Ua tsaug rau koj tuaj xyuas Nature.com. Lub browser version uas koj siv muaj kev txhawb nqa CSS tsawg. Rau qhov kev paub zoo tshaj plaws, peb xav kom koj siv lub browser hloov tshiab (lossis kaw Compatibility Mode hauv Internet Explorer). Lub sijhawm no, kom ntseeg tau tias muaj kev txhawb nqa txuas ntxiv, peb yuav ua rau lub xaib tsis muaj cov qauv thiab JavaScript.
Tsis ntev los no, ib lub platform tshuaj tua kab mob uas tsis muaj tshuaj lom neeg raws li nanotechnology siv cov dej nanostructures (EWNS) tau tsim. EWNS muaj qhov them siab ntawm qhov chaw thiab muaj cov reactive oxygen species (ROS) uas tuaj yeem cuam tshuam nrog thiab ua rau ntau yam kab mob me me, suav nrog cov kab mob uas los ntawm zaub mov. Ntawm no nws tau qhia tias lawv cov khoom thaum lub sijhawm tsim khoom tuaj yeem kho kom zoo thiab ua kom zoo dua kom txhim kho lawv cov peev xwm tua kab mob. Lub platform kuaj mob EWNS tau tsim los kho cov khoom ntawm EWNS los ntawm kev hloov cov txheej txheem tsim khoom. Kev piav qhia ntawm EWNS cov khoom (them, qhov loj me thiab cov ntsiab lus ntawm ROS) siv cov txheej txheem niaj hnub. Tsis tas li ntawd, lawv tau soj ntsuam rau lawv cov peev xwm tsis ua haujlwm ntawm cov kab mob me me tiv thaiv cov kab mob me me uas los ntawm zaub mov xws li Escherichia coli, Salmonella enterica, Listeria innocuous, Mycobacterium paraaccidentum thiab Saccharomyces cerevisiae. Cov txiaj ntsig tau nthuav tawm ntawm no qhia tau tias cov khoom ntawm EWNS tuaj yeem kho kom zoo thaum lub sijhawm tsim khoom, ua rau muaj kev nce ntxiv ntawm kev ua haujlwm tsis ua haujlwm. Tshwj xeeb, qhov them ntawm qhov chaw nce ntxiv los ntawm plaub qhov thiab cov hom pa oxygen reactive nce ntxiv. Tus nqi tshem tawm cov kab mob me me yog nyob ntawm cov kab mob me me thiab nyob ntawm 1.0 txog 3.8 log tom qab 45 feeb raug rau cov tshuaj aerosol ntawm 40,000 # / cc EWNS.
Kev kis kab mob me me yog qhov ua rau muaj mob los ntawm zaub mov uas tshwm sim los ntawm kev noj cov kab mob lossis lawv cov tshuaj lom. Tsuas yog nyob hauv Tebchaws Meskas xwb, kev mob los ntawm zaub mov ua rau muaj li ntawm 76 lab tus neeg mob, 325,000 tus neeg raug mob, thiab 5,000 tus neeg tuag txhua xyoo1. Tsis tas li ntawd, Lub Tsev Haujlwm Saib Xyuas Kev Ua Liaj Ua Teb ntawm Tebchaws Meskas (USDA) kwv yees tias kev noj zaub tshiab ntau ntxiv yog lub luag haujlwm rau 48% ntawm tag nrho cov kab mob los ntawm zaub mov uas tau tshaj tawm hauv Tebchaws Meskas2. Tus nqi ntawm kev mob thiab kev tuag los ntawm cov kab mob los ntawm zaub mov hauv Tebchaws Meskas yog siab heev, uas tau kwv yees los ntawm Lub Chaw Tswj thiab Tiv Thaiv Kab Mob (CDC) ntawm ntau dua US $ 15.6 billion ib xyoos3.
Tam sim no, kev siv tshuaj tua kab mob chemical4, radiation5 thiab thermal6 los xyuas kom meej tias cov zaub mov muaj kev nyab xeeb feem ntau yog ua ntawm cov chaw tswj hwm tseem ceeb (CCPs) raws li cov saw hlau tsim khoom (feem ntau tom qab sau qoob loo thiab/lossis thaum lub sijhawm ntim khoom) es tsis yog ua tas li. yog li, lawv yooj yim kis kab mob. 7. Kev tswj hwm zoo dua ntawm cov kab mob los ntawm zaub mov thiab kev puas tsuaj ntawm zaub mov xav tau kev siv tshuaj tua kab mob uas tuaj yeem siv tau thoob plaws hauv kev ua liaj ua teb mus rau lub rooj noj mov thaum txo cov kev cuam tshuam rau ib puag ncig thiab cov nqi.
Tsis ntev los no, ib lub platform tiv thaiv kab mob uas tsis muaj tshuaj lom neeg, siv nanotechnology tau tsim los uas tuaj yeem ua rau cov kab mob saum npoo av thiab hauv huab cua tsis ua haujlwm siv cov nanostructures dej dag (EWNS). EWNS tau tsim los ntawm kev siv ob txoj kev sib luag, electrospray thiab dej ionization (Daim Duab 1a). Cov kev tshawb fawb yav dhau los tau qhia tias EWNS muaj cov khoom siv lub cev thiab lub cev tshwj xeeb8,9,10. EWNS muaj qhov nruab nrab ntawm 10 electrons ib qho qauv thiab qhov nruab nrab nanoscale loj ntawm 25 nm (Daim Duab 1b,c)8,9,10. Tsis tas li ntawd, electron spin resonance (ESR) tau qhia tias EWNS muaj ntau cov reactive oxygen species (ROS), feem ntau yog hydroxyl (OH•) thiab superoxide (O2-) radicals (Daim Duab 1c)8. EVNS nyob hauv huab cua ntev thiab tuaj yeem sib tsoo nrog cov kab mob me me uas dai hauv huab cua thiab muaj nyob rau ntawm qhov chaw, xa lawv cov ROS payload thiab ua rau cov kab mob me me tsis ua haujlwm (Daim Duab 1d). Cov kev tshawb fawb thaum ntxov no kuj tau qhia tias EWNS tuaj yeem cuam tshuam thiab ua rau ntau yam kab mob gram-negative thiab gram-positive tsis ua haujlwm, suav nrog mycobacteria, ntawm qhov chaw thiab hauv huab cua. Kev siv tshuab hluav taws xob kis tau qhia tias qhov kev ua haujlwm tsis ua haujlwm yog los ntawm kev cuam tshuam ntawm lub cell membrane. Tsis tas li ntawd, kev tshawb fawb txog kev ua pa sai sai tau qhia tias cov koob tshuaj EWNS ntau tsis ua rau lub ntsws puas tsuaj lossis o 8.
(a) Electrospray tshwm sim thaum muaj hluav taws xob siab ntawm lub raj capillary uas muaj kua thiab lub electrode counter. (b) Kev siv lub zog siab ua rau muaj ob qho xwm txheej sib txawv: (i) electrospraying ntawm dej thiab (ii) kev tsim cov tshuaj reactive oxygen (ions) uas raug kaw hauv EWNS. (c) Cov qauv tshwj xeeb ntawm EWNS. (d) Vim lawv qhov xwm txheej nanoscale, EWNS txav tau yooj yim thiab tuaj yeem cuam tshuam nrog cov kab mob hauv huab cua.
Lub peev xwm ntawm EWNS antimicrobial platform los tua cov kab mob me me uas los ntawm cov zaub mov ntawm qhov chaw ntawm cov zaub mov tshiab kuj tau ua pov thawj tsis ntev los no. Nws kuj tau pom tias qhov them ntawm EWNS ua ke nrog lub zog hluav taws xob tuaj yeem siv los ua tiav kev xa khoom. Ntxiv mus, cov txiaj ntsig thawj zaug rau cov txiv lws suav organic tom qab 90 feeb raug rau ntawm EWNS ntawm kwv yees li 50,000 # / cm3 tau txhawb nqa, nrog ntau yam kab mob me me uas los ntawm cov zaub mov xws li E. coli thiab Listeria 11 tau pom. Tsis tas li ntawd, kev sim organoleptic thawj zaug tsis qhia txog kev cuam tshuam kev xav piv rau cov txiv lws suav tswj. Txawm hais tias cov txiaj ntsig inactivation thawj zaug no txhawb nqa rau kev siv zaub mov kev nyab xeeb txawm tias ntawm EWNS koob tshuaj qis heev ntawm 50,000 # / cc. saib, nws yog qhov tseeb tias qhov muaj peev xwm inactivation siab dua yuav muaj txiaj ntsig zoo dua los txo qhov kev pheej hmoo ntawm kev kis kab mob thiab kev puas tsuaj.
Ntawm no, peb yuav tsom peb txoj kev tshawb fawb rau kev tsim lub platform tsim EWNS kom ua tau zoo dua ntawm cov kev sib xyaw ua ke thiab kev ua kom zoo dua ntawm cov khoom siv physicochemical ntawm EWNS kom txhim kho lawv lub peev xwm tiv thaiv kab mob. Tshwj xeeb, kev ua kom zoo dua tau tsom mus rau kev nce lawv cov nqi ntawm qhov chaw (txhawm rau txhim kho kev xa khoom) thiab ROS cov ntsiab lus (txhawm rau txhim kho kev ua haujlwm tsis ua haujlwm). Txheeb xyuas cov yam ntxwv physico-chemical zoo tshaj plaws (qhov loj me, them thiab ROS cov ntsiab lus) siv cov txheej txheem niaj hnub thiab siv cov kab mob me me xws li E.
EVNS tau tsim los ntawm kev siv electrospraying thiab ionization ntawm cov dej huv siab (18 MΩ cm–1). Lub tshuab hluav taws xob nebulizer 12 feem ntau yog siv rau kev ua kom cov kua dej thiab kev tsim cov polymer thiab cov khoom siv ceramic 13 thiab cov fibers 14 ntawm qhov loj me tswj tau.
Raws li tau piav qhia hauv cov ntawv tshaj tawm dhau los 8, 9, 10, 11, hauv kev sim ib txwm muaj, qhov hluav taws xob siab tau siv ntawm cov hlau capillary thiab lub electrode counter uas tau grounded. Thaum lub sijhawm no, ob qho xwm txheej sib txawv tshwm sim: i) electrospray thiab ii) dej ionization. Lub zog hluav taws xob muaj zog ntawm ob lub electrodes ua rau cov nqi tsis zoo tsim rau ntawm qhov chaw ntawm cov dej condensed, ua rau muaj Taylor cones. Yog li ntawd, cov dej uas muaj zog heev tau tsim, uas txuas ntxiv tawg ua cov khoom me me, zoo li hauv Rayleigh theory16. Tib lub sijhawm, cov teb hluav taws xob muaj zog ua rau qee cov dej molecules faib thiab tshem tawm cov electrons (ionize), uas ua rau muaj ntau cov reactive oxygen hom (ROS)17. ROS18 uas tsim tau tib lub sijhawm tau encapsulated hauv EWNS (Daim duab 1c).
Hauv daim duab 2a qhia txog lub tshuab tsim EWNS uas tau tsim thiab siv rau hauv EWNS synthesis hauv txoj kev tshawb fawb no. Cov dej huv uas khaws cia rau hauv lub raj mis kaw tau muab pub los ntawm lub raj Teflon (2 hli txoj kab uas hla sab hauv) rau hauv lub koob hlau tsis xeb 30G (hlau capillary). Cov dej ntws raug tswj los ntawm lub siab cua hauv lub raj mis, raws li pom hauv Daim Duab 2b. Lub koob tau teeb tsa rau ntawm lub console Teflon thiab tuaj yeem kho tau manually mus rau qee qhov deb ntawm lub electrode counter. Lub electrode counter yog lub disk txhuas ci ntsa iab nrog lub qhov hauv nruab nrab rau kev kuaj. Hauv qab lub electrode counter yog lub funnel kuaj txhuas, uas txuas nrog rau lwm qhov ntawm kev teeb tsa kev sim ntawm lub qhov chaw kuaj (Daim Duab 2b). Txhawm rau kom tsis txhob muaj kev sib sau ua ke uas tuaj yeem cuam tshuam kev ua haujlwm ntawm lub sampler, txhua yam khoom ntawm lub sampler tau grounded hluav taws xob.
(a) Lub Tshuab Tsim Dej Nanostructure (EWNS) Uas Tsim Los Ntawm Kev Tsim Kho. (b) Ntu hla ntawm lub tshuab kuaj thiab electrospray, qhia cov yam ntxwv tseem ceeb tshaj plaws. (c) Kev teeb tsa sim rau kev ua kom cov kab mob tsis ua haujlwm.
Lub tshuab tsim hluav taws xob EWNS uas tau piav qhia saum toj no muaj peev xwm hloov cov kev ua haujlwm tseem ceeb kom yooj yim kho cov khoom EWNS. Kho qhov hluav taws xob siv (V), qhov deb ntawm koob thiab lub electrode counter (L), thiab dej ntws (φ) los ntawm cov capillary kom kho cov yam ntxwv EWNS. Lub cim siv los sawv cev rau ntau yam kev sib xyaw ua ke: [V (kV), L (cm)]. Kho cov dej ntws kom tau txais Taylor cone ruaj khov ntawm qee qhov teeb tsa [V, L]. Rau lub hom phiaj ntawm txoj kev tshawb fawb no, qhov aperture diameter ntawm lub electrode counter (D) tau khaws cia ntawm 0.5 nti (1.29 cm).
Vim yog qhov geometry txwv thiab asymmetry, lub zog hluav taws xob tsis tuaj yeem suav los ntawm cov ntsiab cai thawj zaug. Hloov chaw, QuickField™ software (Svendborg, Denmark)19 tau siv los xam lub zog hluav taws xob. Lub zog hluav taws xob tsis sib xws, yog li tus nqi ntawm lub zog hluav taws xob ntawm qhov kawg ntawm capillary tau siv ua tus nqi siv rau ntau yam kev teeb tsa.
Thaum lub sijhawm kawm, ntau qhov kev sib xyaw ua ke ntawm qhov hluav taws xob thiab qhov deb ntawm lub koob thiab lub electrode counter tau raug soj ntsuam hauv Taylor cone tsim, Taylor cone ruaj khov, EWNS ntau lawm ruaj khov, thiab rov ua dua. Ntau yam kev sib xyaw ua ke tau qhia hauv Supplementary Table S1.
Cov zis ntawm lub tshuab tsim hluav taws xob EWNS tau txuas ncaj qha rau Scanning Mobility Particle Size Analyzer (SMPS, Qauv 3936, TSI, Shoreview, MN) rau kev ntsuas qhov concentration ntawm cov khoom me me, nrog rau Aerosol Faraday Electrometer (TSI, Qauv 3068B, Shoreview, MN). ) rau cov dej ntws aerosol tau ntsuas raws li tau piav qhia hauv peb cov ntawv tshaj tawm dhau los. Ob qho tib si SMPS thiab aerosol electrometer kuaj ntawm tus nqi ntws ntawm 0.5 L / min (tag nrho cov qauv ntws 1 L / min). Tus lej concentration ntawm cov khoom me me thiab cov dej ntws aerosol tau ntsuas rau 120 vib nas this. Kev ntsuas rov ua dua 30 zaug. Raws li kev ntsuas tam sim no, tag nrho cov nqi aerosol raug suav thiab qhov nruab nrab EWNS nqi raug kwv yees rau tag nrho cov lej ntawm cov khoom me me EWNS xaiv. Tus nqi nruab nrab ntawm EWNS tuaj yeem suav tau siv Equation (1):
qhov twg IEl yog qhov ntsuas tam sim no, NSMPS yog qhov ntsuas digital nrog SMPS, thiab φEl yog tus nqi ntws ib electrometer.
Vim tias qhov av noo (RH) cuam tshuam rau qhov them ntawm qhov chaw, qhov kub thiab (RH) tau khaws cia tas li thaum lub sijhawm sim ntawm 21 ° C thiab 45%, raws li.
Siv lub tshuab Atomic force microscopy (AFM), Asylum MFP-3D (Asylum Research, Santa Barbara, CA) thiab AC260T probe (Olympus, Tokyo, Nyiv Pooj) los ntsuas qhov loj thiab lub neej ntawm EWNS. Lub zaus scanning AFM yog 1 Hz, thaj chaw scanning yog 5 μm × 5 μm, thiab 256 kab scan. Tag nrho cov duab tau raug rau 1st order image alignment siv Asylum software (mask range 100 nm, threshold 100 pm).
Lub raj xa dej kuaj tau raug tshem tawm thiab qhov chaw mica tau muab tso rau ntawm qhov deb ntawm 2.0 cm ntawm lub electrode counter rau lub sijhawm nruab nrab ntawm 120 s kom tsis txhob muaj cov khoom me me sib sau ua ke thiab tsim cov tee dej tsis sib xws ntawm qhov chaw mica. EWNS tau txau ncaj qha rau ntawm qhov chaw ntawm mica txiav tshiab (Ted Pella, Redding, CA). Duab ntawm qhov chaw mica tam sim ntawd tom qab AFM sputtering. Lub kaum sab xis ntawm qhov chaw ntawm mica txiav tshiab tsis hloov pauv yog ze rau 0 °, yog li EVNS tau faib rau ntawm qhov chaw mica hauv daim ntawv ntawm lub dome. Lub cheeb tsam (a) thiab qhov siab (h) ntawm cov tee dej diffusing tau ntsuas ncaj qha los ntawm AFM topography thiab siv los xam EWNS domed diffusion ntim siv peb txoj kev tau lees paub ua ntej. Xav tias cov EWNS onboard muaj tib lub ntim, qhov sib npaug txoj kab uas hla tuaj yeem suav tau siv Equation (2):
Raws li peb txoj kev tsim ua ntej, lub electron spin resonance (ESR) spin trap tau siv los ntes qhov muaj cov radical intermediates luv luv hauv EWNS. Aerosols tau bubbled los ntawm 650 μm Midget sparger (Ace Glass, Vineland, NJ) uas muaj 235 mM kua ntawm DEPMPO (5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide) (Oxis International Inc.). Portland, Oregon). Txhua qhov kev ntsuas ESR tau ua tiav siv Bruker EMX spectrometer (Bruker Instruments Inc. Billerica, MA, USA) thiab lub cell tiaj tus. Lub Acquisit software (Bruker Instruments Inc. Billerica, MA, USA) tau siv los sau thiab tshuaj xyuas cov ntaub ntawv. Kev txiav txim siab ntawm cov yam ntxwv ntawm ROS tau ua tiav tsuas yog rau ib pawg ntawm cov xwm txheej ua haujlwm [-6.5 kV, 4.0 cm]. EWNS concentrations tau ntsuas siv SMPS tom qab suav nrog EWNS poob hauv lub impactor.
Cov theem ozone raug saib xyuas siv 205 Dual Beam Ozone Monitor™ (2B Technologies, Boulder, Co)8,9,10.
Rau txhua yam khoom EWNS, tus nqi nruab nrab yog siv ua tus nqi ntsuas, thiab qhov sib txawv ntawm tus qauv yog siv ua qhov yuam kev ntsuas. T-kev xeem tau ua los sib piv cov nqi ntawm cov yam ntxwv EWNS zoo tshaj plaws nrog cov nqi sib xws ntawm cov EWNS puag.
Daim Duab 2c qhia txog ib qho system "rub" uas tau tsim thiab piav qhia txog electrostatic precipitation (EPES) uas tau tsim ua ntej thiab siv tau rau kev xa EWNS mus rau saum npoo av. EPES siv cov nqi EVNS uas tuaj yeem "coj" ncaj qha mus rau saum npoo av ntawm lub hom phiaj nyob rau hauv kev cuam tshuam ntawm lub zog hluav taws xob muaj zog. Cov ntsiab lus ntawm EPES system tau nthuav tawm hauv kev tshaj tawm tsis ntev los no los ntawm Pyrgiotakis et al. 11. Yog li, EPES muaj ib lub chamber PVC luam tawm 3D nrog cov kawg tapered thiab muaj ob lub phaj hlau stainless hlau sib luag (304 stainless hlau, iav coated) ntawm qhov chaw nruab nrab 15.24 cm sib nrug. Cov laug cam tau txuas nrog lub zog hluav taws xob sab nraud (Bertran 205B-10R, Spellman, Hauppauge, NY), lub phaj hauv qab yeej ib txwm txuas nrog lub zog hluav taws xob zoo, thiab lub phaj saum toj kawg nkaus yeej ib txwm txuas nrog av (av ntab). Cov phab ntsa chamber tau npog nrog ntawv ci txhuas, uas yog hluav taws xob hauv av kom tiv thaiv kev poob ntawm cov khoom me me. Lub chamber muaj lub qhov rooj pem hauv ntej uas kaw ruaj ruaj uas tso cai rau cov chaw kuaj kom muab tso rau ntawm cov yas sawv ntsug uas tsa lawv siab dua lub phaj hlau hauv qab kom tsis txhob muaj kev cuam tshuam hluav taws xob siab.
Qhov ua tau zoo ntawm kev tso dej ntawm EWNS hauv EPES tau suav raws li cov txheej txheem tsim ua ntej uas tau piav qhia hauv Daim Duab Ntxiv S111.
Ua ib lub chamber tswj, lub chamber thib ob cylindrical flow chamber tau txuas ua ke rau EPES system, uas siv lub lim HEPA nruab nrab los tshem tawm EWNS. Raws li pom hauv Daim Duab 2c, EWNS aerosol tau raug pumped los ntawm ob lub chamber uas ua tiav. Lub lim dej ntawm chav tswj thiab EPES tshem tawm cov EWNS seem uas ua rau tib qhov kub (T), qhov av noo (RH) thiab cov theem ozone.
Cov kab mob me me tseem ceeb uas kis tau los ntawm zaub mov tau pom tias ua rau cov zaub mov tshiab muaj kuab paug xws li E. coli (ATCC #27325), cov kab mob uas qhia txog cov quav, Salmonella enterica (ATCC #53647), cov kab mob uas kis tau los ntawm zaub mov, Listeria harmless (ATCC #33090), tus neeg sawv cev rau cov kab mob Listeria monocytogenes, uas tau los ntawm ATCC (Manassas, VA) Saccharomyces cerevisiae (ATCC #4098), ib yam khoom siv hloov cov poov xab uas lwj, thiab ib hom kab mob uas tiv taus dua, Mycobacterium paralucky (ATCC #19686).
Yuav cov txiv lws suav organic uas muaj ntau lub thawv los ntawm koj lub khw hauv zos thiab muab tso rau hauv lub tub yees ntawm 4°C kom txog thaum siv tau (txog li 3 hnub). Cov txiv lws suav uas tau sim tag nrho puav leej loj ib yam, li ntawm 1/2 nti hauv txoj kab uas hla.
Cov txheej txheem kev coj noj coj ua, kev txhaj tshuaj, kev raug mob, thiab kev suav cov pawg tau piav qhia meej hauv peb cov ntawv tshaj tawm dhau los thiab tau piav qhia meej hauv Cov Ntaub Ntawv Ntxiv. Kev ua haujlwm ntawm EWNS tau soj ntsuam los ntawm kev tso cov txiv lws suav uas tau txhaj tshuaj rau 40,000 # / cm3 rau 45 feeb. Hauv luv luv, peb lub txiv lws suav tau siv los soj ntsuam cov kab mob me me uas tseem muaj sia nyob thaum lub sijhawm t = 0 feeb. Peb lub txiv lws suav tau muab tso rau hauv EPES thiab raug rau EWNS ntawm 40,000 # / cc (EWNS raug cov txiv lws suav) thiab peb lub seem tau muab tso rau hauv chav tswj (tswj cov txiv lws suav). Kev ua tiav ntxiv ntawm cov txiv lws suav hauv ob pawg tsis tau ua tiav. Cov txiv lws suav uas raug EWNS thiab cov txiv lws suav tswj tau raug tshem tawm tom qab 45 feeb los soj ntsuam cov txiaj ntsig ntawm EWNS.
Txhua qhov kev sim tau ua tiav ua peb zaug. Kev tshuaj xyuas cov ntaub ntawv tau ua raws li cov txheej txheem piav qhia hauv Cov Ntaub Ntawv Ntxiv.
Cov txheej txheem ua kom tsis muaj zog tau raug soj ntsuam los ntawm kev tso cov qauv EWNS uas raug rau (45 feeb ntawm 40,000 # / cm3 EWNS aerosol concentration) thiab cov qauv tsis muaj teeb meem ntawm cov kab mob tsis muaj teeb meem E. coli, Salmonella enterica thiab Lactobacillus. Cov khoom me me tau kho rau hauv 2.5% glutaraldehyde, 1.25% paraformaldehyde thiab 0.03% picric acid hauv 0.1 M sodium cacodylate buffer (pH 7.4) rau 2 teev ntawm chav sov. Tom qab ntxuav, kho tom qab nrog 1% osmium tetroxide (OsO4) / 1.5% potassium ferrocyanide (KFeCN6) rau 2 teev, ntxuav 3 zaug hauv dej thiab incubate hauv 1% uranyl acetate rau 1 teev, tom qab ntawd ntxuav ob zaug hauv dej, tom qab ntawd dehydrate rau 10 feeb hauv 50%, 70%, 90%, 100% cawv. Cov qauv 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 embedded rau hauv TAAB Epon thiab polymerized ntawm 60 ° C rau 48 teev. Cov granular resin kho tau txiav thiab visualized los ntawm TEM siv lub tshuab hluav taws xob kis tau tus qauv JEOL 1200EX (JEOL, Tokyo, Nyiv) nruab nrog lub koob yees duab AMT 2k CCD (Advanced Microscopy Techniques, Corp., Woburn, Massachusetts, USA).
Tag nrho cov kev sim tau ua tiav ua peb daim. Rau txhua lub sijhawm, cov kab mob ntxuav tau cog ua peb daim, ua rau muaj tag nrho cuaj cov ntaub ntawv ib qho, qhov nruab nrab ntawm qhov ntawd tau siv ua qhov concentration ntawm cov kab mob rau cov kab mob tshwj xeeb ntawd. Qhov kev hloov pauv tus qauv tau siv ua qhov yuam kev ntsuas. Txhua cov ntsiab lus suav.
Lub logarithm ntawm qhov txo qis hauv qhov concentration ntawm cov kab mob piv rau t = 0 min tau suav los ntawm kev siv cov mis hauv qab no:
qhov twg C0 yog qhov concentration ntawm cov kab mob hauv cov qauv tswj thaum lub sijhawm 0 (piv txwv li tom qab qhov chaw tau qhuav tab sis ua ntej muab tso rau hauv chav) thiab Cn yog qhov concentration ntawm cov kab mob ntawm qhov chaw tom qab n feeb ntawm kev raug.
Yuav kom suav nrog qhov kev puas tsuaj ntuj tsim ntawm cov kab mob thaum lub sijhawm 45 feeb raug, qhov kev txo qis ntawm cov cav piv rau kev tswj hwm tom qab 45 feeb kuj tau suav raws li hauv qab no:
qhov twg Cn yog qhov concentration ntawm cov kab mob hauv cov qauv tswj thaum lub sijhawm n thiab Cn-Control yog qhov concentration ntawm cov kab mob tswj thaum lub sijhawm n. Cov ntaub ntawv tau nthuav tawm ua qhov kev txo qis piv rau kev tswj (tsis muaj EWNS raug).
Thaum lub sijhawm kawm, ntau qhov kev sib xyaw ua ke ntawm lub zog thiab qhov deb ntawm lub koob thiab lub electrode counter tau raug soj ntsuam hauv Taylor cone tsim, Taylor cone ruaj khov, EWNS ntau lawm ruaj khov, thiab rov ua dua. Ntau yam kev sib xyaw ua ke tau pom hauv Supplementary Table S1. Ob rooj plaub uas qhia txog cov khoom ruaj khov thiab rov ua dua (Taylor cone, EWNS tiam, thiab kev ruaj khov dhau sijhawm) tau raug xaiv rau kev kawm dav dav. Hauv daim duab. Daim duab 3 qhia cov txiaj ntsig rau qhov them, qhov loj me, thiab cov ntsiab lus ntawm ROS hauv ob qho tib si. Cov txiaj ntsig kuj tau muab tso ua ke hauv Rooj 1. Rau kev siv, ob daim duab 3 thiab Rooj 1 suav nrog cov khoom ntawm EWNS8, 9, 10, 11 uas tau tsim ua ntej tsis tau zoo (baseline-EWNS). Kev suav qhov tseem ceeb ntawm kev suav lej siv ob-tailed t-test tau rov luam tawm hauv Supplementary Table S2. Tsis tas li ntawd, cov ntaub ntawv ntxiv suav nrog kev tshawb fawb txog cov nyhuv ntawm lub qhov counter electrode sampling txoj kab uas hla (D) thiab qhov deb ntawm av electrode thiab lub taub hau (L) (Supplementary Figures S2 thiab S3).
(ac) Kev faib tawm qhov loj me ntsuas los ntawm AFM. (df) Tus yam ntxwv ntawm qhov chaw them. (g) ROS tus yam ntxwv ntawm EPR.
Nws tseem ceeb heev uas yuav tsum nco ntsoov tias rau txhua yam xwm txheej saum toj no, qhov ntsuas tam sim no ionization yog ntawm 2 thiab 6 μA thiab voltage ntawm -3.8 thiab -6.5 kV, ua rau siv hluav taws xob tsawg dua 50 mW rau lub module EWNS no. Txawm hais tias EWNS tau tsim nyob rau hauv qhov siab siab, cov theem ozone qis heev, tsis pub tshaj 60 ppb.
Daim Duab Ntxiv S4 qhia txog cov teb hluav taws xob simulated rau cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm], raws li. Rau cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm], cov kev suav teb yog 2 × 105 V/m thiab 4.7 × 105 V/m, raws li. Qhov no xav tau, vim tias nyob rau hauv rooj plaub thib ob qhov sib piv ntawm voltage-distance yog siab dua.
Hauv daim duab 3a, b qhia txog txoj kab uas hla ntawm EWNS uas ntsuas nrog AFM8. Qhov nruab nrab ntawm txoj kab uas hla ntawm EWNS uas tau xam yog 27 nm thiab 19 nm rau cov phiaj xwm [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm], raws li. Rau cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm], qhov sib txawv ntawm cov qauv geometric ntawm kev faib tawm yog 1.41 thiab 1.45, raws li, qhia txog kev faib tawm qhov loj me nqaim. Ob qho tib si qhov loj me nruab nrab thiab qhov sib txawv ntawm cov qauv geometric yog ze heev rau EWNS pib, ntawm 25 nm thiab 1.41, raws li. Hauv daim duab 3c qhia txog kev faib tawm qhov loj me ntawm EWNS pib ntsuas siv tib txoj kev hauv qab tib yam xwm txheej.
Hauv daim duab 3d, e qhia cov txiaj ntsig ntawm kev piav qhia txog tus nqi. Cov ntaub ntawv yog qhov nruab nrab ntawm 30 qhov kev ntsuas tib lub sijhawm ntawm qhov concentration (#/cm3) thiab tam sim no (I). Qhov kev tshuaj xyuas qhia tau hais tias qhov nruab nrab ntawm tus 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], raws li. Lawv muaj cov nqi saum npoo av siab dua piv rau EWNS pib (10 ± 2 e-), ob zaug ntau dua li qhov xwm txheej [-6.5 kV, 4.0 cm] thiab plaub zaug ntau dua li [-3 .8 kV, 0.5 cm]. Daim duab 3f qhia cov ntaub ntawv them rau Baseline-EWNS.
Los ntawm cov duab qhia txog qhov concentration ntawm tus lej EWNS (Cov Duab Ntxiv S5 thiab S6), nws tuaj yeem pom tias qhov xwm txheej [-6.5 kV, 4.0 cm] muaj ntau cov khoom me me dua li qhov xwm txheej [-3.8 kV, 0.5 cm]. Nws kuj tsim nyog sau tseg tias qhov concentration ntawm tus lej EWNS tau saib xyuas txog 4 teev (Cov Duab Ntxiv S5 thiab S6), qhov twg qhov ruaj khov ntawm EWNS tiam tau qhia txog tib theem ntawm cov khoom me me hauv ob qho tib si.
Hauv daim duab 3g qhia txog EPR spectrum tom qab rho tawm ntawm qhov kev tswj hwm EWNS zoo tshaj plaws (keeb kwm yav dhau) ntawm [-6.5 kV, 4.0 cm]. Cov ROS spectra kuj tau muab piv rau qhov xwm txheej Baseline-EWNS hauv ib daim ntawv tshaj tawm ua ntej. Tus naj npawb ntawm EWNS uas cuam tshuam nrog cov cuab yeej tig tau suav tias yog 7.5 × 104 EWNS/s, uas zoo ib yam li Baseline-EWNS8 uas tau tshaj tawm ua ntej. Cov EPR spectra tau qhia meej meej tias muaj ob hom ROS, nrog rau O2- yog hom tsiaj tseem ceeb thiab OH• tsis tshua muaj. Tsis tas li ntawd, kev sib piv ncaj qha ntawm qhov siab tshaj plaws tau qhia tias EWNS zoo tshaj plaws muaj cov ntsiab lus ROS siab dua piv rau EWNS pib.
Hauv daim duab 4 qhia txog qhov ua tau zoo ntawm EWNS hauv EPES. Cov ntaub ntawv kuj tau muab sau ua ke hauv Rooj I thiab piv rau cov ntaub ntawv EWNS thawj. Rau ob qho xwm txheej ntawm EUNS, qhov kev tso tawm ze li ntawm 100% txawm tias ntawm qhov hluav taws xob qis ntawm 3.0 kV. Feem ntau, 3.0 kV txaus rau 100% kev tso tawm, tsis hais txog qhov kev hloov pauv ntawm qhov chaw. Hauv qab cov xwm txheej zoo sib xws, qhov ua tau zoo ntawm kev tso tawm ntawm Baseline-EWNS tsuas yog 56% vim lawv qhov kev them qis dua (nruab nrab 10 electrons ib EWNS).
Hauv daim duab 5 thiab hauv lub rooj 2 qhia txog qhov tseem ceeb ntawm kev ua haujlwm tsis zoo ntawm cov kab mob me me uas tau txhaj tshuaj rau ntawm qhov chaw ntawm cov txiv lws suav tom qab raug rau kwv yees li 40,000 # / cm3 EWNS rau 45 feeb ntawm hom zoo tshaj plaws [-6.5 kV, 4.0 cm]. Cov kab mob E. coli thiab Lactobacillus innocuous uas tau txhaj tshuaj tau pom tias muaj kev txo qis ntawm 3.8 cav thaum lub sijhawm raug 45 feeb. Hauv qab cov xwm txheej zoo sib xws, S. enterica muaj kev txo qis 2.2-log, thaum S. cerevisiae thiab M. parafortutum muaj kev txo qis 1.0-log.
Cov duab hluav taws xob me me (Daim Duab 6) piav qhia txog kev hloov pauv lub cev uas EWNS ua rau ntawm Escherichia coli, Streptococcus, thiab Lactobacillus hlwb tsis muaj teeb meem ua rau lawv tsis ua haujlwm. Cov kab mob tswj tau muaj cov hlwb ntawm lub hlwb zoo, thaum cov kab mob uas raug rau cov hlwb ntawd tau ua rau cov hlwb sab nraud puas tsuaj.
Kev thaij duab hluav taws xob ntawm cov kab mob tswj thiab cov kab mob uas raug tshuaj xyuas tau qhia txog kev puas tsuaj ntawm daim nyias nyias.
Cov ntaub ntawv ntawm cov khoom siv physicochemical ntawm EWNS uas tau ua kom zoo tshaj plaws ua ke qhia tau tias cov khoom (nqa ntawm qhov chaw thiab ROS cov ntsiab lus) ntawm EWNS tau zoo dua piv rau cov ntaub ntawv EWNS uas tau luam tawm ua ntej8,9,10,11. Ntawm qhov tod tes, lawv qhov loj me tseem nyob hauv nanometer ntau yam, zoo ib yam li cov txiaj ntsig tau tshaj tawm ua ntej, tso cai rau lawv nyob hauv huab cua ntev ntev. Qhov polydispersity uas tau pom tuaj yeem piav qhia los ntawm kev hloov pauv ntawm qhov chaw uas txiav txim siab qhov loj me ntawm EWNS, qhov randomness ntawm Rayleigh effect, thiab qhov muaj peev xwm coalescence. Txawm li cas los xij, raws li Nielsen et al. 22 tau piav qhia meej, qhov chaw siab txo qhov evaporation los ntawm kev ua kom lub zog / kev ntxhov siab ntawm qhov dej poob zoo dua. Hauv peb cov ntawv tshaj tawm ua ntej8 txoj kev xav no tau lees paub los ntawm kev sim rau microdroplets 22 thiab EWNS. Kev poob ntawm qhov chaw thaum lub sijhawm dhau mus kuj tseem tuaj yeem cuam tshuam rau qhov loj me thiab pab txhawb rau qhov kev faib tawm ntawm qhov loj me uas tau pom.
Ntxiv mus, tus nqi ib qho qauv yog li ntawm 22-44 e-, nyob ntawm qhov xwm txheej, uas yog siab dua piv rau EWNS yooj yim, uas muaj tus nqi nruab nrab ntawm 10 ± 2 electrons ib qho qauv. Txawm li cas los xij, nws yuav tsum tau sau tseg tias qhov no yog tus nqi nruab nrab ntawm EWNS. Seto et al. Nws tau pom tias tus nqi tsis sib xws thiab ua raws li kev faib tawm log-normal21. Piv rau peb txoj haujlwm yav dhau los, ob npaug ntawm tus nqi saum npoo av ua rau qhov ua tau zoo ntawm kev tso dej hauv EPES system yuav luag 100%11.