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Kungekudala, i-platform ye-antimicrobial engenamichiza esekelwe kwi-nanotechnology esebenzisa i-nanostructures yamanzi eyenziweyo (EWNS) yenziwe. I-EWNS inomrhumo ophezulu ophezulu kwaye izityebi kwiintlobo ze-oksijini ezisebenzayo (ROS) ezinokusebenzisana kunye nokunciphisa inani le-microorganisms, kubandakanywa i-pathogens yokutya. Apha kuboniswa ukuba iipropathi zabo ngexesha lokudibanisa zinokulungiswa kakuhle kwaye ziphuculwe ngakumbi ukunyusa amandla abo okulwa ne-antibacterial. Iqonga lebhubhoratri ye-EWNS yenzelwe ukulungisa kakuhle iipropati ze-EWNS ngokuguqula iiparamitha ze-synthesis. Ukubonakaliswa kweempawu ze-EWNS (intlawulo, ubungakanani, kunye nomxholo we-ROS) kwenziwa ngokusebenzisa iindlela zokuhlalutya zanamhlanje. Ukongeza, ii-microorganisms zokutya ezifana ne-Escherichia coli, i-Salmonella enterica, i-Listeria innocua, i-Mycobacterium para fortitum, kunye ne-Saccharomyces cerevisiae ziye zatofwa kumphezulu weetumato zomdiliya wendalo ukuvavanya amandla azo okungasebenzi kwe-microbial. Iziphumo ezithiwe thaca apha zibonisa ukuba iipropathi ze-EWNS zinokulungiswa kakuhle ngexesha lokudityaniswa, okukhokelela ekwandeni okubonakalayo kokusebenza kakuhle kokungasebenzi kakuhle. Ngokukodwa, umrhumo womphezulu unyuke ngenani lesine, kwaye umxholo we-ROS wanda. Izinga lokususwa kwe-microbial lalixhomekeke kwi-microbially kwaye livela kwi-1.0 ukuya kwi-3.8 log emva kwemizuzu ye-45 yokuvezwa kwi-dose ye-aerosol ye-40,000 #/cm3 EWNS.
Ungcoliseko lweMicrobial ngoyena nobangela wokugula kokutya okubangelwa kukutya iintsholongwane okanye ityhefu yazo. Izigulo ezibangelwa kukutya zibangela izigulo ezimalunga nezigidi ezingama-76, abantu abalaliswa esibhedlele abangama-325 000, yaye abangama-5 000 bafa nyaka ngamnye eUnited States kuphela1. Ukongezelela, iSebe Lezolimo laseUnited States (USDA) liqikelela ukuba ukusetyenziswa okwandisiweyo kwemveliso esandul’ ukuvunwa kubangele ama-48 ekhulwini azo zonke izifo ezibangelwa kukutya ezichazwe eUnited States2. Iindleko zokugula kunye nokufa kwi-pathogens yokutya e-United States iphezulu kakhulu, iqikelelwa ngamaZiko oLawulo lweSifo kunye noThintelo (CDC) ngaphezu kwe-US $ 15.6 yezigidigidi ngonyaka3.
Okwangoku, imichiza ye-4, i-radiation5 kunye ne-thermal6 yongenelelo lwe-antimicrobial ukuqinisekisa ukhuseleko lokutya luphunyezwa ikakhulu kwiindawo zokulawula ezibalulekileyo (CCPs) kwikhonkco lemveliso (ngokuqhelekileyo emva kokuvuna kunye / okanye ngexesha lokupakisha) kunokuba iphunyezwe ngokuqhubekayo ngendlela yokuba imveliso entsha ixhomekeke ekungcolisekeni okunqamlezayo ifama-to-itafile eqhubekayo. Impembelelo encinci kunye neendleko.
I-platform ye-antimicrobial esekelwe kwi-nanotechnology-free-antimicrobial platform iye yaphuhliswa kutshanje ukuze ingasebenzi ibhaktheriya kwiindawo eziphezulu kunye nomoya usebenzisa i-nanostructures yamanzi eyenziweyo (EWNS). Ukwenziwa kwe-EVNS, iinkqubo ezimbini ezihambelanayo zisetyenzisiwe: i-electrospray kunye ne-ionization yamanzi (umzobo 1a). I-EWNS ngaphambili ibonakaliswe ukuba ineseti eyodwa yezinto eziphathekayo kunye nebhayoloji8,9,10. I-EWNS inomlinganiselo wee-electron ezili-10 kwisakhiwo ngasinye kunye nobukhulu be-nanometer obuyi-25 nm (Fig. 1b,c)8,9,10. Ukongezelela, i-electron spin resonance (ESR) ibonise ukuba i-EWNS iqulethe inani elikhulu leentlobo ze-oksijeni ezisebenzayo (ROS), ngokukodwa i-hydroxyl (OH•) kunye ne-superoxide (O2-) i-radicals (Fig. 1c) 8. I-EWNS yahlala emoyeni ixesha elide kwaye inokungqubana ne-microbes emisiwe emoyeni kwaye ikhoyo kwiindawo, ihambisa i-ROS yokuhlawula i-ROS kwaye ibangele ukungasebenzi kwe-microbial (Fig. 1d). Ezi zifundo zangaphambili zikwabonisa ukuba i-EWNS inokunxibelelana kwaye ingasebenzi iibhaktheriya ezahlukeneyo zegram-negative kunye negram-positive ebalulekileyo kwimpilo yoluntu, kubandakanywa i-mycobacteria, kwindawo kunye ne-air8,9. Ukuhanjiswa kwe-electron microscopy kubonise ukuba ukungasebenzi kubangelwa ukuphazamiseka kwe-membrane yeseli. Ukongezelela, izifundo zokuphefumla ngokukhawuleza zibonise ukuba iidosi eziphezulu ze-EWNS azibangeli umonakalo wemiphunga okanye ukuvutha8.
(a) I-Electrospray yenzeka xa kusetyenziswa amandla ombane aphezulu phakathi kwecapillary equlathe ulwelo kunye ne-counter electrode. (b) Ukusetyenziswa kwamandla ombane aphezulu kuphumela kwiziganeko ezibini ezahlukeneyo: (i) ukutshizwa nge-electrospraying yamanzi kunye (ii) nokuveliswa kweentlobo zeoksijini esebenzayo (iiion) ezivaleleke kwi-EWNS. (c) Ulwakhiwo olulodwa lwe-EWNS. (d) Ii-EWNS zihamba kakhulu ngenxa yendalo yazo ye-nanoscale kwaye zinokusebenzisana ne-pathogens emoyeni.
Ukukwazi kweqonga le-antimicrobial ye-EWNS ukwenza i-microorganisms yokutya ingasebenzi kwindawo yokutya okutsha nayo ibonakalisiwe kutshanje. Kukwabonisiwe ukuba i-EWNS intlawulo yomphezulu ingasetyenziswa ngokudityaniswa nebala lombane ukulungiselela unikezelo olujoliswe kuko. Okubaluleke ngakumbi, isiphumo sokuqala esithembisayo malunga ne-1.4 yelogi yokunciphisa umsebenzi we-organic tomato ngokuchasene ne-microorganisms yokutya eyahlukeneyo efana ne-E. coli kunye ne-Listeria yabonwa kwimizuzu engama-90 yokuvezwa kwi-EWNS kuxinzelelo olumalunga ne-50,000 #/cm311. Ukongeza, iimvavanyo zokuqala zovavanyo lwe-organoleptic zibonise ukuba akukho siphumo se-organoleptic xa kuthelekiswa netamatato yokulawula. Nangona ezi ziphumo zokuqala zokungasebenzi zithembisa ukhuseleko lokutya nokuba ngamadosi e-EWNS asezantsi kakhulu angama-50,000#/cc. bona, kucacile ukuba amandla aphezulu okungasebenzi anokuba luncedo ngakumbi ekunciphiseni ngakumbi umngcipheko wosulelo kunye nokonakala.
Apha, siza kugxila kuphando lwethu kuphuhliso lweqonga lesizukulwana se-EWNS ukulungelelanisa iiparamitha ze-synthesis kunye nokwandisa iimpawu ze-physicochemical ze-EWNS ukuphucula amandla abo okulwa ne-antibacterial. Ngokukodwa, ukulungelelaniswa kugxininise ekwandiseni intlawulo yabo yomhlaba (ukuphucula ukuhanjiswa okujoliswe kuyo) kunye nomxholo we-ROS (ukuphucula ukusebenza kakuhle kokungasebenzi). Ukubonakaliswa kweempawu ze-physico-chemicals eziphuculweyo (ubungakanani, intlawulo kunye nomxholo we-ROS) usebenzisa iindlela zokuhlalutya zanamhlanje kunye nokusebenzisa ii-microorganisms zokutya eziqhelekileyo ezifana ne-E. coli, S. enterica, L. innocua, S. cerevisiae kunye ne-M. parafortuitum.
I-EVNS yenziwe nge-electrospraying ngaxeshanye kunye ne-ionization yamanzi ahlambulukileyo aphezulu (18 MΩ cm-1). I-atomizer yombane i-12 isetyenziswa ngokuqhelekileyo ukwenza i-atomize ulwelo kunye ne-polymer yokwenziwa kunye ne-ceramic particles 13 kunye ne-fibers 14 yobukhulu obulawulwayo.
Njengoko kuchaziwe kupapasho lwangaphambili 8, 9, 10, 11, kuvavanyo oluqhelekileyo, amandla ombane aphezulu asetyenziswa phakathi kwecapillary yentsimbi kunye ne-grounded counter electrode. Ngethuba le nkqubo, kwenzeka izinto ezimbini ezahlukeneyo: 1) i-electrospray kunye ne-2) i-ionization yamanzi. Intsimi yombane eyomeleleyo phakathi kwee-electrode ezimbini ibangela ukuba iintlawulo ezingalunganga zakheke phezu kwamanzi ajiyileyo, okukhokelela ekuyilweni kweecones zeTaylor. Ngenxa yoko, amaconsi amanzi ahlawuliswa kakhulu akhiwa, aqhubeka eqhekeza kwiincinci ezincinci, ngokutsho kweRayleigh theory16. Ngelo xesha, intsimi yombane enamandla ibangela ukuba ezinye iimolekyuli zamanzi zihlulwe kwaye zihluthe ii-electron (ionization), ngaloo ndlela zivelise inani elikhulu leentlobo ze-oksijeni ezisebenzayo (ROS)17. Iipakethi ze-ROS18 ezenziwe ngaxeshanye zifakwe kwi-EWNS (Umfanekiso 1c).
Kwikhiwane. I-2a ibonisa inkqubo yokuvelisa i-EWNS ephuhliswe kwaye isetyenziswe kwi-EWNS synthesis kolu phononongo. Amanzi ahlambulukileyo agcinwe kwibhotile evaliweyo yondliwa nge-tube yeTeflon (2 mm ububanzi bangaphakathi) kwi-30G yensimbi engenasici (i-metal capillary). Njengoko kuboniswe kwi-Figure 2b, ukuhamba kwamanzi kulawulwa nguxinzelelo lomoya ngaphakathi kwebhotile. Inaliti ifakwe kwi-console yeTeflon enokuthi ilungiswe ngesandla kumgama othile ukusuka kwi-electrode counter. I-electrode ye-counter yidiski ye-aluminiyam ekhazimlisiweyo kunye nomngxuma phakathi kwisampuli. Ngaphantsi kwe-electrode ye-counter yi-aluminium yesampulu ye-funnel, edityaniswe kuyo yonke isethingi yovavanyo ngokusebenzisa i-port yesampuli (Umfanekiso we-2b). Onke amacandelo esampulu asekelwe ngombane ukunqanda ukwakhiwa kwentlawulo okunokuthoba umgangatho wesampulu yamasuntswana.
(a) INkqubo yobuNjineli yokuDala iNanostructure yaManzi (EWNS). (b) Icandelo elinqamlezayo lesampulu kunye neyunithi ye-electrospray ebonisa eyona parameters ibalulekileyo. (c) Ukuseta umfuniselo wokungasebenzi kwebhaktiriya.
Inkqubo yokuvelisa i-EWNS echazwe ngasentla iyakwazi ukutshintsha iiparameters eziphambili zokusebenza ukuququzelela ukulungiswa kakuhle kweepropati ze-EWNS. Lungisa i-voltage esetyenzisiweyo (V), umgama phakathi kwenaliti kunye ne-electrode counter (L), kunye nokuhamba kwamanzi (φ) nge-capillary ukulungelelanisa iimpawu ze-EWNS. Iisimboli [V (kV), L (cm)] zisetyenziselwa ukubonisa indibaniselwano eyahlukeneyo. Lungisa ukuhamba kwamanzi ukuze ufumane i-Taylor cone ezinzileyo yesethi ethile [V, L]. Ngenjongo yolu cwaningo, i-aperture ye-counter electrode (D) ibekwe kwi-0.5 intshi (1.29 cm).
Ngenxa yejometri encinci kunye ne-asymmetry, amandla ombane ombane akanakubalwa kwimigaqo yokuqala. Endaweni yoko, isoftware ye-QuickField™ (eSvendborg, eDenmark)19 yasetyenziswa ukubala indawo yombane. Intsimi yombane ayifani, ngoko ke ixabiso lendawo yombane kwinqanaba le-capillary lisetyenziswe njengexabiso lokubhekisela kwiindlela ezahlukeneyo.
Ngexesha lophononongo, udibaniso oluninzi lombane kunye nomgama phakathi kwenaliti kunye ne-electrode ye-counter yavavanywa ngokwemiqathango ye-Taylor cone formation, i-Taylor cone stability, i-EWNS yokuzinza kwemveliso, kunye nokuphindaphinda. Iindibaniso ezahlukeneyo zibonisiwe kwiTheyibhile eyoNgezelelweyo S1.
Imveliso yenkqubo yokuvelisa i-EWNS idibaniswe ngokuthe ngqo kwi-Scanning Mobility Particle Sizer (SMPS, imodeli 3936, TSI, Shoreview, Minnesota) ukulinganisa i-particle number concentration kwaye isetyenziswe ngeFaraday aerosol electrometer (TSI, imodeli 3068B, Shoreview, USA). MN) ukulinganisa ukuhamba kweaerosol, njengoko kuchaziwe kupapasho lwethu lwangaphambili9. Zombini i-SMPS kunye ne-aerosol electrometer isampuli kwisantya sokuhamba kwe-0.5 L / min (iisampulu iyonke yokuhamba kwe-1 L / min). Ugxininiso lwamacandelo kunye nokuhamba kwe-aerosol kulinganiswe kwi-120 s. Phinda umlinganiselo amaxesha angama-30. Itotali yentlawulo ye-aerosol ibalwa kwimilinganiselo yangoku, kwaye i-avareji yentlawulo ye-EWNS iqikelelwa kwinani lilonke lamasuntswana e-EWNS esampula. I-avareji yeendleko ze-EWNS ingabalwa kusetyenziswa i-Equation (1):
apho i-Iel ingumlinganiselo wangoku, i-NSMPS yinombolo yoxinaniso olulinganiswa ne-SMPS, kwaye i-φEl yizinga lokuhamba kwi-electrometer.
Ngenxa yokuba umswakama ohambelanayo (RH) uchaphazela intlawulo yomhlaba, ubushushu kunye (RH) zigcinwe rhoqo kwi-21 ° C kunye ne-45%, ngokulandelanayo, ngexesha lovavanyo.
I-Atomic force microscopy (AFM), i-Asylum MFP-3D (i-Asylum Research, i-Santa Barbara, i-CA) kunye ne-AC260T probe (i-Olympus, i-Tokyo, eJapan) zisetyenziselwa ukulinganisa ubungakanani kunye nobomi be-EWNS. Ireyithi yokuskena ye-AFM yi-1 Hz kwaye indawo yokuskena yi-5 µm×5 µm kunye nemigca yokuskena engama-256. Yonke imifanekiso yayiphantsi komyalelo wokuqala wokulungelelaniswa komfanekiso usebenzisa i-Asylum software (imaski enoluhlu lwe-100 nm kunye nomda we-100 pm).
Susa i-funnel yesampula kwaye ubeke i-mica surface kumgama we-2.0 cm ukusuka kwi-electrode ye-counter kwi-avareji ye-120 s ukuphepha ukudibanisa kwamaqhekeza kunye nokwakhiwa kwamaconsi angaqhelekanga kwi-mica surface. I-EWNS isetyenziswe ngokuthe ngqo kwiindawo ezisandul 'ukusikwa ze-mica (Ted Pella, Redding, CA). Ngokukhawuleza emva kokutshiza, i-mica surface yabonwa ngokusebenzisa i-AFM. I-engile yoqhagamshelwano yomphezulu ye-mica esanda kusikwa engalungiswanga isondele ku-0 °, ngoko ke i-EWNS isasaza phezu komphezulu we-mica kwi-domed shape20. Idayamitha (a) kunye nobude (h) bamathontsi asasazayo balinganiswe ngokuthe ngqo ukusuka kwi-AFM topography kwaye isetyenziselwa ukubala umthamo we-domed diffusion ye-EWNS kusetyenziswa indlela yethu eqinisekisiweyo yangaphambili8. Kucingelwa ukuba i-EVNS ekwibhodi inomthamo ofanayo, idiameter elinganayo ingabalwa ukusuka kwi-equation (2):
Ngokuhambelana nendlela yethu eyaphuhliswa ngaphambili, i-electron spin resonance (ESR) i-spin trap yayisetyenziselwa ukubona ubukho bexesha elifutshane eliphakathi kwe-radical intermediates kwi-EWNS. I-aerosols yadluliselwa ngesisombululo esiqulethe i-235 mM DEPMPO (5- (diethoxyphosphoryl) -5-methyl-1-pyrroline-N-oxide) (Oxis International Inc., Portland, Oregon). Yonke imilinganiselo ye-EPR yenziwa ngokusebenzisa i-spectrometer ye-Bruker EMX (i-Bruker Instruments Inc. Billerica, MA, USA) kunye ne-flat cell arrays. I-software ye-Acquisit (i-Bruker Instruments Inc. Billerica, MA, USA) yayisetyenziselwa ukuqokelela kunye nokuhlalutya idatha. Uphawu lwe-ROS lwenziwa kuphela kwisethi yeemeko zokusebenza [-6.5 kV, 4.0 cm]. Ugxininiso lwe-EWNS lulinganiswe ngokusebenzisa i-SMPS emva kokuqwalasela ukulahlekelwa kwe-EWNS kwimpembelelo.
Amanqanaba e-ozone abekwe esweni kusetyenziswa i-205 Dual Beam Ozone Monitor™ (2B Technologies, Boulder, Co)8,9,10.
Kuzo zonke iipropathi ze-EWNS, ixabiso lomlinganiselo lithetha imilinganiselo, kwaye impazamo yomlinganiselo kukutenxa okusemgangathweni. Uvavanyo lwe-t lwenziwa ukuthelekisa ixabiso le-EWNS ephuculweyo kunye nexabiso elihambelana nesiseko se-EWNS.
Umzobo 2c ubonisa i-Electrostatic Precipitation Pass Through System (EPES) ephuhliswe ngaphambili kwaye ibonakaliswe enokuthi isetyenziswe ukujolisa kwi-EWNS11 kumphezulu. I-EPES isebenzisa intlawulo ye-EWNS ngokudityaniswa nendawo yombane eyomeleleyo ukuze “ikhombe” ngokuthe ngqo kwindawo ekujoliswe kuyo. Iinkcukacha zenkqubo ye-EPES zichazwe kupapasho lwakutshanje nguPyrgiotakis et al.11. Ngaloo ndlela, i-EPES iqulethe i-3D eprintiweyo ye-PVC yegumbi elineziphelo ezinqamlekileyo eziqulethe i-parallel stainless steel stainless (304 insimbi engenasici, i-mirror polished) iipleyiti zetsimbi phakathi kwe-15.24 cm ngaphandle. Iibhodi zixhunywe kumthombo wangaphandle we-voltage ephezulu (i-Bertran 205B-10R, i-Spellman, i-Hauppauge, i-NY), ibhodi ephantsi yayihlala ilungile kwaye ibhodi ephezulu yayihlala iphantsi (ijikeleza). Iindonga zegumbi zigqunywe ngefoyile ye-aluminium, esekelwe ngombane ukuthintela ukulahleka kweesuntswana. Igumbi linomnyango ovaliweyo wokulayisha wangaphambili ovumela umgangatho wovavanyo ukuba ubekwe kwiirakhi zeplastiki, uziphakamise kwipleyiti yentsimbi esezantsi ukuphepha ukuphazamiseka kombane ophezulu.
Ukusebenza kakuhle kokubekwa kwe-EWNS kwi-EPES kubalwe ngokomgaqo ophuhliswe ngaphambili ochazwe kwi-Supplementary Figure S111.
Njengegumbi lokulawula, ukuhamba kwesibini ngegumbi le-cylindrical lixhunywe kwichungechunge kunye nenkqubo ye-EPES usebenzisa i-HEPA filter ephakathi ukususa i-EWNS. Njengoko kubonisiwe kwifig. 2c, i-aerosol ye-EWNS yampontshwa ngamagumbi amabini aqhagamshelwe kuthotho. Isihluzi phakathi kwegumbi lolawulo kunye ne-EPES sisusa nayiphi na i-EWNS eseleyo ebangela ubushushu obufanayo (T), ukufuma okuhambelanayo (RH) kunye namanqanaba e-ozone.
I-microorganisms ebalulekileyo yokutya ifunyenwe ukuba ingcolise imveliso entsha efana ne-Escherichia coli (ATCC #27325), isalathisi se-fecal, i-Salmonella enterica (ATCC #53647), i-pathogen yokutya, i-Listeria innocua (ATCC #33090), enye indlela ye-pathogenic Listeria monocy. , i-Saccharomyces cerevisiae (ATCC #4098) njengenye indlela yegwele lokubola, kunye neMycobacterium parafortuitous (ATCC #19686) njengebhaktiriya ephilayo ekwaziyo ukumelana nangakumbi zathengwa kwi-ATCC (Manassas, Virginia).
Thenga ngokungacwangciswanga iibhokisi zeetumato zomdiliya ophilayo kwimarike yasekhaya kwaye uzifake efrijini kwi-4°C de uyisebenzise (ukuya kwiintsuku ezi-3). Khetha iitumato ukuzama ubungakanani obunye, malunga ne-1/2 intshi ubukhulu.
Iiprothokholi ze-incubation, i-inoculation, i-exposure kunye ne-coloni counting zichazwe kwiimpapasho zethu zangaphambili kwaye zichazwe ngokucacileyo kwi-Supplementary Data 11. Ukusebenza kwe-EWNS kwavavanywa ngokutyhila iitumato ezifakwe kwi-40,000 #/cm3 imizuzu engama-45. Ngokufutshane, ngexesha t = 0 min, iitumato ezintathu zazisetyenziselwa ukuvavanya i-microorganisms ephilayo. Iitamatisi ezintathu zafakwa kwi-EPES kwaye zavezwa kwi-EWNS kwi-40,000 # / cc (i-EWNS i-tomato evezwe) kunye nezinye ezintathu zafakwa kwigumbi lokulawula (iitamatisi zokulawula). Akukho nalinye kumaqela etumata aphantsi koqwalaselo olongezelelweyo. Iitamatisi eziveziweyo ze-EWNS kunye nolawulo zisuswe emva kwemizuzu ye-45 ukuvavanya umphumo we-EWNS.
Uvavanyo ngalunye lwenziwa ngokuphindwe kathathu. Uhlalutyo lwedatha lwenziwa ngokweprotocol echazwe kwiDatha eyoNgezelelweyo.
I-E. coli, i-Enterobacter, kunye ne-L. i-innocua iisampuli zebhaktheriya ezivezwe kwi-EWNS (i-45 min, i-EWNS i-aerosol concentration ye-40,000 # / cm3) kwaye ingabonakali ifakwe i-pellets ukuvavanya iindlela zokungasebenzi. I-precipitate yayilungiswe kwiiyure ze-2 kwiqondo lokushisa lokushisa kwi-0.1 M isisombululo se-sodium cacodylate (pH 7.4) kunye ne-fixative ye-2.5% ye-glutaraldehyde, i-1.25% ye-paraformaldehyde kunye ne-0.03% ye-picric acid. Emva kokuhlamba, zilungiswe nge-1% ye-osmium tetroxide (OsO4) / 1.5% ye-potassium ferrocyanide (KFeCN6) ye-2 h, ihlanjwe ngamaxesha angama-3 ngamanzi kwaye ifakwe kwi-1% ye-uranyl acetate ye-1 h, ize ihlanjwe kabini ngamanzi. Ukuphelelwa ngamanzi emzimbeni okulandelayo 10 imizuzu nganye 50%, 70%, 90%, 100% utywala. Iisampuli zaye zafakwa kwi-propylene oxide kwiyure ye-1 kwaye zifakwe ngomxube we-1: 1 wepropylene oxide kunye ne-TAAP Epon (Marivac Canada Inc. St. Laurent, CA). Iisampuli zifakwe kwi-TAAB Epon kwaye zenziwe nge-polymerized kwi-60 ° C kwiiyure ze-48. I-resin ye-granular ephilisiwe yasikwa kwaye yabonwa yi-TEM usebenzisa i-JEOL 1200EX (JEOL, Tokyo, Japan), i-microscope ye-electron yokudluliselwa eqhelekileyo exhotywe ngekhamera ye-AMT 2k CCD (i-Advanced Microscopy Techniques, Corp., Woburn, MA, USA).
Zonke iimvavanyo zenziwe ngokuphindwe kathathu. Ngexesha ngalinye, ukuhlanjwa kwebhaktheriya kuye kwafakwa kathathu, okubangele inani elipheleleyo lamanqaku edatha alithoba kwindawo nganye, umyinge owawusetyenziswa njengogxininiso lwebhaktiriya kuloo nto ithile. Ukutenxa okusemgangathweni kusetyenziswe njengempazamo yokulinganisa. Onke amanqaku abalwa.
I-logarithm yokuhla kwe-concentration yebhaktheriya xa kuthelekiswa ne-t = i-0 min ibalwe kusetyenziswa le fomula ilandelayo:
apho i-C0 yingqokelela yebhaktheriya kwisampulu yolawulo ngexesha le-0 (oko kukuthi emva kokuba umphezulu womile kodwa ngaphambi kokuba ubekwe kwigumbi) kunye ne-Cn kukuxinana kweebhaktheriya kumphezulu emva kwemizuzu ye-exposure.
Ukujonga ukuthotywa kwendalo kweebhaktheriya ngexesha le-45 yemizuzu yokuvezwa, ukuNcitshiswa kwe-Log-Nciphiso nayo ibalwe xa kuthelekiswa nokulawula kwimizuzu ye-45 ngolu hlobo lulandelayo:
Apho i-Cn i-concentration yebhaktheriya kwisampuli yokulawula ngexesha n kunye ne-Cn-Control kukugxininiswa kwebhaktheriya yokulawula ngexesha n. Idatha inikezelwa njengokunciphisa ilogi xa kuthelekiswa nolawulo (akukho kubonakaliswa kwe-EWNS).
Ngexesha lophononongo, udibaniso oluninzi lombane kunye nomgama phakathi kwenaliti kunye ne-electrode ye-counter yavavanywa ngokwemiqathango ye-Taylor cone formation, i-Taylor cone stability, i-EWNS yokuzinza kwemveliso, kunye nokuphindaphinda. Iindibaniso ezahlukeneyo zibonisiwe kwiTheyibhile eyoNgezelelweyo S1. Amatyala amabini akhethwe kwisifundo esipheleleyo esibonisa iipropathi ezizinzile kunye nezinokuveliswa kwakhona (i-Taylor cone, imveliso ye-EWNS, kunye nokuzinza kwexesha). Kwikhiwane. I-3 ibonisa iziphumo kwintlawulo, ubungakanani kunye nomxholo we-ROS kwiimeko ezimbini. Iziphumo zikwashwankathelwa kwiThebhile 1. Ngokubhekiselele kwireferensi, iSazobe 3 kunye neTheyibhile 1 ibandakanya iimpawu ze-EWNS8, 9, 10, 11 (esisiseko-EWNS) eyazenziwe ngaphambili. Ubalo lokubaluleka kwamanani kusetyenziswa uvavanyo lwe-t olunemisila emibini lupapashwa kwakhona kwiTheyibhile eyoNgezelelweyo S2. Ukongezelela, idatha eyongezelelweyo iquka izifundo malunga nefuthe le-counter electrode isampuli ye-sampling ye-diameter (D) kunye nomgama phakathi kwe-electrode yomhlaba kunye nencam yenaliti (L) (iMizobo eyoNgezelelweyo ye-S2 kunye ne-S3).
(a–c) Ubungakanani bosasazo lwe-AFM. (d – f) Uphawu lwentlawulo engaphezulu. (g) Ukubonakaliswa kwe-ROS kunye ne-ESR.
Kwakhona kubalulekile ukuqaphela ukuba kuzo zonke ezi meko zingasentla, umlinganiselo we-ionization currents wawukuluhlu lwe-2-6 µA, kwaye ii-voltages zazikuluhlu lwe--3.8 ukuya kwi- -6.5 kV, okubangele ukusetyenziswa kwamandla kule EWNS enye-terminal engaphantsi kwe-50 mW. . imodyuli yokuvelisa. Nangona i-EWNS yenziwa phantsi koxinzelelo oluphezulu, amanqanaba e-ozone ayephantsi kakhulu, awazange adlule kwi-60 ppb.
Umzobo owongezelelweyo S4 ubonisa iindawo zombane ezifanisiweyo ukwenzela [-6.5 kV, 4.0 cm] kunye ne [-3.8 kV, 0.5 cm] iimeko, ngokulandelanayo. Amasimi ngokweemeko [-6.5 kV, 4.0 cm] kunye [-3.8 kV, 0.5 cm] zibalwa njenge-2 × 105 V / m kunye ne-4.7 × 105 V / m, ngokulandelanayo. Oku kulindelekile, ekubeni umlinganiselo wombane ukuya kumgama uphezulu kakhulu kwimeko yesibini.
Kwikhiwane. I-3a,b ibonisa i-EWNS idayamitha elinganiswa nge-AFM8. Umlinganiselo we-EWNS diameters we [-6.5 kV, 4.0 cm] kunye ne [-3.8 kV, 0.5 cm] iimeko zibalwa njenge-27 nm kunye ne-19 nm, ngokulandelelanayo. Ukutenxa komgangatho wejometri yonikezelo lwamatyala [-6.5 kV, 4.0 cm] kunye ne- [-3.8 kV, 0.5 cm] yi-1.41 kunye ne-1.45, ngokulandelanayo, ebonisa ukusabalalisa ubungakanani obumxinwa. Zombini ubungakanani bentsingiselo kunye nokuphambuka komgangatho wejometri zisondele kakhulu kwisiseko-EWNS, ibe yi-25 nm kunye ne-1.41, ngokulandelanayo. Kwikhiwane. I-3c ibonisa ukuhanjiswa kobungakanani besiseko se-EWNS esilinganiswe kusetyenziswa indlela efanayo phantsi kweemeko ezifanayo.
Kwikhiwane. 3d,e ibonisa iziphumo zokuchazwa kwentlawulo. Idatha yimilinganiselo ye-avareji ye-30 yokulinganisa ngexesha elinye lokugxininiswa (#/cm3) kunye ne-current (I). Uhlalutyo lubonisa ukuba umyinge wentlawulo kwi-EWNS yi-22 ± 6 e- kunye ne-44 ± 6 e-ye- [-6.5 kV, 4.0 cm] kunye ne- [-3.8 kV, 0.5 cm], ngokulandelanayo. Xa kuthelekiswa ne-Baseline-EWNS (i-10 ± 2 e-), intlawulo yabo yomphezulu iphezulu kakhulu, iphindwe kabini loo [-6.5 kV, 4.0 cm] imeko kunye nezihlandlo ezine ze [-3 .8 kV, 0.5 cm]. I-3f ibonisa idatha yentlawulo ye-EWNS esisiseko.
Ukusuka kwiimephu zoxinaniso lwamanani e-EWNS (Amanani abongezelelweyo S5 kunye ne-S6), kunokubonwa ukuba indawo [-6.5 kV, 4.0 cm] inenani eliphezulu kakhulu lamasuntswana kune [-3.8 kV, 0.5 cm] indawo. Kufuneka kwakhona kuqatshelwe ukuba ugxininiso lwamanani e-EWNS lubekwe esweni ukuya kwiiyure ze-4 (Amanani abongezelelweyo S5 kunye ne-S6), apho ukuzinza kwesizukulwana se-EWNS kubonise amanqanaba afanayo okugxininiswa kwamanani amasuntswana kwiimeko zombini.
Umzobo we-3g ubonisa i-spectrum ye-EPR emva kokulawula (imvelaphi) ukuthabatha kwi-EWNS ephuculweyo kwi- [-6.5 kV, 4.0 cm]. I-spectrum ye-ROS iphinda ifaniswe nesiseko se-EWNS kwiphepha elipapashwe ngaphambili. Inani elibaliweyo le-EWNS ephendula nge-spin trap yi-7.5 × 104 EWNS / s, efana ne-Baseline-EWNS8 epapashwe ngaphambili. I-spectra ye-EPR ibonise ngokucacileyo ubukho beentlobo ezimbini ze-ROS, apho i-O2- iphambili, ngelixa i-OH• yayikhona ngexabiso elincinci. Ukongezelela, uthelekiso oluthe ngqo lokuqina kwencopho lubonise ukuba i-EWNS ephuculweyo inomxholo we-ROS ophezulu kakhulu xa kuthelekiswa nesiseko se-EWNS.
Kwikhiwane. I-4 ibonisa ukusebenza kakuhle kwe-EWNS kwi-EPES. Idatha iphinde ishwankathelwe kwiThebhile I kwaye ithelekiswa nedatha ye-EWNS yokuqala. Kuzo zombini iimeko ze-EUNS, i-deposition yayisondele kwi-100% nakwi-voltage ephantsi ye-3.0 kV. Ngokuqhelekileyo, i-3.0 kV yanele ukufikelela kwi-100% yokubekwa ngaphandle kokutshintsha kwentlawulo yomphezulu. Ngaphantsi kweemeko ezifanayo, ukusebenza kwe-deposition ye-Baseline-EWNS yayiyi-56% kuphela ngenxa yentlawulo ephantsi (i-avareji ye-electron ye-10 nge-EWNS).
Umfanekiso wesi-5 kunye neThebhile 2 ishwankathela iqondo lokungasebenzi kwe-microorganisms efakwe kumphezulu weetumato emva kokuvezwa malunga ne-40,000 #/cm3 EWNS imizuzu engama-45 phantsi kwemeko efanelekileyo [-6.5 kV, 4.0 cm]. Inoculated E. coli kunye L. innocua ibonise ukunciphisa okukhulu kwelogi ye-3.8 emva kwemizuzu ye-45 yokuvezwa. Ngaphantsi kweemeko ezifanayo, i-S. enterica ibonise ukucuthwa kwelogi ephantsi ye-2.2 logs, ngelixa i-S. cerevisiae kunye ne-M. parafortuitum ibonisa ukunciphisa i-1.0 log.
I-Electron micrographs (Umfanekiso 6) ebonisa utshintsho lomzimba olubangelwa yi-EWNS kwi-E. coli, i-Salmonella enterica, kunye ne-L. innocua iiseli ezikhokelela ekubeni zingasebenzi. Iibhaktheriya zokulawula zibonise i-membrane zeseli ephilileyo, ngelixa iibhaktheriya eziveziweyo zonakalise iimbumba zangaphandle.
I-electron microscopic imaging yolawulo kunye neebhaktheriya eziveziweyo zibonise umonakalo we-membrane.
Idatha kwiipropati ze-physicochemical ze-EWNS eziphuculweyo zibonisa ukuba iipropati ze-EWNS (intlawulo ephezulu kunye nomxholo we-ROS) ziphuculwe kakhulu xa kuthelekiswa nedatha yesiseko ye-EWNS epapashwe ngaphambili8,9,10,11. Ngakolunye uhlangothi, ubukhulu babo buhlala kuluhlu lwe-nanometer, olufana kakhulu neziphumo ezipapashwe ngaphambili, ezivumela ukuba bahlale emoyeni ixesha elide. I-polydispersity ebonwayo inokuchazwa ngotshintsho kwintlawulo yomhlaba, emisela ubukhulu besiphumo se-Rayleigh, ukungahambi kakuhle, kunye nokudibanisa okunokwenzeka kwe-EWNS. Nangona kunjalo, njengoko kucacisiwe ngu-Nielsen et al.22, intlawulo ephezulu yomphezulu inciphisa ukuguquka kwamanzi ngokwandisa ngokufanelekileyo amandla angaphezulu / uxinzelelo lokuhla kwamanzi. Le ithiyori yaqinisekiswa ngokomfuniselo kwi-microdroplets22 kunye ne-EWNS kushicilelo lwethu lwangaphambili8. Ukulahleka kwexesha elongezelelweyo nako kunokuchaphazela ubungakanani kunye negalelo ekwabiweni kobungakanani obuqatshelweyo.
Ukongeza, intlawulo ngesakhiwo malunga ne-22-44 e-, kuxhomekeke kwiimeko, eziphezulu kakhulu xa kuthelekiswa ne-EWNS esisiseko, ene-avareji yentlawulo ye-10 ± 2 electron kwisakhiwo ngasinye. Nangona kunjalo, kufuneka kuqatshelwe ukuba le yintlawulo eqhelekileyo ye-EWNS. Seto et al. Kuye kwaboniswa ukuba intlawulo ayifani kwaye ilandela i-log-normal distribution21. Xa kuthelekiswa nomsebenzi wethu wangaphambili, ukuphinda kabini intlawulo yomphezulu kuphinda-phinda ukusebenza kakuhle kwedeposition kwinkqubo ye-EPES ukuya phantse kwi-100% 11.