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Tsis ntev los no, lub platform tsis muaj tshuaj tua kab mob raws li nanotechnology siv cov khoom siv dej nanostructures (EWNS) tau tsim. EWNS muaj tus nqi siab tshaj plaws thiab nplua nuj nyob rau hauv cov pa oxygen reactive (ROS) uas tuaj yeem cuam tshuam nrog thiab ua rau muaj ntau yam kab mob, suav nrog cov kab mob hauv cov zaub mov. Ntawm no nws tau pom tias lawv cov khoom thaum lub sijhawm sib txuas tuaj yeem raug kho kom zoo thiab kho kom zoo ntxiv txhawm rau txhim kho lawv cov peev xwm tiv thaiv kab mob. Lub EWNS lub chaw kuaj sim platform tau tsim los kho cov khoom ntawm EWNS los ntawm kev hloov cov khoom sib txuas. Tus cwj pwm ntawm EWNS cov khoom (them nqi, qhov loj me, thiab cov ntsiab lus ROS) tau ua los ntawm kev siv cov kev ntsuas niaj hnub no. Tsis tas li ntawd, cov kab mob zaub mov xws li Escherichia coli, Salmonella enterica, Listeria innocua, Mycobacterium para fortitum, thiab Saccharomyces cerevisiae tau inoculated rau saum npoo ntawm txiv lws suav organic los ntsuas lawv cov microbial inactivation peev xwm. Cov txiaj ntsig tau nthuav tawm ntawm no qhia tau tias cov khoom ntawm EWNS tuaj yeem raug kho kom zoo thaum lub sijhawm sib txuas, ua rau muaj kev nce ntxiv hauv kev ua haujlwm tsis zoo. Hauv particular, tus nqi saum npoo tau nce los ntawm ib qho ntawm plaub, thiab ROS cov ntsiab lus tau nce. Tus nqi tshem tawm cov kab mob microbial yog nyob ntawm microbially thiab thaj tsam ntawm 1.0 txog 3.8 teev tom qab 45 feeb ntawm kev raug rau aerosol koob tshuaj ntawm 40,000 # / cm3 EWNS.
Kev kis kab mob microbial yog qhov ua rau muaj kab mob hauv cov zaub mov los ntawm kev noj cov kab mob los yog lawv cov co toxins. Cov kab mob noj zaub mov muaj txog li 76 lab tus mob, 325,000 mus pw hauv tsev kho mob, thiab 5,000 tus neeg tuag txhua xyoo hauv Tebchaws Meskas ib leeg. Tsis tas li ntawd, Tebchaws Meskas Lub Tsev Haujlwm Saib Xyuas Kev Ua Liaj Ua Teb (USDA) kwv yees tias kev noj cov khoom tshiab ntxiv yog lub luag haujlwm rau 48 feem pua ​​​​ntawm tag nrho cov khoom noj uas muaj mob tau tshaj tawm hauv Tebchaws Meskas2. Tus nqi ntawm kev mob thiab kev tuag los ntawm cov kab mob ua rau cov zaub mov hauv Tebchaws Meskas yog siab heev, kwv yees los ntawm Lub Chaw Tiv Thaiv thiab Tiv Thaiv Kab Mob (CDC) ntawm ntau dua US $ 15.6 billion toj ib xyoo.
Tam sim no, chemical4, radiation5 thiab thermal6 antimicrobial interventions los xyuas kom meej cov zaub mov kev nyab xeeb yog tsuas yog siv nyob rau hauv lub txwv tseem ceeb tswj cov ntsiab lus (CCPs) nyob rau hauv cov saw hlau ntau lawm (feem ntau tom qab sau thiab / los yog thaum lub sij hawm ntim) es tsis tu ncua siv nyob rau hauv xws li cov khoom tshiab yog raug mus rau cross-contamination 7. Antimicrobial interventions yog xav tau los tswj cov zaub mov zoo dua thiab muaj peev xwm borne. ua liaj ua teb-rau- rooj txuas ntxiv. Tsawg cuam tshuam thiab raug nqi.
Lub nanotechnology-based chemical-free antimicrobial platform tsis ntev los no tau tsim los ua kom tsis muaj kab mob ntawm qhov chaw thiab hauv huab cua siv cov khoom siv dej nanostructures (EWNS). Rau kev sib txuas ntawm EVNS, ob txoj kev sib txuas tau siv: electrospray thiab dej ionization (Fig. 1a). EWNS yav dhau los tau pom tias muaj qhov tshwj xeeb ntawm lub cev thiab cov khoom siv lom neeg 8,9,10. EWNS muaj qhov nruab nrab ntawm 10 electrons ib tus qauv thiab qhov nruab nrab nanometer loj ntawm 25 nm (Fig. 1b,c)8,9,10. Tsis tas li ntawd, electron spin resonance (ESR) tau qhia tias EWNS muaj ntau hom reactive oxygen (ROS), feem ntau hydroxyl (OH•) thiab superoxide (O2-) radicals (Fig. 1c) 8 . EWNS tseem nyob hauv huab cua ntev thiab tuaj yeem sib tsoo nrog cov microbes raug tshem tawm hauv huab cua thiab tam sim no ntawm cov chaw, xa lawv cov ROS payload thiab ua rau microbial inactivation (Fig. 1d). Cov kev tshawb fawb yav dhau los no kuj tau pom tias EWNS tuaj yeem cuam tshuam nrog thiab ua rau muaj ntau yam kab mob gram-tsis zoo thiab gram-zoo ntawm pej xeem kev noj qab haus huv tseem ceeb, suav nrog mycobacteria, ntawm qhov chaw thiab hauv huab cua8,9. Kev xa tawm electron microscopy qhia tias qhov tsis ua haujlwm yog tshwm sim los ntawm kev cuam tshuam ntawm cov cell membrane. Tsis tas li ntawd, cov kev tshawb fawb txog kev nqus nqus tau pom tau tias cov koob tshuaj ntau ntawm EWNS tsis ua rau lub ntsws puas lossis mob 8.
(a) Electrospray tshwm sim thaum muaj hluav taws xob siab siv ntawm lub capillary uas muaj kua thiab lub txee electrode. (b) Kev siv hluav taws xob siab ua rau muaj ob qhov xwm txheej sib txawv: (i) electrospraying dej thiab (ii) tiam ntawm cov pa oxygen reactive (ions) daig hauv EWNS. (c) Tus qauv tshwj xeeb ntawm EWNS. (d) EWNS yog cov xov tooj ntawm tes vim lawv qhov xwm txheej nanoscale thiab tuaj yeem cuam tshuam nrog cov kab mob hauv huab cua.
Lub peev xwm ntawm EWNS antimicrobial platform rau inactivate foodborne microorganisms nyob rau saum npoo ntawm cov zaub mov tshiab kuj tsis ntev los no tau tshwm sim. Nws kuj tau pom tias EWNS tus nqi saum npoo tuaj yeem siv ua ke nrog lub chaw hluav taws xob rau kev xa khoom. Qhov tseem ceeb tshaj, qhov kev cog lus thawj zaug ntawm kwv yees li 1.4 teev txo qis hauv cov kua txiv lws suav tawm tsam ntau yam khoom noj xws li E. coli thiab Listeria tau pom nyob rau hauv 90 feeb ntawm kev raug EWNS ntawm qhov concentration ntawm kwv yees li 50,000 # / cm311. Tsis tas li ntawd, qhov kev ntsuam xyuas organoleptic ua ntej tsis pom muaj cov nyhuv organoleptic piv rau cov txiv lws suav tswj. Txawm hais tias qhov kev tshwm sim thawj zaug no tau cog lus tias muaj kev nyab xeeb ntawm zaub mov txawm tias tsawg heev EWNS koob tshuaj 50,000 # / cc. pom, nws yog qhov tseeb tias qhov muaj peev xwm ua kom tsis muaj zog ntau dua yuav muaj txiaj ntsig ntxiv los txo qis kev pheej hmoo ntawm kev kis kab mob thiab lwj.
Ntawm no, peb yuav tsom mus rau peb cov kev tshawb fawb txog kev txhim kho ntawm EWNS tiam platform kom zoo kho cov kev sib xyaw ua ke thiab ua kom zoo dua cov khoom siv hluav taws xob ntawm EWNS txhawm rau txhim kho lawv cov peev xwm tiv thaiv kab mob. Tshwj xeeb, kev ua kom zoo tau tsom mus rau kev nce lawv cov nqi saum npoo (kom txhim kho lub hom phiaj xa khoom) thiab ROS cov ntsiab lus (los txhim kho kev ua haujlwm tsis zoo). Kev ua kom zoo tshaj plaws ntawm cov khoom siv physico-chemical (qhov loj me, nqi thiab ROS cov ntsiab lus) siv cov kev ntsuas niaj hnub thiab siv cov khoom noj khoom haus xws li E. coli, S. enterica, L. innocua, S. cerevisiae thiab M. parafortuitum.
EVNS tau tsim los ntawm ib txhij electrospraying thiab ionization ntawm cov dej purity siab (18 MΩ cm-1). Lub tshuab hluav taws xob atomizer 12 feem ntau yog siv rau atomize kua thiab hluavtaws polymer thiab ceramic hais 13 thiab fibers 14 ntawm kev tswj loj.
Raws li cov ncauj lus kom ntxaws hauv cov ntawv tshaj tawm yav dhau los 8, 9, 10, 11, hauv kev sim ib txwm muaj, qhov hluav taws xob siab yog siv los ntawm cov hlau capillary thiab cov khoom siv hluav taws xob hauv av. Thaum lub sijhawm txheej txheem no, ob qhov xwm txheej sib txawv tshwm sim: 1) electrospray thiab 2) ionization ntawm dej. Ib qho hluav taws xob muaj zog nruab nrab ntawm ob lub electrodes ua rau cov nqi tsis zoo los ua rau ntawm cov dej condensed, uas ua rau tsim Taylor cones. Raws li qhov tshwm sim, cov tee dej uas tau them nyiaj ntau yog tsim, uas txuas ntxiv mus rau hauv cov khoom me me, raws li Rayleigh txoj kev xav 16. Nyob rau tib lub sijhawm, qhov hluav taws xob muaj zog ua rau qee cov dej molecules sib cais thiab tshem tawm cov hluav taws xob (ionization), yog li tsim kom muaj ntau cov pa oxygen reactive (ROS) 17. Ib txhij generated ROS18 pob ntawv tau encapsulated hauv EWNS (Fig. 1c).
Ntawm daim duab. 2a qhia EWNS tiam system tsim thiab siv hauv EWNS synthesis hauv txoj kev tshawb no. Cov dej huv uas khaws cia rau hauv lub raj mis kaw tau pub los ntawm Teflon raj (2 hli puab txoj kab uas hla) mus rau 30G stainless hlau koob (hlau capillary). Raws li pom hauv daim duab 2b, cov dej ntws yog tswj los ntawm huab cua hauv lub raj mis. Lub koob txuas nrog Teflon console uas tuaj yeem hloov kho manually rau qee qhov kev ncua deb ntawm lub txee electrode. Lub txee electrode yog polished aluminium disk nrog lub qhov nyob hauv nruab nrab rau kev kuaj. Hauv qab ntawm lub txee electrode yog ib qho txhuas sampling funnel, uas txuas nrog rau qhov seem ntawm kev sim teeb tsa ntawm qhov chaw nres nkoj sampling (Fig. 2b). Tag nrho cov khoom siv sampler yog hluav taws xob hauv av kom tsis txhob muaj nqi tsim khoom uas tuaj yeem degrade particle sampling.
(a) Engineered Water Nanostructure Generation System (EWNS). (b) Hla ntu ntawm sampler thiab electrospray chav tsev qhia txog qhov tseem ceeb tshaj plaws. (c) Kev sim teeb tsa rau cov kab mob inactivation.
EWNS tiam txheej txheem tau piav qhia saum toj no muaj peev xwm hloov pauv qhov tseem ceeb ntawm kev ua haujlwm los pab txhawb kev kho kom zoo ntawm EWNS cov khoom. Kho qhov kev siv hluav taws xob (V), qhov kev ncua deb ntawm rab koob thiab lub txee electrode (L), thiab cov dej ntws (φ) los ntawm cov capillary kom zoo-tune EWNS cov yam ntxwv. Cov cim [V (kV), L (cm)] yog siv los qhia qhov sib txawv ua ke. Kho cov dej ntws kom tau txais lub khob Taylor ruaj khov ntawm ib qho teeb [V, L]. Rau lub hom phiaj ntawm txoj kev tshawb no, lub aperture ntawm lub txee electrode (D) tau teem rau ntawm 0.5 nti (1.29 cm).
Vim qhov txwv geometry thiab asymmetry, lub zog hluav taws xob tsis tuaj yeem xam los ntawm thawj cov hauv paus ntsiab lus. Hloov chaw, QuickField™ software (Svendborg, Denmark)19 tau siv los suav cov hluav taws xob. Lub teb hluav taws xob tsis sib xws, yog li tus nqi hluav taws xob ntawm qhov kawg ntawm lub capillary tau siv los ua tus nqi siv rau ntau yam kev teeb tsa.
Thaum lub sij hawm txoj kev tshawb no, ob peb ua ke ntawm voltage thiab nyob deb ntawm lub koob thiab lub counter electrode tau soj ntsuam nyob rau hauv cov nqe lus ntawm Taylor cone tsim, Taylor cone stability, EWNS ntau lawm stability, thiab reproducibility. Ntau qhov sib xyaw ua ke tau qhia hauv Cov Lus Ntxiv S1.
Cov zis ntawm EWNS tiam system tau txuas ncaj qha mus rau Scanning Mobility Particle Sizer (SMPS, model 3936, TSI, Shoreview, Minnesota) los ntsuas particle number concentration thiab tau siv nrog Faraday aerosol electrometer (TSI, model 3068B, Shoreview, USA). MN) txhawm rau ntsuas aerosol ntws, raws li tau piav qhia hauv peb tsab ntawv tshaj tawm dhau los 9. Ob qho tib si SMPS thiab aerosol electrometer coj mus kuaj ntawm tus nqi ntws ntawm 0.5 L / min (tag nrho cov qauv ntws 1 L / min). Particle concentrations thiab aerosol fluxes tau ntsuas rau 120 s. Rov ua qhov ntsuas 30 zaug. Tag nrho cov nqi aerosol yog xam los ntawm kev ntsuas tam sim no, thiab qhov nruab nrab EWNS tus nqi yog kwv yees los ntawm tag nrho cov EWNS cov khoom ua piv txwv. Tus nqi nruab nrab ntawm EWNS tuaj yeem suav nrog siv Equation (1):
qhov twg IEl yog qhov ntsuas tam sim no, NSMPS yog tus lej concentration ntsuas nrog SMPS, thiab φEl yog tus nqi ntws mus rau electrometer.
Vim tias qhov txheeb ze av noo (RH) cuam tshuam rau saum npoo, qhov kub thiab txias (RH) tau nyob ruaj khov ntawm 21 ° C thiab 45%, feem, thaum lub sijhawm sim.
Atomic force microscopy (AFM), Asylum MFP-3D (Asylum Research, Santa Barbara, CA) thiab AC260T sojntsuam (Olympus, Tokyo, Nyiv) tau siv los ntsuas qhov loj thiab lub neej ntawm EWNS. AFM scan tus nqi yog 1 Hz thiab cheeb tsam scan yog 5 µm × 5 µm nrog 256 scan kab. Tag nrho cov duab tau raug ua ntej kev txiav txim duab sib dhos siv Asylum software (lub npog ntsej muag nrog ntau yam ntawm 100 nm thiab qhov pib ntawm 100 teev tsaus ntuj).
Tshem cov sampling funnel thiab tso lub mica nto ntawm qhov deb ntawm 2.0 cm ntawm lub txee electrode rau ib lub sij hawm nruab nrab ntawm 120 s kom tsis txhob coalescence ntawm hais thiab tsim ntawm irregular droplets ntawm mica nto. EWNS tau siv ncaj qha mus rau qhov chaw txiav mica tshiab (Ted Pella, Redding, CA). Tam sim ntawd tom qab sputtering, mica nto tau pom tau siv AFM. Lub kaum sab xis ntawm lub ntsej muag ntawm cov tshiab txiav tsis hloov kho mica yog ze rau 0 °, yog li EWNS propagates hla lub mica nto nyob rau hauv ib tug domed duab20. Txoj kab uas hla (a) thiab qhov siab (h) ntawm diffusing droplets tau ntsuas ncaj qha los ntawm AFM topography thiab siv los xam cov domed diffusion ntim EWNS siv peb txoj kev siv tau dhau los 8. Piv txwv tias onboard EVNS muaj tib lub ntim, qhov sib npaug ntawm txoj kab uas hla tuaj yeem xam los ntawm kev sib npaug (2):
Raws li peb txoj kev tsim yav dhau los, ib qho hluav taws xob spin resonance (ESR) spin trap tau siv los kuaj pom muaj cov kab mob luv luv nyob hauv EWNS. Aerosols tau dhau los ntawm cov tshuaj uas muaj 235 mM DEPMPO (5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide) (Oxis International Inc., Portland, Oregon). Txhua qhov kev ntsuas EPR tau ua tiav siv Bruker EMX spectrometer (Bruker Instruments Inc. Billerica, MA, USA) thiab cov xov tooj ntawm tes. Lub Acquisit software (Bruker Instruments Inc. Billerica, MA, USA) tau siv los sau thiab txheeb xyuas cov ntaub ntawv. ROS characterization tsuas yog ua rau cov txheej txheem kev khiav hauj lwm [-6.5 kV, 4.0 cm]. EWNS concentrations tau ntsuas siv SMPS tom qab txiav txim siab qhov poob ntawm EWNS hauv qhov cuam tshuam.
Ozone qib tau saib xyuas siv 205 Dual Beam Ozone Monitor™ (2B Technologies, Boulder, Co) 8,9,10.
Rau tag nrho EWNS cov khoom, qhov ntsuas tus nqi yog qhov nruab nrab ntawm qhov ntsuas, thiab qhov ntsuas qhov yuam kev yog tus qauv sib txawv. Ib qho t-test tau ua los sib piv tus nqi ntawm qhov optimized EWNS tus cwj pwm nrog tus nqi sib xws ntawm lub hauv paus EWNS.
Daim duab 2c qhia tau hais tias yav dhau los tsim thiab tus yam ntxwv Electrostatic Precipitation Pass Through System (EPES) uas tuaj yeem siv los tsom EWNS11 rau qhov chaw. EPES siv tus nqi EWNS ua ke nrog lub zog hluav taws xob kom "taw tes" ncaj qha ntawm lub hom phiaj ntawm qhov chaw. Cov ntsiab lus ntawm EPES system tau nthuav tawm nyob rau hauv kev tshaj tawm tsis ntev los no los ntawm Pyrgiotakis li al.11. Yog li, EPES muaj 3D luam tawm PVC chamber nrog tapered kawg uas muaj ob qho tib si stainless hlau (304 stainless hlau, daim iav polished) hlau daim hlau nyob rau hauv nruab nrab 15.24 cm sib nrug. Cov laug cam tau txuas nrog rau qhov chaw muaj hluav taws xob sab nraud (Bertran 205B-10R, Spellman, Hauppauge, NY), lub rooj tsav xwm hauv qab yeej ib txwm zoo thiab lub rooj tsavxwm sab saum toj yeej ib txwm nyob hauv av (floating). Lub chamber phab ntsa yog them nrog aluminium ntawv ci, uas yog hluav taws xob hauv av los tiv thaiv particle poob. Lub chamber muaj lub qhov rooj kaw cia rau pem hauv ntej uas tso cai rau cov chaw kuaj kom muab tso rau ntawm cov yas racks, nqa lawv tawm ntawm lub phaj hlau hauv qab kom tsis txhob muaj kev cuam tshuam loj heev.
Qhov kev ua tau zoo ntawm EWNS hauv EPES tau suav nrog raws li cov txheej txheem tsim tawm yav dhau los tau piav qhia hauv Daim Duab Ntxiv S111.
Raws li lub chamber tswj, qhov thib ob ntws los ntawm lub cylindrical chamber yog kev cob cog rua nyob rau hauv series nrog lub EPES system siv lub intermediate HEPA lim kom tshem tawm EWNS. Raws li qhia hauv daim duab. 2c, EWNS aerosol tau nqus los ntawm ob chav sib txuas hauv series. Lub lim nruab nrab ntawm chav tswj thiab EPES tshem tawm qhov seem EWNS uas ua rau tib qhov kub thiab txias (T), txheeb ze av noo (RH) thiab qib ozone.
Cov kab mob tseem ceeb ntawm cov khoom noj tau raug pom tias muaj paug cov khoom tshiab xws li Escherichia coli (ATCC #27325), qhov taw qhia fecal, Salmonella enterica (ATCC #53647), cov kab mob hauv cov zaub mov, Listeria innocua (ATCC #33090), lwm txoj hauv kev rau cov kab mob Listeria monocytogenes. , Saccharomyces cerevisiae (ATCC #4098) ua lwm txoj rau cov poov xab spoilage, thiab Mycobacterium parafortuitous (ATCC #19686) raws li cov kab mob muaj sia nyob ntau dua tau yuav los ntawm ATCC (Manassas, Virginia).
Random yuav cov thawv ntawm cov txiv lws suav organic los ntawm koj lub khw hauv zos thiab tso rau hauv tub yees ntawm 4 ° C kom txog thaum siv (txog 3 hnub). Xaiv cov txiv lws suav los sim nrog ib qhov loj me, txog 1/2 nti hauv txoj kab uas hla.
Cov txheej txheem rau incubation, inoculation, exposure thiab colony suav tau piav qhia hauv peb cov ntawv tshaj tawm yav dhau los thiab tau piav qhia meej hauv Cov Ntaub Ntawv Ntxiv 11. EWNS kev ua tau zoo tau raug ntsuas los ntawm kev nthuav tawm cov txiv lws suav rau 40,000 # / cm3 rau 45 feeb. Luv luv, thaum lub sij hawm t = 0 min, peb txiv lws suav tau siv los ntsuas cov kab mob uas muaj sia nyob. Peb lub txiv lws suav tau muab tso rau hauv EPES thiab raug EWNS ntawm 40,000 #/cc (EWNS raug txiv lws suav) thiab peb lwm tus tau muab tso rau hauv chav tswj (tswj txiv lws suav). Tsis muaj ib pawg txiv lws suav raug rau kev ua haujlwm ntxiv. EWNS-tshuaj txiv lws suav thiab tswj tau raug tshem tawm tom qab 45 feeb los ntsuas cov txiaj ntsig ntawm EWNS.
Txhua qhov kev sim tau ua tiav hauv triplicate. Kev txheeb xyuas cov ntaub ntawv tau ua raws li cov txheej txheem tau piav qhia hauv Cov Ntaub Ntawv Ntxiv.
Cov kab mob E. coli, Enterobacter, thiab L. innocua cov kab mob kis tau rau EWNS (45 min, EWNS aerosol concentration 40,000 #/cm3) thiab tsis raug pelleted tau pelleted los soj ntsuam cov txheej txheem inactivation. Lub precipitate yog tsau rau 2 teev nyob rau hauv chav tsev kub nyob rau hauv 0.1 M sodium cacodylate tov (pH 7.4) nrog ib tug fixative ntawm 2.5% glutaraldehyde, 1.25% paraformaldehyde thiab 0.03% picric acid. Tom qab ntxuav, lawv tau kho nrog 1% osmium tetroxide (OsO4) / 1.5% potassium ferrocyanide (KFeCN6) rau 2 h, ntxuav 3 zaug nrog dej thiab incubated hauv 1% uranyl acetate rau 1 h, ces ntxuav ob zaug nrog dej. Tom qab lub cev qhuav dej 10 feeb txhua 50%, 70%, 90%, 100% cawv. Cov qauv no tau muab tso rau hauv propylene oxide rau 1 teev thiab impregnated nrog 1: 1 sib tov ntawm propylene oxide thiab TAAP Epon (Marivac Canada Inc. St. Laurent, CA). Cov qauv tau muab tso rau hauv TAAB Epon thiab polymerized ntawm 60 ° C rau 48 teev. Cov tshuaj kho granular tau raug txiav thiab pom los ntawm TEM siv JEOL 1200EX (JEOL, Tokyo, Nyiv), cov khoom siv hluav taws xob sib kis tau nruab nrog lub koob yees duab AMT 2k CCD (Advanced Microscopy Techniques, Corp., Woburn, MA, USA).
Txhua qhov kev sim tau ua tiav hauv triplicate. Rau txhua lub sij hawm taw tes, cov kab mob ntxuav tau plated nyob rau hauv triplicate, ua rau tag nrho ntawm cuaj cov ntaub ntawv ib tug point, qhov nruab nrab ntawm uas yog siv raws li cov kab mob concentration rau tej yam kab mob. Tus qauv sib txawv tau siv los ntsuas qhov yuam kev. Tag nrho cov ntsiab lus suav.
Lub logarithm ntawm qhov txo qis hauv qhov concentration ntawm cov kab mob piv rau t = 0 min tau suav nrog cov qauv hauv qab no:
qhov twg C0 yog qhov concentration ntawm cov kab mob hauv cov qauv tswj ntawm lub sijhawm 0 (piv txwv li tom qab lub npoo tau qhuav tab sis ua ntej muab tso rau hauv lub chamber) thiab Cn yog cov concentration ntawm cov kab mob ntawm qhov chaw tom qab n feeb ntawm raug.
Txhawm rau suav rau cov kab mob hauv lub cev tsis zoo thaum lub sijhawm 45 feeb raug, Log-Reduction kuj tau xam piv rau kev tswj ntawm 45 feeb raws li hauv qab no:
Qhov twg Cn yog qhov concentration ntawm cov kab mob hauv cov qauv tswj ntawm lub sij hawm n thiab Cn-Control yog qhov concentration ntawm cov kab mob tswj lub sij hawm n. Cov ntaub ntawv raug nthuav tawm raws li kev txo qis piv rau kev tswj hwm (tsis muaj EWNS raug).
Thaum lub sij hawm txoj kev tshawb no, ob peb ua ke ntawm voltage thiab nyob deb ntawm lub koob thiab lub counter electrode tau soj ntsuam nyob rau hauv cov nqe lus ntawm Taylor cone tsim, Taylor cone stability, EWNS ntau lawm stability, thiab reproducibility. Ntau qhov sib xyaw ua ke tau qhia hauv Cov Lus Ntxiv S1. Ob qhov xwm txheej tau raug xaiv rau kev kawm tiav uas qhia txog cov khoom ruaj khov thiab rov tsim dua tshiab (Taylor cone, EWNS ntau lawm, thiab kev ruaj khov nyob rau lub sijhawm). Ntawm daim duab. 3 qhia cov txiaj ntsig ntawm tus nqi, qhov loj thiab cov ntsiab lus ntawm ROS rau ob kis. Cov txiaj ntsig kuj tau sau tseg hauv Table 1. Rau kev siv, Daim duab 3 thiab Table 1 suav nrog cov khoom ntawm cov khoom siv yav dhau los uas tsis yog qhov zoo EWNS8, 9, 10, 11 (baseline-EWNS). Kev txheeb xyuas qhov tseem ceeb suav nrog siv ob-tailed t-test yog rov luam tawm hauv Cov Lus Ntxiv S2. Tsis tas li ntawd, cov ntaub ntawv ntxiv muaj xws li kev tshawb fawb txog cov txiaj ntsig ntawm lub txee electrode sampling qhov taub txoj kab uas hla (D) thiab qhov kev ncua deb ntawm cov av electrode thiab qhov kawg ntawm rab koob (L) (Cov duab ntxiv S2 thiab S3).
(a–c) AFM loj faib. (d – f) Nto them tus yam ntxwv. (g) Tus cwj pwm ntawm ROS thiab ESR.
Nws tseem yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias rau tag nrho cov xwm txheej saum toj no, ntsuas ionization tam sim no nyob rau hauv thaj tsam ntawm 2-6 µA, thiab cov voltages nyob rau hauv thaj tsam ntawm -3.8 txog -6.5 kV, uas ua rau lub zog noj rau qhov no ib leeg-terminal EWNS tsawg dua 50 mW. . tiam module. Txawm hais tias EWNS tau tsim nyob rau hauv kev kub siab, ozone qib qis heev, tsis pub tshaj 60 ppb.
Ntxiv daim duab S4 qhia cov simulated hluav taws xob teb rau [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] scenarios, ntsig txog. Cov teb raws li qhov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] raug xam raws li 2 × 105 V / m thiab 4.7 × 105 V / m, ntsig txog. Qhov no yuav tsum tau xav, txij li qhov piv ntawm qhov voltage mus rau qhov deb yog ntau dua nyob rau hauv rooj plaub thib ob.
Ntawm daim duab. 3a, b qhia EWNS txoj kab uas hla ntsuas nrog AFM8. Qhov nruab nrab EWNS txoj kab uas hla rau [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] scenarios raug xam raws li 27 nm thiab 19 nm, raws li. Cov qauv geometric sib txawv ntawm qhov kev faib tawm rau cov rooj plaub [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] yog 1.41 thiab 1.45, raws li, qhia qhov nqaim faib. Ob qho tib si qhov loj me thiab qhov sib txawv ntawm tus qauv geometric yog ze rau lub hauv paus-EWNS, yog 25 nm thiab 1.41, raws li. Ntawm daim duab. 3c qhia txog qhov loj me ntawm cov kab hauv paus EWNS ntsuas siv tib txoj kev raws li tib yam kev mob.
Ntawm daim duab. 3d, e qhia cov txiaj ntsig ntawm kev them tus cwj pwm. Cov ntaub ntawv yog qhov ntsuas nruab nrab ntawm 30 kev ntsuas ib txhij ntawm kev ntsuas (# / cm3) thiab tam sim no (I). Kev tsom xam qhia tau hais tias qhov nruab nrab nqi ntawm EWNS yog 22 ± 6 e- thiab 44 ± 6 e- rau [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm], feem. Piv rau Baseline-EWNS (10 ± 2 e-), lawv cov nqi saum npoo yog qhov siab dua, ob zaug ntawm qhov xwm txheej [-6.5 kV, 4.0 cm] thiab plaub npaug ntawm [-3 .8 kV, 0.5 cm]. 3f qhia cov ntaub ntawv them nyiaj EWNS yooj yim.
Los ntawm EWNS tus lej concentration daim duab qhia chaw (Cov duab ntxiv S5 thiab S6), nws tuaj yeem pom tau tias [-6.5 kV, 4.0 cm] scene muaj ntau cov khoom ntau dua li qhov [-3.8 kV, 0.5 cm] scene. Nws tseem yuav tsum tau muab sau tseg tias EWNS tus naj npawb concentrations tau soj ntsuam txog li 4 teev (Ntxiv cov duab S5 thiab S6), qhov twg EWNS tiam stability tau pom tib theem ntawm particle tooj concentrations nyob rau hauv ob qho tib si.
Daim duab 3g qhia cov EPR spectrum tom qab tswj (tom qab) rho tawm rau optimized EWNS ntawm [-6.5 kV, 4.0 cm]. ROS spectrum kuj tseem muab piv rau EWNS lub hauv paus hauv ib daim ntawv luam tawm yav dhau los. Tus lej suav ntawm EWNS reacting nrog lub cuab yeej yog 7.5 × 104 EWNS / s, uas zoo ib yam li cov ntawv tshaj tawm yav dhau los Baseline-EWNS8. EPR spectra qhia meej meej tias muaj ob hom ROS, qhov twg O2- predominated, thaum OH• tam sim no nyob rau hauv ib qho me me. Tsis tas li ntawd, kev sib piv ncaj qha ntawm qhov siab tshaj plaws tau pom tias qhov ua tau zoo EWNS muaj cov ntsiab lus ROS ntau dua piv rau cov hauv paus EWNS.
Ntawm daim duab. 4 qhia txog kev tso nyiaj ua haujlwm ntawm EWNS hauv EPES. Cov ntaub ntawv kuj tau sau tseg hauv Table I thiab muab piv nrog cov ntaub ntawv EWNS qub. Rau ob qho tib si EUNS, deposition yog ze rau 100% txawm nyob rau ntawm ib tug tsawg voltage ntawm 3.0 kV. Feem ntau, 3.0 kV yog txaus kom ua tiav 100% deposition tsis hais tus nqi deg hloov. Raws li cov xwm txheej zoo ib yam, qhov kev tso nyiaj tso tawm ntawm Baseline-EWNS tsuas yog 56% vim yog tus nqi qis (nruab nrab 10 electrons ib EWNS).
Daim duab 5 thiab Table 2 piav qhia txog qib ntawm inactivation ntawm microorganisms inoculated nyob rau saum npoo ntawm txiv lws suav tom qab kis mus rau kwv yees li 40,000 #/cm3 EWNS rau 45 feeb nyob rau hauv qhov kev pom zoo scenario [-6.5 kV, 4.0 cm]. Inoculated E. coli thiab L. innocua pom qhov txo qis ntawm 3.8 teev tom qab 45 feeb ntawm kev kis. Raws li cov xwm txheej qub, S. enterica pom qhov txo qis ntawm 2.2 cav, thaum S. cerevisiae thiab M. parafortuitum pom qhov txo qis ntawm 1.0.
Electron micrographs (Daim duab 6) qhia txog cov kev hloov ntawm lub cev uas tshwm sim los ntawm EWNS hauv E. coli, Salmonella enterica, thiab L. innocua hlwb ua rau inactivation. Cov kab mob tswj tau pom cov kab mob ntawm tes tsis zoo, thaum cov kab mob kis tau ua rau cov tawv nqaij puas lawm.
Electron microscopic imaging ntawm kev tswj thiab raug cov kab mob nthuav tawm cov membrane puas.
Cov ntaub ntawv ntawm physicochemical zog ntawm optimized EWNS sau qhia tias EWNS cov khoom (nto nqi thiab ROS cov ntsiab lus) tau txhim kho zoo dua piv rau yav dhau los EWNS cov ntaub ntawv hauv qab 8,9,10,11. Ntawm qhov tod tes, lawv qhov loj me tseem nyob hauv thaj tsam nanometer, uas zoo ib yam li cov txiaj ntsig tau tshaj tawm yav dhau los, tso cai rau lawv nyob hauv huab cua rau lub sijhawm ntev. Qhov pom pom polydispersity tuaj yeem piav qhia los ntawm kev hloov pauv ntawm tus nqi saum npoo, uas txiav txim siab qhov loj ntawm Rayleigh nyhuv, randomness, thiab muaj peev xwm sib koom ua ke ntawm EWNS. Txawm li cas los xij, raws li tau piav qhia los ntawm Nielsen li al.22, tus nqi siab saum npoo yuav txo tau evaporation los ntawm kev ua kom lub zog saum npoo av / nro ntawm cov dej poob. Qhov kev xav no tau sim ua pov thawj rau microdroplets22 thiab EWNS hauv peb qhov kev tshaj tawm yav dhau los 8. Qhov poob ntawm kev ua haujlwm dhau sijhawm tuaj yeem cuam tshuam qhov loj me thiab ua rau pom qhov loj me me.
Tsis tas li ntawd, tus nqi ntawm ib tus qauv yog kwv yees li 22-44 e-, nyob ntawm qhov xwm txheej, uas yog qhov loj dua piv rau cov qauv EWNS, uas muaj qhov nruab nrab nqi ntawm 10 ± 2 electrons ib tus qauv. Txawm li cas los xij, nws yuav tsum raug sau tseg tias qhov no yog tus nqi nruab nrab ntawm EWNS. Seto et al. Nws tau raug pom tias tus nqi tsis sib xws thiab ua raws li kev faib tawm ntawm cov log-ib txwm 21. Piv nrog rau peb qhov kev ua haujlwm dhau los, ob npaug ntawm tus nqi saum npoo ob npaug ntawm qhov kev tso nyiaj tso tawm hauv EPES qhov system yuav luag 100% 11.