Enkosi ngokutyelela iNature.com. Usebenzisa inguqulelo yesikhangeli esinenkxaso encinci yeCSS. Ukuze ufumane amava angcono, sicebisa ukuba usebenzise isikhangeli esihlaziyiweyo (okanye ukhubaze iMowudi yokuHlanganisa kwi-Internet Explorer). Ukongeza, ukuqinisekisa inkxaso eqhubekayo, sibonisa indawo ngaphandle kwezitayile kunye neJavaScript.
Ibonisa i-carousel yee-slides ezintathu ngaxeshanye. Sebenzisa amaqhosha e-Okwangaphambili ne-Elandelayo ukuhamba kwii-slides ezintathu ngexesha, okanye sebenzisa amaqhosha e-slider ekupheleni ukuhamba kwii-slides ezintathu ngexesha.
Ngophuhliso lwezinto ezintsha ezithambileyo kakhulu kwizixhobo zonyango kunye nokusetyenziswa kwezonyango, ukuchazwa ngokupheleleyo kweempawu zazo zomzimba neze-mechanical kubalulekile kwaye kuyinselele. Indlela ye-nanoindentation ye-atomic force microscopy (AFM) eguquliweyo isetyenziswe ukuchaza i-modulus yomphezulu ophantsi kakhulu we-lehfilcon entsha. Ilensi yoqhagamshelwano ye-biomimetic silicone hydrogel egqunywe ngomaleko wezakhiwo zebrashi ye-polymer ene-branched. Le ndlela ivumela ukumisela ngokuchanekileyo iindawo zoqhagamshelwano ngaphandle kwemiphumo ye-viscous extrusion xa isondela kwi-branched polymers. Ukongeza, yenza kube nokwenzeka ukumisela iimpawu ze-mechanical zezinto zebrashi nganye ngaphandle kwempembelelo ye-poroelasticity. Oku kufezekiswa ngokukhetha i-probe ye-AFM enoyilo (ubungakanani bencam, i-geometry kunye nesantya sentwasahlobo) efanelekileyo ngokukodwa ekulinganiseni iimpawu zezinto ezithambileyo kunye neesampuli zebhayoloji. Le ndlela iphucula uvakalelo kunye nokuchaneka kokulinganisa ngokuchanekileyo izinto ezithambileyo kakhulu lehfilcon A, ene-modulus ephantsi kakhulu yokuqina kwindawo yomphezulu (ukuya kuthi ga kwi-2 kPa) kunye nokuqina okuphezulu kakhulu kwindawo yangaphakathi (phantse i-100%) yamanzi. Iziphumo zophando lomphezulu azizange zityhile kuphela iimpawu zomphezulu ezithambileyo kakhulu zelensi ye-lehfilcon A, kodwa zikwabonise ukuba imodulus yeebhrashi zepolymer ezinamasebe yayifana neye-substrate ye-silicon-hydrogen. Le ndlela yokuchonga umphezulu ingasetyenziswa kwezinye izinto ezithambileyo kakhulu kunye nezixhobo zonyango.
Iimpawu zoomatshini zezinto ezenzelwe ukunxibelelana ngqo nezicubu eziphilayo zihlala zimiselwa yindawo engqongileyo yezinto eziphilayo. Ukuhambelana ngokugqibeleleyo kwezi mpawu zezinto kunceda ukufezekisa iimpawu zeklinikhi ezifunekayo zezinto ngaphandle kokubangela iimpendulo ezimbi zeseli1,2,3. Kwizinto ezilinganayo ngobuninzi, ukuchazwa kweempawu zoomatshini kulula kakhulu ngenxa yokufumaneka kweenkqubo ezisemgangathweni kunye neendlela zovavanyo (umz., i-microindentation4,5,6). Nangona kunjalo, kwizinto ezithambileyo kakhulu ezifana neejeli, ii-hydrogels, ii-biopolymers, iiseli eziphilayo, njl.njl., ezi ndlela zovavanyo ngokubanzi azisebenzi ngenxa yokunqongophala kwesisombululo sokulinganisa kunye nokungafani kwezinye izinto7. Kwiminyaka edlulileyo, iindlela zendabuko zokungena ziye zatshintshwa kwaye zahlengahlengiswa ukuze zichaze uluhlu olubanzi lwezinto ezithambileyo, kodwa iindlela ezininzi zisajongene neentsilelo ezinkulu ezithintela ukusetyenziswa kwazo8,9,10,11,12,13. Ukungabikho kweendlela zovavanyo ezikhethekileyo ezinokuchaza ngokuchanekileyo nangokuthembekileyo iimpawu zoomatshini zezinto ezithambileyo kunye neengqimba zomphezulu kunciphisa kakhulu ukusetyenziswa kwazo kwizicelo ezahlukeneyo.
Kumsebenzi wethu wangaphambili, sazise ilensi yokunxibelelana ye-lehfilcon A (CL), into ethambileyo eyahlukileyo eneempawu zomphezulu ezithambileyo kakhulu ezivela kwiindlela ezinokuba yi-biomimetic designs eziphefumlelwe ngumphezulu we-cornea yeliso. Le nto yendalo yaphuhliswa ngokufaka umaleko we-polymer onamagatsha, odibeneyo we-poly(2-methacryloyloxyethylphosphorylcholine (MPC)) (PMPC) kwi-silicone hydrogel (SiHy) 15 eyenzelwe izixhobo zonyango ngokusekelwe kuyo. Le nkqubo yokufakela idala umaleko kumphezulu oquka isakhiwo sebrashi ye-polymeric esithambileyo kakhulu nesinobubanzi obuphezulu. Umsebenzi wethu wangaphambili uqinisekisile ukuba isakhiwo se-biomimetic se-lehfilcon A CL sinika iimpawu zomphezulu eziphezulu ezifana nokukhusela okuphuculweyo kokumanzisa kunye nokungcolisa, ukwanda kokuthambisa, kunye nokuncipha kokunamathela kweseli kunye nebhaktheriya15,16. Ukongeza, ukusetyenziswa kunye nophuhliso lwezi zinto ze-biomimetic kukwacebisa ukwanda ngakumbi kwezinye izixhobo ze-biomedical. Ngoko ke, kubalulekile ukuchaza iimpawu zomphezulu wale nto ithambileyo kakhulu kwaye uqonde ukusebenzisana kwayo ngoomatshini neliso ukuze kudalwe isiseko solwazi esibanzi ukuxhasa uphuhliso kunye nokusetyenziswa kwexesha elizayo. Uninzi lweelensi zonxibelelwano zeSiHy ezithengiswayo zenziwe ngumxube ofanayo weepolymers eziphila emanzini kunye ne-hydrophobic ezenza isakhiwo sezinto ezifanayo17. Izifundo ezininzi zenziwe ukuphanda iimpawu zazo zoomatshini kusetyenziswa iindlela zovavanyo lwendabuko lokucinezela, ukuxinana kunye ne-microindentation18,19,20,21. Nangona kunjalo, uyilo olutsha lwe-biomimetic lwe-lehfilcon A CL lwenza ukuba ibe yinto eyahlukileyo eyahlukileyo apho iimpawu zoomatshini zezakhiwo zebrashi zepolymer ezinamasebe zahluke kakhulu kwezo ze-substrate yesiseko seSiHy. Ke ngoko, kunzima kakhulu ukulinganisa ngokuchanekileyo ezi mpawu kusetyenziswa iindlela zemveli kunye ne-indentation. Indlela ethembisayo isebenzisa indlela yokuvavanya i-nanoindentation ephunyezwe kwi-atomic force microscopy (AFM), indlela esetyenzisiweyo ukumisela iimpawu zoomatshini zezinto ezithambileyo ze-viscoelastic ezifana neeseli zebhayoloji kunye nezicubu, kunye neepolymers ezithambileyo22,23,24,25. ,26,27,28,29,30. Kwi-nanoindentation ye-AFM, iziseko zovavanyo lwe-nanoindentation zidibene nenkqubela phambili yamva nje kwitekhnoloji ye-AFM ukubonelela ngovakalelo oluphezulu lokulinganisa kunye novavanyo lwezixhobo ezahlukeneyo ezithambileyo31,32,33,34,35,36. Ukongeza, itekhnoloji inika ezinye izibonelelo ezibalulekileyo ngokusebenzisa iijometri ezahlukeneyo, i-indenter kunye ne-probe kunye nokwenzeka kokuvavanya kwiindidi ezahlukeneyo ze-liquid.
I-nanoindentation ye-AFM inokwahlulwa ngokwemiqathango ibe ziinxalenye ezintathu eziphambili: (1) izixhobo (ii-sensors, ii-detectors, ii-probes, njl.njl.); (2) iiparameter zokulinganisa (ezifana namandla, ukufuduka, isantya, ubungakanani be-ramp, njl.njl.); (3) Ukucutshungulwa kwedatha (ukulungiswa kwesiseko, uqikelelo lwenqaku lokuchukumisa, ukufakwa kwedatha, ukumodela, njl.njl.). Ingxaki ebalulekileyo ngale ndlela kukuba izifundo ezininzi kwiincwadi ezisebenzisa i-nanoindentation ye-AFM zixela iziphumo ezahlukeneyo zobungakanani zesampulu/iseli/uhlobo lwezinto ezifanayo37,38,39,40,41. Umzekelo, uLekka et al. Impembelelo ye-AFM probe geometry kwi-modulus kaYoung elinganisiweyo yeesampulu ze-hydrogel ehambelanayo ngoomatshini kunye neeseli ezahlukeneyo zafundwa zaza zathelekiswa. Baxela ukuba amaxabiso e-modulus axhomekeke kakhulu ekukhetheni i-cantilever kunye nesimo se-tip, ngexabiso eliphezulu le-probe efana nephiramidi kunye nexabiso eliphantsi le-42 kwi-probe eyi-spherical. Ngokufanayo, uSelhuber-Unkel et al. Kuye kwaboniswa indlela isantya se-indenter, ubungakanani be-indenter kunye nobukhulu beesampuli ze-polyacrylamide (PAAM) ezichaphazela ngayo i-Young's modulus elinganiswe yi-ACM43 nanoindentation. Enye into eyenza kube nzima kukungabikho kwezixhobo zovavanyo lwe-modulus ezisemgangathweni ophantsi kakhulu kunye neenkqubo zovavanyo zasimahla. Oku kwenza kube nzima kakhulu ukufumana iziphumo ezichanekileyo ngokuzithemba. Nangona kunjalo, le ndlela iluncedo kakhulu kwiimilinganiselo ezihambelanayo kunye novavanyo oluthelekisayo phakathi kweentlobo ezifanayo zeesampuli, umzekelo ukusebenzisa i-AFM nanoindentation ukwahlula iiseli eziqhelekileyo kwiiseli zomhlaza 44, 45.
Xa kuvavanywa izinto ezithambileyo nge-nanoindentation ye-AFM, umthetho oqhelekileyo kukusebenzisa i-probe ene-low spring constant (k) ehambelana ngokusondeleyo ne-sample modulus kunye ne-hemispherical/round tip ukuze i-probe yokuqala ingagqobhozi kwiindawo zesampulu xa idibana nezinto ezithambileyo okokuqala. Kubalulekile nokuba isignali yokuphambuka eveliswa yi-probe ibe namandla ngokwaneleyo ukuba ifunyanwe yi-laser detector system24,34,46,47. Kwimeko yeeseli ezithambileyo kakhulu, izicubu kunye neejeli, omnye umngeni kukunqoba amandla okunamathela phakathi kwe-probe kunye nomphezulu wesampulu ukuqinisekisa ukulinganiswa okuphindaphindwayo nokuthembekileyo48,49,50. Kude kube kutshanje, uninzi lomsebenzi kwi-nanoindentation ye-AFM lugxile ekufundeni ukuziphatha koomatshini kweeseli zebhayoloji, izicubu, iijeli, ii-hydrogels, kunye nee-biomolecules kusetyenziswa ii-probes ezinkulu ezijikelezayo, ezibizwa ngokuba zii-colloidal probes (CPs). , 47, 51, 52, 53, 54, 55. Ezi ngcebiso zinobubanzi obuyi-1 ukuya kwi-50 µm kwaye zihlala zenziwe ngeglasi ye-borosilicate, i-polymethyl methacrylate (PMMA), i-polystyrene (PS), i-silicon dioxide (SiO2) kunye ne-diamond-like carbon (DLC). Nangona i-CP-AFM nanoindentation idla ngokuba lolona khetho lokuqala lokuchazwa kwesampuli ethambileyo, ineengxaki kunye nemida yayo. Ukusetyenziswa kwee-spherical tips ezinkulu, ezinobukhulu be-micron kwandisa indawo yoqhagamshelwano iyonke ye-tip kunye nesampuli kwaye kuphumela ekulahlekelweni okukhulu kwesisombululo sendawo. Kwiisampuli ezithambileyo, ezingenayo i-homogeneous, apho iipropati zoomatshini zezinto zasekhaya zinokwahluka kakhulu kumndilili kwindawo ebanzi, i-CP indentation inokufihla naluphi na ukungalingani kwiipropati kwisikali sendawo52. Ii-Colloidal probes zihlala zenziwa ngokuncamathisela ii-colloidal spheres ezinobukhulu be-micron kwii-cantilevers ezingenaziphene zisebenzisa ii-epoxy adhesives. Inkqubo yokuvelisa ngokwayo izaliswe ziingxaki ezininzi kwaye inokukhokelela ekungahambelani kwinkqubo yokulinganisa iprobe. Ukongeza, ubungakanani kunye nobunzima bee-colloidal particles zichaphazela ngokuthe ngqo iiparameter eziphambili zokulinganisa i-cantilever, ezifana ne-resonant frequency, ukuqina kwentwasahlobo, kunye novakalelo lokuphambuka56,57,58. Ke ngoko, iindlela ezisetyenziswa rhoqo kwii-probes ze-AFM eziqhelekileyo, ezifana nokulinganisa ubushushu, zisenokungaboneleli ngokulinganisa okuchanekileyo kwe-CP, kwaye ezinye iindlela zinokufuneka ukwenza ezi zilungiso57, 59, 60, 61. Uvavanyo oluqhelekileyo lwe-CP indentation lusebenzisa i-large deviations cantilever ukufunda iipropati zeesampuli ezithambileyo, nto leyo edala enye ingxaki xa kulinganiswa ukuziphatha okungekho kumgca we-cantilever kwii-deviations ezinkulu62,63,64. Iindlela zanamhlanje ze-colloidal probe indentation zihlala ziqwalasela i-geometry ye-cantilever esetyenziselwa ukulinganisa i-probe, kodwa aziyihoyi impembelelo yee-colloidal particles, nto leyo edala ukungaqiniseki okongezelelweyo ekuchanekeni kwendlela38,61. Ngokufanayo, i-elastic moduli ebalwe ngokufaka imodeli yoqhagamshelwano ixhomekeke ngokuthe ngqo kwi-geometry ye-indentation probe, kwaye ukungafani phakathi kweempawu zomphezulu we-tip kunye nesampulu kunokukhokelela ekungachaneki27, 65, 66, 67, 68. Umsebenzi wakutshanje kaSpencer et al. Izinto ekufuneka ziqwalaselwe xa kuchazwa iibrashi ze-polymer ezithambileyo kusetyenziswa indlela ye-CP-AFM nanoindentation zigqanyisiwe. Baxele ukuba ukugcinwa kolwelo oluthambileyo kwiibrashi ze-polymer njengomsebenzi wesantya kubangela ukwanda komthwalo wentloko kwaye ngenxa yoko imilinganiselo eyahlukeneyo yeempawu ezixhomekeke kwisantya30,69,70,71.
Kolu phononongo, sichaze imodulus yomphezulu wezinto ezithambileyo kakhulu ezithambileyo ze-lehfilcon A CL sisebenzisa indlela ye-nanoindentation ye-AFM eguquliweyo. Ngenxa yeempawu kunye nesakhiwo esitsha sale nto, uluhlu lovakalelo lwendlela yendabuko yokuzibopha alwanelanga ngokucacileyo ukuchaza imodulus yale nto ithambileyo kakhulu, ngoko ke kuyimfuneko ukusebenzisa indlela ye-nanoindentation ye-AFM enovakalelo oluphezulu kunye nenqanaba lovakalelo oluphantsi. Emva kokuphonononga iziphene kunye neengxaki zeendlela ezikhoyo ze-colloidal AFM probe nanoindentation, sibonisa ukuba kutheni sikhethe i-probe encinci, eyenzelwe ngokwezifiso i-AFM ukuze kupheliswe uvakalelo, ingxolo yangasemva, indawo yokunxibelelana, ukulinganisa i-velocity modulus yezinto ezithambileyo ezahlukeneyo ezifana nokuxhomekeka kokugcinwa kolwelo. kunye nokulinganisa okuchanekileyo. Ukongeza, sikwazile ukulinganisa ngokuchanekileyo imo kunye nobukhulu bencam yokuzibopha, okusivumela ukuba sisebenzise imodeli yokulingana kwe-cone-sphere ukumisela imodulus yokuthamba ngaphandle kokuvavanya indawo yoqhagamshelwano lwencam nezinto. Iingcamango ezimbini ezingacacanga ezilinganiswa kulo msebenzi ziimpawu zezinto ezithambileyo ngokupheleleyo kunye ne-indentation deep-independent modulus. Sisebenzisa le ndlela, siqale savavanya imigangatho ethambileyo kakhulu nge-modulus eyaziwayo ukulinganisa le ndlela, saza sasebenzisa le ndlela ukuchaza iindawo zezixhobo ezimbini ezahlukeneyo ze-contact lens. Le ndlela yokuchonga iindawo ze-AFM nanoindentation ezinovakalelo oluphezulu kulindeleke ukuba isebenze kuluhlu olubanzi lwezinto ze-biomimetic ezahlukeneyo ze-ultrasoft ezinokusetyenziswa kwizixhobo zonyango kunye nezicelo ze-biomedical.
ILehfilcon A iilensi zoqhagamshelwano (eAlcon, eFort Worth, eTexas, e-USA) kunye ne-silicone hydrogel substrates zazo zikhethwe kwiimvavanyo ze-nanoindentation. Kusetyenziswe i-lens mount eyenzelwe ngokukodwa kolu vavanyo. Ukufakela ilensi yokuvavanya, yabekwa ngononophelo kwi-stand efana nedome, kuqinisekiswa ukuba akukho maqamza omoya angena ngaphakathi, yaze yalungiswa ngemiphetho. Umngxuma kwisixhobo esiphezulu se-lens holder unika ukufikelela kwiziko le-optical lens kwiimvavanyo ze-nanoindentation ngelixa ubambe ulwelo endaweni yalo. Oku kugcina iilensi zimanzi ngokupheleleyo. Isisombululo sokupakisha iilensi zoqhagamshelwano ezingama-500 μl sisetyenziswe njengesisombululo sokuvavanya. Ukuqinisekisa iziphumo zobungakanani, ii-hydrogels ze-polyacrylamide (PAAM) ezingasetyenziswanga ezithengiswayo zalungiswa kwi-polyacrylamide-co-methylene-bisacrylamide composition (100 mm Petrisoft Petri dishes, Matrigen, Irvine, CA, USA), i-modulus eyaziwayo ye-1 kPa. Sebenzisa amathontsi ama-4-5 (malunga ne-125 µl) e-phosphate buffered saline (i-PBS evela eCorning Life Sciences, eTewkesbury, MA, e-USA) kunye nethontsi eli-1 lesisombululo se-OPTI-FREE Puremoist contact lens (e-Alcon, eVaud, e-TX, e-USA). ) kwi-AFM hydrogel-probe interface.
Iisampulu zeLehfilcon A CL kunye neSiHy substrates zibonwe kusetyenziswa inkqubo yeFEI Quanta 250 Field Emission Scanning Electron Microscope (FEG SEM) exhotyiswe ngeScanning Transmission Electron Microscope (STEM). Ukulungiselela iisampulu, iilensi zahlanjwa kuqala ngamanzi zaza zanqunyulwa zaba zii-wedges ezimile okwepayi. Ukufezekisa umahluko owahlukileyo phakathi kwezinto eziphila emanzini kunye nezo ziphila emanzini, isisombululo esizinzileyo se-0.10% seRuO4 sasetyenziswa njengedayi, apho iisampulu zantywiliselwa khona imizuzu engama-30. Ukupenda kwe-lehfilcon A CL RuO4 kubalulekile kungekuphela nje ekufezekiseni umahluko ophucukileyo, kodwa kukwanceda ukugcina ulwakhiwo lweebrashi zepolymer ezinamasebe kwimo yazo yokuqala, ezibonakala emva koko kwimifanekiso ye-STEM. Emva koko zahlanjwa zaza zasuswa emanzini kuthotho lwemixube ye-ethanol/water kunye noxinzelelo lwe-ethanol olukhulayo. Iisampulu zaze zaphoswa nge-EMBEd 812/Araldite epoxy, eyanyangeka ubusuku bonke kwi-70°C. Iibhloko zesampulu ezifunyenwe nge-resin polymerization zisikwe nge-ultramicrotome, kwaye amacandelo amancinci avelayo abonwa nge-STEM detector kwimo ye-vacuum ephantsi kwi-voltage ekhawulezayo ye-30 kV. Inkqubo efanayo ye-SEM isetyenziselwe ukuchaza iinkcukacha ze-PFQNM-LC-A-CAL AFM probe (Bruker Nano, Santa Barbara, CA, USA). Imifanekiso ye-SEM ye-probe ye-AFM ifunyenwe kwimo eqhelekileyo ye-vacuum ephezulu ene-voltage ekhawulezayo ye-30 kV. Fumana imifanekiso kwii-engile ezahlukeneyo kunye nokukhulisa ukuze urekhode zonke iinkcukacha zesimo kunye nobukhulu be-AFM probe tip. Zonke izilinganiso zencam ezinomdla kwimifanekiso zilinganiswe ngedijithali.
I-Dimension FastScan Bio Icon atomic force microscope (Bruker Nano, Santa Barbara, CA, USA) enemo ye-“PeakForce QNM in Fluid” isetyenzisiwe ukubonwa kunye nokungangenisi i-nanoindentate lehfilcon I-CL, i-SiHy substrate, kunye neesampuli ze-PAAm hydrogel. Kwizilingo zokufota, i-PEAKFORCE-HIRS-FA probe (Bruker) ene-nominal tip radius ye-1 nm isetyenzisiwe ukufota imifanekiso yesisombululo esiphezulu sesampuli ngesantya sokuskena se-0.50 Hz. Yonke imifanekiso ithathwe kwisisombululo samanzi.
Uvavanyo lwe-nanoindentation lwe-AFM lwenziwe kusetyenziswa i-PFQNM-LC-A-CAL probe (Bruker). I-AFM probe inencam ye-silicon kwi-nitride cantilever enobukhulu obuyi-345 nm, ubude obuyi-54 µm kunye nobubanzi obuyi-4.5 µm kunye ne-resonant frequency ye-45 kHz. Yenzelwe ngokukodwa ukuchaza nokwenza imilinganiselo ye-nanomechanical yobungakanani kwiisampuli zebhayoloji ezithambileyo. Ii-sensors zilinganiswa ngokwahlukeneyo kumzi-mveliso kunye nezicwangciso zentwasahlobo ezilinganisiweyo kwangaphambili. Ii-spring constants zee-probes ezisetyenzisiweyo kolu phononongo zazikuluhlu lwe-0.05–0.1 N/m. Ukuchonga ngokuchanekileyo imo kunye nobukhulu bencam, i-probe ichazwe ngokweenkcukacha kusetyenziswa i-SEM. Kumfanekiso. Umfanekiso 1a ubonisa i-electron micrograph enesisombululo esiphezulu, i-low magnification scanning ye-PFQNM-LC-A-CAL probe, enika umbono opheleleyo woyilo lwe-probe. Kumfanekiso 1b ubonisa umbono owandisiweyo wencopho ye-probe, enika ulwazi malunga nemo kunye nobukhulu bencam. Kwisiphelo esiphezulu, inaliti yi-hemisphere emalunga ne-140 nm ububanzi (Umfanekiso 1c). Ngaphantsi kwale ndawo, incam iyancipha ibe yimo yekhoni, ifikelela kubude obulinganisiweyo obumalunga ne-500 nm. Ngaphandle kwendawo yokuncipha, incam iyisilinda kwaye iphela kubude bencam iyonke obuyi-1.18 µm. Le yinxalenye ephambili yokusebenza kwencam yeprobe. Ukongeza, iprobe enkulu ye-polystyrene (PS) engqukuva (Novascan Technologies, Inc., Boone, Iowa, USA) enobubanzi bencam obuyi-45 µm kunye ne-spring constant eyi-2 N/m nayo yasetyenziswa kuvavanyo njengeprobe ye-colloidal. kunye neprobe ye-PFQNM-LC-A-CAL 140 nm yokuthelekisa.
Kuye kwaxelwa ukuba ulwelo lunokubanjwa phakathi kweprobe ye-AFM kunye nesakhiwo sebrashi yepolymer ngexesha le-nanoindentation, eya kusebenzisa amandla aphezulu kwiprobe ye-AFM ngaphambi kokuba ichukumise umphezulu69. Esi siphumo sokuphuma kwe-viscous ngenxa yokugcinwa kolwelo sinokutshintsha indawo ebonakalayo yokunxibelelana, ngaloo ndlela sichaphazele ukulinganiswa kwe-surface modulus. Ukuze kufundwe isiphumo se-probe geometry kunye nesantya sokungena kwi-fluid retention, ii-indentation force curves zadwetshwa kwiisampulu ze-lehfilcon A CL kusetyenziswa i-140 nm diameter probe kwizinga lokuhamba eliqhubekayo le-1 µm/s kunye ne-2 µm/s. i-probe diameter yi-45 µm, i-fixed force setting yi-6 nN efezekisiweyo kwi-1 µm/s. Iimvavanyo ngeprobe eyi-140 nm diameter zenziwe ngesantya sokungena kwi-1 µm/s kunye ne-set force ye-300 pN, ekhethwe ukudala uxinzelelo lonxibelelwano ngaphakathi koluhlu lwe-physiological (1–8 kPa) ye-eyelid ephezulu. uxinzelelo 72. Iisampulu ezithambileyo ezenziwe nge-PAA hydrogel enoxinzelelo lwe-1 kPa zivavanyiwe amandla okutsalwa kwe-50 pN kwisantya se-1 μm/s kusetyenziswa iprobe enobubanzi be-140 nm.
Ekubeni ubude benxalenye yekhoni yencam yeprobe yePFQNM-LC-A-CAL imalunga ne-500 nm, kuyo nayiphi na inzulu ye-indentation < 500 nm kunokucingelwa ngokukhuselekileyo ukuba i-geometry yeprobe ngexesha le-indentation iya kuhlala iyinyani kwimo yayo yekhoni. Ukongeza, kucingelwa ukuba umphezulu wezinto ezivavanywayo uya kubonisa impendulo eguquguqukayo, eya kuqinisekiswa nakwiziqendu ezilandelayo. Ke ngoko, ngokuxhomekeke kwimo kunye nobukhulu bencam, sikhethe imodeli yokulinganisa i-cone-sphere eyenziwe nguBriscoe, uSebastian kunye no-Adams, ekhoyo kwisoftware yomthengisi, ukuze sicubungule iimvavanyo zethu ze-nanoindentation ze-AFM (i-NanoScope). Isoftware yohlalutyo lwedatha yokwahlulahlula, iBruker) 73. Imodeli ichaza ubudlelwane be-force-displacement F(δ) kwikhoni ene-sphere defect. Kumfanekiso. Umfanekiso 2 ubonisa ijiyometri yoqhagamshelwano ngexesha lokusebenzisana kwekhowuni eqinileyo nencam engqukuva, apho u-R yirediyasi yencam engqukuva, u-a yirediyasi yoqhagamshelwano, u-b yirediyasi yoqhagamshelwano ekupheleni kwencam engqukuva, u-δ yirediyasi yoqhagamshelwano. ubunzulu bokutsalwa, u-θ yi-half-angle yekhowuni. Umfanekiso we-SEM wale probe ubonisa ngokucacileyo ukuba incam engqukuva ye-140 nm ububanzi idibana nge-tangentially ibe yikhowuni, ngoko ke apha u-b uchazwa kuphela ngo-R, oko kukuthi u-b = R cos θ. Isoftware ebonelelwa ngumthengisi ibonelela ngobudlelwane bekhowuni-sphere ukubala amaxabiso e-modulus (E) kaYoung kwidatha yokwahlulwa kwamandla ethatha u-a > b. Ulwalamano:
apho u-F ngamandla okutsalela umva, u-E yimodulus kaYoung, u-ν yi-ratio kaPoisson. Irediyasi yoqhagamshelwano u-a inokuqikelelwa kusetyenziswa:
Iskimu sejometri yoqhagamshelwano lwekhowuni eqinileyo enencam engqukuva ecinezelwe kwizinto zelensi yoqhagamshelwano yeLefilcon kunye nomaleko womphezulu weebhrashi zepolymer ezinamasebe.
Ukuba u-≤ b, ulwalamano luyancitshiswa lube yi-equation ye-conventional spherical indenter;
Sikholelwa ukuba ukusebenzisana kweprobe yokutsalela ngaphakathi kunye nesakhiwo esinamasebe sebrashi yepolymer ye-PMPC kuya kubangela ukuba i-contact radius a ibe nkulu kune-spherical contact radius b. Ke ngoko, kuzo zonke izilinganiso zobungakanani ze-elastic modulus ezenziwe kolu phononongo, sisebenzise ukuxhomekeka okufunyenweyo kwimeko a > b.
Izinto ze-biomimetic ezithambileyo ezifundwe kolu phononongo zithathwe umfanekiso opheleleyo kusetyenziswa i-scanning transmission electron microscopy (STEM) yesampulu yecandelo elinqamlezileyo kunye ne-atomic force microscopy (AFM) yomphezulu. Olu phawu oluneenkcukacha lomphezulu lwenziwe njengolwandiso lomsebenzi wethu opapashwe ngaphambili, apho sigqibe khona ukuba isakhiwo se-polymeric brush esine-dynamically somphezulu we-lehfilcon A CL oguqulweyo we-PMPC sibonise iimpawu ezifanayo zoomatshini kwizicubu ze-cornea zendalo 14. Ngenxa yesi sizathu, sibhekisa kwiindawo ze-contact lens njengezinto ze-biomimetic14. Kumfanekiso 3a,b sibonisa iindawo ezinqamlezileyo zezakhiwo ze-brashi ze-polymer ze-PMPC ezine-branched kumphezulu we-substrate ye-lehfilcon A CL kunye ne-substrate ye-SiHy enganyangwanga, ngokwahlukeneyo. Iindawo zesampulu zombini zihlalutywe ngakumbi kusetyenziswa imifanekiso ye-AFM enesisombululo esiphezulu, eyaqinisekisa ngakumbi iziphumo zohlalutyo lwe-STEM (Umzobo 3c, d). Xa zidibene, ezi mifanekiso zinika ubude obuqikelelweyo besakhiwo se-polymer brashi esine-branched ye-PMPC kwi-300–400 nm, ebaluleke kakhulu ekutolikeni imilinganiselo ye-AFM nanoindentation. Enye into ebalulekileyo efunyenwe kwimifanekiso kukuba ulwakhiwo lomphezulu wezinto ze-CL biomimetic lwahlukile ngokwemo yazo kunezo zezinto ze-SiHy substrate. Lo mahluko kwimo yazo yomphezulu unokubonakala ngexesha lokunxibelelana kwazo ngoomatshini ne-indenting AFM probe kwaye emva koko kwimilinganiselo ye-modulus elinganisiweyo.
Imifanekiso ye-STEM enqamlezileyo ye-(a) lehfilcon A CL kunye (b) ne-SiHy substrate. I-Scale bar, 500 nm. Imifanekiso ye-AFM yomphezulu we-lehfilcon A CL substrate (c) kunye ne-base SiHy substrate (d) (3 µm × 3 µm).
Iipolymers eziphefumlelwe yi-bio kunye nezakhiwo zebrashi zepolymer zithambile ngokwemvelo kwaye ziye zafundwa ngokubanzi kwaye zasetyenziswa kwizicelo ezahlukeneyo ze-biomedical74,75,76,77. Ke ngoko, kubalulekile ukusebenzisa indlela ye-AFM nanoindentation, enokulinganisa ngokuchanekileyo nangokuthembekileyo iipropati zazo zoomatshini. Kodwa kwangaxeshanye, iipropati ezikhethekileyo zezi zinto zithambileyo kakhulu, ezifana ne-modulus ephantsi kakhulu, umxholo ophezulu wolwelo kunye nokuqina okuphezulu, zihlala zenza kube nzima ukukhetha izinto ezifanelekileyo, imo kunye nobukhulu beprobe yokutsalela. Oku kubalulekile ukuze i-indenter ingagqobhozi umphezulu othambileyo wesampuli, nto leyo eya kukhokelela kwiimpazamo ekumiseleni indawo yokudibana nomphezulu kunye nendawo yokudibana.
Ukuze oku kwenzeke, ukuqonda okubanzi malunga nokwakheka kwezinto ezithambileyo kakhulu ze-biomimetic (lehfilcon A CL) kubalulekile. Ulwazi malunga nobukhulu kunye nesakhiwo seebrashi ze-polymer ezinamasebe ezifunyenwe kusetyenziswa indlela yokufota lubonelela ngesiseko sokuchazwa koomatshini bomphezulu kusetyenziswa iindlela ze-AFM nanoindentation. Endaweni yeeprobe ze-colloidal ezisikwe ngobukhulu be-micron, sikhethe i-PFQNM-LC-A-CAL silicon nitride probe (Bruker) enobubanzi obuyi-140 nm, eyenzelwe ngokukodwa imephu yobungakanani beempawu zoomatshini zeesampulu zebhayoloji 78, 79, 80, 81, 82, 83, 84. Isizathu sokusebenzisa iiprobe ezibukhali xa kuthelekiswa neeprobe ze-colloidal eziqhelekileyo sinokuchazwa ziimpawu zesakhiwo sezinto. Ukuthelekisa ubungakanani bencam yeprobe (~140 nm) neebrashi zepolymer ezinamasebe kumphezulu we-CL lehfilcon A, eziboniswe kwiFig. 3a, kungagqitywa kwelokuba incam inkulu ngokwaneleyo ukuba idibane ngqo nezi zakhiwo zebrashi, nto leyo enciphisa amathuba okuba incam igqobhoze kuzo. Ukubonisa le ngongoma, kwiFig. 4 kukho umfanekiso we-STEM we-lehfilcon A CL kunye nencam ye-indenting yeprobe ye-AFM (etsalwe kwisikali).
I-Schematic ebonisa umfanekiso we-STEM we-lehfilcon A CL kunye ne-ACM indentation probe (ezotywe kwisikali).
Ukongeza, ubungakanani bencam ye-140 nm buncinci ngokwaneleyo ukuphepha umngcipheko weziphumo ze-sticky extrusion ezichazwe ngaphambili kwiibrashi ze-polymer eziveliswe yindlela ye-CP-AFM nanoindentation69,71. Sicinga ukuba ngenxa yesimo esikhethekileyo se-cone-spherical kunye nobukhulu obuncinci bale ncam ye-AFM (Umzobo 1), uhlobo lwe-force curve oluveliswa yi-lehfilcon A CL nanoindentation aluyi kuxhomekeka kwisantya se-indentation okanye isantya sokulayisha/sokukhupha. Ke ngoko, aluchaphazeleki ziziphumo ze-poroelastic. Ukuvavanya le ngcamango, iisampulu ze-lehfilcon A CL zafakwa kwi-fixed maximum force kusetyenziswa i-PFQNM-LC-A-CAL probe, kodwa kwi-velocities ezimbini ezahlukeneyo, kwaye ii-tensile force curves eziphumayo kunye ne-retract force zasetyenziswa ukudweba amandla (nN) ngokwahlulwa (µm) kuboniswe kuMfanekiso 5a. Kuyacaca ukuba amandla ajikajika ngexesha lokulayisha nokukhupha adibana ngokupheleleyo, kwaye akukho bungqina bucacileyo bokuba ukucheba kwamandla kubunzulu be-zero indentation kuyanda ngesantya se-indentation kumfanekiso, nto leyo ebonisa ukuba izinto zebrashi nganye zibonakaliswe ngaphandle kwesiphumo se-poroelastic. Ngokwahlukileyo koko, iziphumo zokugcina ulwelo (imiphumo ye-viscous extrusion kunye ne-poroelasticity) ziyabonakala kwi-AFM probe ye-45 µm ububanzi ngesantya esifanayo se-indentation kwaye zigqanyiswa yi-hysteresis phakathi kwe-stretch kunye ne-retract curves, njengoko kubonisiwe kuMfanekiso 5b. Ezi ziphumo zixhasa ingcamango kwaye zibonisa ukuba ii-probes ze-140 nm ububanzi ziyindlela elungileyo yokubonisa ezo ndawo zithambileyo.
i-lehfilcon A CL indentation force curves isebenzisa i-ACM; (a) ukusebenzisa i-probe enobubanzi obuyi-140 nm kwizinga ezimbini zokulayisha, ebonisa ukungabikho kwesiphumo se-poroelastic ngexesha lokuxinana komphezulu; (b) ukusebenzisa ii-probe ezinobubanzi obuyi-45 µm kunye ne-140 nm. s zibonisa imiphumo ye-viscous extrusion kunye ne-poroelasticity kwii-probe ezinkulu xa kuthelekiswa nee-probe ezincinci.
Ukuze kuchazwe iindawo ezithambileyo kakhulu, iindlela ze-AFM nanoindentation kufuneka zibe ne-probe engcono yokufunda iimpawu zezinto ezifundwayo. Ukongeza kwimilo kunye nobukhulu be-tip, uvakalelo lwenkqubo ye-AFM detector, uvakalelo lokuphambuka kwe-tip kwindawo yovavanyo, kunye nokuqina kwe-cantilever kudlala indima ebalulekileyo ekumiseleni ukuchaneka kunye nokuthembeka kwemilinganiselo ye-nanoindentation. Kwinkqubo yethu ye-AFM, umda wokufumanisa we-Position Sensitive Detector (PSD) umalunga ne-0.5 mV kwaye usekelwe kwisantya sentwasahlobo esilinganisiweyo kwangaphambili kunye novakalelo lokuphambuka kolwelo olubaliweyo lwe-PFQNM-LC-A-CAL probe, ehambelana novakalelo lomthwalo wethiyori. ungaphantsi kwe-0.1 pN. Ke ngoko, le ndlela ivumela ukulinganiswa kwamandla amancinci okuphambuka ≤ 0.1 pN ngaphandle kwenxalenye yengxolo ye-peripheral. Nangona kunjalo, akunakwenzeka ukuba inkqubo ye-AFM inciphise ingxolo ye-peripheral ukuya kweli nqanaba ngenxa yezinto ezifana nokungcangcazela koomatshini kunye ne-fluid dynamics. Ezi zinto zithintela uvakalelo olupheleleyo lwendlela ye-AFM nanoindentation kwaye zikwakhokelela kwisignali yengxolo yangasemva emalunga ne-≤ 10 pN. Ukuchonga umphezulu, iisampulu ze-lehfilcon A CL kunye ne-SiHy substrate zafakwa phantsi kweemeko ezimanzi ngokupheleleyo kusetyenziswa i-probe ye-140 nm yokuchonga i-SEM, kwaye ii-force curves eziphumayo zafakwa phakathi kwamandla (pN) kunye noxinzelelo. Iploti yokwahlulahlula (µm) iboniswe kuMfanekiso 6a. Xa kuthelekiswa ne-substrate yesiseko se-SiHy, i-lehfilcon A CL force curve ibonisa ngokucacileyo isigaba sokutshintsha esiqala kwindawo yokunxibelelana nebrashi ye-polymer efakwe ifolokhwe kwaye iphela ngotshintsho olubukhali kunxibelelwano oluphawulayo lwe-slope lwe-tip kunye nezinto ezingaphantsi. Le nxalenye yokutshintsha kwe-force curve igxininisa ukuziphatha okuthambileyo kwebrashi ye-polymer ehlanganisiweyo kumphezulu, njengoko kungqinwa yi-compression curve elandela ngokusondeleyo i-tension curve kunye nomahluko kwiipropati zoomatshini phakathi kwesakhiwo sebrashi kunye nezinto ezinkulu ze-SiHy. Xa uthelekisa i-lefilcon. Ukwahlulwa kobude obuqhelekileyo bebrashi yepolymer enamasebe kumfanekiso we-STEM we-PCS (Umzobo 3a) kunye ne-force curve yayo ecaleni kwe-abscissa kuMfanekiso 3a. 6a kubonisa ukuba le ndlela iyakwazi ukubona incam kunye ne-branched polymer efikelela phezulu kumphezulu. Ukudibana phakathi kwezakhiwo zebrashi. Ukongeza, ukudibana okusondeleyo kwee-force curves kubonisa ukuba akukho mpembelelo yokugcina ulwelo. Kule meko, akukho kunamathelana phakathi kwenaliti kunye nomphezulu wesampuli. Amacandelo aphezulu e-force curves kwiisampuli ezimbini ayadibana, ebonisa ukufana kweempawu ze-mechanical zezinto ze-substrate.
(a) Ii-AFM nanoindentation force curves ze-lehfilcon A CL substrates kunye ne-SiHy substrates, (b) ii-force curves ezibonisa uqikelelo lwendawo yoqhagamshelwano kusetyenziswa indlela yomgca wengxolo yangasemva.
Ukuze kufundwe iinkcukacha ezicokisekileyo ze-force curve, i-tension curve yesampulu ye-lehfilcon A CL idwetshwe kwakhona kwiFig. 6b ngamandla aphezulu angama-50 pN ecaleni kwe-y-axis. Le grafu inika ulwazi olubalulekileyo malunga nengxolo yangasemva yokuqala. Ingxolo ikuluhlu lwe-±10 pN, esetyenziselwa ukumisela ngokuchanekileyo indawo yoqhagamshelwano kunye nokubala ubunzulu bokungena. Njengoko kuxeliwe kwiincwadi, ukuchongwa kwamanqaku oqhagamshelwano kubalulekile ukuvavanya ngokuchanekileyo iipropati zezinto ezifana ne-modulus85. Indlela ebandakanya ukucutshungulwa ngokuzenzekelayo kwedatha ye-force curve ibonise ukulingana okuphuculweyo phakathi kokufakwa kwedatha kunye nokulinganiswa kobuninzi bezinto ezithambileyo86. Kulo msebenzi, ukukhetha kwethu amanqaku oqhagamshelwano kulula kwaye kunenjongo, kodwa kunemida yayo. Indlela yethu yokugcina yokumisela indawo yoqhagamshelwano inokubangela amaxabiso e-modulus agqithisiweyo kancinci kubunzulu obuncinci bokungena (< 100 nm). Ukusetyenziswa kokufunyanwa kwe-touchpoint esekwe kwi-algorithm kunye nokucutshungulwa kwedatha ezenzekelayo kunokuba kukuqhubeka kwalo msebenzi kwixesha elizayo ukuphucula ngakumbi indlela yethu. Ngoko ke, kwingxolo yangasemva engaphakathi kwi-odolo ye-±10 pN, sichaza indawo yoqhagamshelwano njengenqaku lokuqala ledatha kwi-x-axis kuMfanekiso 6b enexabiso le-≥10 pN. Emva koko, ngokuhambelana nomda wengxolo we-10 pN, umgca othe nkqo kwinqanaba le-~0.27 µm uphawula indawo yokunxibelelana nomphezulu, emva koko i-stretching curve iyaqhubeka ide i-substrate idibane nobunzulu bokungena obuyi-~270 nm. Okunomdla kukuba, ngokusekelwe kubukhulu beempawu zebrashi ye-polymer ene-branched (300–400 nm) ezilinganiswe kusetyenziswa indlela yokucinga, ubunzulu bokungena kwe-CL lehfilcon Isampulu ebonwe kusetyenziswa indlela yomda wengxolo yangasemva imalunga ne-270 nm, esondele kakhulu kubungakanani bokulinganisa nge-STEM. Ezi ziphumo ziqinisekisa ngakumbi ukuhambelana kunye nokusebenza kobume kunye nobukhulu be-AFM probe tip yokungena kwesi sakhiwo sebrashi ye-polymer ene-branched branched ethambileyo ne-elastic kakhulu. Le datha ikwabonelela ngobungqina obuqinileyo bokuxhasa indlela yethu yokusebenzisa ingxolo yangasemva njengomda wokuchonga iindawo zonxibelelwano. Ngoko ke, naziphi na iziphumo zobungakanani ezifunyenwe kwimodeli yezibalo kunye nokufakelwa kwegophe lamandla kufuneka zichaneke ngokwentelekiso.
Ukulinganiswa kobungakanani ngeendlela ze-nanoindentation ze-AFM kuxhomekeke ngokupheleleyo kwiimodeli zezibalo ezisetyenziselwa ukukhetha idatha kunye nohlalutyo olulandelayo. Ke ngoko, kubalulekile ukuqwalasela zonke izinto ezinxulumene nokukhetha i-indenter, iimpawu zezinto kunye neendlela zokunxibelelana kwazo ngaphambi kokukhetha imodeli ethile. Kule meko, i-tip geometry yachazwa ngononophelo kusetyenziswa ii-SEM micrographs (Umzobo 1), kwaye ngokusekelwe kwiziphumo, i-probe ye-nanoindenting ye-AFM ye-140 nm ububanzi ene-hard cone kunye ne-spherical tip geometry lukhetho olufanelekileyo lokuchonga iisampulu ze-lehfilcon A CL79. Enye into ebalulekileyo ekufuneka ihlolwe ngononophelo kukuthamba kwezinto ze-polymer ezivavanywayo. Nangona idatha yokuqala ye-nanoindentation (Imizobo 5a kunye ne-6a) ichaza ngokucacileyo iimpawu zokugqithana kwee-tension kunye ne-compression curves, oko kukuthi, ukubuyiswa okupheleleyo kwezinto, kubaluleke kakhulu ukuqinisekisa uhlobo lwe-elastic kuphela lwee-contacts. Ngenxa yoku, kwenziwe ukutsalwa kabini ngokulandelelanayo kwindawo enye kumphezulu wesampuli ye-lehfilcon A CL ngesantya sokutsalwa kwe-1 µm/s phantsi kweemeko zokufuma ngokupheleleyo. Idatha ye-force curve ephumayo iboniswe kumzobo 7 kwaye, njengoko kulindelekile, ii-expansion kunye ne-compression curves zezi prints zimbini ziphantse zifane, zigqamisa ukuthamba okuphezulu kwesakhiwo sebrashi ye-polymer ene-branched.
Iijika ezimbini zamandla okutsalwa kwindawo enye kumphezulu we-lehfilcon A CL zibonisa ukuthamba okufanelekileyo komphezulu welensi.
Ngokusekelwe kulwazi olufunyenwe kwimifanekiso ye-SEM kunye ne-STEM ye-probe tip kunye ne-lehfilcon A CL surface, ngokulandelanayo, imodeli ye-cone-sphere yindlela efanelekileyo yokubonisa ukusebenzisana phakathi kwe-AFM probe tip kunye nezinto ze-polymer ezithambileyo ezivavanywayo. Ukongeza, kule modeli ye-cone-sphere, iingcamango ezisisiseko malunga neempawu ze-elastic zezinto eziprintiweyo ziyinyani kule nto intsha ye-biomimetic kwaye zisetyenziselwa ukulinganisa i-elastic modulus.
Emva kovavanyo olupheleleyo lwendlela ye-AFM nanoindentation kunye nezinto zayo, kubandakanya iimpawu ze-indentation probe (imilo, ubungakanani, kunye nokuqina kwentwasahlobo), uvakalelo (ingxolo yangasemva kunye noqikelelo lwendawo yoqhagamshelwano), kunye neemodeli zokufakela idatha (ukulinganiswa kwe-modulus yobuninzi), le ndlela isetyenzisiwe. chaza iisampulu ezithambileyo ezifumaneka kurhwebo ukuqinisekisa iziphumo zobungakanani. I-hydrogel ye-polyacrylamide (PAAM) yorhwebo ene-modulus elastiki ye-1 kPa ivavanyiwe phantsi kweemeko ezimanzi kusetyenziswa i-probe ye-140 nm. Iinkcukacha zovavanyo lwemodyuli kunye nokubala zibonelelwe kwiNkcazelo eyoNgezelelweyo. Iziphumo zibonise ukuba i-modulus ephakathi elinganisiweyo yayiyi-0.92 kPa, kwaye i-%RSD kunye nepesenti (%) yokuphambuka kwi-modulus eyaziwayo yayingaphantsi kwe-10%. Ezi ziphumo ziqinisekisa ukuchaneka kunye nokuphindaphinda kwendlela ye-AFM nanoindentation esetyenziswe kulo msebenzi ukulinganisa i-moduli yezinto ezithambileyo. Imiphezulu yeesampuli ze-lehfilcon A CL kunye nesiseko se-SiHy zichazwe ngakumbi kusetyenziswa indlela efanayo ye-AFM nanoindentation ukufunda i-aspirate contact modulus yomphezulu we-ultrasoft njengomsebenzi wobunzulu be-indentation. Ii-curves zokwahlulwa kwamandla okutsalwa kwe-indentation zenziwe kwiisampuli ezintathu zohlobo ngalunye (n = 3; i-indentation enye kwisampuli nganye) ngamandla angama-300 pN, isantya se-1 µm/s, kunye ne-hydration epheleleyo. I-indentation force sharing curve iqikelelwe kusetyenziswa imodeli ye-cone-sphere. Ukufumana i-modulus exhomekeke kubunzulu be-indentation, inxalenye ebanzi ye-40 nm ye-force curve yamiselwa kunyuko ngalunye lwe-20 nm ukusuka kwindawo yokunxibelelana, kwaye kwalinganiswa amaxabiso e-modulus kwinqanaba ngalinye le-force curve. Spin Cy et al. Indlela efanayo isetyenzisiwe ukuchaza i-modulus gradient yeebrashi ze-polymer ze-poly(lauryl methacrylate) (P12MA) kusetyenziswa i-colloidal AFM probe nanoindentation, kwaye ziyahambelana nedatha esebenzisa imodeli yoqhagamshelwano lweHertz. Le ndlela inika isicwangciso se-apparent contact modulus (kPa) ngokuchasene nobunzulu be-indentation (nm), njengoko kubonisiwe kuMfanekiso 8, obonisa i-apparent contact modulus/depth gradient. I-calculated elastic modulus yesampuli ye-CL lehfilcon A ikuluhlu lwe-2–3 kPa ngaphakathi kwe-100 nm ephezulu yesampuli, ngaphaya kwayo iqala ukwanda ngobunzulu. Kwelinye icala, xa kuvavanywa isiseko se-SiHy ngaphandle kwefilimu efana nebhrashi kumphezulu, ubunzulu be-indentation obuphezulu obufunyenweyo ngamandla e-300 pN bungaphantsi kwe-50 nm, kwaye ixabiso le-modulus elifunyenwe kwidatha limalunga ne-400 kPa, elifana namaxabiso e-Young's modulus yezinto ezibanzi.
I-contact modulus ebonakalayo (kPa) ngokuchasene nobunzulu bokutsalwa (nm) kwi-lehfilcon A CL kunye ne-SiHy substrates kusetyenziswa indlela ye-AFM nanoindentation ene-cone-sphere geometry ukulinganisa i-modulus.
Umphezulu ophezulu wesakhiwo sebrashi yepolymer entsha ene-biomimetic brashe ubonisa i-modulus ephantsi kakhulu yokuthamba (2–3 kPa). Oku kuya kuhambelana nesiphelo esikhululekileyo sebrashi yepolymer enefolokhwe njengoko kubonisiwe kumfanekiso we-STEM. Nangona kukho ubungqina be-modulus gradient kumda wangaphandle we-CL, i-substrate ephambili ye-modulus ephezulu inefuthe ngakumbi. Nangona kunjalo, i-100 nm ephezulu yomphezulu ingaphakathi kwe-20% yobude bebrashi yepolymer ene-branched, ngoko ke kusengqiqweni ukucinga ukuba amaxabiso alinganisiweyo e-modulus kolu luhlu lobunzulu be-indentation achanekile kwaye awaxhomekekanga kakhulu kwisiphumo sento esezantsi.
Ngenxa yoyilo olulodwa lwe-biomimetic lwe-lehfilcon A contact lens, oluquka izakhiwo zebrashi ze-polymer ze-PMPC ezifakwe kumphezulu we-SiHy substrates, kunzima kakhulu ukuchaza ngokuthembekileyo iimpawu zoomatshini zezakhiwo zazo zomphezulu kusetyenziswa iindlela zokulinganisa zendabuko. Apha sibonisa indlela ephucukileyo ye-AFM nanoindentation yokuchonga ngokuchanekileyo izinto ezithambileyo kakhulu ezifana ne-lefilcon A enomxholo wamanzi aphezulu kunye nokuqina okuphezulu kakhulu. Le ndlela isekelwe ekusebenziseni i-probe ye-AFM enobukhulu bencam kunye nejometri ezikhethwe ngononophelo ukuze zihambelane nobukhulu bezakhiwo zeempawu zomphezulu ezithambileyo kakhulu eziza kuprintwa. Olu dibaniso lobukhulu phakathi kweprobe kunye nesakhiwo lubonelela ngovakalelo oluphezulu, olusivumela ukuba silinganise i-modulus ephantsi kunye neempawu ze-elastic ezingaphakathi zezinto zebrashi ze-polymer ezihlanganisiweyo, nokuba ziziphumo ze-poroelastic. Iziphumo zibonise ukuba iibrashi ze-polymer ze-PMPC ezihlanganisiweyo ezizodwa ezibonakala kumphezulu welensi zazine-modulus ephantsi kakhulu (ukuya kuthi ga kwi-2 kPa) kunye nokuqina okuphezulu kakhulu (phantse i-100%) xa kuvavanywa kwindawo enamanzi. Iziphumo ze-AFM nanoindentation zikwasivumele ukuba sichaze i-contact modulus/depth gradient ebonakalayo (30 kPa/200 nm) yomphezulu welensi ye-biomimetic. Le gradient isenokuba ngenxa yomahluko we-modulus phakathi kweebrashi ze-polymer ezinamasebe kunye ne-SiHy substrate, okanye isakhiwo esinamasebe/ubuninzi beebrashi ze-polymer, okanye indibaniselwano yazo. Nangona kunjalo, kufuneka uphando oluthe kratya ukuze kuqondwe ngokupheleleyo ubudlelwane phakathi kwesakhiwo kunye neepropati, ingakumbi impembelelo yebrashi enamasebe kwiipropati ze-mechanical. Ukulinganisa okufanayo kunokunceda ukuchaza iipropati ze-mechanical zomphezulu wezinye izixhobo ezithambileyo kakhulu kunye nezixhobo zonyango.
Iiseti zedatha eziveliswe kunye/okanye ezihlalutyiweyo ngexesha lophando lwangoku ziyafumaneka kubabhali abafanelekileyo xa beceliwe ngokufanelekileyo.
URahmati, M., uSilva, EA, uReseland, JE, uHayward, K. kunye noHaugen, HJ Iimpendulo zebhayoloji kwiimpawu zomzimba nezekhemikhali zomphezulu wezinto eziphilayo. Uluntu lwekhemikhali. Umhl. 49, 5178–5224 (2020).
UChen, FM kunye noLiu, X. Ukuphuculwa kwezinto eziphilayo ezifunyenwe ngabantu zobunjineli bezicubu. ucwangciso. ipolymer. isayensi. 53, 86 (2016).
USadtler, K. et al. Uyilo, ukuphunyezwa kweklinikhi, kunye nempendulo yomzimba kwizinto eziphilayo kwiyeza lokuvuselela. I-National Matt Rev. 1, 16040 (2016).
U-Oliver WK kunye noFarr GM Indlela ephuculweyo yokufumanisa ubulukhuni kunye ne-elastic modulus kusetyenziswa iimvavanyo zokutsalwa kwe-indentation ngokulinganisa umthwalo kunye nokufuduka. J. Alma mater. itanki yokugcina. 7, 1564–1583 (2011).
Wally, SM Imvelaphi yembali yovavanyo lobunzima bokutsalwa kwe-indentation. alma mater. isayensi. ubuchwepheshe. 28, 1028–1044 (2012).
UBroitman, E. Ukulinganisa Ubunzima Bokujika Kwi-Macro-, Micro-, kunye neNanoscale: Uhlolo Olubalulekileyo. isizwe. Wright. 65, 1–18 (2017).
Kaufman, JD kunye noClapperich, iimpazamo zokufumanisa umphezulu we-SM zikhokelela kwi-modulus overestimation kwi-nanoindentation yezinto ezithambileyo. J. Mecha. Behavior. Biomedical Science. alma mater. 2, 312–317 (2009).
UKarimzade A., Koloor SSR, Ayatollakhi MR, Bushroa AR kunye noYahya M.Yu. Uvavanyo lwendlela ye-nanoindentation yokumisela iimpawu zoomatshini ze-nanocomposites ezahlukeneyo kusetyenziswa iindlela zovavanyo kunye nezibalo. isayensi. Indlu 9, 15763 (2019).
ULiu, K., uVanLendingham, uMR, kunye no-Owart, TS Ukuchazwa kweendlela zobuchwephesha zeejeli ezithambileyo ze-viscoelastic ngokuhlaziywa kwezinto ezinqamlezileyo ezisekwe kwi-inverse finite. J. Mecha. Ukuziphatha. Isayensi yezebhayoloji. i-alma mater. 2, 355–363 (2009).
UAndrews JW, uBowen J kunye noChaneler D. Ukuphucula ukuqinisekiswa kwe-viscoelasticity kusetyenziswa iinkqubo zokulinganisa ezihambelanayo. Soft Matter 9, 5581–5593 (2013).
UBriscoe, BJ, Fiori, L. kunye noPellillo, E. Ukwenziwa kwe-nanoindent ye-polymeric surfaces. J. Physics. D. Faka isicelo se-physics. 31, 2395 (1998).
UMiyailovich AS, uTsin B., uFortunato D. kunye noVan Vliet KJ Ukuchazwa kweempawu ze-viscoelastic mechanical ze-polymers ezithambileyo kakhulu kunye nezicubu zebhayoloji kusetyenziswa i-shock indentation. Ijenali yeBiomaterials. 71, 388–397 (2018).
UPerepelkin NV, Kovalev AE, Gorb SN, Borodich FM Uvavanyo lwe-elastic modulus kunye nomsebenzi wokunamathela kwezinto ezithambileyo kusetyenziswa indlela ye-Borodich-Galanov (BG) eyoluliweyo kunye nokutsalwa okunzulu. uboya. i-alma mater. 129, 198–213 (2019).
UShi, X. et al. Imo ye-nanoscale kunye neempawu zoomatshini ze-biomimetic polymeric surfaces ze-silicone hydrogel contact lens. Langmuir 37, 13961–13967 (2021).