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Ukugqwala kwama-microbial (MIC) kuyinkinga enkulu ezimbonini eziningi, njengoba kungaholela ekulahlekelweni okukhulu kwezomnotho. I-Super duplex stainless steel 2707 (2707 HDSS) isetshenziswa ezindaweni zasolwandle ngenxa yokumelana kwayo okuhle kwamakhemikhali. Kodwa-ke, ukumelana kwayo ne-MIC akukaboniswa ngokuhlola. Lolu cwaningo luhlole ukuziphatha kwe-MIC 2707 HDSS okubangelwa yi-bacterium ye-aerobic yasolwandle i-Pseudomonas aeruginosa. Ukuhlaziywa kwe-electrochemical kubonise ukuthi lapho kukhona i-Pseudomonas aeruginosa biofilm endaweni ye-2216E, kwenzeka ushintsho oluhle emandleni okugqwala kanye nokwanda kobuningi bamanje okugqwala. Ukuhlaziywa kwe-X-ray photoelectron spectroscopy (XPS) kubonise ukwehla kokuqukethwe kwe-Cr ebusweni besampula ngaphansi kwe-biofilm. Ukuhlaziywa okubonakalayo kwemigodi kubonise ukuthi i-P. aeruginosa biofilm ikhiqize ukujula okuphezulu komgodi okungu-0.69 µm phakathi nezinsuku ezingu-14 zokufukamela. Nakuba lokhu kuncane, kubonisa ukuthi i-2707 HDSS ayivikelekile ngokuphelele ku-MIC yama-biofilms e-P. aeruginosa.
Izinsimbi ezingenalutho eziphindwe kabili (i-DSS) zisetshenziswa kabanzi ezimbonini ezahlukahlukene ngenxa yokuhlanganiswa okuphelele kwezakhiwo ezinhle kakhulu zemishini kanye nokumelana nokugqwala1,2. Kodwa-ke, ukufakwa kwemigodi endaweni ethile kusenzeka futhi kuthinta ubuqotho bale nsimbi3,4. I-DSS ayimelani nokugqwala kwamagciwane (i-MIC)5,6. Naphezu kobubanzi bezicelo ze-DSS, kusenezindawo lapho ukumelana nokugqwala kwe-DSS kunganele ukusetshenziswa kwesikhathi eside. Lokhu kusho ukuthi izinto ezibiza kakhulu ezinokumelana nokugqwala okuphezulu ziyadingeka. UJeon et al7 bathole ukuthi ngisho nezinsimbi ezingenalutho eziphindwe kabili (i-SDSS) zinemikhawulo ethile maqondana nokumelana nokugqwala. Ngakho-ke, kwezinye izimo, kudingeka izinsimbi ezingenalutho eziphindwe kabili (i-HDSS) ezinokumelana nokugqwala okuphezulu. Lokhu kwaholela ekuthuthukisweni kwe-HDSS exutshwe kakhulu.
Ukumelana nokugqwala i-DSS kuncike esilinganisweni sezigaba ze-alpha ne-gamma futhi kuncishisiwe ezifundeni ze-Cr, Mo kanye ne-W 8, 9, 10 eduze kwesigaba sesibili. I-HDSS iqukethe okuqukethwe okuphezulu kwe-Cr, Mo kanye ne-N11, ngakho-ke inokumelana nokugqwala okuhle kakhulu kanye nenani eliphezulu (45-50) lenombolo yokumelana nokugoba elinganayo (PREN) enqunywe yi-wt.% Cr + 3.3 (wt.% Mo + 0.5 wt. .%W) + 16% wt. N12. Ukumelana kwayo okuhle kakhulu nokugqwala kuncike ekwakhiweni okulinganiselayo okuqukethe cishe izigaba ze-ferritic (α) ezingama-50% kanye ne-austenitic (γ). I-HDSS inezakhiwo ezingcono zemishini kanye nokumelana okuphezulu nokugqwala kwe-chloride. Ukumelana nokugqwala okuthuthukisiwe kwandisa ukusetshenziswa kwe-HDSS ezindaweni ezinolaka kakhulu ze-chloride njengezindaweni zasolwandle.
Ama-MIC ayinkinga enkulu ezimbonini eziningi ezifana nezimboni zikawoyela negesi namanzi14. I-MIC ibangela u-20% wawo wonke umonakalo wokugqwala15. I-MIC iwukugqwala kwe-bioelectrochemical okungabonakala ezindaweni eziningi. Ama-biofilms akheka ezindaweni zensimbi ashintsha izimo ze-electrochemical, ngaleyo ndlela ethinta inqubo yokugqwala. Kukholelwa kabanzi ukuthi ukugqwala kwe-MIC kubangelwa ama-biofilms. Ama-microorganism e-electrogenic adla izinsimbi ukuze athole amandla awadingayo ukuze asinde17. Izifundo zakamuva ze-MIC zikhombisile ukuthi i-EET (ukudluliselwa kwe-electron yangaphandle) iyisici esikhawulela izinga ku-MIC esibangelwa ama-microorganism e-electrogenic. UZhang et al. 18 ukhombisile ukuthi abaxhumanisi be-electron basheshisa ukudluliselwa kwama-electron phakathi kwamaseli e-Desulfovibrio sessificans kanye nensimbi engagqwali engu-304, okuholela ekuhlaselweni kwe-MIC okunzima kakhulu. U-Anning et al. 19 kanye no-Wenzlaff et al. 20 bakhombisile ukuthi ama-biofilms ama-bacteria anciphisa i-sulfate ebolayo (ama-SRB) angamunca ngqo ama-electron avela kuma-substrates ensimbi, okuholela ekuqhekekeni okukhulu.
I-DSS yaziwa ukuthi isengozini ye-MIC ezindaweni eziqukethe ama-SRB, amabhaktheriya anciphisa insimbi (ama-IRB), njll. 21. Lawa mabhaktheriya abangela ukugoba kwendawo ebusweni be-DSS ngaphansi kwe-biofilms22,23. Ngokungafani ne-DSS, i-HDSS24 MIC ayaziwa kahle.
I-Pseudomonas aeruginosa iyigciwane eliyi-Gram-negative, elihambayo, elinomumo wenduku elisakazeke kabanzi emvelweni25. I-Pseudomonas aeruginosa nayo iyiqembu elikhulu lamagciwane endaweni yasolwandle, okubangela ukugcwala okuphezulu kwe-MIC. I-Pseudomonas ihileleke kakhulu enkambisweni yokugqwala futhi iqashelwa njenge-colonizer yokuqala ngesikhathi sokwakheka kwe-biofilm. UMahat et al. 28 noYuan et al. 29 babonise ukuthi i-Pseudomonas aeruginosa ivame ukwandisa izinga lokugqwala kwensimbi ethambile kanye nama-alloy ezindaweni zasemanzini.
Inhloso eyinhloko yalo msebenzi kwakuwukuphenya izakhiwo ze-MIC 2707 HDSS ezibangelwa yi-bacterium ye-aerobic yasolwandle i-Pseudomonas aeruginosa kusetshenziswa izindlela ze-electrochemical, izindlela zokuhlaziya ubuso kanye nokuhlaziywa komkhiqizo wokugqwala. Izifundo ze-electrochemical, okuhlanganisa amandla okuvula isekethe (OCP), ukumelana nokuvuleka kwe-linear polarization (LPR), i-electrochemical impedance spectroscopy (EIS), kanye ne-polarization enamandla e-dynamic, zenziwe ukuze kufundwe ukuziphatha kwe-MIC 2707 HDSS. Ukuhlaziywa kwe-spectrometric ye-Energy dispersive (EDS) kwenziwa ukuze kutholakale izakhi zamakhemikhali endaweni egqwalile. Ngaphezu kwalokho, i-X-ray photoelectron spectroscopy (XPS) yasetshenziswa ukunquma ukuzinza kwe-oxide film passivation ngaphansi kwethonya lendawo yasolwandle equkethe i-Pseudomonas aeruginosa. Ukujula kwemigodi kwalinganiswa ngaphansi kwe-confocal laser scanning microscope (CLSM).
Ithebula 1 likhombisa ukwakheka kwamakhemikhali kwe-2707 HDSS. Ithebula 2 likhombisa ukuthi i-2707 HDSS inezakhiwo ezinhle kakhulu zemishini ezinamandla okukhiqiza angu-650 MPa. Kumfanekiso 1 likhombisa isakhiwo esincane se-optical sesisombululo esiphathwe ngokushisa i-2707 HDSS. Esimweni esincane esiqukethe cishe izigaba ze-austenite ezingama-50% kanye nezigaba ze-ferrite ezingama-50%, kubonakala amabhande amade ezigaba ze-austenite kanye ne-ferrite ngaphandle kwezigaba zesibili.
Ku-fig. 2a kukhombisa amandla okuvula i-open circuit (Eocp) uma kuqhathaniswa nesikhathi sokuchayeka se-2707 HDSS ku-2216E abiotic medium kanye nomhluzi we-P. aeruginosa izinsuku eziyi-14 ku-37°C. Kubonisa ukuthi ushintsho olukhulu nolubaluleke kakhulu ku-Eocp lwenzeka phakathi kwamahora okuqala angu-24. Amanani e-Eocp kuzo zombili izimo afinyelele ku--145 mV (uma kuqhathaniswa ne-SCE) cishe emahoreni ayi-16 bese ehla kakhulu, afinyelela ku--477 mV (uma kuqhathaniswa ne-SCE) kanye no--236 mV (uma kuqhathaniswa ne-SCE) yesampula ye-abiotic. kanye namakhuphoni e-P Pseudomonas aeruginosa, ngokulandelana). Ngemuva kwamahora angama-24, inani le-Eocp 2707 HDSS le-P. aeruginosa lalizinzile ku--228 mV (uma kuqhathaniswa ne-SCE), kanti inani elihambisanayo lamasampula angewona awebhayoloji lalicishe libe ngu--442 mV (uma kuqhathaniswa ne-SCE). I-Eocp lapho kukhona i-P. aeruginosa yayiphansi kakhulu.
Ucwaningo lwe-electrochemical lwamasampula e-HDSS angu-2707 ku-abiotic medium kanye nomhluzi we-Pseudomonas aeruginosa ku-37 °C:
(a) I-Eocp njengomsebenzi wesikhathi sokuchayeka, (b) ama-polarization curves ngosuku lwe-14, (c) i-Rp njengomsebenzi wesikhathi sokuchayeka, kanye (d) i-icorr njengomsebenzi wesikhathi sokuchayeka.
Ithebula 3 libonisa amapharamitha okugqwala kwe-electrochemical kwamasampula e-HDSS angu-2707 avezwe ku-abiotic kanye ne-Pseudomonas aeruginosa afakwe i-incubated media esikhathini esiyizinsuku ezingu-14. Ama-tangent ama-anode kanye nama-cathode curve akhishwe ukuze kutholakale iziphambano ezinikeza ukuminyana kwamanje kokugqwala (icorr), amandla okugqwala (Ecorr) kanye nomthambeka we-Tafel (βα kanye ne-βc) ngokwezindlela ezijwayelekile30,31.
Njengoba kuboniswe ku-fig. 2b, ukushintsha okuya phezulu ku-P. aeruginosa curve kuholele ekwandeni kwe-Ecorr uma kuqhathaniswa ne-abiotic curve. Inani le-icorr, elilingana nesilinganiso sokugqwala, lenyuke laya ku-0.328 µA cm-2 kusampula ye-Pseudomonas aeruginosa, elikhulu ngokuphindwe kane kunesampula engeyona eyebhayoloji (0.087 µA cm-2).
I-LPR iyindlela yakudala ye-electrochemical engabhubhisi yokuhlaziya ukugqwala okusheshayo. Iphinde yasetshenziswa ukutadisha i-MIC32. Ku-Fig. 2c ikhombisa ukumelana kwe-polarization (Rp) njengomsebenzi wesikhathi sokuchayeka. Inani eliphakeme le-Rp lisho ukugqwala okuncane. Phakathi kwamahora okuqala angu-24, i-Rp 2707 HDSS yafinyelela ku-1955 kΩ cm2 yamasampula abiotic kanye ne-1429 kΩ cm2 yamasampula e-Pseudomonas aeruginosa. Isibalo 2c sibonisa nokuthi inani le-Rp lehle ngokushesha ngemva kosuku olulodwa labe selihlala lingashintshi ezinsukwini ezingu-13 ezalandela. Inani le-Rp lesampula ye-Pseudomonas aeruginosa licishe libe ngu-40 kΩ cm2, elingaphansi kakhulu kunenani elingu-450 kΩ cm2 lesampula engeyona eyebhayoloji.
Inani le-icorr lilingana nesilinganiso sokugqwala esifanayo. Inani lalo lingabalwa kusukela ku-equation elandelayo ye-Stern-Giri:
Ngokusho kukaZoe et al. 33, inani elijwayelekile le-Tafel slope B kulo msebenzi lithathwe njengelingu-26 mV/dec. Isithombe 2d sibonisa ukuthi i-icorr yesampula engeyona eyebhayoloji engu-2707 yahlala izinzile, kuyilapho isampula ye-P. aeruginosa ishintshashintsha kakhulu ngemva kwamahora okuqala angu-24. Amanani e-icorr amasampula e-P. aeruginosa ayephezulu kakhulu kunalawo okulawula okungeyona eyebhayoloji. Lo mkhuba uhambisana nemiphumela yokumelana nokuqhekeka.
I-EIS ingenye indlela engeyona ebhubhisayo esetshenziselwa ukuchaza ukusabela kwe-electrochemical ezindaweni ezibolile. Ama-spectra e-Impedance kanye namanani e-capacitance abaliwe amasampula avezwe endaweni engabonakali kanye nesisombululo se-Pseudomonas aeruginosa, ukumelana kwefilimu/i-biofilm okungashukumiyo okwakhiwe ebusweni besampula, ukumelana kokudluliselwa kweshaja i-Rct, i-capacitance kagesi enezingqimba ezimbili i-Cdl (EDL) kanye namapharamitha e-QCPE Phase element ahlala njalo (CPE). Lawa mapharamitha ahlaziywe kabanzi ngokufaka idatha kusetshenziswa imodeli yesekethe elinganayo (EEC).
Ku-fig. 3 kukhombisa ama-Nyquist plots ajwayelekile (a no-b) kanye nama-Bode plots (a' no-b') amasampula angu-2707 e-HDSS kuma-abiotic media kanye nomhluzi we-P. aeruginosa ngezikhathi ezahlukene zokufukamela. Ububanzi bendandatho ye-Nyquist buyancipha uma kukhona i-Pseudomonas aeruginosa. I-Bode plot (Fig. 3b') ikhombisa ukwanda kwe-total impedance. Ulwazi mayelana nesikhathi sokuphumula lungatholakala ku-phase maxima. Ku-fig. 4 kukhombisa izakhiwo zomzimba ezisekelwe ku-monolayer (a) kanye ne-bilayer (b) kanye nama-EEC ahambisanayo. I-CPE yethulwa kumodeli ye-EEC. Ukwamukelwa kwayo kanye ne-impedance kuvezwa kanje:
Amamodeli amabili angokwenyama kanye nezifunda ezilinganayo ezihambisanayo zokufaka i-spectrum ye-impedance yesampula 2707 HDSS:
lapho u-Y0 eyinani le-KPI, u-j uyinombolo ecatshangelwayo noma (-1)1/2, u-ω uyimvamisa ye-angular, u-n uyinkomba yamandla e-KPI engaphansi kweyodwa. Ukuguqulwa kokumelana nokudluliselwa kweshaja (okungukuthi i-1/Rct) kuhambisana nesilinganiso sokugqwala. Uma i-Rct encane, izinga lokugqwala liphezulu27. Ngemva kwezinsuku ezingu-14 zokufukamela, amasampula e-Rct of Pseudomonas aeruginosa afinyelele ku-32 kΩ cm2, okungaphansi kakhulu kune-489 kΩ cm2 yamasampula angewona awebhayoloji (Ithebula 4).
Izithombe ze-CLSM kanye nezithombe ze-SEM kuMfanekiso 5 zibonisa ngokusobala ukuthi uqweqwe lwe-biofilm ebusweni besampula ye-HDSS 2707 ngemva kwezinsuku eziyi-7 luminyene. Kodwa-ke, ngemva kwezinsuku eziyi-14, ukumbozwa kwe-biofilm kwakukubi futhi kwavela amanye amangqamuzana afile. Ithebula 5 likhombisa ukujiya kwe-biofilm kumasampula e-HDSS angu-2707 ngemva kokuchayeka ku-P. aeruginosa izinsuku eziyi-7 neziyi-14. Ubukhulu obukhulu be-biofilm bushintshe kusuka ku-23.4 µm ngemva kwezinsuku eziyi-7 kuya ku-18.9 µm ngemva kwezinsuku eziyi-14. Ubukhulu obujwayelekile be-biofilm buqinisekisile lo mkhuba. Kwehle kusuka ku-22.2 ± 0.7 μm ngemva kwezinsuku eziyi-7 kuya ku-17.8 ± 1.0 μm ngemva kwezinsuku eziyi-14.
(a) Isithombe se-3-D CLSM ezinsukwini eziyi-7, (b) Isithombe se-3-D CLSM ezinsukwini eziyi-14, (c) Isithombe se-SEM ezinsukwini eziyi-7, kanye (d) Isithombe se-SEM ezinsukwini eziyi-14.
I-EMF yembule izakhi zamakhemikhali kuma-biofilms kanye nemikhiqizo yokugqwala kumasampula avezwe ku-P. aeruginosa izinsuku ezingu-14. Ku-Fig. Isithombe 6 sibonisa ukuthi okuqukethwe yi-C, N, O, kanye ne-P kuma-biofilms kanye nemikhiqizo yokugqwala kuphakeme kakhulu kunezinsimbi ezihlanzekile, njengoba lezi zakhi zihlotshaniswa nama-biofilms kanye nama-metabolites azo. Amagciwane adinga kuphela inani elincane le-chromium kanye ne-iron. Amazinga aphezulu e-Cr kanye ne-Fe ku-biofilm kanye nemikhiqizo yokugqwala ebusweni bamasampula abonisa ukuthi i-matrix yensimbi ilahlekelwe izakhi ngenxa yokugqwala.
Ngemva kwezinsuku ezingu-14, imigodi ene-P. aeruginosa nengenayo yabonwa ku-2216E ephakathi nendawo. Ngaphambi kokufukulwa, ubuso bamasampula babubushelelezi futhi bungenasici (Isithombe 7a). Ngemva kokufukulwa nokususwa kwemikhiqizo ye-biofilm kanye nokugqwala, imigodi ejulile ebusweni bamasampula yahlolwa kusetshenziswa i-CLSM, njengoba kuboniswe ku-Fig. 7b no-c. Akukho mgodi ocacile owatholakala ebusweni bezilawuli ezingezona ezebhayoloji (ukujula okuphezulu kwemigodi engu-0.02 µm). Ukujula okuphezulu kwemigodi okubangelwe yi-P. aeruginosa kwakungu-0.52 µm ezinsukwini ezingu-7 kanye no-0.69 µm ezinsukwini ezingu-14, ngokusekelwe ekujuleni okuphezulu kwemigodi okumaphakathi okuvela kumasampula angu-3 (kukhethwe ukujula okuphezulu kwemigodi engu-10 ngesampula ngayinye). Ukufinyelela okungu-0.42 ± 0.12 µm kanye no-0.52 ± 0.15 µm, ngokulandelana (Ithebula 5). Lawa manani okujula kwemigodi mancane kodwa abalulekile.
(a) ngaphambi kokuchayeka, (b) izinsuku ezingu-14 endaweni engenazo izinto eziphilayo, kanye (c) izinsuku ezingu-14 emhluzi we-Pseudomonas aeruginosa.
Ku-Fig. Ithebula 8 libonisa ama-spectra e-XPS ezindawo ezahlukahlukene zesampula, kanti ukwakheka kwamakhemikhali okuhlaziywe endaweni ngayinye kufingqiwe kuThebula 6. KuThebula 6, amaphesenti e-athomu e-Fe ne-Cr lapho kukhona i-P. aeruginosa (amasampula A no-B) ayephansi kakhulu kunalawo okulawula okungezona okwebhayoloji. (amasampula C no-D). Kwisampula ye-P. aeruginosa, ijika le-spectral ezingeni le-nucleus ye-Cr 2p lafakwa ezingxenyeni ezine ze-peak ezinamandla okubopha (BE) angu-574.4, 576.6, 578.3 kanye no-586.8 eV, okungabangwa yi-Cr, Cr2O3, CrO3. kanye ne-Cr(OH)3, ngokulandelana (Isithombe 9a kanye no-b). Kumasampula angezona ezebhayoloji, i-spectrum yezinga eliyinhloko le-Cr 2p iqukethe iziqongo ezimbili eziyinhloko ze-Cr (573.80 eV ye-BE) kanye ne-Cr2O3 (575.90 eV ye-BE) ku-Figs. 9c kanye no-d, ngokulandelana. Umehluko ovelele kakhulu phakathi kwamasampula e-abiotic namasampula e-P. aeruginosa kwakuwukuba khona kwe-Cr6+ kanye nengxenye ephezulu ye-Cr(OH)3 (BE 586.8 eV) ngaphansi kwe-biofilm.
I-spectra ebanzi ye-XPS yobuso besampula engu-2707 HDSS kuma-media amabili iyizinsuku ezingu-7 kanye nezingu-14 ngokulandelana.
(a) Ukuchayeka izinsuku eziyi-7 ku-P. aeruginosa, (b) Ukuchayeka izinsuku eziyi-14 ku-P. aeruginosa, (c) Izinsuku eziyi-7 endaweni engenazo izinto eziphilayo, kanye (d) Izinsuku eziyi-14 endaweni engenazo izinto eziphilayo.
I-HDSS ikhombisa izinga eliphezulu lokumelana nokugqwala ezindaweni eziningi. UKim nabanye.2 babike ukuthi i-HDSS UNS S32707 ihlonzwe njenge-DSS exutshwe kakhulu ene-PREN engaphezu kuka-45. Inani le-PREN lesampula engu-2707 HDSS kulo msebenzi lalingu-49. Lokhu kungenxa yokuqukethwe okuphezulu kwe-chromium kanye nokuqukethwe okuphezulu kwe-molybdenum ne-nickel, okuwusizo ezindaweni ezine-acidic. kanye nezindawo ezinokuqukethwe okuphezulu kwe-chloride. Ngaphezu kwalokho, ukwakheka okulinganiselayo kanye nesakhiwo esincane esingenamaphutha kuyazuzisa ekuzinzeni kwesakhiwo kanye nokumelana nokugqwala. Kodwa-ke, naphezu kokumelana kwayo okuhle kwamakhemikhali, idatha yokuhlola kulo msebenzi iphakamisa ukuthi i-2707 HDSS ayivikelekile ngokuphelele kuma-MIC e-P. aeruginosa biofilm.
Imiphumela ye-electrochemical ikhombisile ukuthi izinga lokugqwala kwe-2707 HDSS kumhluzi we-P. aeruginosa landa kakhulu ngemva kwezinsuku eziyi-14 uma kuqhathaniswa nendawo engeyona eyebhayoloji. Ku-Figure 2a, ukwehla kwe-Eocp kwabonwa kokubili endaweni ye-abiotic kanye nomhluzi we-P. aeruginosa phakathi namahora okuqala angama-24. Ngemuva kwalokho, i-biofilm imboza ngokuphelele ubuso besampula, futhi i-Eocp iba yinto ezinzile. Kodwa-ke, izinga le-Eocp lebhayoloji laliphezulu kakhulu kunezinga le-Eocp elingeyona eyebhayoloji. Kunezizathu zokukholelwa ukuthi lo mehluko uhlotshaniswa nokwakheka kwe-biofilms ye-P. aeruginosa. Ku-Fig. 2d lapho kukhona i-P. aeruginosa, inani le-icorr 2707 HDSS lifinyelele ku-0.627 μA cm-2, okuyi-oda lobukhulu obuphakeme kunelokulawulwa kwe-abiotic (0.063 μA cm-2), okwakuhambisana nenani le-Rct elilinganiswe yi-EIS. Phakathi nezinsuku ezimbalwa zokuqala, amanani e-impedance kumhluzi we-P. aeruginosa anda ngenxa yokunamathela kwamaseli e-P. aeruginosa kanye nokwakheka kwama-biofilms. Kodwa-ke, lapho i-biofilm imboza ngokuphelele indawo yesampula, i-impedance iyancipha. Ingqimba yokuvikela ihlaselwa ngokuyinhloko ngenxa yokwakheka kwama-biofilms nama-metabolites e-biofilm. Ngenxa yalokho, ukumelana nokugqwala kwehla ngokuhamba kwesikhathi futhi ukunamathela kwe-P. aeruginosa kubangele ukugqwala kwendawo. Izitayela ezindaweni ezi-abiotic zazihlukile. Ukumelana nokugqwala kokulawulwa okungeyona eyebhayoloji kwakuphakeme kakhulu kunenani elihambisanayo lamasampula adalulwe kumhluzi we-P. aeruginosa. Ngaphezu kwalokho, kuma-abiotic accessions, inani le-Rct 2707 HDSS lifinyelele ku-489 kΩ cm2 ngosuku lwe-14, okuphindwe izikhathi eziyi-15 kunenani le-Rct (32 kΩ cm2) lapho kukhona i-P. aeruginosa. Ngakho-ke, i-2707 HDSS inokumelana okuhle kakhulu nokugqwala endaweni engcolile, kodwa ayimelani nama-MIC avela kuma-biofilms e-P. aeruginosa.
Le miphumela ingabonakala futhi kusukela kuma-polarization curves ku-Figs. 2b. Ukusabalala kwe-anodic kuye kwahlotshaniswa nokwakheka kwe-Pseudomonas aeruginosa biofilm kanye nokusabela kwe-oxidation yensimbi. Kulesi simo, ukusabela kwe-cathodic ukunciphisa umoya-mpilo. Ukuba khona kwe-P. aeruginosa kwandise kakhulu ubuningi bamanje okugqwala, cishe ngomyalelo wobukhulu obuphakeme kunokulawulwa kwe-abiotic. Lokhu kubonisa ukuthi i-P. aeruginosa biofilm ithuthukisa ukugqwala kwendawo kwe-2707 HDSS. UYuan et al.29 bathole ukuthi ubuningi bamanje okugqwala kwe-Cu-Ni 70/30 alloy banda ngaphansi kwesenzo se-P. aeruginosa biofilm. Lokhu kungase kube ngenxa ye-biocatalysis yokunciphisa umoya-mpilo yi-Pseudomonas aeruginosa biofilms. Lokhu kuqaphela kungachaza ne-MIC 2707 HDSS kulo msebenzi. Kungase kube nomoya-mpilo omncane ngaphansi kwe-aerobic biofilms. Ngakho-ke, ukwenqaba ukuphinda kudlule ubuso bensimbi nge-oxygen kungaba yisici esifaka isandla ku-MIC kulo msebenzi.
UDickinson nabanye 38 basikisele ukuthi izinga lokusabela kwamakhemikhali kanye ne-electrochemical lingathinteka ngqo ngumsebenzi we-metabolic wamabhaktheriya e-sessile ebusweni besampula kanye nohlobo lwemikhiqizo yokugqwala. Njengoba kuboniswe ku-Figure 5 kanye neThebula 5, inani lamaseli kanye nobukhulu be-biofilm lehle ngemva kwezinsuku ezingu-14. Lokhu kungachazwa ngokunengqondo iqiniso lokuthi ngemva kwezinsuku ezingu-14, iningi lamaseli e-sessile ebusweni be-2707 HDSS lafa ngenxa yokuncipha kwezakhamzimba endaweni ye-2216E noma ukukhishwa kwama-ion ensimbi anobuthi avela ku-2707 HDSS matrix. Lokhu kungumkhawulo wokuhlolwa kwe-batch.
Kulo msebenzi, i-biofilm ye-P. aeruginosa inegalelo ekunciphiseni i-Cr ne-Fe endaweni ngaphansi kwe-biofilm ebusweni be-2707 HDSS (Isithombe 6). Ithebula 6 likhombisa ukwehla kwe-Fe ne-Cr kusampula D uma kuqhathaniswa nesampula C, okubonisa ukuthi i-Fe ne-Cr encibilikisiwe ebangelwe yi-biofilm ye-P. aeruginosa yaqhubeka izinsuku eziyi-7 zokuqala. Indawo ezungezile engu-2216E isetshenziselwa ukulingisa indawo ezungezile yasolwandle. Iqukethe i-17700 ppm Cl-, efana nokuqukethwe kwayo emanzini olwandle emvelo. Ukuba khona kwe-17700 ppm Cl- kwakuyisizathu esiyinhloko sokwehla kwe-Cr kumasampula e-abiotic ezinsuku eziyi-7 nezinsuku eziyi-14 ahlaziywe yi-XPS. Uma kuqhathaniswa namasampula e-P. aeruginosa, ukuncibilika kwe-Cr kumasampula e-abiotic kwakuncane kakhulu ngenxa yokumelana okunamandla kwe-2707 HDSS ne-chlorine ngaphansi kwezimo ze-abiotic. Kumfanekiso 9 kukhombisa ukuba khona kwe-Cr6+ kufilimu edlulayo. Kungase kuhileleke ekususweni kwe-chromium ezindaweni zensimbi yi-P. aeruginosa biofilms, njengoba kuphakanyiswe nguChen noClayton.
Ngenxa yokukhula kwamagciwane, amanani e-pH ye-medium ngaphambi nangemva kokutshala ayengu-7.4 no-8.2, ngokulandelana. Ngakho-ke, ngaphansi kwe-biofilm ye-P. aeruginosa, ukugqwala kwe-organic acid akunakwenzeka ukuthi kufake isandla kulo msebenzi ngenxa ye-pH ephezulu kakhulu ku-bulk medium. I-pH ye-non-biological control medium ayizange ishintshe kakhulu (kusukela ku-7.4 yokuqala kuya ku-7.5 yokugcina) phakathi nesikhathi sokuhlolwa sezinsuku ezingu-14. Ukwanda kwe-pH ku-seed medium ngemva kokufukamela kwakungenxa yomsebenzi we-metabolic we-P. aeruginosa futhi kwatholakala ukuthi kunomphumela ofanayo ku-pH lapho kungekho khona imichilo yokuhlola.
Njengoba kuboniswe kuMfanekiso 7, ukujula okukhulu komgodi okubangelwa yi-P. aeruginosa biofilm kwakungu-0.69 µm, okungaphezulu kakhulu kunalokho kwe-abiotic medium (0.02 µm). Lokhu kuhambisana nedatha ye-electrochemical echazwe ngenhla. Ukujula komgodi okungu-0.69 µm kuncane ngokuphindwe kayishumi kunenani elingu-9.5 µm elibikwe nge-2205 DSS ngaphansi kwezimo ezifanayo. Le datha ikhombisa ukuthi i-2707 HDSS ikhombisa ukumelana okungcono nama-MIC kune-2205 DSS. Lokhu akufanele kumangaze ngoba i-2707 HDSS inamazinga aphezulu e-Cr ahlinzeka ngokungasebenzi isikhathi eside, kunzima kakhulu ukuyisusa i-P. aeruginosa, futhi ngenxa yesakhiwo sayo sesigaba esilinganiselayo ngaphandle kwemvula yesibili eyingozi kubangela umgodi.
Ekuphetheni, imigodi ye-MIC itholakale ebusweni be-2707 HDSS kumhluzi we-P. aeruginosa uma kuqhathaniswa nemigodi engabalulekile endaweni engeyona i-abiotic. Lo msebenzi ukhombisa ukuthi i-2707 HDSS inokumelana okungcono ne-MIC kune-2205 DSS, kodwa ayivikelekile ngokuphelele ku-MIC ngenxa ye-P. aeruginosa biofilm. Le miphumela isiza ekukhetheni izinsimbi ezingagqwali ezifanele kanye nobude besikhathi sokuphila kwemvelo yasolwandle.
Ikhuphoni le-2707 HDSS elinikezwe yi-Northeastern University (NEU) School of Metallurgy eShenyang, eShayina. Ukwakheka kwezakhi ze-2707 HDSS kuboniswe kuThebula 1, elahlaziywa yi-NEU Materials Analysis and Testing Department. Wonke amasampula aphathwa ngesisombululo esiqinile ku-1180°C ihora eli-1. Ngaphambi kokuhlolwa kokugqwala, i-2707 HDSS emise okwenhlamvu yesiliva enendawo evulekile ephezulu engu-1 cm2 yapholishwa yaba yi-grit engu-2000 nge-sandpaper ye-silicon carbide yabe isipholishwa nge-slurry yempuphu engu-0.05 µm Al2O3. Izinhlangothi kanye nephansi zivikelwe ngopende ongagqwali. Ngemva kokomiswa, amasampula ahlanzwa ngamanzi angcolile ahlanziwe futhi ahlanzwe nge-ethanol engu-75% (v/v) amahora angu-0.5. Abe eseyomiswa emoyeni ngaphansi kokukhanya kwe-ultraviolet (UV) amahora angu-0.5 ngaphambi kokusetshenziswa.
Uhlobo lwe-Marine Pseudomonas aeruginosa MCCC 1A00099 lwathengwa e-Xiamen Marine Culture Collection Center (MCCC), eShayina. I-Pseudomonas aeruginosa yakhuliswa ngaphansi kwezimo ze-aerobic ku-37° C. emaflaskini angu-250 ml kanye namaseli e-electrochemical engilazi angu-500 ml kusetshenziswa i-Marine 2216E liquid medium (Qingdao Hope Biotechnology Co., Ltd., eQingdao, eShayina). Okuphakathi kuqukethe (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 6NH26NH3, 3.0016 NH3 5.0 peptone, 1.0 yeast extract kanye ne-0.1 iron citrate. I-Autoclave ku-121°C imizuzu engama-20 ngaphambi kokugonywa. Bala amaseli e-sessile kanye ne-planktonic nge-hemocytometer ngaphansi kwe-microscope ekhanyayo ku-400x magnification. Ukuhlushwa kokuqala kwe-planktonic Pseudomonas aeruginosa ngokushesha ngemva kokugonywa kwakungaba amaseli ayi-106/ml.
Ukuhlolwa kwe-electrochemical kwenziwe ngeseli yengilazi yama-electrode amathathu yakudala enomthamo ophakathi ongu-500 ml. Ishidi leplatinum kanye ne-electrode ye-calomel egcwele (SAE) kuxhunywe ku-reactor ngama-capillary e-Luggin agcwele amabhuloho kasawoti, asebenza njengama-electrode aphikisayo nawabhekiselayo, ngokulandelana. Ekwenzeni ama-electrode asebenzayo, ucingo lwethusi olufakwe irabha lwalunamathiselwe kusampula ngayinye futhi lwambozwa nge-epoxy resin, kwasala cishe indawo engu-1 cm2 engavikelekile ye-electrode esebenzayo ohlangothini olulodwa. Ngesikhathi sokulinganisa kwe-electrochemical, amasampula abekwa endaweni ye-2216E futhi agcinwa ekushiseni okuhlala njalo kwe-incubation (37°C) ebhavini lamanzi. Idatha ye-OCP, i-LPR, i-EIS kanye nedatha ye-polarization enamandla engaba khona yalinganiswa kusetshenziswa i-Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA). Ukuhlolwa kwe-LPR kwaqoshwa ngesilinganiso sokuskena esingu-0.125 mV s-1 ebangeni eliphakathi kuka--5 kuya ku-5 mV ne-Eocp kanye nesilinganiso sokusampula esingu-1 Hz. I-EIS yenziwe nge-sine wave phezu kwebanga lemvamisa eliphakathi kuka-0.01 no-10,000 Hz kusetshenziswa i-voltage esetshenzisiwe engu-5 mV ku-Eocp ezinzile. Ngaphambi kokushanela okungenzeka, ama-electrode ayekwimodi yokungenzi lutho kuze kube yilapho kufinyelelwa inani elizinzile le-free corrosion potential. Ama-polarization curves abe eselinganiswa kusukela ku--0.2 kuya ku-1.5 V njengomsebenzi we-Eocp ngesilinganiso sokuskena esingu-0.166 mV/s. Ukuhlolwa ngakunye kwaphindwa izikhathi ezi-3 nge-P. aeruginosa nangaphandle kwayo.
Amasampula okuhlaziywa kwe-metallographic apholishwe ngomshini ngephepha le-SiC elimanzi elingu-2000 grit bese epholishwa ngokwengeziwe nge-0.05 µm Al2O3 powder suspension ukuze kubhekwe ngamehlo. Ukuhlaziywa kwe-Metallographic kwenziwa kusetshenziswa i-optical microscope. Amasampula aqoshwe ngesisombululo se-potassium hydroxide esingu-10% esingu-43.
Ngemva kokufukamela, amasampula ahlanzwa izikhathi ezintathu nge-phosphate buffered saline (PBS) (pH 7.4 ± 0.2) bese elungiswa nge-2.5% (v/v) glutaraldehyde amahora ayi-10 ukuze kulungiswe ama-biofilms. Abe esekhishwa amanzi nge-ethanol ehlanganisiwe (50%, 60%, 70%, 80%, 90%, 95% kanye no-100% ngevolumu) ngaphambi kokumiswa emoyeni. Ekugcineni, ifilimu yegolide ifakwa ebusweni besampula ukuze inikeze ukuhanjiswa kokubona kwe-SEM. Izithombe ze-SEM zigxile ezindaweni ezinamaseli e-P. aeruginosa athambile kakhulu ebusweni besampula ngayinye. Yenza ukuhlaziywa kwe-EDS ukuthola izakhi zamakhemikhali. I-microscope ye-Zeiss confocal laser scanning (CLSM) (LSM 710, Zeiss, Germany) yasetshenziswa ukukala ukujula komgodi. Ukuze kubhekwe imigodi yokugqwala ngaphansi kwe-biofilm, isampula yokuhlola yaqale yahlanzwa ngokwe-Chinese National Standard (CNS) GB/T4334.4-2000 ukuze kususwe imikhiqizo yokugqwala kanye ne-biofilm ebusweni besampula yokuhlola.
Ukuhlaziywa kwe-X-ray photoelectron spectroscopy (XPS, ESCALAB250 surface analysis system, Thermo VG, USA) kwenziwe kusetshenziswa umthombo we-X-ray we-monochromatic (umugqa we-Aluminium Kα onamandla angu-1500 eV kanye namandla angu-150 W) ebangeni elibanzi lamandla okubopha angu-0 ngaphansi kwezimo ezijwayelekile ezingu- –1350 eV. Ama-spectra anesinqumo esiphezulu aqoshwa kusetshenziswa amandla okudlulisa angu-50 eV kanye nesinyathelo esingu-0.2 eV.
Amasampula afakwe esikhumbeni asusiwe futhi ahlanzwa ngobumnene nge-PBS (pH 7.4 ± 0.2) imizuzu engu-15 s45. Ukuze kubonwe ukuthi ama-biofilms aphila kahle yini ngamabhaktheriya kumasampula, ama-biofilms afakwe esikhumbeni kusetshenziswa i-LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA). Ikhithi iqukethe amadayi amabili e-fluorescent: idayi eluhlaza okwesibhakabhaka ye-SYTO-9 kanye nedayi ebomvu ye-propidium iodide (PI). Ku-CLSM, amachashazi aluhlaza okwesibhakabhaka kanye namachashazi abomvu amelela amangqamuzana aphilayo nafile, ngokulandelana. Ukuze kufakwe esikhumbeni, i-1 ml yengxube equkethe i-3 µl yesisombululo se-SYTO-9 kanye ne-3 µl yesisombululo se-PI yafakwa esikhumbeni imizuzu engama-20 ekushiseni kwegumbi (23°C) ebumnyameni. Ngemva kwalokho, amasampula afakwe esikhumbeni ahlolwa ngama-wavelength amabili (488 nm yamaseli aphilayo kanye ne-559 nm yamaseli afile) kusetshenziswa idivayisi ye-Nikon CLSM (C2 Plus, Nikon, Japan). Ubukhulu be-biofilm balinganiswa ngemodi yokuskena ye-3D.
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