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Tsatsa ta ƙwayoyin cuta (MIC) babbar matsala ce a masana'antu da yawa domin tana iya haifar da asarar tattalin arziki mai yawa. An yi amfani da ƙarfe mai ƙarfi mai duplex (2707 HDSS) a cikin yanayin ruwa saboda kyakkyawan juriyarsa ga sinadarai. Duk da haka, ba a nuna juriyarsa ga MIC ta hanyar gwaji ba. A cikin wannan binciken, an binciki halayen MIC na 2707 HDSS wanda kwayar halittar iskar gas ta ruwa Pseudomonas aeruginosa ta haifar. Binciken lantarki ya nuna cewa a gaban biofilm na Pseudomonas aeruginosa a cikin matsakaiciyar 2216E, an sami canji mai kyau a cikin yuwuwar tsatsa da ƙaruwa a yawan tsatsa. Binciken X-ray photoelectron spectroscopy (XPS) ya nuna raguwar abun ciki na Cr akan saman samfurin da ke ƙarƙashin biofilm. Binciken hoto na ramukan ya nuna cewa biofilm na P. aeruginosa ya samar da zurfin rami na 0.69 μm a cikin kwanaki 14 na ƙullawa. Kodayake wannan ƙarami ne, yana nuna cewa 2707 HDSS ba shi da cikakken kariya ga MIC. na fina-finan P. aeruginosa na biofilms.
Ana amfani da ƙarfe mai kauri (DSS) sosai a masana'antu daban-daban don haɗakar su ta musamman ta kyawawan halayen injiniya da juriya ga tsatsa1,2. Duk da haka, ramin da aka gina a cikin gida har yanzu yana faruwa kuma yana shafar amincin wannan ƙarfe3,4.DSS ba ta da juriya ga tsatsa mai ƙwayoyin cuta (MIC)5,6. Duk da yawan aikace-aikacen DSS, har yanzu akwai wurare inda juriyar tsatsa ta DSS ba ta isa ba don amfani na dogon lokaci. Wannan yana nufin ana buƙatar kayan da suka fi tsada tare da juriya ga tsatsa.Jeon et al7 sun gano cewa har ma da ƙarfe mai kauri (SDSS) suna da wasu ƙuntatawa dangane da juriya ga tsatsa. Saboda haka, ana buƙatar ƙarfe mai kauri (HDSS) tare da juriya ga tsatsa a wasu aikace-aikace. Wannan ya haifar da haɓaka HDSS mai kauri.
Juriyar tsatsa ta DSS ta dogara ne akan rabon matakan alpha da gamma da yankunan Cr, Mo da W da suka lalace 8, 9, 10 kusa da mataki na biyu. HDSS ya ƙunshi babban abun ciki na Cr, Mo da N11, don haka yana da kyakkyawan juriya ga tsatsa da kuma babban ƙima (45-50) Pitting Resistance Equivalent Number (PREN), wanda aka ƙaddara ta wt.% Cr + 3.3 (wt.% Mo + 0.5 wt% W) + 16 wt% N12. Kyakkyawan juriyarsa ta tsatsa ya dogara ne akan daidaitaccen abun ciki wanda ya ƙunshi kusan 50% ferrite (α) da 50% austenite (γ), HDSS yana da kyawawan kaddarorin injiniya da juriya mafi girma fiye da DSS13 na al'ada. Halayen tsatsa na Chloride. Ingantaccen juriyar tsatsa yana faɗaɗa amfani da HDSS a cikin yanayin chloride mai lalata, kamar yanayin ruwa.
MICs babbar matsala ce a masana'antu da yawa kamar su mai da iskar gas da kuma ayyukan ruwa14. MIC tana da kashi 20% na duk lalacewar tsatsa15. MIC tsatsa ce ta bioelectrochemical da za a iya gani a wurare da yawa. Biofilms da ke samuwa a saman ƙarfe suna canza yanayin electrochemical, ta haka suna shafar tsarin tsatsa. Ana kyautata zaton cewa MIC tsatsa ce ke haifar da biofilms. Kwayoyin cuta masu amfani da lantarki suna lalata ƙarfe don samun kuzari mai dorewa don rayuwa17. Binciken MIC na baya-bayan nan ya nuna cewa EET (canja wurin lantarki daga ƙwayoyin halitta) shine abin da ke iyakance saurin MIC wanda ƙwayoyin cuta masu amfani da lantarki ke haifarwa. Zhang et al. 18 sun nuna cewa masu shiga tsakani na lantarki suna hanzarta canja wurin electron tsakanin ƙwayoyin Desulfovibrio sessificans da ƙarfe 304 na bakin ƙarfe, wanda ke haifar da mummunan harin MIC. Enning et al. 19 da Venzlaff et al. 20 sun nuna cewa ƙwayoyin cuta masu rage sulfate (SRB) masu lalata ƙwayoyin cuta na iya sha electrons kai tsaye daga abubuwan ƙarfe, wanda ke haifar da tsatsa mai tsanani.
An san DSS tana da saurin kamuwa da MIC a cikin muhallin da ke ɗauke da SRB, ƙwayoyin cuta masu rage ƙarfe (IRB), da sauransu. 21. Waɗannan ƙwayoyin cuta suna haifar da ramuka a saman DSS a ƙarƙashin biofilms22,23. Ba kamar DSS ba, MIC na HDSS24 ba a san shi sosai ba.
Pseudomonas aeruginosa kwayar cuta ce mai siffar sanda mai kama da gram-negative wadda take yaɗuwa sosai a yanayi25. Pseudomonas aeruginosa kuma babbar ƙungiyar ƙwayoyin cuta ce a cikin yanayin ruwa, wanda ke haifar da MIC zuwa ƙarfe. Pseudomonas yana da hannu sosai a cikin ayyukan lalata kuma an san shi a matsayin majagaba a cikin mamaya yayin ƙirƙirar biofilm. Mahat et al. 28 da Yuan et al. 29 sun nuna cewa Pseudomonas aeruginosa yana da halin ƙara yawan tsatsa na ƙarfe mai laushi da ƙarfe a cikin yanayin ruwa.
Babban manufar wannan aikin shine bincika halayen MIC na 2707 HDSS wanda kwayar halittar iskar oxygen ta ruwa Pseudomonas aeruginosa ke haifarwa ta amfani da hanyoyin lantarki, dabarun nazarin saman da kuma nazarin samfurin lalata. An gudanar da nazarin lantarki ciki har da Buɗewar Ƙarfin Zagaye (OCP), Juriya ta Layi (LPR), Electrochemical Impedance Spectroscopy (EIS), da Potential Dynamic Polarization don nazarin halayen MIC na 2707 HDSS. An gudanar da nazarin Energy dispersive spectrometer (EDS) don nemo abubuwan sinadarai a saman da ya lalace. Bugu da ƙari, an yi amfani da nazarin X-ray photoelectron spectroscopy (XPS) don tantance kwanciyar hankali na oxide film passivation a ƙarƙashin tasirin yanayin ruwa wanda ke ɗauke da Pseudomonas aeruginosa. An auna zurfin ramin a ƙarƙashin na'urar duba laser confocal (CLSM).
Tebur na 1 ya lissafa sinadaran da ke cikin 2707 HDSS. Tebur na 2 ya nuna cewa 2707 HDSS yana da kyawawan kaddarorin injiniya tare da ƙarfin yawan amfanin ƙasa na 650 MPa. Hoto na 1 yana nuna tsarin gani na maganin zafi da aka yi wa magani da zafi na 2707 HDSS. Ana iya ganin madaukai masu tsayi na matakan austenite da ferrite ba tare da matakan sakandare ba a cikin tsarin microstructure wanda ke ɗauke da kusan kashi 50% na matakan austenite da 50% na matakan ferrite.
Siffa ta 2a tana nuna yiwuwar buɗewar da'ira (Eocp) idan aka kwatanta da bayanan lokacin fallasa don 2707 HDSS a cikin ruwan abiotic 2216E matsakaici da P. aeruginosa na tsawon kwanaki 14 a zafin jiki na 37 °C. Yana nuna cewa babban canji mai mahimmanci a cikin Eocp yana faruwa a cikin awanni 24 na farko. Ƙimar Eocp a duka lamuran biyu sun kai kololuwa a -145 mV (idan aka kwatanta da SCE) kimanin awanni 16 sannan suka faɗi da ƙarfi, suka kai -477 mV (idan aka kwatanta da SCE) da -236 mV (idan aka kwatanta da SCE) don samfurin abiotic da P, bi da bi). Takardun shaida na Pseudomonas aeruginosa, bi da bi. Bayan awanni 24, ƙimar Eocp na 2707 HDSS ga P. aeruginosa ta kasance mai daidaito a -228 mV (idan aka kwatanta da SCE), yayin da ƙimar da ta dace da samfuran da ba na halitta ba ta kasance kusan -442 mV (idan aka kwatanta da SCE). Eocp a gaban P. aeruginosa ya yi ƙasa sosai.
Gwajin lantarki na samfuran HDSS 2707 a cikin ruwan abiotic da ruwan Pseudomonas aeruginosa a zafin digiri 37 na Celsius:
(a) Eocp a matsayin aikin lokacin fallasa, (b) lanƙwasa polarization a rana ta 14, (c) Rp a matsayin aikin lokacin fallasa da (d) icorr a matsayin aikin lokacin fallasa.
Tebur na 3 ya lissafa ƙimar sigar lalata lantarki ta lantarki na samfuran HDSS 2707 da aka fallasa ga matsakaiciyar abiotic da kuma maganin Pseudomonas aeruginosa na tsawon kwanaki 14. An cire tangent na lanƙwasa na anodic da cathodic don isa ga mahadar da ke samar da yawan lalata (icorr), yuwuwar lalata (Ecorr) da gangaren Tafel (βα da βc) bisa ga hanyoyin da aka saba amfani da su30,31.
Kamar yadda aka nuna a Hoto na 2b, canjin sama na lanƙwasa P. aeruginosa ya haifar da ƙaruwa a cikin Ecorr idan aka kwatanta da lanƙwasa abiotic. Ƙimar icorr, wadda take daidai da ƙimar tsatsa, ta ƙaru zuwa 0.328 μA cm-2 a cikin samfurin Pseudomonas aeruginosa, sau huɗu fiye da samfurin da ba na halitta ba (0.087 μA cm-2).
LPR wata hanya ce ta lantarki wadda ba ta lalata ba don nazarin lalata cikin sauri. An kuma yi amfani da ita don nazarin MIC32. Hoto na 2c yana nuna juriyar polarization (Rp) a matsayin aikin lokacin fallasa. Babban ƙimar Rp yana nufin ƙarancin tsatsa. A cikin awanni 24 na farko, Rp na 2707 HDSS ya kai matsakaicin ƙimar 1955 kΩ cm2 don samfuran abiotic da 1429 kΩ cm2 don samfuran Pseudomonas aeruginosa. Hoto na 2c kuma ya nuna cewa ƙimar Rp ta ragu da sauri bayan kwana ɗaya sannan ta kasance ba ta canzawa ba tsawon kwanaki 13 masu zuwa. Ƙimar Rp na samfurin Pseudomonas aeruginosa kusan 40 kΩ cm2 ne, wanda ya yi ƙasa da ƙimar 450 kΩ cm2 na samfurin da ba na halitta ba.
Ƙimar icorr tana daidai da ƙimar tsatsa iri ɗaya. Ana iya ƙididdige ƙimar ta daga lissafin Stern-Geary mai zuwa,
Bayan Zou da abokan aikinsa 33, an ɗauka cewa ƙimar da aka saba gani ta gangaren Tafel B a cikin wannan aikin ita ce 26 mV/dec. Hoto na 2d ya nuna cewa alamar samfurin 2707 mara ilimin halitta ta kasance mai ƙarfi sosai, yayin da samfurin P. aeruginosa ya canza sosai bayan awanni 24 na farko. Ƙimar alamar P. aeruginosa ta kasance mafi girma fiye da ikon sarrafawa mara ilimin halitta. Wannan yanayin ya yi daidai da sakamakon juriyar polarization.
EIS wata dabara ce da ba ta lalata ba da ake amfani da ita don siffanta halayen lantarki a wuraren da suka lalace. Bakan gizo na impedance da ƙimar capacitance da aka ƙididdige na samfuran da aka fallasa ga kafofin watsa labarai na abiotic da maganin Pseudomonas aeruginosa, juriyar Rb na fim/biofilm mai wucewa da aka samar a saman samfurin, juriyar canja wurin caji na Rct, ƙarfin Cdl na lantarki mai layi biyu (EDL) da sigogin QCPE Constant Phase Element (CPE). An ƙara yin nazarin waɗannan sigogi ta hanyar haɗa bayanai ta amfani da samfurin da'ira mai daidai (EEC).
Siffa ta 3 tana nuna zane-zanen Nyquist (a da b) da kuma zane-zanen Bode (a' da b') na samfuran HDSS 2707 a cikin matsakaicin abiotic da ruwan P. aeruginosa don lokutan haɗuwa daban-daban. Diamita na zoben Nyquist yana raguwa idan aka sami Pseudomonas aeruginosa. Tsarin Bode (Hoto na 3b') yana nuna ƙaruwa a cikin girman jimlar impedance. Ana iya bayar da bayanai kan ma'aunin lokacin shakatawa ta hanyar maxima na mataki. Siffa ta 4 tana nuna tsarin zahiri na monolayer (a) da bilayer (b) da EECs ɗinsu masu dacewa. An gabatar da CPE cikin samfurin EEC. An bayyana shigarsa da impedance kamar haka:
Samfura biyu na zahiri da da'irori masu dacewa don daidaita bakan impedance na samfurin 2707 HDSS:
inda Y0 shine girman CPE, j shine lambar tunani ko (-1) 1/2, ω shine mitar kusurwa, kuma n shine ma'aunin wutar lantarki na CPE ƙasa da haɗin kai35. Juyawar juriyar canja wurin caji (watau 1/Rct) yayi daidai da ƙimar tsatsa. Ƙaramin Rct yana nufin saurin tsatsa27. Bayan kwanaki 14 na haɗuwa, Rct na samfuran Pseudomonas aeruginosa sun kai 32 kΩ cm2, wanda ya fi ƙanƙanta fiye da 489 kΩ cm2 na samfuran da ba na halitta ba (Tebur 4).
Hotunan CLSM da hotunan SEM a cikin Hoto na 5 sun nuna a sarari cewa murfin biofilm ɗin da ke saman samfurin 2707 HDSS bayan kwana 7 yana da yawa. Duk da haka, bayan kwana 14, murfin biofilm ɗin ya yi ƙaranci kuma wasu ƙwayoyin halitta matattun sun bayyana. Tebur na 5 yana nuna kauri na biofilm akan samfuran 2707 HDSS bayan fallasa su ga P. aeruginosa na tsawon kwanaki 7 da 14. Matsakaicin kauri na biofilm ya canza daga 23.4 μm bayan kwana 7 zuwa 18.9 μm bayan kwana 14. Matsakaicin kauri na biofilm shi ma ya tabbatar da wannan yanayin. Ya ragu daga 22.2 ± 0.7 μm bayan kwana 7 zuwa 17.8 ± 1.0 μm bayan kwana 14.
(a) Hoton CLSM mai 3-D bayan kwana 7, (b) Hoton CLSM mai 3-D bayan kwana 14, (c) Hoton SEM bayan kwana 7 da (d) Hoton SEM bayan kwana 14.
EDS ta bayyana sinadaran da ke cikin biofilms da kayayyakin tsatsa a kan samfuran da aka fallasa ga P. aeruginosa na tsawon kwanaki 14. Hoto na 6 ya nuna cewa abubuwan da ke cikin C, N, O, da P a cikin biofilms da kayayyakin tsatsa sun fi na ƙarfe da babu komai a ciki, saboda waɗannan abubuwan suna da alaƙa da biofilms da metabolites ɗinsu. Microbes suna buƙatar ƙaramin adadin chromium da baƙin ƙarfe kawai. Babban matakan Cr da Fe a cikin biofilm da samfuran tsatsa a saman samfuran suna nuna cewa matrix ɗin ƙarfe ya rasa abubuwa saboda tsatsa.
Bayan kwana 14, an lura da ramin da aka yi da kuma ba tare da P. aeruginosa ba a cikin matsakaicin 2216E. Kafin a rufe, saman samfurin ya kasance mai santsi kuma babu lahani (Hoto na 7a). Bayan an rufe da kuma cire samfuran biofilm da tsatsa, an duba mafi zurfin ramuka a saman samfuran a ƙarƙashin CLSM, kamar yadda aka nuna a Hoto na 7b da c. Ba a sami ramuka a bayyane ba a saman samfuran da ba na halitta ba (zurfin rami mafi girma 0.02 μm). Matsakaicin zurfin ramin da Pseudomonas aeruginosa ya haifar shine 0.52 μm bayan kwana 7 da 0.69 μm bayan kwana 14, bisa ga matsakaicin zurfin rami na samfura 3 (an zaɓi matsakaicin ƙimar zurfin rami 10 ga kowane samfurin) ya kai 0.42 ± 0.12 μm da 0.52 ± 0.15 μm, bi da bi (Tebur na 5). Waɗannan ƙimar zurfin rami ƙanana ne amma suna da mahimmanci.
(a) Kafin a fallasa shi, (b) kwana 14 a cikin ruwan da ba ya haifar da rashin lafiyan jiki da kuma (c) kwana 14 a cikin ruwan Pseudomonas aeruginosa.
Hoto na 8 yana nuna siginar XPS na saman samfura daban-daban, kuma an taƙaita abubuwan da aka haɗa na sinadarai don kowane saman a cikin Jadawali na 6. A cikin Jadawali na 6, kashi-kashi na atomic na Fe da Cr a gaban P. aeruginosa (samfura A da B) sun yi ƙasa da na samfuran sarrafawa marasa ilimin halitta (samfura C da D). Ga samfurin P. aeruginosa, an sanya lanƙwasa na matakin tsakiya na Cr 2p zuwa ga sassan kololuwa huɗu tare da ƙimar kuzarin ɗaurewa (BE) na 574.4, 576.6, 578.3 da 586.8 eV, wanda za'a iya dangantawa da Cr, Cr2O3, CrO3 da Cr(OH)3, bi da bi (Hoto na 9a da b). Ga samfuran da ba na ilimin halitta ba, siginar matakin tsakiya na Cr 2p ya ƙunshi manyan kololuwa biyu don Cr (573.80 eV don BE) da Cr2O3 (575.90 eV don BE) a cikin Hoto na 1. 9c da d, bi da bi. Bambanci mafi ban mamaki tsakanin samfuran abiotic da P. aeruginosa shine kasancewar Cr6+ da kuma babban kaso na Cr(OH)3 (BE na 586.8 eV) a ƙarƙashin biofilm ɗin.
Faɗin XPS na saman samfurin 2707 HDSS a cikin kafofin watsa labarai guda biyu shine kwanaki 7 da kwanaki 14, bi da bi.
(a) Kwanaki 7 na fallasa ga P. aeruginosa, (b) Kwanaki 14 na fallasa ga P. aeruginosa, (c) Kwanaki 7 a yanayin rashin lafiyar jiki da (d) Kwanaki 14 a yanayin rashin lafiyar jiki.
HDSS yana nuna matakan juriya ga tsatsa a mafi yawan muhalli. Kim et al. 2 sun ruwaito cewa an ayyana UNS S32707 HDSS a matsayin DSS mai haɗakar sinadarai masu yawa tare da PREN fiye da 45. Ƙimar PREN na samfurin 2707 HDSS a cikin wannan aikin shine 49. Wannan ya faru ne saboda yawan sinadarin chromium da matakan molybdenum da Ni masu yawa, waɗanda ke da amfani a cikin muhallin acidic da high chloride. Bugu da ƙari, tsari mai kyau da tsari mara lahani suna da amfani don kwanciyar hankali na tsari da juriya ga tsatsa. Duk da haka, duk da kyakkyawan juriyar sinadarai, bayanan gwaji a cikin wannan aikin sun nuna cewa 2707 HDSS ba ta da kariya gaba ɗaya ga MIC na biofilms na P. aeruginosa.
Sakamakon lantarki ya nuna cewa yawan tsatsa na 2707 HDSS a cikin ruwan P. aeruginosa ya karu sosai bayan kwana 14 idan aka kwatanta da ruwan da ba na halitta ba. A cikin Hoto na 2a, an lura da raguwar Eocp a cikin ruwan abiotic da ruwan P. aeruginosa a cikin awanni 24 na farko. Bayan haka, ruwan biofilm ɗin ya gama rufe saman samfurin kuma Eocp ya zama mai karko sosai36. Duk da haka, matakin Eocp na halitta ya fi na Eocp wanda ba na halitta ba. Akwai dalilin yarda cewa wannan bambanci ya faru ne saboda samuwar fim ɗin P. aeruginosa. A cikin Hoto na 2d, a gaban P. aeruginosa, ƙimar icorr na 2707 HDSS ta kai 0.627 μA cm-2, wanda tsari ne na girma fiye da na sarrafa abiotic (0.063 μA cm-2), wanda ya yi daidai da ƙimar Rct da EIS ta auna. A cikin 'yan kwanakin farko, ƙimar impedance a cikin Ruwan P. aeruginosa ya ƙaru saboda haɗewar ƙwayoyin P. aeruginosa da kuma samuwar biofilms. Duk da haka, lokacin da biofilm ɗin ya rufe saman samfurin gaba ɗaya, juriyar ta ragu. Ana kai hari ga layin kariya da farko saboda samuwar biofilms da metabolites na biofilm. Saboda haka, juriyar tsatsa ta ragu akan lokaci, kuma haɗewar P. aeruginosa ta haifar da tsatsa ta gida. Yanayin da ke cikin kafofin watsa labarai na abiotic ya bambanta. Juriyar tsatsa ta ikon sarrafa ba ta halitta ba ta fi ƙimar da ta dace da samfuran da aka fallasa ga ruwan P. aeruginosa. Bugu da ƙari, ga samfuran abiotic, ƙimar Rct na 2707 HDSS ta kai 489 kΩ cm2 a rana ta 14, wanda ya ninka ƙimar Rct sau 15 (32 kΩ cm2) a gaban P. aeruginosa. Saboda haka, 2707 HDSS yana da kyakkyawan juriyar tsatsa a cikin yanayi mara tsabta, amma ba ya jure wa harin MIC ta hanyar biofilms na P. aeruginosa.
Ana iya ganin waɗannan sakamakon daga lanƙwasa na polarization a cikin Hoto na 2b. An danganta reshen anodic da samuwar biofilm na Pseudomonas aeruginosa da halayen iskar shaka na ƙarfe. A lokaci guda kuma, amsawar cathodic shine rage iskar oxygen. Kasancewar P. aeruginosa ya ƙara yawan tsatsa na yanzu, kusan girman girma fiye da ikon abiotic. Wannan yana nuna cewa biofilm na P. aeruginosa yana ƙara tsatsa na gida na 2707 HDSS. Yuan et al29 sun gano cewa yawan tsatsa na 70/30 Cu-Ni gami ya ƙaru a ƙarƙashin ƙalubalen biofilm na P. aeruginosa. Wannan na iya zama saboda biocatalysis na rage iskar shaka ta hanyar biofilm na Pseudomonas aeruginosa. Wannan lura kuma na iya bayyana MIC na 2707 HDSS a cikin wannan aikin. Biofilm na Aerobic na iya samun ƙarancin iskar shaka a ƙarƙashinsu. Saboda haka, gazawar sake lalata saman ƙarfe ta hanyar iskar shaka na iya zama abin da ke ba da gudummawa ga MIC a cikin wannan aikin.
Dickinson da abokan aikinsa 38 sun ba da shawarar cewa yawan halayen sinadarai da na lantarki na iya shafar kai tsaye ta hanyar aikin metabolism na ƙwayoyin cuta masu narkewa a saman samfurin da kuma yanayin samfuran tsatsa. Kamar yadda aka nuna a Hoto na 5 da Tebur na 5, duka adadin ƙwayoyin halitta da kauri na biofilm sun ragu bayan kwana 14. Wannan za a iya bayyana shi da kyau cewa bayan kwana 14, yawancin ƙwayoyin sessile a saman 2707 HDSS sun mutu saboda ƙarancin sinadarai a cikin matsakaiciyar 2216E ko sakin ions na ƙarfe masu guba daga matrix na 2707 HDSS. Wannan iyakance ne na gwaje-gwajen rukuni.
A cikin wannan aikin, fim ɗin P. aeruginosa biofilm ya haɓaka raguwar Cr da Fe a cikin gida a ƙarƙashin fim ɗin biofilm akan saman 2707 HDSS (Hoto na 6). A cikin Jadawali na 6, raguwar Fe da Cr a cikin samfurin D idan aka kwatanta da samfurin C, yana nuna cewa Fe da Cr da aka narkar da shi wanda fim ɗin P. aeruginosa biofilm ya haifar ya ci gaba fiye da kwanaki 7 na farko. Ana amfani da matsakaiciyar 2216E don kwaikwayon yanayin ruwa. Ya ƙunshi 17700 ppm Cl-, wanda yayi daidai da wanda aka samu a cikin ruwan teku na halitta. Kasancewar 17700 ppm Cl- shine babban dalilin raguwar Cr a cikin samfuran abiotic na kwanaki 7 da 14 da XPS ta bincika. Idan aka kwatanta da samfuran P. aeruginosa, rushewar Cr a cikin samfuran abiotic ya ragu sosai saboda ƙarfin juriyar Cl− na 2707 HDSS a cikin yanayin abiotic. Hoto na 9 yana nuna kasancewar Cr6+ a cikin fim ɗin passivation. Yana iya shiga cikin cire Cr daga saman ƙarfe ta hanyar biofilms na P. aeruginosa, kamar yadda Chen da Clayton suka ba da shawara.
Saboda girman ƙwayoyin cuta, ƙimar pH na matsakaici kafin da bayan noma sun kasance 7.4 da 8.2, bi da bi. Saboda haka, a ƙasa da biofilm na P. aeruginosa, lalata acid na halitta ba zai zama abin da ke ba da gudummawa ga wannan aikin ba saboda babban pH a cikin matsakaiciyar girma. pH na matsakaiciyar sarrafawa mara ilimin halitta bai canza sosai ba (daga 7.4 na farko zuwa 7.5 na ƙarshe) a lokacin gwajin kwanaki 14. Ƙaruwar pH a cikin matsakaiciyar allurar bayan shiryawa ya faru ne saboda aikin metabolism na P. aeruginosa kuma an gano yana da irin wannan tasiri akan pH idan babu tsiri na gwaji.
Kamar yadda aka nuna a Hoto na 7, matsakaicin zurfin ramin da biofilm na P. aeruginosa ya haifar shine 0.69 μm, wanda ya fi girma fiye da na matsakaiciyar abiotic (0.02 μm). Wannan ya yi daidai da bayanan lantarki da aka bayyana a sama. Zurfin ramin 0.69 μm ya fi ƙasa da ƙimar 9.5 μm da aka ruwaito don 2205 DSS a ƙarƙashin irin wannan yanayi. Waɗannan bayanan sun nuna cewa 2707 HDSS yana nuna juriya mafi kyau ga MIC idan aka kwatanta da 2205 DSS. Wannan bai kamata ya zama abin mamaki ba, kamar yadda 2707 HDSS yana da mafi girman abun ciki na chromium, yana samar da passivation mai ɗorewa, saboda daidaitaccen tsarin lokaci ba tare da ɓarna na biyu mai cutarwa ba, yana sa ya yi wa P. aeruginosa wahala don cirewa da kuma fara eclipse maki.
A ƙarshe, an gano ramin MIC a saman 2707 HDSS a cikin ruwan P. aeruginosa idan aka kwatanta da ramin da ba a saba gani ba a cikin kafofin watsa labarai na abiotic. Wannan aikin ya nuna cewa 2707 HDSS yana da juriyar MIC mafi kyau fiye da 2205 DSS, amma ba shi da cikakken kariya daga MIC saboda biofilm na P. aeruginosa. Waɗannan binciken suna taimakawa wajen zaɓar ƙarfe masu dacewa da bakin ƙarfe da kuma tsawon lokacin sabis da aka kiyasta don yanayin ruwa.
Makarantar Nazarin Ƙarfe ta Jami'ar Arewa maso Gabas (NEU) da ke Shenyang, China ce ta bayar da takardar shaidar 2707 HDSS. An nuna sinadarin 2707 HDSS a cikin Jadawali na 1, wanda Sashen Binciken Kayan Aiki da Gwaji na NEU ya yi nazari a kai. An yi wa dukkan samfuran maganin a zafin 1180 °C na tsawon awa 1. Kafin gwajin tsatsa, an goge 2707 HDSS mai siffar tsabar kuɗi tare da saman saman da aka fallasa na 1 cm2 zuwa grit 2000 da takardar silicon carbide sannan aka ƙara goge shi da foda na Al2O3 mai 0.05 μm. Gefen da ƙasan suna da fenti mara aiki. Bayan bushewa, an wanke samfuran da ruwan da aka cire daga ion kuma an yi musu maganin ethanol 75% (v/v) na tsawon awa 0.5. Sannan an busar da su ta iska a ƙarƙashin hasken ultraviolet (UV) na tsawon awanni 0.5 kafin amfani.
An sayi nau'in Pseudomonas aeruginosa na Marine Pseudomonas aeruginosa MCCC 1A00099 daga Cibiyar Tarin Al'adu ta Xiamen (MCCC), China. An noma Pseudomonas aeruginosa ta hanyar iska a zafin jiki na 37°C a cikin kwalba 250 ml da ƙwayoyin gilashin lantarki na 500 ml ta amfani da ruwan Marine 2216E (Qingdao Hope Biotechnology Co., Ltd., Qingdao, China). Matsakaici (g/L): 19.45 NaCl, 5.98 MgCl2, 3.24 Na2SO4, 1.8 CaCl2, 0.55 KCl, 0.16 Na2CO3, 0.08 KBr, 0.034 SrCl2, 0.08 SrBr2, 0.022 H3BO3, 0.004 NaSiO3, 0016 NH3, 0016 NH3, 0016 NH3, 0016 NaH2PO4, peptone 5.0, cirewar yisti 1.0 da kuma citrate ferric 0.1. Autoclave a zafin jiki na 121°C na minti 20 kafin a yi allurar. A ƙirga ƙwayoyin sessile da planktonic ta amfani da na'urar auna jini a ƙarƙashin na'urar hangen nesa mai haske a girman 400X. Yawan ƙwayoyin planktonic Pseudomonas aeruginosa na farko bayan an yi allurar ya kai kimanin ƙwayoyin 106/ml.
An yi gwaje-gwajen lantarki a cikin wani tantanin gilashin lantarki mai ƙarfin lantarki uku na gargajiya tare da matsakaicin girma na 500 ml. An haɗa takardar platinum da kuma cikakken calomel electrode (SCE) zuwa reactor ta hanyar capillaries na Luggin da aka cika da gadoji na gishiri, suna aiki azaman electrodes na counter da reference, bi da bi. Don yin electrodes masu aiki, an haɗa wayar jan ƙarfe mai rufi da roba a kan kowane samfurin kuma an rufe shi da epoxy, yana barin kusan 1 cm2 na yankin saman gefe ɗaya da aka fallasa don electrode mai aiki. A lokacin ma'aunin lantarki, an sanya samfuran a cikin matsakaici na 2216E kuma an kiyaye su a yanayin zafi mai ɗorewa (37 °C) a cikin wanka na ruwa. An auna OCP, LPR, EIS da bayanan polarization mai yuwuwar amfani da Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., Amurka). An yi rikodin gwaje-gwajen LPR a ƙimar scan na 0.125 mV s-1 akan kewayon -5 da 5 mV tare da Eocp kuma mitar samfurin 1 Hz. An yi EIS tare da raƙuman sine a cikin mita Matsakaicin 0.01 zuwa 10,000 Hz ta amfani da ƙarfin lantarki mai amfani da 5 mV a yanayin da ya dace na Eocp. Kafin a iya share wutar lantarki, wayoyin lantarki suna cikin yanayin buɗewa har sai an kai ga ƙimar yuwuwar tsatsa mai ƙarfi. Sannan an gudanar da lanƙwasa na Polarization daga -0.2 zuwa 1.5 V idan aka kwatanta da Eocp a ƙimar scan na 0.166 mV/s. Kowane gwaji an maimaita shi sau 3 tare da kuma ba tare da P. aeruginosa ba.
An goge samfuran nazarin ƙarfe ta hanyar injiniya da takardar SiC mai launin toka mai launin 2000 sannan aka ƙara goge su da maganin foda na Al2O3 mai girman 0.05 μm don lura da ido. An yi nazarin ƙarfe ta amfani da na'urar hangen nesa. An zana samfuran da maganin potassium hydroxide mai girman 10% 43.
Bayan an gama, an wanke samfuran sau 3 da maganin saline na phosphate-buffered saline (PBS) (pH 7.4 ± 0.2) sannan a gyara su da glutaraldehyde 2.5% (v/v) na tsawon awanni 10 don gyara biofilms. Daga baya an bushe su da jerin ethanol masu daraja (50%, 60%, 70%, 80%, 90%, 95% da 100% v/v) kafin a busar da su ta iska. A ƙarshe, an yayyafa saman samfurin da fim ɗin zinare don samar da wutar lantarki don lura da SEM. An mayar da hankali kan hotunan SEM akan wuraren da ƙwayoyin P. aeruginosa mafi kunkuntar a saman kowane samfurin. Yi nazarin EDS don nemo abubuwan sinadarai. An yi amfani da na'urar gano hasken laser ta Zeiss Confocal (CLSM) (LSM 710, Zeiss, Jamus) don auna zurfin ramin. Domin lura da ramukan tsatsa a ƙarƙashin biofilm ɗin, an fara tsaftace wurin gwajin bisa ga ƙa'idar ƙasar Sin. (CNS) GB/T4334.4-2000 don cire samfuran tsatsa da biofilm ɗin da ke saman kayan gwajin.
An yi nazarin X-ray photoelectron spectroscopy (XPS, tsarin nazarin saman ESCALAB250, Thermo VG, Amurka) ta amfani da tushen X-ray monochromatic (layin aluminum Kα a makamashin eV 1500 da ƙarfin W 150) a kan kewayon makamashi mai ɗaurewa 0 a ƙarƙashin yanayi na yau da kullun -1350 eV. An yi rikodin manyan spectra ta amfani da makamashin wucewa na eV 50 da girman mataki na eV 0.2.
An cire samfuran da aka saka a cikin kwano aka wanke a hankali da PBS (pH 7.4 ± 0.2) na tsawon 15 s45. Domin lura da yuwuwar ƙwayoyin cuta na biofilms ɗin da ke kan samfuran, an yi wa biofilms ɗin fenti ta amfani da LIVE/DEAD BacLight BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, Amurka). Kayan aikin yana da launuka biyu masu haske, launin kore mai haske SYTO-9 da kuma launin ja mai haske mai haske propidium iodide (PI). A ƙarƙashin CLSM, ɗigogi masu haske kore da ja suna wakiltar ƙwayoyin halitta masu rai da matattu, bi da bi. Don yin fenti, an saka cakuda 1 ml wanda ya ƙunshi 3 μl SYTO-9 da 3 μl PI mafita na minti 20 a zafin ɗaki (23 oC) a cikin duhu. Bayan haka, an lura da samfuran da aka saka a cikin raƙuman ruwa guda biyu (488 nm don ƙwayoyin halitta masu rai da 559 nm don ƙwayoyin halitta matattu) ta amfani da injin Nikon CLSM (C2 Plus, Nikon, Japan). An auna kauri na biofilm a cikin yanayin duba 3-D.
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