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Ukugqwala kweMicrobial (MIC) yingxaki enkulu kumashishini amaninzi, njengoko kunokukhokelela ekulahlekelweni okukhulu kwezoqoqosho. I-Super duplex stainless steel 2707 (2707 HDSS) isetyenziswa kwiindawo zaselwandle ngenxa yokuxhathisa kwayo kakuhle kweekhemikhali. Nangona kunjalo, ukuxhathisa kwayo kwiMIC akukabonakaliswa ngovavanyo. Olu phononongo luhlolisise indlela esebenza ngayo iMIC 2707 HDSS ebangelwa yibhaktiriya ye-aerobic yolwandle iPseudomonas aeruginosa. Uhlalutyo lwe-electrochemical lubonise ukuba xa kukho iPseudomonas aeruginosa biofilm kwi-2216E medium, utshintsho oluhle kwi-corrosion potential kunye nokwanda koxinano lwangoku lokugqwala kwenzeka. Uhlalutyo lwe-X-ray photoelectron spectroscopy (XPS) lubonise ukwehla komxholo weCr kumphezulu wesampuli phantsi kwe-biofilm. Uhlalutyo olubonakalayo lwemigodi lubonise ukuba i-P. aeruginosa biofilm ivelise ubunzulu obukhulu bomngxuma obuyi-0.69 µm ngexesha leentsuku ezili-14 zokufukamela. Nangona oku kuncinci, kubonisa ukuba i-2707 HDSS ayikhuselekanga ngokupheleleyo kwi-MIC ye-P. aeruginosa biofilms.
Iintsimbi eziqinileyo eziphindwe kabini (DSS) zisetyenziswa kakhulu kumashishini ahlukeneyo ngenxa yokudibanisa okugqibeleleyo kweempawu ezibalaseleyo zoomatshini kunye nokumelana nokugqwala1,2. Nangona kunjalo, ukugoba okukwindawo ethile kusenzeka kwaye kuchaphazela ukuthembeka kwale ntsimbi3,4. I-DSS ayimelani nokugqwala kweentsholongwane (MIC)5,6. Nangona kukho uluhlu olubanzi lwezicelo ze-DSS, kusekho iindawo apho ukumelana nokugqwala kwe-DSS kungonelanga ukusetyenziswa ixesha elide. Oku kuthetha ukuba kufuneka izinto ezibiza kakhulu ezinokumelana nokugqwala okuphezulu. UJeon et al7 bafumanise ukuba neentsimbi eziqinileyo eziphindwe kabini (SDSS) zinemida ethile ngokubhekiselele ekumelaneni nokugqwala. Ke ngoko, kwezinye iimeko, kufuneka iintsimbi eziqinileyo eziphindwe kabini (HDSS) ezinokumelana nokugqwala okuphezulu. Oku kukhokelele ekuphuhlisweni kwe-HDSS exutywe kakhulu.
Ukumelana nokugqwala I-DSS ixhomekeke kumlinganiselo wezigaba ze-alpha kunye ne-gamma kwaye inciphile kwiindawo ze-Cr, Mo kunye ne-W 8, 9, 10 ezikufutshane nesigaba sesibini. I-HDSS iqulethe umxholo ophezulu we-Cr, Mo kunye ne-N11, ngoko ke inokumelana nokugqwala okugqwesileyo kunye nexabiso eliphezulu (45-50) lenani elilinganayo lokumelana nokugqwala (PREN) elimiselwe yi-wt.% Cr + 3.3 (wt.% Mo + 0.5 wt. .%W) + 16% wt. N12. Ukumelana kwayo nokugqwala okugqwesileyo kuxhomekeke kulwakhiwo olulinganiselayo oluqulethe malunga ne-50% ye-ferritic (α) kunye ne-50% ye-austenitic (γ). I-HDSS ineempawu ezingcono zoomatshini kunye nokumelana okuphezulu nokugqwala kwe-chloride. Ukumelana nokugqwala okuphuculweyo kwandisa ukusetyenziswa kwe-HDSS kwiindawo ezinoburhalarhume ngakumbi ze-chloride ezifana neendawo zaselwandle.
Ii-MIC ziyingxaki enkulu kumashishini amaninzi afana neoyile, igesi kunye namanzi14. I-MIC ibangela i-20% yomonakalo wonke wokugqwala15. I-MIC yi-bioelectrochemical corrosion enokubonwa kwiindawo ezininzi. Ii-biofilms ezikwiindawo zesinyithi zitshintsha iimeko ze-electrochemical, ngaloo ndlela zichaphazela inkqubo yokugqwala. Kukholelwa ngokubanzi ukuba ukugqwala kwe-MIC kubangelwa zii-biofilms. Ii-microorganisms ze-electrogenic zidla iisinyithi ukuze zifumane amandla eziwadingayo ukuze ziphile17. Izifundo zamva nje ze-MIC zibonise ukuba i-EET (ukudluliselwa kwee-electron ezingaphandle kweseli) yeyona nto ithintela izinga kwi-MIC ebangelwa zii-microorganisms ze-electrogenic. UZhang et al. 18 ubonise ukuba abalamli bee-electron bakhawulezisa ukudluliselwa kwee-electron phakathi kweeseli ze-Desulfovibrio sessificans kunye ne-304 stainless steel, nto leyo ebangela uhlaselo olubi kakhulu lwe-MIC. U-Anning et al. 19 kunye no-Wenzlaff et al. 20 babonise ukuba ii-biofilms zeebhaktheriya ezinciphisa i-sulfate erhabaxa (ii-SRB) zinokufunxa ngokuthe ngqo ii-electron kwi-substrates zesinyithi, nto leyo ebangela ukungxwelerha okukhulu.
I-DSS yaziwa ngokuba sengozini ye-MIC kwiindawo eziqulethe ii-SRB, iibhaktheriya ezinciphisa isinyithi (ii-IRB), njl. 21. Ezi bhaktheriya zibangela ukuqhekeka kwendawo ethile kumphezulu we-DSS phantsi kwe-biofilms22,23. Ngokungafaniyo ne-DSS, i-HDSS24 MIC ayaziwa kakuhle.
I-Pseudomonas aeruginosa yintsholongwane ene-Gram-negative, ehambayo, efana nenduku esasazeke kakhulu kwindalo25. I-Pseudomonas aeruginosa ikwaliqela elikhulu leentsholongwane kwindalo yaselwandle, nto leyo ebangela ubuninzi be-MIC. I-Pseudomonas ibandakanyeka ngokukhutheleyo kwinkqubo yokugqwala kwaye iqatshelwa njenge-colonizer yokuqala ngexesha lokwenziwa kwe-biofilm. UMahat et al. 28 kunye noYuan et al. 29 babonise ukuba i-Pseudomonas aeruginosa ithambekele ekonyuseni izinga lokugqwala kwentsimbi ethambileyo kunye nee-alloys kwiindawo zasemanzini.
Injongo ephambili yalo msebenzi yayikukuphanda iipropati ze-MIC 2707 HDSS ezibangelwa yibhaktiriya ye-aerobic yolwandle i-Pseudomonas aeruginosa kusetyenziswa iindlela ze-electrochemical, iindlela zohlalutyo lomphezulu kunye nohlalutyo lwemveliso yokugqwala. Izifundo ze-electrochemical, kuquka i-open circuit potential (OCP), i-linear polarization resistance (LPR), i-electrochemical impedance spectroscopy (EIS), kunye ne-potential dynamic polarization, zenziwe ukuze kufundwe indlela yokuziphatha kwe-MIC 2707 HDSS. Uhlalutyo lwe-Energy dispersive spectrometric (EDS) lwenziwe ukuze kubonwe izinto zeekhemikhali kumphezulu ogqwalileyo. Ukongeza, i-X-ray photoelectron spectroscopy (XPS) yasetyenziswa ukufumanisa uzinzo lwe-oxide film passivation phantsi kwempembelelo yendawo yolwandle equlethe i-Pseudomonas aeruginosa. Ubunzulu bemigodi bulinganiswe phantsi kwe-confocal laser scanning microscope (CLSM).
Itheyibhile 1 ibonisa ukwakheka kweekhemikhali ze-2707 HDSS. Itheyibhile 2 ibonisa ukuba i-2707 HDSS ineempawu ezibalaseleyo zoomatshini ezinamandla okuvelisa angama-650 MPa. Kumfanekiso 1 ibonisa isakhiwo se-optical microstructure sesisombululo esiphathwe ngobushushu se-2707 HDSS. Kwisakhiwo se-microstructure esine-50% ye-austenite kunye ne-50% ye-ferrite, iibhendi ezinde zesigaba se-austenite kunye ne-ferrite ngaphandle kwesigaba sesibini ziyabonakala.
Kumfanekiso 2a ubonisa amandla okuvula isekethe (i-Eocp) xa kuthelekiswa nexesha lokuvezwa kwe-2707 HDSS kwi-2216E abiotic medium kunye nomhluzi we-P. aeruginosa iintsuku ezili-14 kwi-37°C. Ubonisa ukuba utshintsho olukhulu nolubalulekileyo kwi-Eocp lwenzeka kwiiyure ezingama-24 zokuqala. Amaxabiso e-Eocp kuzo zombini iimeko afikelele kwi--145 mV (xa kuthelekiswa ne-SCE) malunga neeyure ezili-16 aze ehle kakhulu, afikelela kwi--477 mV (xa kuthelekiswa ne-SCE) kunye ne--236 mV (xa kuthelekiswa ne-SCE) kwisampuli ye-abiotic. kunye neekhuphoni ze-P Pseudomonas aeruginosa, ngokulandelelana). Emva kweeyure ezingama-24, ixabiso le-Eocp 2707 HDSS le-P. aeruginosa lalizinzile kwi--228 mV (xa kuthelekiswa ne-SCE), ngelixa ixabiso elihambelanayo leesampuli ezingezizo zebhayoloji lalimalunga ne--442 mV (xa kuthelekiswa ne-SCE). I-Eocp xa kukho i-P. aeruginosa yayiphantsi kakhulu.
Uphononongo lwe-electrochemical lweesampuli ze-HDSS ezingama-2707 kwi-abiotic medium kunye nomhluzi we-Pseudomonas aeruginosa kwi-37 °C:
(a) I-Eocp njengomsebenzi wexesha lokuvezwa, (b) ii-polarization curves ngomhla we-14, (c) i-Rp njengomsebenzi wexesha lokuvezwa, kunye (d) i-icorr njengomsebenzi wexesha lokuvezwa.
Itheyibhile 3 ibonisa iiparameter ze-electrochemical corrosion zeesampulu ze-HDSS ezingama-2707 ezivezwe kwi-abiotic kunye ne-Pseudomonas aeruginosa ezifakwe kwi-inculated media kwixesha leentsuku ezili-14. Ii-tangents ze-anode kunye ne-cathode curves zahlulwahlulwa ukuze kufunyanwe iindlela ezinika i-corrosion current density (icorr), i-corrosion potential (Ecorr) kunye ne-Tafel slope (βα kunye ne-βc) ngokweendlela eziqhelekileyo30,31.
Njengoko kubonisiwe kumzobo 2b, utshintsho oluphezulu kwi-P. aeruginosa curve lubangele ukwanda kwe-Ecorr xa kuthelekiswa ne-abiotic curve. Ixabiso le-icorr, elilingana nesantya sokugqwala, linyuke laya kwi-0.328 µA cm-2 kwisampuli ye-Pseudomonas aeruginosa, elikhulu ngokuphindwe kane kunesampuli engeyiyo yebhayoloji (0.087 µA cm-2).
I-LPR yindlela ye-electrochemical engaqhelekanga engatshabalalisiyo yohlalutyo lokugqwala ngokukhawuleza. Ikwasetyenzisiwe ekufundeni i-MIC32. Kumfanekiso 2c ubonisa ukumelana kwe-polarization (Rp) njengomsebenzi wexesha lokuvezwa. Ixabiso eliphezulu le-Rp lithetha ukugqwala okuncinci. Kwiiyure zokuqala ezingama-24, i-Rp 2707 HDSS ifikelele kwi-1955 kΩ cm2 kwiisampuli ze-abiotic kunye ne-1429 kΩ cm2 kwiisampuli ze-Pseudomonas aeruginosa. Umfanekiso 2c ubonisa nokuba ixabiso le-Rp lehle ngokukhawuleza emva kosuku olunye laza lahlala lingatshintshanga kwiintsuku ezili-13 ezilandelayo. Ixabiso le-Rp lesampuli ye-Pseudomonas aeruginosa limalunga ne-40 kΩ cm2, eliphantsi kakhulu kunexabiso le-450 kΩ cm2 lesampuli engeyiyo yebhayoloji.
Ixabiso le-icorr lilingana nezinga lokugqwala elifanayo. Ixabiso layo lingabalwa kwi-equation elandelayo ye-Stern-Giri:
Ngokutsho kukaZoe et al. 33, ixabiso eliqhelekileyo le-Tafel slope B kulo msebenzi lithathwe njenge-26 mV/dec. Umfanekiso 2d ubonisa ukuba i-icorr yesampulu engeyoyebhayoloji engu-2707 yahlala izinzile, ngelixa isampulu ye-P. aeruginosa yatshintshatshintsha kakhulu emva kweeyure zokuqala ezingama-24. Amaxabiso e-icorr eesampulu ze-P. aeruginosa ayephezulu kakhulu kunezolawulo ezingezizo zebhayoloji. Olu hlobo luhambelana neziphumo zokumelana ne-polarization.
I-EIS yenye indlela engonakalisiyo esetyenziselwa ukuchaza iimpendulo ze-electrochemical kwiindawo ezibolileyo. I-Impedance spectra kunye ne-calculated capacitance values ​​​​zeesampuli ezivezwe kwindawo engabonakaliyo kunye nesisombululo se-Pseudomonas aeruginosa, i-passive film/biofilm resistance Rb eyenziwe kumphezulu wesampuli, i-charge transfer resistance Rct, i-electrical double layer capacitance Cdl (EDL) kunye ne-constant QCPE Phase element parameters (CPE). Ezi parameters zahlalutywa ngakumbi ngokufakela idatha kusetyenziswa imodeli ye-equivalent circuit (EEC).
Kumfanekiso 3 kubonisa iiploti eziqhelekileyo zeNyquist (a kunye no-b) kunye neeploti zeBode (a' kunye no-b') zeesampuli ze-HDSS ezingama-2707 kwimidiya ye-abiotic kunye nomhluzi we-P. aeruginosa ngamaxesha ahlukeneyo okufunxa. Ububanzi bendandatho yeNyquist buyancipha xa kukho iPseudomonas aeruginosa. Iploti yeBode (Umfanekiso 3b') ibonisa ukwanda kwe-impedance iyonke. Ulwazi malunga ne-relaxation time constant lunokufunyanwa kwi-phase maxima. Kumfanekiso 4 kubonisa izakhiwo zomzimba ezisekelwe kwi-monolayer (a) kunye ne-bilayer (b) kunye nee-EECs ezifanelekileyo. I-CPE ingeniswa kwimodeli ye-EEC. Ukwamkelwa kwayo kunye ne-impedance zivezwa ngolu hlobo lulandelayo:
Iimodeli ezimbini ezibonakalayo kunye neesekethe ezilinganayo ezifanelekileyo zokufaka i-impedance spectrum yesampuli 2707 HDSS:
apho u-Y0 lixabiso le-KPI, u-j linani elicingelwayo okanye (-1)1/2, u-ω li-angular frequency, u-n li-KPI power index engaphantsi kwe-135. Ukuguqulwa kokumelana nokudluliselwa kwetshaja (oko kukuthi i-1/Rct) kuhambelana nesantya sokugqwala. I-Rct encinci, kokukhona izinga lokugqwala liphezulu27. Emva kweentsuku ezili-14 zokufukamela, iisampulu ze-Rct ze-Pseudomonas aeruginosa zifikelele kwi-32 kΩ cm2, ezingaphantsi kakhulu kune-489 kΩ cm2 yeesampulu ezingezizo zebhayoloji (Itheyibhile 4).
Imifanekiso ye-CLSM kunye nemifanekiso ye-SEM kuMfanekiso 5 ibonisa ngokucacileyo ukuba uqweqwe lwe-biofilm kumphezulu wesampuli ye-HDSS 2707 emva kweentsuku ezi-7 luxinene. Nangona kunjalo, emva kweentsuku ezili-14, ukugqunywa kwe-biofilm kwakungacacanga kwaye kwavela ezinye iiseli ezifileyo. Itheyibhile 5 ibonisa ubukhulu be-biofilm kwiisampulu ze-HDSS ezingama-2707 emva kokuvezwa kwi-P. aeruginosa kangangeentsuku ezi-7 kunye ne-14. Ubukhulu be-biofilm obukhulu butshintshe ukusuka kwi-23.4 µm emva kweentsuku ezi-7 ukuya kwi-18.9 µm emva kweentsuku ezili-14. Ubukhulu be-biofilm obuqhelekileyo nabo buqinisekisile le ndlela. Yehle ukusuka kwi-22.2 ± 0.7 μm emva kweentsuku ezi-7 ukuya kwi-17.8 ± 1.0 μm emva kweentsuku ezili-14.
(a) Umfanekiso we-3-D CLSM kwiintsuku ezisi-7, (b) Umfanekiso we-3-D CLSM kwiintsuku ezili-14, (c) Umfanekiso we-SEM kwiintsuku ezisi-7, kunye (d) nomfanekiso we-SEM kwiintsuku ezili-14.
I-EMF ityhile izinto zeekhemikhali kwi-biofilms nakwiimveliso zokugqwala kwiisampuli ezivezwe kwi-P. aeruginosa kangangeentsuku ezili-14. Kumfanekiso 6, ubonisa ukuba umxholo we-C, N, O, kunye ne-P kwi-biofilms nakwiimveliso zokugqwala uphezulu kakhulu kunakwiintsimbi ezicocekileyo, kuba ezi zinto zinxulunyaniswa ne-biofilms kunye nee-metabolites zazo. Iintsholongwane zifuna kuphela izixa ezincinci ze-chromium kunye ne-iron. Amanqanaba aphezulu e-Cr kunye ne-Fe kwi-biofilm kunye neemveliso zokugqwala kumphezulu weesampuli abonisa ukuba i-metal matrix ilahlekelwe zizinto ngenxa yokugqwala.
Emva kweentsuku ezili-14, imingxunya ene-P. aeruginosa nengenayo yabonwa kwi-medium 2216E. Ngaphambi kokufunxwa, umphezulu weesampuli wawugudile kwaye ungenaziphene (Umzobo 7a). Emva kokufunxwa nokususwa kweemveliso ze-biofilm kunye nokugqwala, imingxunya enzulu kumphezulu weesampuli yahlolwa kusetyenziswa i-CLSM, njengoko kubonisiwe kwiFig. 7b kunye no-c. Akukho mingxunya icacileyo yafunyanwa kumphezulu wolawulo olungengolwebhayoloji (ubunzulu obukhulu bemingxunya yi-0.02 µm). Ubunzulu obukhulu bemingxunya obubangelwe yi-P. aeruginosa yayiyi-0.52 µm kwiintsuku ezisi-7 kunye ne-0.69 µm kwiintsuku ezili-14, ngokusekelwe kubunzulu obukhulu bemingxunya ukusuka kwiisampuli ezi-3 (ubunzulu obukhulu bemingxunya bukhethwe kwisampuli nganye). Ukufezekiswa kwe-0.42 ± 0.12 µm kunye ne-0.52 ± 0.15 µm, ngokulandelanayo (Itheyibhile 5). La maxabiso obunzulu bemingxunya mancinci kodwa abalulekile.
(a) ngaphambi kokuvezwa, (b) iintsuku ezili-14 kwindawo engenazo izinto eziphilayo, kunye (c) iintsuku ezili-14 kwi-Pseudomonas aeruginosa broth.
Kwitheyibhile 8 ibonisa ii-spectra ze-XPS zeendawo ezahlukeneyo zeesampuli, kwaye ukwakheka kweekhemikhali okuhlalutyiweyo kumphezulu ngamnye kushwankathelwe kwiTheyibhile 6. KwiTheyibhile 6, iipesenti ze-athomu ze-Fe kunye ne-Cr xa kukho i-P. aeruginosa (iisampuli A kunye ne-B) zaziphantsi kakhulu kunezo zolawulo olungelulo lwebhayoloji. (iisampuli C kunye ne-D). Kwisampuli ye-P. aeruginosa, i-spectral curve kwinqanaba le-nucleus ye-Cr 2p ifakwe kwiinxalenye ezine ze-peak ezine-binding energy (BE) ze-574.4, 576.6, 578.3 kunye ne-586.8 eV, ezinokubangelwa yi-Cr, Cr2O3, CrO3. kunye ne-Cr(OH)3, ngokulandelelana (Umzobo 9a kunye no-b). Kwiisampuli ezingezizo zebhayoloji, i-spectrum yenqanaba eliphambili le-Cr 2p iqulethe iincopho ezimbini eziphambili ze-Cr (573.80 eV ye-BE) kunye ne-Cr2O3 (575.90 eV ye-BE) kwiMifanekiso. 9c kunye no-d, ngokulandelelana. Umahluko omkhulu phakathi kweesampuli ze-abiotic kunye neesampuli ze-P. aeruginosa yayikukubakho kwe-Cr6+ kunye nenani eliphezulu le-Cr(OH)3 (BE 586.8 eV) phantsi kwe-biofilm.
I-spectra ebanzi ye-XPS yomphezulu wesampulu ye-2707 HDSS kwiimidiya ezimbini ziintsuku ezisi-7 kunye nezili-14, ngokulandelelana.
(a) Ukuchatshazelwa yi-P. aeruginosa iintsuku ezisi-7, (b) Ukuchatshazelwa yi-P. aeruginosa iintsuku ezili-14, (c) Ukuchatshazelwa yi-abiotic iintsuku ezisi-7, kunye (d) Ukuchatshazelwa yi-abiotic iintsuku ezili-14.
I-HDSS ibonisa inqanaba eliphezulu lokuxhathisa ukugqwala kwiindawo ezininzi. UKim et al.2 baxele ukuba i-HDSS UNS S32707 ichongiwe njenge-DSS exutywe kakhulu ene-PREN engaphezulu kwama-45. Ixabiso le-PREN lesampulu ye-2707 HDSS kulo msebenzi yayiyi-49. Oku kungenxa yomxholo ophezulu we-chromium kunye nomxholo ophezulu we-molybdenum kunye ne-nickel, eziluncedo kwiindawo ezine-acidic. kunye neendawo ezinomxholo ophezulu we-chloride. Ukongeza, ukwakheka okulinganisiweyo kakuhle kunye nesakhiwo esingenaziphene ziluncedo ekuzinzeni kwesakhiwo kunye nokuxhathisa ukugqwala. Nangona kunjalo, nangona ixhathisa kakhulu iikhemikhali, idatha yovavanyo kulo msebenzi ibonisa ukuba i-2707 HDSS ayikhuselekanga ngokupheleleyo kwi-P. aeruginosa biofilm MICs.
Iziphumo ze-electrochemical zibonise ukuba izinga lokugqwala kwe-2707 HDSS kumhluzi we-P. aeruginosa linyuke kakhulu emva kweentsuku ezili-14 xa kuthelekiswa nendawo engeyiyo yebhayoloji. KuMfanekiso 2a, ukwehla kwe-Eocp kwabonwa kokubini kwindawo ye-abiotic nakwi-P. aeruginosa broth kwiiyure zokuqala ezingama-24. Emva koko, i-biofilm igubungela ngokupheleleyo umphezulu wesampulu, kwaye i-Eocp iba nozinzo36. Nangona kunjalo, inqanaba le-Eocp yebhayoloji laliphezulu kakhulu kunenqanaba le-Eocp engeyiyo yebhayoloji. Kukho izizathu zokukholelwa ukuba lo mahluko unxulunyaniswa nokwakheka kwe-biofilms ze-P. aeruginosa. Kwi-fig. 2d phambi kwe-P. aeruginosa, ixabiso le-icorr 2707 HDSS lifikelele kwi-0.627 μA cm-2, eliyi-order yobukhulu obuphezulu kunelo lolawulo lwe-abiotic (0.063 μA cm-2), elalihambelana nexabiso le-Rct elilinganiswe yi-EIS. Kwiintsuku ezimbalwa zokuqala, amaxabiso e-impedance kumhluzi we-P. aeruginosa anda ngenxa yokuncamathiselwa kweeseli ze-P. aeruginosa kunye nokwenziwa kwee-biofilms. Nangona kunjalo, xa i-biofilm igubungela ngokupheleleyo umphezulu wesampulu, i-impedance iyancipha. Umaleko okhuselayo uhlaselwa ikakhulu ngenxa yokwenziwa kwee-biofilms kunye nee-biofilm metabolites. Ngenxa yoko, ukumelana nokugqwala kwehla ngokuhamba kwexesha kwaye ukunamathela kwe-P. aeruginosa kubangele ukugqwala kwendawo. Iindlela kwiindawo ze-abiotic zahlukile. Ukuxhathisa ukugqwala kolawulo olungelulo lwebhayoloji kwakuphezulu kakhulu kunexabiso elihambelanayo leesampuli ezivezwe kumhluzi we-P. aeruginosa. Ukongeza, kwi-abiotic accessions, ixabiso le-Rct 2707 HDSS lifikelele kwi-489 kΩ cm2 ngomhla we-14, eliphindwe kalishumi elinesihlanu kunexabiso le-Rct (32 kΩ cm2) xa kukho i-P. aeruginosa. Ngoko ke, i-2707 HDSS inokumelana nokugqwala okugqwesileyo kwindawo engenazintsholongwane, kodwa ayimelani nee-MIC ezivela kwi-P. aeruginosa biofilms.
Ezi ziphumo zinokubonwa nakwii-polarization curves kwiFigs. 2b. Ukuqhekeka kwe-anodic kuye kwanxulunyaniswa nokwakheka kwe-Pseudomonas aeruginosa biofilm kunye neempendulo ze-metal oxidation. Kule meko, i-cathodic reaction kukunciphisa i-oxygen. Ubukho be-P. aeruginosa bunyuse kakhulu uxinano lwangoku lwe-corrosion, malunga nomyalelo ophezulu kakhulu kunolawulo lwe-abiotic. Oku kubonisa ukuba i-P. aeruginosa biofilm inyusa ukubola kwendawo ye-2707 HDSS. UYuan et al.29 bafumanise ukuba uxinano lwangoku lwe-corrosion lwe-Cu-Ni 70/30 alloy lwanda phantsi kwesenzo se-P. aeruginosa biofilm. Oku kusenokubangelwa yi-biocatalysis yokunciphisa i-oxygen yi-Pseudomonas aeruginosa biofilms. Olu qwalaselo lunokuchaza ne-MIC 2707 HDSS kulo msebenzi. Kunokubakho ne-oxygen encinci phantsi kwe-aerobic biofilms. Ke ngoko, ukwala ukuphinda kudlulise umphezulu wesinyithi nge-oxygen kunokuba yinto enegalelo kwi-MIC kulo msebenzi.
UDickinson et al. 38 bacebise ukuba izinga leempendulo zeekhemikhali kunye nee-electrochemical zinokuchaphazeleka ngokuthe ngqo ngumsebenzi we-metabolic weebhaktheriya ze-sessile kumphezulu wesampuli kunye nohlobo lweemveliso zokugqwala. Njengoko kubonisiwe kuMfanekiso 5 kunye neTheyibhile 5, inani leeseli kunye nobukhulu be-biofilm lehlile emva kweentsuku ezili-14. Oku kunokuchazwa ngokufanelekileyo kukuba emva kweentsuku ezili-14, uninzi lweeseli ze-sessile kumphezulu we-2707 HDSS zafa ngenxa yokuphela kwezondlo kwi-2216E medium okanye ukukhululwa kwee-ion zesinyithi ezinobuthi kwi-2707 HDSS matrix. Oku kungumda wovavanyo lwebatch.
Kulo msebenzi, i-biofilm ye-P. aeruginosa inegalelo ekunciphiseni kwe-Cr kunye ne-Fe phantsi kwe-biofilm kumphezulu we-2707 HDSS (Umzobo 6). Itheyibhile 6 ibonisa ukwehla kwe-Fe kunye ne-Cr kwisampulu D xa kuthelekiswa nesampulu C, nto leyo ebonisa ukuba i-Fe kunye ne-Cr enyibilikisiweyo ebangelwe yi-biofilm ye-P. aeruginosa iqhubeke iintsuku ezi-7 zokuqala. Indawo engqongileyo ye-2216E isetyenziselwa ukulinganisa indawo engqongileyo yolwandle. Iqulethe i-17700 ppm Cl-, ethelekiswa nomxholo wayo emanzini olwandle endalo. Ubukho be-17700 ppm Cl- yayiyeyona nto iphambili yokwehla kwe-Cr kwiisampulu ze-abiotic zeentsuku ezi-7 kunye ne-14 ezihlalutywe yi-XPS. Xa kuthelekiswa neesampulu ze-P. aeruginosa, ukunyibilika kwe-Cr kwiisampulu ze-abiotic bekuncinci kakhulu ngenxa yokumelana okunamandla kwe-2707 HDSS kwi-chlorine phantsi kweemeko ze-abiotic. Kumzobo 9 kubonisa ubukho be-Cr6+ kwifilimu edlulayo. Isenokuba negalelo ekususweni kwe-chromium kwiindawo zentsimbi yi-P. aeruginosa biofilms, njengoko kucetyisiwe nguChen noClayton.
Ngenxa yokukhula kweebhaktheriya, amaxabiso e-pH yesixhobo ngaphambi nasemva kokulima ayeyi-7.4 kunye ne-8.2, ngokulandelelana. Ngoko ke, ngaphantsi kwe-P. aeruginosa biofilm, ukubola kwe-organic acid akunakwenzeka ukuba kufake isandla kulo msebenzi ngenxa ye-pH ephezulu kwisixhobo esikhulu. I-pH yesixhobo sokulawula esingesiso sebhayoloji ayizange itshintshe kakhulu (ukusuka kwi-7.4 yokuqala ukuya kwi-7.5 yokugqibela) ngexesha lovavanyo lweentsuku ezili-14. Ukunyuka kwe-pH kwisixhobo sembewu emva kokufunxwa kwakubangelwa ngumsebenzi we-metabolic we-P. aeruginosa kwaye kwafunyaniswa ukuba kunefuthe elifanayo kwi-pH xa kungekho migca yovavanyo.
Njengoko kubonisiwe kuMfanekiso 7, ubunzulu bomngxuma obuphezulu obubangelwe yi-P. aeruginosa biofilm yayiyi-0.69 µm, nto leyo inkulu kakhulu kuneyo ye-abiotic medium (0.02 µm). Oku kuhambelana nedatha ye-electrochemical echazwe apha ngasentla. Ubunzulu bomngxuma obuyi-0.69 µm buncinci ngokuphindwe kalishumi kunexabiso le-9.5 µm elixelwe kwi-2205 DSS phantsi kweemeko ezifanayo. Ezi datha zibonisa ukuba i-2707 HDSS ibonisa ukumelana okungcono kwi-MICs kune-2205 DSS. Oku akufanele kumangalise kuba i-2707 HDSS inamanqanaba aphezulu e-Cr anika i-passivation ende, kunzima ukuyisusa i-P. aeruginosa, kwaye ngenxa yesakhiwo sayo sesigaba esilinganayo ngaphandle kwemvula yesibini eyingozi ibangela i-pitting.
Ukuqukumbela, imingxuma ye-MIC ifunyenwe kumphezulu we-2707 HDSS kumhluzi we-P. aeruginosa xa kuthelekiswa nemingxuma engabalulekanga kwindawo engeyongozi. Lo msebenzi ubonisa ukuba i-2707 HDSS inokumelana okungcono ne-MIC kune-2205 DSS, kodwa ayikhuselekanga ngokupheleleyo kwi-MIC ngenxa ye-P. aeruginosa biofilm. Ezi ziphumo zinceda ekukhetheni iintsimbi ezingenasici ezifanelekileyo kunye nexesha lokuphila ubomi obude kwindawo yolwandle.
Ikhuphoni ye-2707 HDSS ebonelelwe yiNortheastern University (NEU) School of Metallurgy eShenyang, eTshayina. Ulwakhiwo lwe-2707 HDSS luboniswe kwiTheyibhile 1, eyahlalutywa yi-NEU Materials Analysis and Testing Department. Zonke iisampuli zanyangwa ukuze zifumane isisombululo esiqinileyo kwi-1180°C kangangeyure e-1. Ngaphambi kovavanyo lokugqwala, i-2707 HDSS enesimo seengqekembe enommandla ovulekileyo ophezulu we-1 cm2 yapholishwa ukuya kwi-2000 grit ngephepha le-silicon carbide yaze yapholishwa nge-0.05 µm Al2O3 powder slurry. Amacala kunye nasezantsi akhuselwe ngepeyinti engafakwanga. Emva kokomiswa, iisampuli zahlanjwa ngamanzi acocekileyo kwaye zapholishwa nge-75% (v/v) ethanol kangangeeyure eziyi-0.5. Emva koko zomiswa emoyeni phantsi kokukhanya kwe-ultraviolet (UV) kangangeeyure eziyi-0.5 ngaphambi kokusetyenziswa.
Uhlobo lweMarine Pseudomonas aeruginosa MCCC 1A00099 luthengwe kwiXiamen Marine Culture Collection Center (MCCC), eTshayina. I-Pseudomonas aeruginosa ikhuliswe phantsi kweemeko ze-aerobic kuma-37° C. kwiiflasks ezingama-250 ml kunye neeseli ze-electrochemical zeglasi ezingama-500 ml kusetyenziswa iMarine 2216E liquid medium (Qingdao Hope Biotechnology Co., Ltd., eQingdao, eTshayina). I-Medium iqulethe (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 kunye ne-0.1 iron citrate. I-Autoclave kwi-121°C imizuzu engama-20 ngaphambi kokugonywa. Bala iiseli ze-sessile kunye ne-planktonic nge-hemocytometer phantsi kwe-microscope ekhanyayo kwi-400x magnification. Uxinzelelo lokuqala lwe-planktonic Pseudomonas aeruginosa emva nje kokugonywa yayimalunga neeseli ezili-106/ml.
Uvavanyo lwe-electrochemical lwenziwe kwiseli yeglasi ye-electrode ezintathu eqhelekileyo enomthamo ophakathi we-500 ml. Iphepha leplatinum kunye ne-electrode ye-calomel eyomeleleyo (SAE) ziqhagamshelwe kwi-reactor nge-capillaries zeLuggin ezizaliswe ziibridges zetyuwa, ezazisebenza njengee-electrodes ezichaseneyo kunye nezereferensi, ngokwahlukeneyo. Ukwenziwa kwee-electrodes ezisebenzayo, ucingo lwe-copper olufakwe ngerabha luqhotyoshelwe kwisampuli nganye kwaye lugqunywe nge-epoxy resin, kwasala malunga ne-1 cm2 yendawo engakhuselekanga ye-electrode esebenzayo kwelinye icala. Ngexesha lokulinganisa i-electrochemical, iisampulu zibekwe kwi-2216E medium kwaye zigcinwe kubushushu obuhlala buhleli (37°C) kwindawo yokuhlambela ngamanzi. Idatha ye-OCP, i-LPR, i-EIS kunye nedatha ye-polarization enokubakho ilinganiswe kusetyenziswa i-Autolab potentiostat (Reference 600TM, Gamry Instruments, Inc., USA). Uvavanyo lwe-LPR lurekhodwe kwisantya sokuskena se-0.125 mV s-1 kuluhlu lwe--5 ukuya kwi-5 mV nge-Eocp kunye nesantya sokusampula se-1 Hz. I-EIS yenziwe nge-sine wave phezu koluhlu lwe-frequency oluyi-0.01 ukuya kwi-10,000 Hz kusetyenziswa i-voltage esetyenzisiweyo ye-5 mV kwi-Eocp ezinzileyo. Ngaphambi kokuba i-potential sweep, ii-electrodes zazikwi-idle mode de kufikelelwe kwixabiso elizinzileyo le-free corrosion potential. Ii-polarization curves emva koko zalinganiswa ukusuka kwi--0.2 ukuya kwi-1.5 V njengomsebenzi we-Eocp kwisantya se-scan se-0.166 mV/s. Uvavanyo ngalunye luphindwe kathathu nge-P. aeruginosa kwaye ngaphandle kwayo.
Iisampulu zohlalutyo lwe-metallographic zicoliwe ngoomatshini ngephepha le-SiC elimanzi elingama-2000 grit zaze zacoliwe ngakumbi nge-0.05 µm Al2O3 powder suspension ukuze zijongwe ngamehlo. Uhlalutyo lwe-Metallographic lwenziwe kusetyenziswa i-optical microscope. Iisampulu zicoliwe ngesisombululo se-10 wt% se-potassium hydroxide 43.
Emva kokufunxa, iisampulu zahlanjwa izihlandlo ezi-3 nge-phosphate buffered saline (PBS) (pH 7.4 ± 0.2) zaze zalungiswa nge-2.5% (v/v) glutaraldehyde kangangeeyure ezili-10 ukuze kulungiswe ii-biofilms. Emva koko zasuswa emanzini nge-ethanol exutyiweyo (50%, 60%, 70%, 80%, 90%, 95% kunye ne-100% ngomthamo) ngaphambi kokuba zomiswe emoyeni. Okokugqibela, ifilimu yegolide ifakwa kumphezulu wesampulu ukuze ibonelele ngokuhanjiswa kwe-SEM. Imifanekiso ye-SEM igxile kwiindawo ezineeseli ze-P. aeruginosa ezithambileyo kumphezulu wesampulu nganye. Yenza uhlalutyo lwe-EDS ukuze ufumane izinto zeekhemikhali. I-microscope ye-Zeiss confocal laser scanning (CLSM) (LSM 710, Zeiss, eJamani) yasetyenziswa ukulinganisa ubunzulu bomngxuma. Ukuze kujongwe imingxuma yokugqwala phantsi kwe-biofilm, isampuli yovavanyo yaqala yacocwa ngokwe-Chinese National Standard (CNS) GB/T4334.4-2000 ukuze kususwe iimveliso zokugqwala kunye ne-biofilm kumphezulu wesampuli yovavanyo.
Uhlalutyo lwe-X-ray photoelectron spectroscopy (XPS, ESCALAB250 surface analysis system, Thermo VG, USA) lwenziwe kusetyenziswa umthombo we-X-ray one-monochromatic (umgca we-Aluminium Kα onamandla ayi-1500 eV kunye namandla ayi-150 W) kuluhlu olubanzi lwamandla okubopha ayi-0 phantsi kweemeko eziqhelekileyo ze--1350 eV. Iispectra ezinesisombululo esiphezulu zarekhodwa kusetyenziswa amandla okudlulisa angama-50 eV kunye nenyathelo le-0.2 eV.
Iisampulu ezifakwe kwi-incubation zisusiwe zaza zahlanjwa ngobunono nge-PBS (pH 7.4 ± 0.2) kangange-15 s45. Ukuze kubonwe ukuba iibhayofilms ziphila na kwiisampulu, iibhayofilms zafakwa idayi kusetyenziswa i-LIVE/DEAD BacLight Bacterial Viability Kit (Invitrogen, Eugene, OR, USA). Le khithi ineedayi ezimbini ze-fluorescent: idayi ye-SYTO-9 eluhlaza kunye nedayi ye-propidium iodide (PI) ebomvu ye-fluorescent. Kwi-CLSM, amachaphaza aluhlaza kunye nabomvu amele iiseli eziphilayo kunye nezifileyo, ngokulandelelana. Ukuze kufakwe idayi, i-1 ml yomxube oqulethe i-3 µl ye-SYTO-9 kunye ne-3 µl yesisombululo se-PI yafakwa kwi-incubation imizuzu engama-20 kubushushu begumbi (23°C) ebumnyameni. Emva koko, iisampulu ezifakwe kwi-incubation zahlolwa kwii-wavelengths ezimbini (488 nm kwiiseli eziphilayo kunye ne-559 nm kwiiseli ezifileyo) kusetyenziswa isixhobo se-Nikon CLSM (C2 Plus, Nikon, Japan). Ubukhulu be-biofilm bulinganiswe kwimodi yokuskena ye-3D.
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