ali ndi madzi okwanira. 500 μl ya yankho loyika ma contact lens linagwiritsidwa ntchito ngati yankho loyesera. Kuti zitsimikizire zotsatira zake, ma non-activated polyacrylamide (PAAM) hydrogels omwe amapezeka m'masitolo adakonzedwa kuchokera ku polyacrylamide-co-methylene-bisacrylamide composition (100 mm Petrisoft Petri dishes, Matrigen, Irvine, CA, USA), modulus yodziwika bwino ya 1 kPa. Gwiritsani ntchito madontho 4-5 (pafupifupi 125 µl) a phosphate buffered saline (PBS kuchokera ku Corning Life Sciences, Tewkesbury, MA, USA) ndi dontho limodzi la OPTI-FREE Puremoist contact lens solution (Alcon, Vaud, TX, USA). ) pa AFM hydrogel-probe interface.
Zitsanzo za Lehfilcon A CL ndi SiHy substrates zinawonetsedwa pogwiritsa ntchito makina a FEI Quanta 250 Field Emission Scanning Electron Microscope (FEG SEM) okhala ndi chowunikira cha Scanning Transmission Electron Microscope (STEM). Pofuna kukonzekera zitsanzozo, magalasiwo anayamba kutsukidwa ndi madzi ndikudulidwa m'magawo ofanana ndi pie. Kuti apeze kusiyana kosiyana pakati pa zigawo za hydrophilic ndi hydrophobic za zitsanzozo, yankho lokhazikika la 0.10% la RuO4 linagwiritsidwa ntchito ngati utoto, momwe zitsanzozo zinamizidwa kwa mphindi 30. Kupaka utoto kwa lehfilcon A CL RuO4 ndikofunikira osati kokha kuti pakhale kusiyana kosiyana, komanso kumathandiza kusunga kapangidwe ka maburashi a polymer okhala ndi nthambi mu mawonekedwe awo oyambirira, omwe kenako amaonekera pazithunzi za STEM. Kenako anatsukidwa ndikuumitsa madzi m'mitundu yosiyanasiyana ya ethanol/madzi ndi kuchuluka kwa ethanol. Zitsanzozo zinapangidwa ndi EMBEd 812/Araldite epoxy, yomwe inachira usiku wonse pa 70°C. Zitsanzo zopezeka pogwiritsa ntchito resin polymerization zinadulidwa ndi ultramicrotome, ndipo zigawo zoonda zomwe zinatuluka zinawonetsedwa ndi STEM detector mu vacuum mode yotsika pa voltage yothamanga ya 30 kV. Dongosolo lomweli la SEM linagwiritsidwa ntchito pofotokoza mwatsatanetsatane probe ya PFQNM-LC-A-CAL AFM (Bruker Nano, Santa Barbara, CA, USA). Zithunzi za SEM za probe ya AFM zinapezeka mu vacuum mode yothamanga kwambiri yokhala ndi voltage yothamanga ya 30 kV. Pezani zithunzi pa ngodya zosiyanasiyana ndi kukula kuti mulembe tsatanetsatane wonse wa mawonekedwe ndi kukula kwa nsonga ya probe ya AFM. Miyeso yonse ya nsonga yosangalatsa pazithunzizo inayesedwa ndi digito.
Maikulosi amphamvu a atomiki a Dimension FastScan Bio Icon (Bruker Nano, Santa Barbara, CA, USA) okhala ndi "PeakForce QNM in Fluid" adagwiritsidwa ntchito kuti aone ndi kuyika zitsanzo za lehfilcon A CL, SiHy substrate, ndi PAAm hydrogel. Pa kuyesa kujambula, probe ya PEAKFORCE-HIRS-FA (Bruker) yokhala ndi radius ya nominal nm ya 1 nm idagwiritsidwa ntchito kujambula zithunzi zapamwamba za chitsanzocho pamlingo wa scan wa 0.50 Hz. Zithunzi zonse zidatengedwa mu yankho lamadzi.
Kuyesa kwa AFM nanoindentation kunachitika pogwiritsa ntchito probe ya PFQNM-LC-A-CAL (Bruker). Probe ya AFM ili ndi nsonga ya silicon pa nitride cantilever yokhuthala 345 nm, 54 µm kutalika ndi 4.5 µm m'lifupi ndi frequency yozungulira ya 45 kHz. Yapangidwa mwapadera kuti iwonetse ndikuchita miyeso ya nanomechanical pa zitsanzo zofewa zamoyo. Masensa amakonzedwa payekhapayekha ku fakitale ndi makonzedwe a masika okonzedwa kale. Zokhazikika za masika za ma probe omwe adagwiritsidwa ntchito mu kafukufukuyu zinali pakati pa 0.05–0.1 N/m. Kuti adziwe bwino mawonekedwe ndi kukula kwa nsonga, probeyi idafotokozedwa mwatsatanetsatane pogwiritsa ntchito SEM. Pa chithunzi. Chithunzi 1a chikuwonetsa ma electron micrograph apamwamba, otsika kukula kwa probe ya PFQNM-LC-A-CAL, kupereka mawonekedwe onse a kapangidwe ka probe. Pa chithunzi 1b chikuwonetsa mawonekedwe okulirapo pamwamba pa nsonga ya probe, kupereka chidziwitso chokhudza mawonekedwe ndi kukula kwa nsonga. Kumapeto kwenikweni, singano ndi gawo la hemisphere pafupifupi 140 nm m'mimba mwake (Chithunzi 1c). Pansi pake, nsonga imapindika kukhala mawonekedwe a conical, kufika kutalika koyezedwa kwa pafupifupi 500 nm. Kunja kwa dera lopindika, nsongayo ndi yozungulira ndipo imatha kutalika konse kwa nsonga ya 1.18 µm. Iyi ndi gawo lalikulu la ntchito ya nsonga ya probe. Kuphatikiza apo, probe yayikulu yozungulira ya polystyrene (PS) (Novascan Technologies, Inc., Boone, Iowa, USA) yokhala ndi nsonga ya m'mimba mwake ya 45 µm ndi spring constant ya 2 N/m idagwiritsidwanso ntchito poyesa ngati probe ya colloidal. ndi probe ya PFQNM-LC-A-CAL 140 nm yoyerekeza.
Zanenedwa kuti madzi amatha kutsekeredwa pakati pa probe ya AFM ndi kapangidwe ka burashi ya polymer panthawi ya nanoindentation, yomwe imagwiritsa ntchito mphamvu yokwera pa probe ya AFM isanakhudze pamwamba69. Mphamvu yotuluka iyi yokhuthala chifukwa cha kusunga madzi imatha kusintha malo owonekera olumikizirana, motero imakhudza muyeso wa pamwamba pa modulus. Kuti aphunzire zotsatira za geometry ya probe ndi liwiro la indentation pa kusunga madzi, ma curve a mphamvu yolowerera adajambulidwa pa zitsanzo za lehfilcon A CL pogwiritsa ntchito probe ya 140 nm m'mimba mwake pamlingo wosasunthika wa 1 µm/s ndi 2 µm/s. m'mimba mwake wa probe 45 µm, kukhazikitsa mphamvu yokhazikika 6 nN kudachitika pa 1 µm/s. Kuyesera ndi probe ya 140 nm m'mimba mwake kunachitika pa liwiro la indentation la 1 µm/s ndi mphamvu yokhazikika ya 300 pN, yosankhidwa kuti ipange kupsinjika kolumikizana mkati mwa physiological range (1–8 kPa) ya chikope chapamwamba. kupanikizika 72. Zitsanzo zofewa zopangidwa ndi PAA hydrogel zokhala ndi kupanikizika kwa 1 kPa zinayesedwa mphamvu yolowera ya 50 pN pa liwiro la 1 μm/s pogwiritsa ntchito probe yokhala ndi mainchesi a 140 nm.
Popeza kutalika kwa gawo lozungulira la nsonga ya probe ya PFQNM-LC-A-CAL kuli pafupifupi 500 nm, pa kuya kulikonse kwa indentation < 500 nm, tinganene kuti geometry ya probe panthawi ya indentation idzakhalabe yofanana ndi mawonekedwe ake a cone. Kuphatikiza apo, akuganiza kuti pamwamba pa chinthu chomwe chikuyesedwa chidzawonetsa yankho losinthika, lomwe lidzatsimikiziridwanso m'magawo otsatirawa. Chifukwa chake, kutengera mawonekedwe ndi kukula kwa nsonga, tidasankha chitsanzo cholumikizira cone-sphere chomwe chidapangidwa ndi Briscoe, Sebastian ndi Adams, chomwe chikupezeka mu pulogalamu ya wogulitsa, kuti tigwiritse ntchito mayeso athu a AFM nanoindentation (NanoScope). Mapulogalamu osanthula deta yolekanitsa, Bruker) 73. Chitsanzocho chikufotokoza ubale wa mphamvu-kusuntha F(δ) wa cone yokhala ndi vuto la apex lozungulira. Pa chithunzi. Chithunzi 2 chikuwonetsa mawonekedwe a kulumikizana panthawi yolumikizana kwa koni yolimba ndi nsonga yozungulira, komwe R ndiye radius ya nsonga yozungulira, a ndiye radius yolumikizirana, b ndiye radius yolumikizirana kumapeto kwa nsonga yozungulira, δ ndiye radius yolumikizirana. kuya kwa indentation, θ ndiye theka la ngodya ya koni. Chithunzi cha SEM cha probe iyi chikuwonetsa momveka bwino kuti nsonga yozungulira ya 140 nm diameter imalumikizana mozungulira kukhala koni, kotero apa b imangofotokozedwa kudzera mu R, mwachitsanzo b = R cos θ. Mapulogalamu operekedwa ndi ogulitsa amapereka ubale wa koni-sphere kuti awerengere ma values ​​​​a Young's modulus (E) kuchokera ku deta yolekanitsa mphamvu poganiza kuti a > b. Ubale:
kumene F ndi mphamvu yolowera mkati, E ndi modulus ya Young, ν ndi chiŵerengero cha Poisson. Utali wolumikizirana a ukhoza kuyerekezeredwa pogwiritsa ntchito:
Ndondomeko ya mawonekedwe a kulumikizana kwa kondomu yolimba yokhala ndi nsonga yozungulira yolumikizidwa mu zinthu za lenzi yolumikizirana ya Lefilcon yokhala ndi maburashi a polima opangidwa ndi nthambi.
Ngati a ≤ b, ubalewo umachepa kufika pa equation ya indenter yozungulira yokhazikika;
Tikukhulupirira kuti kuyanjana kwa probe yolowera mkati ndi kapangidwe ka nthambi ya burashi ya polymer ya PMPC kudzapangitsa kuti radius yolumikizirana a ikhale yayikulu kuposa radius yolumikizirana yozungulira b. Chifukwa chake, pamiyeso yonse yowerengera ya modulus yolumikizidwa yomwe idachitika mu kafukufukuyu, tidagwiritsa ntchito kudalira komwe kudapezeka pankhaniyi a > b.
Zipangizo za biomimetic zofewa kwambiri zomwe zidaphunziridwa mu kafukufukuyu zidajambulidwa bwino pogwiritsa ntchito scanning transmission electron microscopy (STEM) ya sample cross section ndi atomic force microscopy (AFM) ya pamwamba. Kufotokozera mwatsatanetsatane kwa pamwambaku kunachitika ngati kuwonjezera ntchito yathu yomwe idasindikizidwa kale, momwe tidazindikira kuti kapangidwe ka polymeric branch ka PMPC-modified lehfilcon A CL surface kanawonetsa mawonekedwe ofanana ndi a makina a native cornea tissue 14. Pachifukwa ichi, timatchula malo olumikizirana ndi lens ngati zinthu za biomimetic14. Pa chithunzi 3a,b kuwonetsa magawo opingasa a nthambi za PMPC polymer structures pamwamba pa lehfilcon A CL substrate ndi SiHy substrate yosakonzedwa, motsatana. Malo a zitsanzo zonse ziwiri adawunikidwanso pogwiritsa ntchito zithunzi za AFM zapamwamba, zomwe zidatsimikiziranso zotsatira za kusanthula kwa STEM (Chithunzi 3c, d). Pophatikizidwa, zithunzi izi zimapereka kutalika kwa pafupifupi kapangidwe ka PMPC branch polymer brush pa 300–400 nm, komwe ndikofunikira kwambiri potanthauzira miyeso ya AFM nanoindentation. Chinthu china chofunika chomwe chapezeka kuchokera ku zithunzizi ndichakuti kapangidwe ka pamwamba pa zinthu za CL biomimetic ndi kosiyana kwambiri ndi kapangidwe ka zinthu za SiHy substrate. Kusiyana kumeneku kwa mawonekedwe awo pamwamba kumatha kuwonekera bwino panthawi yolumikizana kwawo ndi probe ya AFM yomwe imalowa mkati ndipo pambuyo pake m'mayeso a modulus.
Zithunzi za STEM zopingasa za (a) lehfilcon A CL ndi (b) SiHy substrate. Scale bar, 500 nm. Zithunzi za AFM za pamwamba pa lehfilcon A CL substrate (c) ndi maziko a SiHy substrate (d) (3 µm × 3 µm).
Ma polima ouziridwa ndi bioinspired ndi kapangidwe ka burashi ya polima ndi ofewa mwachibadwa ndipo aphunziridwa kwambiri ndikugwiritsidwa ntchito m'njira zosiyanasiyana zamankhwala74,75,76,77. Chifukwa chake, ndikofunikira kugwiritsa ntchito njira ya AFM nanoindentation, yomwe imatha kuyeza molondola komanso modalirika momwe imagwirira ntchito. Koma nthawi yomweyo, mawonekedwe apadera a zinthu zofewa kwambiri, monga modulus yotsika kwambiri, kuchuluka kwamadzimadzi ambiri komanso kusinthasintha kwakukulu, nthawi zambiri zimapangitsa kuti zikhale zovuta kusankha kukula koyenera kwa chipangizocho, mawonekedwe ndi mawonekedwe ake. Izi ndizofunikira kuti indenter isapyole pamwamba pofewa pa chitsanzocho, zomwe zingayambitse zolakwika pakuzindikira malo olumikizirana ndi pamwamba ndi malo olumikizirana.
Pachifukwa ichi, kumvetsetsa bwino mawonekedwe a zinthu zofewa kwambiri za biomimetic (lehfilcon A CL) ndikofunikira. Chidziwitso chokhudza kukula ndi kapangidwe ka maburashi a polima opangidwa ndi nthambi omwe amapezeka pogwiritsa ntchito njira yojambulira zithunzi chimapereka maziko a mawonekedwe a makina a pamwamba pogwiritsa ntchito njira za AFM nanoindentation. M'malo mwa ma probe a colloidal ozungulira kukula kwa micron, tinasankha probe ya silicon nitride (Bruker) ya PFQNM-LC-A-CAL yokhala ndi m'mimba mwake wa nsonga ya 140 nm, yopangidwira makamaka kupanga mapu ochulukirapo a mawonekedwe a makina a zitsanzo zamoyo 78, 79, 80, 81, 82, 83, 84 Chifukwa chogwiritsa ntchito ma probe akuthwa poyerekeza ndi ma probe a colloidal achikhalidwe chingathe kufotokozedwa ndi kapangidwe ka zinthuzo. Poyerekeza kukula kwa nsonga ya probe (~140 nm) ndi maburashi a polima okhala ndi nthambi pamwamba pa CL lehfilcon A, omwe akuwonetsedwa pa Chithunzi 3a, zitha kutsimikiziridwa kuti nsongayo ndi yayikulu mokwanira kuti igwirizane mwachindunji ndi mapangidwe a burashi awa, zomwe zimachepetsa mwayi woti nsonga iwaboole. Kuti tifotokoze mfundo iyi, pa Chithunzi 4 pali chithunzi cha STEM cha lehfilcon A CL ndi nsonga yolowera ya probe ya AFM (yojambulidwa pa sikelo).
Chithunzi chosonyeza chithunzi cha STEM cha lehfilcon A CL ndi probe ya indentation ya ACM (yojambulidwa pa sikelo).
Kuphatikiza apo, kukula kwa nsonga ya 140 nm ndi kochepa mokwanira kupewa chiopsezo cha zotsatira zilizonse zomata zomwe zidanenedwa kale za maburashi a polima opangidwa ndi njira ya nanoindentation ya CP-AFM69,71. Tikuganiza kuti chifukwa cha mawonekedwe apadera a cone-spherical ndi kukula kochepa kwa nsonga iyi ya AFM (Chithunzi 1), mtundu wa force curve wopangidwa ndi lehfilcon A CL nanoindentation sudzadalira liwiro la indentation kapena liwiro la loading/download. Chifukwa chake, sichikhudzidwa ndi zotsatira za poroelastic. Kuti muyese lingaliro ili, zitsanzo za lehfilcon A CL zidayikidwa indented pa fixed maximum force pogwiritsa ntchito probe ya PFQNM-LC-A-CAL, koma pa liwiro ziwiri zosiyana, ndipo ma tensile ndi retract force curve omwe adabwera adagwiritsidwa ntchito pojambula mphamvu (nN) mu leating (µm) akuwonetsedwa mu Chithunzi 5a. N'zoonekeratu kuti mphamvu imazungulira panthawi yokweza ndi kutsitsa zinthu, ndipo palibe umboni womveka bwino wakuti kudulidwa kwa mphamvu pa kuya kwa zero indentation kumawonjezeka ndi liwiro la indentation pachithunzichi, zomwe zikusonyeza kuti zinthu za burashi payekhapayekha zinadziwika popanda zotsatira za poroelastic. Mosiyana ndi zimenezi, zotsatira za kusunga madzi (zotulutsa za viscous ndi poroelasticity) zimawonekera pa probe ya AFM ya mainchesi 45 µm pa liwiro lomwelo indentation ndipo zimawonetsedwa ndi hysteresis pakati pa ma curve otambasula ndi obweza, monga momwe zasonyezedwera pa Chithunzi 5b. Zotsatirazi zikugwirizana ndi lingaliroli ndipo zikusonyeza kuti ma probe a mainchesi 140 nm ndi chisankho chabwino chofotokozera malo ofewa otere.
lehfilcon A CL indentation force curves pogwiritsa ntchito ACM; (a) kugwiritsa ntchito probe yokhala ndi diameter ya 140 nm pa loading rates ziwiri, kusonyeza kusakhalapo kwa poroelastic effect panthawi ya surface indentation; (b) kugwiritsa ntchito probe yokhala ndi diameter ya 45 µm ndi 140 nm. s ikuwonetsa zotsatira za viscous extrusion ndi poroelasticity pa probe zazikulu poyerekeza ndi probe zazing'ono.
Kuti mudziwe malo ofewa kwambiri, njira zoyezera kuwala kwa AFM ziyenera kukhala ndi probe yabwino kwambiri yophunzirira makhalidwe a zinthu zomwe zikuphunziridwa. Kuwonjezera pa mawonekedwe ndi kukula kwa nsonga, kukhudzidwa kwa dongosolo lozindikira kuwala kwa AFM, kukhudzidwa ndi kupotoka kwa nsonga pamalo oyesera, ndi kuuma kwa cantilever zimagwira ntchito yofunika kwambiri pozindikira kulondola ndi kudalirika kwa miyeso ya nanoindentation. Pa dongosolo lathu la AFM, malire a kuzindikira a Position Sensitive Detector (PSD) ndi pafupifupi 0.5 mV ndipo amachokera pa liwiro la masika lomwe linakhazikitsidwa kale komanso kukhudzidwa kwa madzimadzi kwa probe ya PFQNM-LC-A-CAL, yomwe ikugwirizana ndi kukhudzidwa kwa katundu wa theoretical. ndi yochepera 0.1 pN. Chifukwa chake, njira iyi imalola kuyeza mphamvu yocheperako ya indentation ≤ 0.1 pN popanda gawo lililonse la phokoso la peripheral. Komabe, n'zosatheka kuti dongosolo la AFM lichepetse phokoso la peripheral kufika pamlingo uwu chifukwa cha zinthu monga kugwedezeka kwa makina ndi mphamvu zamadzimadzi. Zinthu izi zimachepetsa kukhudzidwa konse kwa njira ya AFM nanoindentation ndipo zimapangitsanso chizindikiro cha phokoso chakumbuyo cha pafupifupi ≤ 10 pN. Pakulongosola pamwamba, zitsanzo za lehfilcon A CL ndi SiHy substrate zinayikidwa pansi pa mikhalidwe yonyowa mokwanira pogwiritsa ntchito probe ya 140 nm kuti ziwonetse SEM, ndipo ma force curve omwe adatuluka adayikidwa pakati pa mphamvu (pN) ndi kupanikizika. Chithunzi cholekanitsa (µm) chikuwonetsedwa mu Chithunzi 6a. Poyerekeza ndi substrate ya SiHy base, lehfilcon A CL force curve ikuwonetsa bwino gawo losinthira kuyambira pamalo olumikizirana ndi burashi ya polymer yolumikizidwa ndi foloko ndikutha ndi kusintha kwakukulu kwa kukhudzana kwa slope ndi nsonga ndi zinthu zomwe zili pansi. Gawo losinthirali la force curve likuwonetsa momwe burashi ya polymer yolumikizidwa imagwirira ntchito pamwamba, monga momwe zikuwonekera ndi compression curve yomwe ikutsatira tension curve komanso kusiyana kwa mawonekedwe amakina pakati pa kapangidwe ka burashi ndi zinthu zazikulu za SiHy. Poyerekeza lefilcon. Kulekanitsidwa kwa kutalika kwapakati pa burashi ya polima yokhala ndi nthambi pachithunzi cha STEM cha PCS (Chithunzi 3a) ndi curve yake yamphamvu motsatira abscissa mu Chithunzi 3a. 6a kukuwonetsa kuti njirayo imatha kuzindikira nsonga ndi polima yokhala ndi nthambi yomwe ikufika pamwamba penipeni pa pamwamba. Kukhudzana pakati pa kapangidwe ka burashi. Kuphatikiza apo, kuphatikizika kwa ma force curve kumasonyeza kuti palibe mphamvu yosungira madzi. Pankhaniyi, palibe kugwirizana pakati pa singano ndi pamwamba pa chitsanzo. Magawo apamwamba kwambiri a force curve a zitsanzo ziwiri amaphatikizika, kuwonetsa kufanana kwa mawonekedwe a makina a zinthu za substrate.
(a) Ma curve a mphamvu ya AFM nanoindentation a ma substrate a lehfilcon A CL ndi ma substrate a SiHy, (b) ma curve amphamvu omwe akuwonetsa kuyerekezera kwa malo olumikizirana pogwiritsa ntchito njira yochepetsera phokoso lakumbuyo.
Pofuna kuphunzira tsatanetsatane wa mphamvu yozungulira, mphamvu yozungulira ya chitsanzo cha lehfilcon A CL yalembedwanso mu Chithunzi 6b ndi mphamvu yayikulu ya 50 pN motsatira y-axis. Chithunzichi chimapereka chidziwitso chofunikira chokhudza phokoso loyambirira. Phokoso lili pamtunda wa ±10 pN, lomwe limagwiritsidwa ntchito kudziwa molondola malo olumikizirana ndikuwerengera kuya kwa indentation. Monga momwe zanenedwera m'mabuku, kuzindikira malo olumikizirana ndikofunikira kwambiri kuti muwunikire molondola zinthu monga modulus85. Njira yogwiritsira ntchito yokha kukonza deta ya force curve yawonetsa kuyanjana bwino pakati pa kuyika deta ndi kuyeza kuchuluka kwa zinthu zofewa86. Mu ntchitoyi, kusankha kwathu malo olumikizirana ndi kosavuta komanso kopanda tsankho, koma kuli ndi zoletsa zake. Njira yathu yosamala yodziwira malo olumikizirana ingayambitse kuchuluka kwa modulus komwe kumayesedwa pang'ono kwa kuya kochepa kwa indentation (< 100 nm). Kugwiritsa ntchito algorithm-based touchpoint detection ndi automated data processing kungakhale kupitiliza kwa ntchitoyi mtsogolo kuti tipititse patsogolo njira yathu. Chifukwa chake, pa phokoso lakumbuyo lamkati pa dongosolo la ±10 pN, timatanthauzira malo olumikizirana ngati mfundo yoyamba ya data pa x-axis mu Chithunzi 6b yokhala ndi mtengo wa ≥10 pN. Kenako, mogwirizana ndi malire a phokoso la 10 pN, mzere woyima pamlingo wa ~0.27 µm umawonetsa malo olumikizirana ndi pamwamba, pambuyo pake curve yotambasula imapitirira mpaka gawolo litakumana ndi kuya kwa indentation kwa ~270 nm. Chochititsa chidwi n'chakuti, kutengera kukula kwa mawonekedwe a pulasitiki yokhala ndi nthambi (300–400 nm) yoyesedwa pogwiritsa ntchito njira yojambulira, kuya kwa indentation kwa CL lehfilcon Chitsanzo chomwe chawonedwa pogwiritsa ntchito njira ya background noise threshold ndi pafupifupi 270 nm, chomwe chili pafupi kwambiri ndi kukula kwa muyeso ndi STEM. Zotsatirazi zimatsimikiziranso kugwirizana ndi kugwiritsidwa ntchito kwa mawonekedwe ndi kukula kwa nsonga ya probe ya AFM pakulowetsa mkati mwa kapangidwe ka burashi ya polymer yofewa komanso yotanuka kwambiri. Deta iyi imaperekanso umboni wamphamvu wochirikiza njira yathu yogwiritsira ntchito phokoso lakumbuyo ngati malire owunikira malo olumikizirana. Motero, zotsatira zilizonse zowerengera zomwe zapezeka kuchokera ku masamu ndi kuyika mphamvu ziyenera kukhala zolondola.
Kuyeza kuchuluka kwa zinthu pogwiritsa ntchito njira za AFM nanoindentation kumadalira kwambiri mitundu ya masamu yomwe imagwiritsidwa ntchito posankha deta ndi kusanthula kotsatira. Chifukwa chake, ndikofunikira kuganizira zinthu zonse zokhudzana ndi kusankha indenter, katundu wazinthu ndi momwe zimagwirira ntchito musanasankhe chitsanzo china. Pankhaniyi, mawonekedwe a nsonga adafotokozedwa mosamala pogwiritsa ntchito SEM micrographs (Chithunzi 1), ndipo kutengera zotsatira zake, probe ya 140 nm diameter AFM nanoindenting yokhala ndi cone yolimba komanso mawonekedwe a nsonga yozungulira ndi chisankho chabwino chofotokozera zitsanzo za lehfilcon A CL79. Chinthu china chofunikira chomwe chikufunika kuunikiridwa mosamala ndi kulimba kwa zinthu za polima zomwe zikuyesedwa. Ngakhale deta yoyamba ya nanoindentation (Zithunzi 5a ndi 6a) imafotokoza momveka bwino mawonekedwe a kuphatikizika kwa ma tension ndi compression curves, mwachitsanzo, kuchira kwathunthu kwa zinthuzo, ndikofunikira kwambiri kutsimikizira mtundu wokhazikika wa zolumikizira. Pachifukwa ichi, kuyika ma indentations awiri motsatizana kunachitika pamalo omwewo pamwamba pa chitsanzo cha lehfilcon A CL pamlingo wa indentations wa 1 µm/s pansi pa hydration yonse. Deta ya mphamvu yochokerapo ikuwonetsedwa mu chithunzi 7 ndipo, monga momwe zikuyembekezeredwa, ma expansion ndi compression curves a ma prints awiriwa ndi ofanana, kuwonetsa kulimba kwakukulu kwa kapangidwe ka burashi ya polymer yokhala ndi nthambi.
Ma curve awiri a mphamvu yolowera pamalo omwewo pamwamba pa lehfilcon A CL akusonyeza kusinthasintha koyenera kwa pamwamba pa lens.
Kutengera ndi zomwe zapezeka kuchokera ku zithunzi za SEM ndi STEM za nsonga ya probe ndi lehfilcon A CL, motsatana, chitsanzo cha cone-sphere ndi chiwonetsero choyenera cha masamu cha kuyanjana pakati pa nsonga ya probe ya AFM ndi zinthu zofewa za polima zomwe zikuyesedwa. Kuphatikiza apo, pa chitsanzo ichi cha cone-sphere, malingaliro oyambira okhudza mawonekedwe otanuka a zinthu zosindikizidwa ndi oona pa zinthu zatsopano za biomimetic izi ndipo amagwiritsidwa ntchito poyeza elastic modulus.
Pambuyo pofufuza mokwanira njira ya AFM nanoindentation ndi zigawo zake, kuphatikizapo makhalidwe a indentation probe (mawonekedwe, kukula, ndi kuuma kwa kasupe), kukhudzidwa (phokoso lakumbuyo ndi kuyerekezera malo olumikizirana), ndi mitundu yolumikizira deta (miyezo ya kuchuluka kwa modulus), njirayo idagwiritsidwa ntchito. fotokozani zitsanzo zofewa kwambiri zomwe zimapezeka m'masitolo kuti zitsimikizire zotsatira za kuchuluka. Hydrogel ya polyacrylamide (PAAM) yogulitsa yokhala ndi modulus yosalala ya 1 kPa idayesedwa pansi pa mikhalidwe yonyowa pogwiritsa ntchito probe ya 140 nm. Tsatanetsatane wa mayeso a module ndi kuwerengera kwaperekedwa mu Zowonjezera. Zotsatirazi zidawonetsa kuti avareji ya modulus yomwe idayesedwa inali 0.92 kPa, ndipo kusiyana kwa %RSD ndi peresenti (%) kuchokera ku modulus yodziwika kunali kochepera 10%. Zotsatirazi zimatsimikizira kulondola ndi kubwerezabwereza kwa njira ya AFM nanoindentation yomwe imagwiritsidwa ntchito pantchitoyi poyesa moduli ya zinthu zofewa kwambiri. Malo a zitsanzo za lehfilcon A CL ndi gawo la SiHy base adafotokozedwanso pogwiritsa ntchito njira yomweyo ya AFM nanoindentation kuti aphunzire modulus yolumikizana ya pamwamba pa ultrasoft ngati ntchito ya kuya kwa indentation. Ma curve olekanitsa mphamvu ya indentation adapangidwa pa zitsanzo zitatu za mtundu uliwonse (n = 3; indentation imodzi pa chitsanzo chilichonse) pa mphamvu ya 300 pN, liwiro la 1 µm/s, ndi madzi okwanira. Mzere wogawana mphamvu ya indentation unayesedwa pogwiritsa ntchito chitsanzo cha cone-sphere. Kuti mupeze modulus yodalira kuya kwa indentation, gawo la 40 nm lonse la force curve lidakhazikitsidwa pa kuwonjezeka kulikonse kwa 20 nm kuyambira pomwe adalumikizana, ndikuyesa ma values ​​​​a modulus pa sitepe iliyonse ya force curve. Spin Cy et al. Njira yofananayi yagwiritsidwa ntchito pofotokoza kuchuluka kwa maburashi a polymer a poly(lauryl methacrylate) (P12MA) pogwiritsa ntchito colloidal AFM probe nanoindentation, ndipo amagwirizana ndi deta pogwiritsa ntchito chitsanzo cha Hertz contact. Njirayi imapereka chithunzi cha contact modulus (kPa) motsutsana ndi indentation depth (nm), monga momwe zasonyezedwera pa Chithunzi 8, chomwe chikuwonetsa contact modulus/depth gradient. Modulus yokhazikika yowerengedwa ya CL lehfilcon A sample ili pakati pa 2–3 kPa mkati mwa 100 nm ya pamwamba pa sample, kupitirira apo imayamba kuwonjezeka ndi kuya. Kumbali inayi, poyesa SiHy base substrate popanda filimu yonga burashi pamwamba, kuya kwakukulu kwa indentation komwe kumapezedwa pa mphamvu ya 300 pN ndi kochepera 50 nm, ndipo mtengo wa modulus womwe wapezedwa kuchokera ku deta ndi pafupifupi 400 kPa, zomwe zikufanana ndi mtengo wa Young's modulus pazinthu zambiri.
Kuzama kwa contact modulus (kPa) poyerekeza ndi kuzama kwa indentation (nm) kwa lehfilcon A CL ndi SiHy substrates pogwiritsa ntchito njira ya AFM nanoindentation yokhala ndi cone-sphere geometry poyesa modulus.
Pamwamba kwambiri pa kapangidwe ka burashi yatsopano ya biomimetic branched polymer burashi imakhala ndi modulus yotsika kwambiri ya elasticity (2–3 kPa). Izi zikugwirizana ndi malekezero omasuka a burashi ya polymer yolumikizidwa monga momwe zasonyezedwera pachithunzi cha STEM. Ngakhale pali umboni wina wa modulus gradient m'mphepete mwakunja kwa CL, gawo lalikulu la modulus lalikulu ndi lofunika kwambiri. Komabe, 100 nm yapamwamba pamwamba ili mkati mwa 20% ya kutalika konse kwa burashi ya polymer yolumikizidwa, kotero ndikoyenera kuganiza kuti miyeso yoyezedwa ya modulus mu indentation depth range iyi ndi yolondola kwambiri ndipo sizidalira kwambiri zotsatira za chinthu cha pansi.
Chifukwa cha kapangidwe kapadera ka lens yolumikizirana ya lehfilcon A, yokhala ndi nthambi za PMPC polymer burashi yolumikizidwa pamwamba pa SiHy substrates, zimakhala zovuta kwambiri kufotokoza molondola momwe makina amagwirira ntchito pamwamba pogwiritsa ntchito njira zachikhalidwe zoyezera. Pano tikupereka njira yapamwamba ya AFM nanoindentation yofotokozera molondola zinthu zofewa kwambiri monga lefilcon A yokhala ndi madzi ambiri komanso kusinthasintha kwakukulu. Njirayi imachokera pakugwiritsa ntchito probe ya AFM yomwe kukula kwake ndi mawonekedwe ake zimasankhidwa mosamala kuti zigwirizane ndi kukula kwa kapangidwe ka zinthu zofewa kwambiri zomwe ziyenera kusindikizidwa. Kuphatikiza uku kwa miyeso pakati pa probe ndi kapangidwe kumapereka kukhudzika kwakukulu, zomwe zimatilola kuyeza modulus yotsika komanso mawonekedwe otanuka a zinthu zomata za polymer burashi, mosasamala kanthu za zotsatira za poroelastic. Zotsatira zake zawonetsa kuti maburashi apadera a PMPC polymer omwe ali ndi nthambi omwe ali pamwamba pa lens anali ndi modulus yotsika kwambiri (mpaka 2 kPa) komanso kusinthasintha kwakukulu (pafupifupi 100%) akayesedwa m'malo amadzi. Zotsatira za AFM nanoindentation zinatithandizanso kuzindikira momwe contact modulus/depth gradient imaonekera (30 kPa/200 nm) pamwamba pa biomimetic lens imaonekera. Gradient iyi ikhoza kukhala chifukwa cha kusiyana kwa modulus pakati pa maburashi a polymer okhala ndi nthambi ndi SiHy substrate, kapena kapangidwe ka nthambi/kuchuluka kwa maburashi a polymer, kapena kuphatikiza kwake. Komabe, maphunziro owonjezera akufunikira kuti timvetsetse bwino ubale womwe ulipo pakati pa kapangidwe ndi zinthu, makamaka momwe nthambi ya burashi imakhudzira zinthu zamakina. Miyeso yofanana ingathandize kuzindikira zinthu zamakina pamwamba pa zipangizo zina zofewa kwambiri komanso zipangizo zachipatala.
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