Ua tsaug rau koj tuaj xyuas Nature.com. Koj siv lub browser version uas 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). Tsis tas li ntawd, kom ntseeg tau tias muaj kev txhawb nqa tas mus li, peb qhia 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 dag (EWNS) tau tsim. EWNS muaj qhov them siab ntawm qhov chaw thiab muaj ntau yam 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 nqi, qhov loj me, thiab ROS cov ntsiab lus) tau ua tiav siv cov txheej txheem niaj hnub. Tsis tas li ntawd, cov kab mob me me hauv zaub mov xws li Escherichia coli, Salmonella enterica, Listeria innocua, Mycobacterium para fortitum, thiab Saccharomyces cerevisiae tau txhaj tshuaj rau ntawm qhov chaw ntawm cov txiv lws suav txiv hmab organic los ntsuas lawv cov peev xwm ua rau cov kab mob tsis ua haujlwm. 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 plaub npaug, thiab cov ntsiab lus ROS nce ntxiv. Tus nqi tshem tawm cov kab mob yog nyob ntawm cov kab mob thiab nyob ntawm 1.0 txog 3.8 cav tom qab 45 feeb ntawm kev raug rau cov tshuaj aerosol ntawm 40,000 # / cm3 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. Kev mob los ntawm zaub mov ua rau muaj li ntawm 76 lab tus neeg mob, 325,000 tus neeg pw hauv tsev kho mob, thiab 5,000 tus neeg tuag txhua xyoo hauv Tebchaws Meskas1. 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 feem pua ​​​​​​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 siv rau ntawm cov chaw tswj hwm tseem ceeb (CCPs) hauv cov saw hlau tsim khoom (feem ntau tom qab sau qoob loo thiab/lossis thaum lub sijhawm ntim khoom) es tsis yog siv tas li kom cov khoom tshiab muaj kev sib kis kab mob 7. Kev siv tshuaj tua kab mob yog qhov xav tau los tswj cov kab mob uas kis los ntawm zaub mov thiab kev puas tsuaj ntawm zaub mov thiab muaj peev xwm siv tau thoob plaws hauv kev ua liaj ua teb mus rau lub rooj. Kev cuam tshuam tsawg dua thiab tus nqi tsawg dua.
Tsis ntev los no, ib lub platform tiv thaiv kab mob uas siv cov tshuaj nanotechnology tsis muaj tshuaj lom neeg tau tsim los tua cov kab mob ntawm qhov chaw thiab hauv huab cua siv cov nanostructures dej dag (EWNS). Rau kev tsim cov EVNS, ob txoj kev ua haujlwm sib luag tau siv: electrospray thiab dej ionization (Daim Duab 1a). EWNS tau pom tias 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 nanometer 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. EWNS 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 microbial inactivation (Daim Duab 1d). Cov kev tshawb fawb ua ntej no kuj tau qhia tias EWNS tuaj yeem cuam tshuam thiab ua rau ntau yam kab mob gram-negative thiab gram-positive uas tseem ceeb rau kev noj qab haus huv pej xeem, suav nrog mycobacteria, ntawm qhov chaw thiab hauv huab cua8,9. Kev siv tshuab hluav taws xob kis tau qhia tias qhov kev ua tsis tau zoo 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 o8.
(a) Electrospray tshwm sim thaum muaj hluav taws xob siab ntawm cov kua capillary thiab lub electrode counter. (b) Kev siv hluav taws xob siab ua rau muaj ob qho xwm txheej sib txawv: (i) electrospraying ntawm dej thiab (ii) tiam ntawm cov tshuaj reactive oxygen (ions) uas raug kaw hauv EWNS. (c) Cov qauv tshwj xeeb ntawm EWNS. (d) EWNS txav tau yooj yim 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 los ua kom cov kab mob me me uas nyob hauv cov zaub mov tsis ua haujlwm ntawm qhov chaw ntawm cov zaub mov tshiab kuj tau ua pov thawj tsis ntev los no. Nws kuj tau pom tias EWNS qhov them nqi saum npoo av tuaj yeem siv ua ke nrog lub zog hluav taws xob rau kev xa khoom. Qhov tseem ceeb tshaj, qhov tshwm sim pib zoo ntawm kwv yees li 1.4 log txo qis hauv cov txiv lws suav organic ua haujlwm tawm tsam ntau yam kab mob me me hauv zaub mov xws li E. coli thiab Listeria tau pom hauv 90 feeb ntawm kev raug EWNS ntawm qhov concentration ntawm kwv yees li 50,000 # / cm311. Tsis tas li ntawd, kev ntsuam xyuas organoleptic ua ntej tsis qhia txog cov teebmeem organoleptic piv rau cov txiv lws suav tswj. Txawm hais tias cov txiaj ntsig inactivation thawj zaug no cog lus tias yuav muaj kev nyab xeeb zaub mov 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 txog kev tsim lub platform tsim EWNS kom zoo dua cov kev sib xyaw ua ke thiab ua kom zoo dua cov khoom siv physicochemical ntawm EWNS kom txhim kho lawv lub peev xwm tua 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). Kev piav qhia txog cov khoom siv 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. coli, S. enterica, L. innocua, S. cerevisiae thiab M. parafortuitum.
EVNS tau tsim los ntawm kev siv hluav taws xob electrospraying thiab ionization ntawm cov dej huv siab (18 MΩ cm–1). Lub tshuab hluav taws xob atomizer 12 feem ntau yog siv los ua atomize cov kua thiab cov khoom siv 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: 1) electrospray thiab 2) ionization ntawm dej. 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, raws li Rayleigh theory16. Tib lub sijhawm, lub zog hluav taws xob muaj zog ua rau qee cov dej molecules faib thiab tshem tawm cov electrons (ionization), yog li tsim cov ntau ntawm cov reactive oxygen hom (ROS)17. Cov pob 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 pub los ntawm lub raj Teflon (2 hli txoj kab uas hla sab hauv) rau lub koob hlau tsis xeb 30G (hlau capillary). Raws li pom hauv Daim Duab 2b, cov dej ntws raug tswj los ntawm lub siab cua hauv lub raj mis. Lub koob tau txuas rau lub console Teflon uas tuaj yeem hloov kho tes 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). Txhua yam khoom ntawm lub sampler tau grounded hluav taws xob kom tsis txhob muaj cov nqi hluav taws xob uas tuaj yeem ua rau cov qauv kuaj puas tsuaj.
(a) Lub Tshuab Tsim Dej Nanostructure (EWNS) Uas Tsim Los Ntawm Kws Tsim Dej. (b) Ntug hla ntawm lub tshuab kuaj thiab lub tshuab electrospray uas qhia txog 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 zoo. Cov cim [V (kV), L (cm)] yog siv los qhia txog kev sib xyaw ua ke sib txawv. 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 qhib ntawm lub electrode counter (D) tau teeb tsa 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 EWNS generation system tau txuas ncaj qha rau Scanning Mobility Particle Sizer (SMPS, qauv 3936, TSI, Shoreview, Minnesota) los ntsuas qhov concentration ntawm cov khoom me me thiab tau siv nrog Faraday aerosol electrometer (TSI, qauv 3068B, Shoreview, USA). MN) los ntsuas cov dej ntws aerosol, raws li tau piav qhia hauv peb cov ntawv tshaj tawm dhau los9. Ob qho tib si SMPS thiab aerosol electrometer tau kuaj ntawm tus nqi ntws ntawm 0.5 L / min (tag nrho cov qauv ntws 1 L / min). Cov khoom me me thiab cov dej ntws aerosol tau ntsuas rau 120 s. Rov ua qhov kev ntsuas 30 zaug. Tag nrho cov nqi aerosol tau suav los ntawm kev ntsuas tam sim no, thiab qhov nruab nrab EWNS nqi tau kwv yees los ntawm tag nrho cov lej ntawm EWNS cov khoom me me tau kuaj. 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 concentration ntawm tus lej ntsuas nrog SMPS, thiab φEl yog tus nqi ntws mus rau electrometer.
Vim tias qhov av noo (RH) cuam tshuam rau qhov them ntawm qhov chaw, qhov kub thiab (RH) tau khaws cia tas li ntawm 21 ° C thiab 45%, raws li, thaum lub sijhawm sim.
Atomic force microscopy (AFM), Asylum MFP-3D (Asylum Research, Santa Barbara, CA) thiab AC260T probe (Olympus, Tokyo, Nyiv) tau siv los ntsuas qhov loj thiab lub neej ntawm EWNS. Tus nqi scan AFM yog 1 Hz thiab thaj chaw scan yog 5 µm × 5 µm nrog 256 kab scan. Tag nrho cov duab tau raug rau thawj qhov kev txiav txim duab sib dhos siv Asylum software (lub ntsej muag nrog ntau yam ntawm 100 nm thiab qhov txwv ntawm 100 pm).
Tshem tawm lub raj xa dej kuaj thiab muab qhov chaw mica ntawm qhov deb ntawm 2.0 cm ntawm lub electrode counter rau lub sijhawm nruab nrab ntawm 120 s kom tsis txhob muaj kev sib sau ua ke ntawm cov khoom me me thiab kev tsim cov tee dej tsis sib xws ntawm qhov chaw mica. EWNS tau siv ncaj qha rau qhov chaw mica txiav tshiab (Ted Pella, Redding, CA). Tam sim ntawd tom qab sputtering, qhov chaw mica tau pom siv AFM. Lub kaum sab xis ntawm qhov chaw ntawm qhov chaw mica txiav tshiab tsis hloov pauv yog ze rau 0 °, yog li EWNS kis mus rau saum npoo mica hauv lub duab domed20. 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 qhov ntim diffusion domed EWNS siv peb txoj kev tau lees paub ua ntej8. Xav tias tias EVNS onboard muaj tib lub ntim, qhov sib npaug ntawm txoj kab uas hla tuaj yeem suav los ntawm kab zauv (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 dhau los ntawm cov kua 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 flat cell arrays. Lub Acquisit software (Bruker Instruments Inc. Billerica, MA, USA) tau siv los sau thiab tshuaj xyuas cov ntaub ntawv. Kev piav qhia ROS tau ua tiav tsuas yog rau ib pawg ntawm cov xwm txheej ua haujlwm [-6.5 kV, 4.0 cm]. EWNS concentration tau ntsuas siv SMPS tom qab coj mus rau hauv tus account poob ntawm EWNS 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 ntsuas yog qhov nruab nrab ntawm kev ntsuas, thiab qhov yuam kev ntsuas yog qhov sib txawv ntawm tus qauv. Ib qho t-test tau ua los sib piv tus nqi ntawm cov yam ntxwv EWNS zoo tshaj plaws nrog tus nqi sib xws ntawm cov EWNS puag.
Daim Duab 2c qhia txog Lub Tshuab Electrostatic Precipitation Pass Through System (EPES) uas tau tsim thiab piav qhia ua ntej uas siv tau los tsom EWNS11 rau ntawm qhov chaw. EPES siv lub zog EWNS ua ke nrog lub zog hluav taws xob kom "taw tes" ncaj qha rau ntawm qhov chaw ntawm lub hom phiaj. Cov ntsiab lus ntawm lub tshuab EPES tau nthuav tawm hauv kev tshaj tawm tsis ntev los no los ntawm Pyrgiotakis et al.11. Yog li, EPES muaj lub chamber PVC luam tawm 3D nrog cov kawg tapered uas muaj ob lub phaj hlau stainless hlau sib luag (304 stainless hlau, iav polished) hauv 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 rooj tsavxwm hauv qab yeej ib txwm zoo thiab lub rooj tsavxwm sab saum toj yeej ib txwm grounded (floating). Cov phab ntsa chamber tau npog nrog ntawv ci txhuas, uas yog electrically grounded kom tiv thaiv cov khoom poob. Lub chamber muaj lub qhov rooj thauj khoom pem hauv ntej kaw uas tso cai rau cov chaw sim kom muab tso rau ntawm cov khib yas, tsa lawv tawm ntawm 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, qhov thib ob ntws los ntawm lub chamber cylindrical yog txuas nrog EPES system siv lub lim HEPA nruab nrab kom tshem tawm EWNS. Raws li pom hauv daim duab 2c, EWNS aerosol tau raug pumped los ntawm ob lub chamber txuas nrog ua ke. Lub lim 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 khoom tshiab muaj kuab paug xws li Escherichia coli (ATCC #27325), uas yog ib yam khoom uas qhia txog cov quav, Salmonella enterica (ATCC #53647), uas yog ib yam kab mob uas kis tau los ntawm zaub mov, Listeria innocua (ATCC #33090), uas yog lwm txoj hauv kev los hloov cov kab mob Listeria monocytogenes. , Saccharomyces cerevisiae (ATCC #4098) ua lwm txoj hauv kev los hloov cov poov xab uas ua rau lwj, thiab Mycobacterium parafortuitous (ATCC #19686) ua cov kab mob uas muaj sia nyob uas tiv taus ntau dua tau yuav los ntawm ATCC (Manassas, Virginia).
Yuav cov thawv txiv lws suav organic los ntawm koj lub khw hauv zos thiab tso rau hauv lub tub yees ntawm 4°C kom txog thaum siv (txog li 3 hnub). Xaiv cov txiv lws suav los sim ib qho loj, li ntawm 1/2 nti hauv txoj kab uas hla.
Cov txheej txheem rau kev sib xyaw, kev txhaj tshuaj, kev raug mob thiab kev suav cov pawg tau piav qhia meej hauv peb cov ntawv tshaj tawm dhau los thiab piav qhia meej hauv Cov Ntaub Ntawv Ntxiv 11. Kev ua tau zoo 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, thaum lub sijhawm t = 0 feeb, peb lub txiv lws suav tau siv los soj ntsuam cov kab mob me me uas tseem muaj sia nyob. Peb lub txiv lws suav tau muab tso rau hauv EPES thiab raug rau EWNS ntawm 40,000 # / cc (EWNS raug rau 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 twg tau raug ua tiav ntxiv. Cov txiv lws suav thiab cov tswj uas raug rau EWNS tau raug tshem tawm tom qab 45 feeb los soj ntsuam qhov cuam tshuam 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 qauv kab mob E. coli, Enterobacter, thiab L. innocua uas raug rau EWNS (45 feeb, EWNS aerosol concentration 40,000 #/cm3) thiab tsis raug rau raug tau muab pelleted los ntsuam xyuas cov txheej txheem inactivation. Cov precipitate tau kho rau 2 teev ntawm chav tsev kub hauv 0.1 M sodium cacodylate kua (pH 7.4) nrog cov khoom kho 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 teev, ntxuav 3 zaug nrog dej thiab incubated hauv 1% uranyl acetate rau 1 teev, tom qab ntawd ntxuav ob zaug nrog dej. Tom qab ntawd dehydration 10 feeb txhua ntawm 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 JEOL 1200EX (JEOL, Tokyo, Nyiv), lub tshuab hluav taws xob kis tau tus mob ib txwm muaj nruab nrog lub koob yees duab AMT 2k CCD (Advanced Microscopy Techniques, Corp., Woburn, MA, USA).
Tag nrho cov kev sim tau ua tiav ua peb daim. Rau txhua lub sijhawm, cov kab mob ntxuav tau plated 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.
Txhawm rau suav nrog qhov kev puas tsuaj ntuj tsim ntawm cov kab mob thaum lub sijhawm raug tshuaj lom 45 feeb, Log-Reduction kuj tau suav piv rau kev tswj hwm ntawm 45 feeb 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 tau xaiv rau kev kawm tiav uas qhia txog cov khoom ruaj khov thiab rov ua dua (Taylor cone, EWNS ntau lawm, thiab kev ruaj khov dhau sijhawm). Ntawm daim duab 3 qhia cov txiaj ntsig ntawm tus nqi, qhov loj me thiab cov ntsiab lus ntawm ROS rau ob rooj plaub. Cov txiaj ntsig kuj tau muab sau ua ke hauv Rooj 1. Rau kev siv, Daim duab 3 thiab Rooj 1 suav nrog cov khoom ntawm EWNS8, 9, 10, 11 uas tau tsim ua ntej (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 diameter (D) thiab qhov deb ntawm lub electrode hauv av thiab lub hau ntawm lub koob (L) (Supplementary Figures S2 thiab S3).
(a–c) Kev faib tawm ntawm AFM loj. (d–f) Tus yam ntxwv ntawm qhov chaw them. (g) Kev piav qhia ntawm ROS thiab ESR.
Nws tseem ceeb heev uas yuav tsum nco ntsoov tias rau txhua yam mob saum toj no, cov ntsuas ionization tam sim no yog nyob rau hauv qhov ntau ntawm 2-6 µA, thiab cov voltages yog nyob rau hauv qhov ntau ntawm -3.8 txog -6.5 kV, ua rau lub zog siv rau ib-qhov kawg EWNS no tsawg dua 50 mW. . tiam module. 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. Cov teb raws li cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] raug suav ua 2 × 105 V/m thiab 4.7 × 105 V/m, raws li. Qhov no yuav tsum tau xav txog, txij li qhov piv ntawm voltage rau qhov deb yog siab dua hauv rooj plaub thib ob.
Hauv daim duab 3a, b qhia txog txoj kab uas hla EWNS ntsuas nrog AFM8. Qhov nruab nrab ntawm txoj kab uas hla EWNS rau cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] tau suav ua 27 nm thiab 19 nm, raws li. Cov qauv geometric ntawm kev faib tawm rau cov xwm txheej [-6.5 kV, 4.0 cm] thiab [-3.8 kV, 0.5 cm] yog 1.41 thiab 1.45, raws li, qhia txog kev faib tawm qhov loj me. Ob qho tib si qhov loj me nruab nrab thiab qhov qauv geometric yog ze heev rau baseline-EWNS, yog 25 nm thiab 1.41, raws li. Hauv daim duab 3c qhia txog kev faib tawm qhov loj me ntawm baseline EWNS ntsuas siv tib txoj kev nyob rau hauv tib qho 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. Piv rau Baseline-EWNS (10 ± 2 e-), lawv qhov nqi ntawm qhov chaw siab dua, ob npaug ntawm qhov xwm txheej [-6.5 kV, 4.0 cm] thiab plaub npaug ntawm qhov xwm txheej [-3 .8 kV, 0.5 cm]. 3f qhia cov ntaub ntawv them nqi EWNS yooj yim.
Los ntawm cov ntawv qhia txog cov lej EWNS (Cov Duab Ntxiv S5 thiab S6), nws tuaj yeem pom tias qhov chaw [-6.5 kV, 4.0 cm] muaj cov khoom me me ntau dua li qhov chaw [-3.8 kV, 0.5 cm]. Nws kuj tseem yuav tsum tau sau tseg tias cov lej EWNS tau raug saib xyuas txog li 4 teev (Cov Duab Ntxiv S5 thiab S6), qhov twg EWNS tiam ruaj khov tau qhia tib theem ntawm cov lej khoom me me hauv ob qho tib si.
Daim Duab 3g qhia txog EPR spectrum tom qab kev tswj (keeb kwm yav dhau) rho tawm rau EWNS zoo tshaj plaws ntawm [-6.5 kV, 4.0 cm]. ROS spectrum kuj tau piv rau EWNS baseline hauv daim ntawv luam tawm ua ntej. Tus lej xam ntawm EWNS uas cuam tshuam nrog lub spin trap yog 7.5 × 104 EWNS/s, uas zoo ib yam li Baseline-EWNS8 uas luam tawm ua ntej. EPR spectra qhia meej meej tias muaj ob hom ROS, qhov twg O2- predominant, thaum OH• muaj nyob rau hauv qhov ntau me dua. Tsis tas li ntawd, kev sib piv ncaj qha ntawm qhov siab tshaj plaws qhia tau hais tias EWNS zoo tshaj plaws muaj cov ntsiab lus ROS siab dua piv rau EWNS baseline.
Hauv daim duab 4 qhia txog qhov ua tau zoo ntawm kev tso hluav taws xob 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 EUNS, kev tso hluav taws xob ze li ntawm 100% txawm tias ntawm qhov hluav taws xob qis ntawm 3.0 kV. Feem ntau, 3.0 kV txaus kom ua tiav 100% kev tso hluav taws xob tsis hais txog kev hloov pauv ntawm qhov chaw. Hauv qab cov xwm txheej zoo sib xws, qhov ua tau zoo ntawm kev tso hluav taws xob ntawm Baseline-EWNS tsuas yog 56% vim yog qhov them qis dua (nruab nrab 10 electrons ib EWNS).
Daim Duab 5 thiab Rooj 2 qhia txog qib kev tsis ua haujlwm 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 nyob rau hauv qhov xwm txheej zoo tshaj plaws [-6.5 kV, 4.0 cm]. Cov kab mob E. coli thiab L. innocua uas tau txhaj tshuaj tau pom tias muaj kev txo qis ntawm 3.8 log tom qab 45 feeb ntawm kev raug. Nyob rau hauv tib qho xwm txheej, S. enterica tau pom tias muaj kev txo qis ntawm 2.2 log, thaum S. cerevisiae thiab M. parafortuitum tau pom tias muaj kev txo qis 1.0 log.
Cov duab me me ntawm cov hluav taws xob (Daim Duab 6) qhia txog kev hloov pauv lub cev uas EWNS ua rau hauv cov hlwb E. coli, Salmonella enterica, thiab L. innocua ua rau tsis ua haujlwm. Cov kab mob tswj tau pom tias cov hlwb ntawm cov hlwb tseem 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 EWNS (qhov them ntawm qhov chaw thiab ROS cov ntsiab lus) 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 qhov ntau ntawm nanometer, uas zoo ib yam li cov txiaj ntsig uas tau luam tawm ua ntej, uas tso cai rau lawv nyob hauv huab cua ntev. Qhov polydispersity uas tau pom tuaj yeem piav qhia los ntawm kev hloov pauv ntawm qhov them ntawm qhov chaw, uas txiav txim siab qhov loj ntawm Rayleigh effect, randomness, thiab kev sib koom ua ke ntawm EWNS. Txawm li cas los xij, raws li Nielsen et al.22 tau piav qhia meej, qhov them ntawm qhov chaw siab txo qis kev ua pa los ntawm kev ua kom lub zog ntawm qhov chaw / kev ntxhov siab ntawm qhov dej poob zoo. Txoj kev xav no tau lees paub los ntawm kev sim rau microdroplets22 thiab EWNS hauv peb cov ntawv tshaj tawm ua ntej8. Kev poob ntawm lub sijhawm dhau los kuj tseem tuaj yeem cuam tshuam rau qhov loj me thiab pab txhawb rau qhov kev faib tawm qhov loj me uas tau pom.
Ntxiv mus, tus nqi ib lub 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 lub 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.