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Ingufu za mikorobe (MIC) ni ikibazo gikomeye mu nganda nyinshi kuko zishobora gutera igihombo gikomeye mu bukungu.2707 super duplex stainless steel (2707 HDSS) yakoreshejwe mu bidukikije byo mu mazi bitewe n’ubudahangarwa bwayo bwiza bwa shimi. Ariko, ubudahangarwa bwayo kuri MIC ntibwagaragajwe mu buryo bw’igerageza. Muri ubu bushakashatsi, hakozwe ubushakashatsi ku myitwarire ya MIC ya 2707 HDSS iterwa na bagiteri ya Pseudomonas aeruginosa yo mu mazi. Isesengura rya elegitoroniki ryagaragaje ko mu gihe Pseudomonas aeruginosa biofilm iri muri 2216E medium, habayeho impinduka nziza mu bushobozi bwa corruption no kwiyongera k’ubucucike bw’umuyoboro wa corruption. Isesengura rya X-ray photoelectron spectroscopy (XPS) ryagaragaje igabanuka rya Cr ku buso bw’ingero munsi ya biofilm. Isesengura ry’ibishushanyo ry’imyobo ryagaragaje ko P. aeruginosa biofilm yatanze ubujyakuzimu ntarengwa bwa 0.69 μm mu minsi 14 yo kwibasira. Nubwo ibi ari bito, bigaragaza ko 2707 HDSS idafite ubudahangarwa bwuzuye kuri MIC ya P. aeruginosa biofilms.
Ibyuma bitagira umugese bibiri (DSS) bikoreshwa cyane mu nganda zitandukanye kubera uburyo bwiza bwo guhuza imiterere myiza ya mekanike no kurwanya ingese1,2. Ariko, gufunga ahantu runaka biracyabaho kandi bigira ingaruka ku busugire bw'iki cyuma3,4.DSS ntabwo irwanya ingese (MIC)5,6. Nubwo DSS ikoreshwa mu buryo bwinshi, haracyari ahantu aho kurwanya ingese bya DSS bidahagije kugira ngo bikoreshwe igihe kirekire. Ibi bivuze ko ibikoresho bihenze cyane bifite ubudahangarwa bwinshi bwa ngese birakenewe. Jeon et al7 basanze ndetse n'ibyuma bitagira umugese bibiri (SDSS) bifite imbogamizi zimwe na zimwe mu bijyanye no kurwanya ingese. Kubwibyo, ibyuma bitagira umugese bibiri (HDSS) bifite ubudahangarwa bwinshi bwa ngese birakenewe muri bimwe mu bikorwa. Ibi byatumye habaho HDSS ivanze cyane.
Ubudahangarwa bwa DSS bushingiye ku gipimo cya phase ya alpha na gamma hamwe n'uturere twa Cr, Mo na W twagabanutseho 8, 9, 10 twegeranye n'icyiciro cya kabiri. HDSS irimo Cr, Mo na N11 nyinshi, bityo ifite ubushobozi bwo kurwanya ruswa cyane kandi ifite agaciro kanini (45-50) ko kurwanya imiyoboro y'amazi (PREN), bigenwa na wt.% Cr + 3.3 (wt.% Mo + 0.5 wt% W) + 16 wt% N12. Ubudahangarwa bwayo bwiza bwo kurwanya ruswa bushingiye ku buryo buringaniye burimo hafi 50% ya ferrite (α) na 50% ya austenite (γ), HDSS ifite ubushobozi bwiza bwo gukora no kurwanya kurusha DSS13 isanzwe. Ubudahangarwa bwa Chloride. Ubudahangarwa bwa kanseri bwongereye butuma ikoreshwa rya HDSS mu bidukikije bya chloride byangiza, nko mu bidukikije byo mu mazi.
MIC ni ikibazo gikomeye mu nganda nyinshi nka peteroli na gaze n'amazi14. MIC ifata 20% by'ibyangiritse byose byangiritse15. MIC ni ingese ya bioelectrochemical ishobora kugaragara ahantu henshi. Biofilms zigira ingaruka ku buso bw'icyuma, bityo zigira ingaruka ku ngeso ya ingese. Abantu benshi bemera ko ingese ya MIC iterwa na biofilms. Microorganisms zikoresha amashanyarazi zica ibyuma kugira ngo zibone ingufu zihoraho zo kubaho17. Ubushakashatsi bwa MIC buherutse bwerekanye ko EET (extracellular electron transfer) ari cyo kintu kigabanya igipimo cya MIC giterwa na microorganisms zikoresha amashanyarazi. Zhang et al. 18 bagaragaje ko electron mediators zihutisha ihererekanya rya electron hagati y'uturemangingo twa Desulfovibrio sessificans na 304 stainless steel, bigatera kwibasirwa na MIC cyane. Enning et al. 19 na Venzlaff et al. 20 bagaragaje ko biofilms zikoresha amashanyarazi zica sulfate (SRB) zishobora kwinjiza electrons mu buryo butaziguye mu byuma, bigatera ingese ikomeye.
DSS izwiho kwibasirwa na MIC mu bidukikije birimo SRB, bagiteri zigabanya icyuma (IRB), nibindi. 21. Izi bagiteri zitera imyobo iri ku buso bwa DSS munsi ya biofilms22,23. Bitandukanye na DSS, MIC ya HDSS24 ntabwo izwi neza.
Pseudomonas aeruginosa ni bagiteri ifite ishusho ya garama-negative ikwirakwira cyane mu bidukikije25. Pseudomonas aeruginosa nayo ni itsinda rikomeye rya mikorobe mu bidukikije byo mu mazi, bigatuma MIC iba icyuma. Pseudomonas igira uruhare runini mu mikorere ya corruption kandi izwi nk'umukoloni w'ibanze mu gihe cyo gukora biofilm. Mahat et al. 28 na Yuan et al. 29 bagaragaje ko Pseudomonas aeruginosa ifite umwihariko wo kongera umuvuduko wa corruption w'icyuma cyoroshye n'ibindi birungo mu bidukikije by'amazi.
Intego nyamukuru y'uyu murimo kwari ugusuzuma imiterere ya MIC ya 2707 HDSS iterwa na bagiteri ya Pseudomonas aeruginosa yo mu mazi hakoreshejwe uburyo bwa electrochemical, tekiniki zo gusesengura ubuso n'isesengura ry'ibicuruzwa bya corrosion. Inyigo za electrochemical zirimo Open Circuit Potential (OCP), Linear Polarization Resistance (LPR), Electrochemical Impedance Spectroscopy (EIS), na Porrolization Dynamic Polarization zakozwe kugira ngo higwe imyitwarire ya MIC ya 2707 HDSS. Isesengura rya spectrometer ikwirakwiza ingufu (EDS) ryakozwe kugira ngo haboneke ibintu bya chemical ku buso bwangiritse. Byongeye kandi, isesengura rya X-ray photoelectron spectroscopy (XPS) ryakoreshejwe kugira ngo hamenyekane uburyo oxide film passivation ihamye bitewe n'ibidukikije byo mu mazi birimo Pseudomonas aeruginosa. Ubujyakuzimu bw'icyobo bwapimwe hifashishijwe microscope ya confocal laser scanning (CLSM).
Imbonerahamwe ya 1 igaragaza imiterere ya shimi ya 2707 HDSS. Imbonerahamwe ya 2 igaragaza ko 2707 HDSS ifite imiterere myiza ya mekanike ifite imbaraga zo gutanga umusaruro wa 650 MPa. Ishusho ya 1 igaragaza imiterere ya mikoro optique y'umuti wavuwe n'ubushyuhe wa 2707 HDSS. Imirongo miremire ya austenite na ferrite idafite ibyiciro bya kabiri irashobora kugaragara mu mikoro irimo hafi 50% ya austenite na 50% ya ferrite.
Ishusho ya 2a igaragaza ubushobozi bwo gusohora urumuri (Eocp) ugereranije n'igihe cyo gusohora amakuru kuri 2707 HDSS mu mushongi wa abiotic 2216E medium na P. aeruginosa mu minsi 14 kuri 37 °C. Igaragaza ko impinduka nini kandi ikomeye muri Eocp ibaho mu masaha 24 ya mbere. Agaciro ka Eocp muri ibyo byiciro byombi kageze kuri -145 mV (ugereranije na SCE) mu masaha 16 hanyuma kagabanuka cyane, kagera kuri -477 mV (ugereranije na SCE) na -236 mV (ugereranije na SCE) ku gipimo cya abiotic na P, uko bikurikirana). Kuponi za Pseudomonas aeruginosa, uko bikurikirana. Nyuma y'amasaha 24, agaciro ka Eocp ka 2707 HDSS kuri P. aeruginosa kari gahagaze neza kuri -228 mV (ugereranyije na SCE), mu gihe agaciro gahuye n'ingero zitari iza binyabuzima kari hafi -442 mV (ugereranyije na SCE). Eocp imbere ya P. aeruginosa yari hasi cyane.
Isuzuma rya elegitoroniki rya 2707 HDSS mu buryo budafite abiotic n'umutobe wa Pseudomonas aeruginosa kuri 37 °C:
(a) Eocp nk'uko bigaragara mu gihe cyo kwigaragaza, (b) imiyoboro ya polarization ku munsi wa 14, (c) Rp nk'uko bigaragara mu gihe cyo kwigaragaza na (d) icorr nk'uko bigaragara mu gihe cyo kwigaragaza.
Imbonerahamwe ya 3 igaragaza agaciro k'ibipimo bya electrochemical corrosion parameter ​​by'ibipimo 2707 bya HDSS byagaragaye ku buryo bwa abiotic na Pseudomonas aeruginosa byateweho inshinge mu gihe cy'iminsi 14. Ingano z'imirongo ya anodic na cathodic curves zakuwemo kugira ngo zigere aho zihurira zitanga ubucucike bw'umuyoboro wa corrosion (icorr), ubushobozi bwa corrosion (Ecorr) n'imisozi ya Tafel (βα na βc) hakurikijwe uburyo busanzwe30,31.
Nkuko bigaragara ku Ishusho ya 2b, izamuka ry’umuyoboro wa P. aeruginosa ryatumye Ecorr yiyongera ugereranije n’umuyoboro wa abiotic. Agaciro ka icorr, gahwanye n’igipimo cya corrosion, kiyongereyeho 0.328 μA cm-2 mu gipimo cya Pseudomonas aeruginosa, inshuro enye z’icyitegererezo kitari icya biyolojiya (0.087 μA cm-2).
LPR ni uburyo bwa elegitoroniki budasenya ibintu mu gusesengura ingese byihuse. Bwanakoreshejwe mu kwiga MIC32. Ishusho ya 2c igaragaza ubudahangarwa bwa polarization (Rp) nk'igihe cyo kwigaragaza. Agaciro ka Rp kari hejuru bivuze ingese nke. Mu masaha 24 ya mbere, Rp ya 2707 HDSS yageze ku gaciro ntarengwa ka 1955 kΩ cm2 ku bipimo bya abiotic na 1429 kΩ cm2 ku bipimo bya Pseudomonas aeruginosa. Ishusho ya 2c kandi igaragaza ko agaciro ka Rp kagabanutse vuba nyuma y'umunsi umwe hanyuma kagakomeza kuba kadahindutse mu minsi 13 yakurikiyeho. Agaciro ka Rp k'icyitegererezo cya Pseudomonas aeruginosa ni hafi 40 kΩ cm2, kari munsi cyane y'agaciro ka 450 kΩ cm2 k'icyitegererezo kitari icya binyabuzima.
Agaciro ka icorr gahwanye n'igipimo kimwe cya corruption. Agaciro kayo gashobora kubarwa uhereye kuri equation ya Stern-Geary ikurikira,
Nyuma ya Zou n'abandi 33, agaciro gasanzwe k'umusozi wa Tafel B muri iki gikorwa kari gafatwa nk'aho ari 26 mV/dec. Ishusho ya 2d igaragaza ko icorr y'icyitegererezo kitari icya biyolojiya cya 2707 cyagumye gihamye, mu gihe icyitegererezo cya P. aeruginosa cyahindutse cyane nyuma y'amasaha 24 ya mbere. Agaciro ka icorr k'icyitegererezo cya P. aeruginosa kari hejuru cyane ugereranyije n'igenzura ritari iry'ibinyabuzima. Iyi nzira ijyanye n'ibyavuye mu kurwanya polarisation.
EIS ni ubundi buryo budasenya bukoreshwa mu kugaragaza imikorere ya electrochemical ku miyoboro yangiritse. Impedance spectra n'agaciro ka capacitance kabazwe k'ibipimo byagaragaye ku miyoboro ya abiotic na Pseudomonas aeruginosa, Rb resistance ya passive film/biofilm yakozwe ku buso bw'ibipimo, Rct charge transfer resistance, Cdl electrical double layer capacitance (EDL) na QCPE Constant Phase Element (CPE). Ibi bipimo byasesenguwe cyane hakoreshwa uburyo bwa equivalent circuit (EEC).
Ishusho ya 3 igaragaza ingero zisanzwe za Nyquist (a na b) na Bode (a' na b') z'ibipimo 2707 bya HDSS mu buryo budafite abiotic na P. aeruginosa broth mu bihe bitandukanye byo kwinjiriramo. Umurambararo w'impeta ya Nyquist ugabanuka iyo Pseudomonas aeruginosa ihari. Ishusho ya Bode (Ishusho ya 3b') igaragaza ukwiyongera k'ubunini bwa impedance yose. Amakuru ku gihe cyo kuruhuka ashobora gutangwa na phase maxima. Ishusho ya 4 igaragaza imiterere y'umubiri ishingiye kuri monolayer (a) na bilayer (b) hamwe na EECs bihuye. CPE yinjijwe muri EEC mode. Kwemera kwayo no kwinjirira kwayo bigaragazwa ku buryo bukurikira:
Imiterere ibiri ifatika n'imirongo ingana ijyanye nayo kugira ngo ishyiremo impedance spectrum y'icyitegererezo cya 2707 HDSS:
aho Y0 ari ingano ya CPE, j ni umubare wiyumvirwa cyangwa (-1) 1/2, ω ni frequency ya angular, naho n ikaba ikimenyetso cy'imbaraga za CPE kiri munsi y'ubumwe35. Impinduka y'ubudahangarwa bwo kohereza charge (ni ukuvuga 1/Rct) ihuye n'igipimo cya corruption. Rct ntoya bivuze igipimo cya corruption cyihuta27. Nyuma y'iminsi 14 yo gucukura, Rct y'ibipimo bya Pseudomonas aeruginosa yageze kuri 32 kΩ cm2, nto cyane ugereranyije na 489 kΩ cm2 y'ibipimo bitari ibya binyabuzima (Imbonerahamwe ya 4).
Amashusho ya CLSM n'amashusho ya SEM ku Ishusho ya 5 bigaragaza neza ko imiterere ya biofilm ku buso bw'ingero ya 2707 HDSS nyuma y'iminsi 7 ari myinshi. Ariko, nyuma y'iminsi 14, imiterere ya biofilm yari mike kandi hari uturemangingo twapfuye twagaragaye. Imbonerahamwe ya 5 igaragaza ubunini bwa biofilm ku ngero 2707 za HDSS nyuma yo kwandura P. aeruginosa mu minsi 7 na 14. Ubunini ntarengwa bwa biofilm bwahindutse buva kuri 23.4 μm nyuma y'iminsi 7 bugera kuri 18.9 μm nyuma y'iminsi 14. Ubunini bwa biofilm mpuzandengo nabwo bwemeje iyi ntambwe. Yagabanutse kuva kuri 22.2 ± 0.7 μm nyuma y'iminsi 7 igera kuri 17.8 ± 1.0 μm nyuma y'iminsi 14.
(a) Ishusho ya 3-D CLSM nyuma y'iminsi 7, (b) Ishusho ya 3-D CLSM nyuma y'iminsi 14, (c) Ishusho ya SEM nyuma y'iminsi 7 na (d) Ishusho ya SEM nyuma y'iminsi 14.
EDS yagaragaje ibintu bya shimi muri biofilms n'ibikomoka ku ishwagara ku bipimo byagaragaye kuri P. aeruginosa mu minsi 14. Ishusho ya 6 igaragaza ko ibikubiye muri C, N, O, na P muri biofilms n'ibikomoka ku ishwagara biri hejuru cyane kuruta ibyo mu byuma bidafite ibara, kuko ibyo bintu bifitanye isano na biofilms na metabolites zabyo. Mikorobe zikenera gusa ingano nto ya chromium na fer. Igipimo cyo hejuru cya Cr na Fe muri biofilm n'ibikomoka ku ishwagara ku buso bw'ibipimo bigaragaza ko matrix y'icyuma yatakaje ibintu kubera ishwagara.
Nyuma y'iminsi 14, hagaragaye imyobo irimo na P. aeruginosa mu buryo bwa 2216E. Mbere yo kuyishyiramo, ubuso bw'ingero bwari bworoshye kandi nta nenge bwari bufite (Ishusho ya 7a). Nyuma yo kuyishyiramo no gukuraho biofilm na corruption products, imyobo miremire cyane ku buso bw'ingero yasuzumwe hifashishijwe CLSM, nk'uko bigaragara ku Ishusho ya 7b na c. Nta myobo igaragara yabonetse ku buso bw'ingero zitari iza binyabuzima (ubujyakuzimu ntarengwa bw'imyobo 0.02 μm). Ubujyakuzimu ntarengwa bw'imyobo bwatewe na Pseudomonas aeruginosa bwari 0.52 μm nyuma y'iminsi 7 na 0.69 μm nyuma y'iminsi 14, hashingiwe ku bujyakuzimu ntarengwa bw'imyobo 3 (agaciro ntarengwa k'ubujyakuzimu bw'imyobo 10 katoranyijwe kuri buri ngero) kageze kuri 0.42 ± 0.12 μm na 0.52 ± 0.15 μm, uko bikurikirana (Imbonerahamwe ya 5). Izi myobo ni nto ariko ni ingenzi.
(a) Mbere yo kwishyira mu kanwa, (b) iminsi 14 mu buryo butagira abiotic na (c) iminsi 14 mu mufa wa Pseudomonas aeruginosa.
Ishusho ya 8 igaragaza spectra ya XPS y'ubuso butandukanye bw'icyitegererezo, kandi imiterere y'imiti yasesenguwe kuri buri buso ikubiye mu mbonerahamwe ya 6. Muri Imbonerahamwe ya 6, ijanisha rya atome rya Fe na Cr mu gihe P. aeruginosa (ingero A na B) ryari hasi cyane ugereranyije n'ingero zitari iza biyoloji (ingero C na D). Ku cyitegererezo cya P. aeruginosa, umugozi wa spectra ya Cr 2p y'urwego rw'ibanze washyizwe ku bice bine by'isonga bifite agaciro ka 574.4, 576.6, 578.3 na 586.8 eV, bishobora kwitirirwa Cr, Cr2O3, CrO3 na Cr(OH)3, uko bikurikirana (Ishusho ya 9a na b). Ku bipimo bitari ibya biyoloji, spectra ya Cr 2p y'urwego rw'ibanze irimo imisozi ibiri y'ingenzi ya Cr (573.80 eV kuri BE) na Cr2O3 (575.90 eV kuri BE) muri Ishusho ya 9c na d, uko bikurikirana. Itangaje cyane Itandukaniro riri hagati y’ibipimo bya abiotic na P. aeruginosa ryari ukuboneka kwa Cr6+ n’igice kinini cya Cr(OH)3 (BE ya 586.8 eV) munsi ya biofilm.
Imiterere ya XPS nini y'ubuso bw'icyitegererezo cya 2707 HDSS muri ibyo bice byombi ni iminsi 7 n'iminsi 14, uko bikurikirana.
(a) Iminsi 7 yo kwandura P. aeruginosa, (b) Iminsi 14 yo kwandura P. aeruginosa, (c) Iminsi 7 yo kwandura abiotic na (d) Iminsi 14 yo kwandura abiotic.
HDSS igaragaza urwego rwo hejuru rwo kurwanya ingese mu bidukikije byinshi. Kim n'abandi 2 bavuze ko UNS S32707 HDSS yasobanuwe nk'itsinda rya DSS rifite PREN irenga 45. Agaciro ka PREN k'icyitegererezo cya 2707 HDSS muri iki gikorwa kari 49. Ibi biterwa n'uko ifite chromium nyinshi n'urugero rwa molybdenum na Ni nyinshi, bikaba ingirakamaro mu bidukikije birimo aside na chloride nyinshi. Byongeye kandi, imiterere itunganye neza n'imiterere mito idafite inenge ni ingirakamaro mu gutuma imiterere ikomera kandi irwanya ingese. Ariko, nubwo ifite ubushobozi bwo kurwanya ingese, amakuru y'igerageza muri iki gikorwa agaragaza ko 2707 HDSS idakingiwe burundu na MIC ya P. aeruginosa biofilms.
Ibisubizo bya elegitoroniki byagaragaje ko igipimo cya 2707 HDSS mu musupu wa P. aeruginosa cyiyongereye cyane nyuma y'iminsi 14 ugereranije n'umusupu utari uw'ibinyabuzima. Ku ishusho ya 2a, igabanuka rya Eocp ryagaragaye mu musupu wa abiotic na P. aeruginosa mu masaha 24 ya mbere. Nyuma yaho, biofilm yamaze gutwikira ubuso bw'ingero maze Eocp iba ihamye36. Ariko, urwego rwa Eocp y'ibinyabuzima rwari hejuru cyane urw'urwa Eocp itari uw'ibinyabuzima. Hari impamvu yo kwizera ko iri tandukaniro riterwa no kuba P. aeruginosa yaremwe. Ku ishusho ya 2d, imbere ya P. aeruginosa, agaciro ka icorr ka 2707 HDSS kageze kuri 0.627 μA cm-2, kari hejuru cyane ugereranyije n'uko abiotic igenzura (0.063 μA cm-2), byari bihuye n'agaciro ka Rct kapimwe na EIS. Mu minsi mike ya mbere, agaciro ka impedance Muri P. aeruginosa broth yiyongereye bitewe no gufatana kwa selile za P. aeruginosa no gukora biofilms. Ariko, iyo biofilm itwikiriye ubuso bw'ingero, impedance iragabanuka. Urusobe rw'uburinzi rubanza kwibasirwa bitewe no gukora biofilms na biofilms. Kubwibyo, ubudahangarwa bwa corruption bwaragabanutse uko igihe cyagiye gihita, kandi gufatana kwa P. aeruginosa byateye corruption yo mu gace. Imiterere y'ibice bya abiotic yari itandukanye. Ubudahangarwa bwa corruption bw'igenzura ritari iry'ibinyabuzima bwari hejuru cyane ugereranyije n'agaciro gahuye n'ingero zagaragaye kuri P. aeruginosa broth. Byongeye kandi, ku ngero za abiotic, agaciro ka Rct ka 2707 HDSS kageze kuri 489 kΩ cm2 ku munsi wa 14, kari inshuro 15 z'agaciro ka Rct (32 kΩ cm2) mu gihe P. aeruginosa yari irimo. Kubwibyo, 2707 HDSS ifite ubudahangarwa bwiza bwa corruption mu kirere kitanduye, ariko ntirwanya MIC yatewe na P. aeruginosa biofilms.
Ibi bisubizo bishobora kandi kugaragara uhereye ku miterere ya polarization iri ku Ishusho ya 2b. Ishami rya anodic ryatewe no kuba Pseudomonas aeruginosa biofilm ikora ndetse n'ibikorwa bya oxidation y'icyuma. Muri icyo gihe kandi, reaction ya cathodic ni ukugabanuka kwa ogisijeni. Kuba P. aeruginosa yaragabanije cyane ubucucike bw'umuyoboro wa corrosion, hafi urugero rw'ubunini burenze urugero rw'ubugenzuzi bwa abiotic. Ibi bigaragaza ko P. aeruginosa biofilm yongera corrosion ya localized ya 2707 HDSS. Yuan et al29 basanze ubucucike bw'umuyoboro wa corrosion wa 70/30 Cu-Ni alloy bwiyongereye bitewe n'ikibazo cya P. aeruginosa biofilm. Ibi bishobora guterwa na biocatalysis yo kugabanya ogisijeni hakoreshejwe Pseudomonas aeruginosa biofilms. Iki gitekerezo gishobora kandi gusobanura MIC ya 2707 HDSS muri iki gikorwa. Biofilms za aerobic nazo zishobora kugira ogisijeni nke munsi yazo. Kubwibyo, kunanirwa kongera gukoresha ubuso bw'icyuma hakoreshejwe ogisijeni bishobora kuba impamvu ya MIC muri iki gikorwa.
Dickinson n'abandi 38 bavuze ko igipimo cy'imikorere ya shimi n'amashanyarazi gishobora kugira ingaruka zitaziguye ku mikorere ya bagiteri za sessile ku buso bw'ingero n'imiterere y'ibikomoka ku ingese. Nkuko bigaragara ku Ishusho ya 5 n'Imbonerahamwe ya 5, umubare w'uturemangingo n'ubugari bwa biofilm byagabanutse nyuma y'iminsi 14. Ibi bishobora gusobanurwa neza ko nyuma y'iminsi 14, inyinshi mu turemangingo twa sessile ku buso bwa 2707 HDSS zapfuye kubera kugabanuka kw'intungamubiri mu buryo bwa 2216E cyangwa kurekurwa kwa iyoni z'icyuma zihumanya ziva muri matrix ya 2707 HDSS. Iyi ni imbogamizi ku bushakashatsi bwa batch.
Muri iki gikorwa, biofilm ya P. aeruginosa yateje imbere igabanuka rya Cr na Fe munsi ya biofilm ku buso bwa 2707 HDSS (Ishusho ya 6). Muri Imbonerahamwe ya 6, igabanuka rya Fe na Cr mu cyitegererezo cya D ugereranije n'icyitegererezo cya C, bigaragaza ko Fe na Cr byashongeshejwe byatewe na biofilm ya P. aeruginosa byakomeje nyuma y'iminsi 7 ya mbere. 2216E medium ikoreshwa mu kwigana ibidukikije byo mu mazi. Irimo 17700 ppm Cl-, igereranywa n'iboneka mu mazi karemano yo mu nyanja. Kuba hari 17700 ppm Cl- niyo mpamvu nyamukuru yo kugabanuka kwa Cr mu bipimo bya abiotic by'iminsi 7 na 14 byasesenguwe na XPS. Ugereranije n'ibipimo bya P. aeruginosa, gushonga kwa Cr mu bipimo bya abiotic byari bike cyane bitewe n'ubudahangarwa bukomeye bwa Cl− bwa 2707 HDSS mu bidukikije bya abiotic. Ishusho ya 9 igaragaza ko hari Cr6+ muri filime ya passivation. Ishobora kuba ifite uruhare mu gukura Cr ku buso bw'icyuma na P. aeruginosa biofilms, nk'uko byagaragajwe na Chen na Clayton.
Bitewe n’ubwiyongere bwa bagiteri, agaciro ka pH y’ubuso mbere na nyuma yo guhinga kari 7.4 na 8.2, uko bikurikirana. Kubwibyo, munsi ya P. aeruginosa biofilm, kwangirika kwa aside organic ntibishoboka ko byaba ari byo bitera iki gikorwa bitewe na pH iri hejuru mu buso bwinshi. pH y’ubuso butari ubw’ibinyabuzima ntiyahindutse cyane (kuva kuri 7.4 ya mbere kugeza kuri 7.5 ya nyuma) mu gihe cy’iminsi 14 y’igerageza. Ukwiyongera kwa pH mu buso nyuma yo gukubitwa byatewe n’imikorere ya P. aeruginosa kandi byagaragaye ko bigira ingaruka zimwe kuri pH mu gihe nta mirongo y’igerageza irimo.
Nkuko bigaragara ku Ishusho ya 7, ubujyakuzimu ntarengwa bw'umwobo bwatewe na P. aeruginosa biofilm bwari 0.69 μm, bwari bunini cyane kurusha ubw'umwuka udafite abiotic (0.02 μm). Ibi bihuye n'amakuru ya elegitoroniki yavuzwe haruguru. Ubujyakuzimu bw'umwobo bwa 0.69 μm ni buto inshuro zirenga icumi ugereranyije n'agaciro ka 9.5 μm kavuzwe kuri 2205 DSS mu bihe bimwe. Aya makuru agaragaza ko 2707 HDSS igaragaza ubudahangarwa bwiza bwa MIC ugereranije na 2205 DSS. Ibi ntibikwiye gutungurana, kuko 2707 HDSS ifite chromium nyinshi, itanga passivation irambye, bitewe n'imiterere y'icyiciro ingana nta bintu byangiza bya kabiri, bigatuma bigora P. aeruginosa kuva mu mwanya wa passivation no gutangira icuraburindi.
Mu gusoza, MIC pitting yabonetse ku buso bwa 2707 HDSS mu mushongi wa P. aeruginosa ugereranije n'intoya nkeya mu bintu bitangiza ibidukikije. Uyu murimo ugaragaza ko 2707 HDSS ifite ubushobozi bwo kurwanya MIC kurusha 2205 DSS, ariko ntabwo ifite ubudahangarwa bwuzuye na MIC bitewe na P. aeruginosa biofilm. Ibi byavumbuwe bifasha mu guhitamo ibyuma bitagira umugese bikwiye no kugereranya igihe cyo gukora ku bidukikije byo mu mazi.
Ikarita ya 2707 HDSS itangwa n'Ishuri ry'Ubutabire rya Kaminuza y'Amajyaruguru y'Uburasirazuba (NEU) i Shenyang, mu Bushinwa. Ibigize 2707 HDSS bigaragara mu mbonerahamwe ya 1, yasesenguwe n'Ishami rishinzwe Gusesengura no Gupima Ibikoresho bya NEU. Ingero zose zavuwe ku bushyuhe bwa 1180 °C mu gihe cy'isaha 1. Mbere yo gupimwa ingese, 2707 HDSS ifite ubuso bugaragara hejuru bwa cm2 yasizwe irangi rya 2000 n'impapuro za silicon carbide hanyuma irangi rya Al2O3 rya 0.05 μm. Impande n'inyuma birinzwe irangi ritagira irangi. Nyuma yo kumisha, ingero zogejwe n'amazi yakuwemo irangi hanyuma zishyirwamo ethanol ya 75% (v/v) mu gihe cy'amasaha 0.5. Hanyuma zarumishwaga mu kirere munsi y'urumuri rwa ultraviolet (UV) mu gihe cy'amasaha 0.5 mbere yo gukoreshwa.
Ubwoko bwa Marine Pseudomonas aeruginosa MCCC 1A00099 bwaguzwe mu kigo cya Xiamen Marine Culture Collection Center (MCCC), mu Bushinwa. Pseudomonas aeruginosa yahinzwe mu buryo bwa aerobic kuri 37°C mu macupa ya mililitiro 250 n'uturemangingo tw'ibirahure bya mililitiro 500 hakoreshejwe uburyo bwa Marine 2216E (Qingdao Hope Biotechnology Co., Ltd., Qingdao, mu Bushinwa). Hagati (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 NaH2PO4 , 5.0 peptone, 1.0 y'umusemburo w'imisemburo na 0.1 citrate ya ferric. Shyira kuri 121°C mu gihe cy'iminota 20 mbere yo gutera. Barura uturemangingo twa sessile na planktonic ukoresheje hemocytometer munsi ya mikorosikopi y'urumuri kuri 400X magnification. Ingano ya mbere y'uturemangingo twa planktonic Pseudomonas aeruginosa ako kanya nyuma yo gutera yari hafi uturemangingo 106/ml.
Ibizamini bya elegitoroniki byakorewe mu kazu k’ikirahure ka electrode eshatu gasanzwe gafite ingano iciriritse ya mililitiro 500. Urupapuro rwa platine na electrode ya calomel yuzuye (SCE) byahujwe n’icyuma gishyushya amazi binyuze mu miyoboro ya Luggin yuzuyemo ibiraro by’umunyu, bigakora nk’ibice birwanya n’ibipimo, uko bikurikirana. Kugira ngo hakorwe electrode zikora, insinga y’umuringa yashyizwe kuri buri gipimo maze itwikirwa na epoxy, hasigara hafi cm2 y’ubuso bw’uruhande rumwe bwa electrode ikora. Mu gihe cyo gupima electrochemical, ingero zashyizwe mu buryo bwa 2216E kandi zigumana ubushyuhe buhoraho bwo gucukura (37 °C) mu bwogero bw’amazi. Amakuru ya OCP, LPR, EIS n’ubushobozi bwo gupima imiterere byapimwe hakoreshejwe Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA). Ibizamini bya LPR byafashwe ku gipimo cya scan cya 0.125 mV s-1 mu rugero rwa -5 na 5 mV hamwe na Eocp kandi inshuro zo gupima 1 Hz. EIS yakozwe hakoreshejwe umuraba wa sine mu rugero rwa frequency. 0.01 kugeza 10.000 Hz hakoreshejwe voltage ya 5 mV kuri Eocp ihamye. Mbere yuko electrodes zitangira gukoreshwa, zari mu buryo bwo gufungura kugeza igihe agaciro k’ubushobozi bwo kwangirika kagejejweho. Imirongo ya polarization yakoreshejwe kuva kuri -0.2 kugeza kuri 1.5 V ugereranije na Eocp ku gipimo cya scan cya 0.166 mV/s. Buri kizamini cyasubiwemo inshuro 3 hamwe na P. aeruginosa kandi idafite.
Ingero z'isesengura rya metallographic zaratunganyijwe hakoreshejwe impapuro 2000 za SiC zitose hanyuma zishyirwamo ifu ya Al2O3 ya 0.05 μm kugira ngo zirebe neza. Isesengura rya metallographic ryakozwe hakoreshejwe mikorosikopi y'ijisho. Ingero zashushanyijwe hakoreshejwe umuti wa 10 wt.% wa potassium hydroxide 43.
Nyuma yo gukaraba, ingero zogejwe inshuro 3 n'umuti wa fosfeti-buffered saline (PBS) (pH 7.4 ± 0.2) hanyuma zigashyirwamo 2.5% (v/v) glutaraldehyde mu gihe cy'amasaha 10 kugira ngo hakorwe biofilms. Nyuma yaho byakuwemo amazi hakoreshejwe uruhererekane rwagenwe (50%, 60%, 70%, 80%, 90%, 95% na 100% v/v) bya ethanol mbere yo kumisha umwuka. Amaherezo, ubuso bw'icyitegererezo bushyirwamo agapira ka zahabu kugira ngo habeho uburyo bwo gutwara ibinyabutabire mu isuzuma rya SEM. Amashusho ya SEM yibanze ku duce dufite uturemangingo twa P. aeruginosa twinshi ku buso bwa buri ngero. Kora isesengura rya EDS kugira ngo umenye ibintu bya shimi. Mikorosikopi ya Zeiss Confocal Laser Scanning (CLSM) (LSM 710, Zeiss, Ubudage) yakoreshejwe mu gupima ubujyakuzimu bw'icyobo. Kugira ngo harebwe ibyobo byangiritse munsi ya biofilm, igice cy'igerageza cyabanje gusukurwa hakurikijwe Igipimo cy’Igihugu cy’Ubushinwa (CNS) GB/T4334.4-2000 cyo gukuraho ibikoresho byangiritse na biofilm ku buso bw’igice cy’igerageza.
Isesengura rya X-ray photoelectron spectroscopy (XPS, ESCALAB250 surface analysis system, Thermo VG, USA) ryakozwe hakoreshejwe isoko rya X-ray monochromatic (umurongo wa aluminiyumu Kα kuri energy ya 1500 eV na 150 W) ku ntera nini y'ingufu 0 mu bihe bisanzwe -1350 eV. Spectrum zifite resolution yo hejuru zafashwe amajwi hakoreshejwe energy ya 50 eV pass na 0.2 eV stage.
Ingero zashyizwemo zakuweho hanyuma zozwa buhoro buhoro na PBS (pH 7.4 ± 0.2) mu gihe cy'amasaha 15 45. Kugira ngo harebwe ubushobozi bwa bagiteri bwa biofilms ku bipimo, biofilms zashyizwemo irangi hakoreshejwe LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA). Iyi kit ifite amarangi abiri ya fluorescent, irangi ry'icyatsi kibisi rya SYTO-9 n'irangi ry'umutuku rya propidium iodide (PI). Munsi ya CLSM, utudomo dufite icyatsi kibisi n'umutuku bigaragaza uturemangingo tuzima n'utw'abapfuye, uko bikurikirana. Mu gusiga irangi, uruvange rwa 1 ml rurimo 3 μl SYTO-9 na 3 μl PI rwashyizwemo irangi mu gihe cy'iminota 20 ku bushyuhe bw'icyumba (23 oC) mu mwijima. Nyuma yaho, ingero zashyizwemo irangi zabonetse ku bunini bubiri (488 nm ku turemangingo tuzima na 559 nm ku turemangingo twapfuye) hakoreshejwe imashini ya Nikon CLSM (C2 Plus, Nikon, Ubuyapani). Ubunini bwa Biofilm bwapimwe muri Uburyo bwo gushakisha bwa 3-D.
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