Introduction: Keywords: ZnO nanoparticles, Antibacterial activity, ph, Staphylococcus aureus.

Transcription

1 Effets of ph n onentrtion on ntiteril tivity of ZnO nnofluis ginst Stphyloous ureus R. Jll1,2,3, M. Slini1, E. K. Gohrshi1. 1Deptment of Chemistry, Fulty of Sienes, Ferowsi University of Mshh.91779, Irn. 2Reserh n Tehnology Center of Biomoleules, Ferowsi University of Mshh, 91779, Irn 3Institute of Biotehnology, Ferowsi Univesity of Mshh, Mshh 91779, Irn rzieh@ferowsi.um..ir(rsjll@yhoo.om Astrt: Nnoprtile metl oxies represent new lsses of importnt mterils tht re inresingly eing evelope for use in reserh n helth-relte pplitions. Highly ioni metl oxies re interesting not only for their wie vriety of physil n hemil properties ut lso for their ntiteril tivity. Although the in vitro ntiteril tivity n effiy of regulr zin oxies hve een investigte, little is known out the ntiteril tivity of nnoprtiles of ZnO. In this work, the ntiteril tivity of ZnO nnofluis ws teste ginst Stphyloous ureus (ATCC:25923) t ifferent onentrtion n ro rnge of ph. Antiteril tests were performe y mesuring the growth urve of S.ureus in the TSB roth meium in the presene of nnofluis ontining 1.5,.75,.375,.187,n.9 2g/ml of ZnO nnoprtiles (ZnO NP) n ph rnge of 7-1. Antiteril tivity inrese with inresing nnoprtile onentrtion. Also, it seems tht si ph improves ntiteril tivity of ZnO NP. Keywors: ZnO nnoprtiles, Antiteril tivity, ph, Stphyloous ureus. Introution: The re-emergene of infetious iseses n the ontinuous evelopment of ntiioti resistne mong vriety of isese-using teri pose serious thret to puli helth worlwie. Despite ntimiroil therpy, moriity n mortlity ssoite with teril infetions remin high, prtilly s result of the ility of these orgnisms to evelop resistne to virtully ll ntiiotis. New strtegies re therefore neee to ientify n evelop the next genertion of rugs or gents to ontrol teril infetions. Reent vnes in the fiel of nnotehnology, prtiulrly the ility to prepre highly orere nnoprtiultes of ny size n shpe, hve le to the evelopment of new ioil gents. Severl stuies hve inite tht nnoprtiulte formultions n e use s effetive teriil mterils[1]. Nnoprtiles n e nturlly ourring or they n e mnufture, the ltter n e lsse into severl tegories inluing the following: 885

2 1. Metl nnomterils, suh s gol n silver nnoprtiles 2. Metl oxie nnomterils, suh s titnium ioxie n zin oxie 3. Cron nnomterils suh s fullerenes n nnotues 4. Quntum ots suh s mium tellurie n mium selenie[2]. Amoung mnufture nnoprtiles, nnoprtile metl oxies represent new lsses of importnt mterils. Swi n others[3,4,5] hve evlute the ntiteril tivity of 26 ermi powers, n 1 of them were foun to inhiit teril growth. Among these tive powers, MgO, CO, n ZnO exhiite strong ntiteril tivity. It ws foun tht the tretment with ZnO formultion use net reution in teril ells of 78% n 62% in the se of trete otton n otton/polyester fris respeetively. Our previous report lso showe the ntiteril properties of ZnO nnofluis ginst E.oli DH5?[6]. ZnO is one of the five zin ompouns tht re urrently liste s generlly reognize s sfe (GRAS) y the U.S. Foo n Drug Aministrtion (21CFR ). However, there re few t tht emonstrte ntimiroil effiy of ZnO in foos[7]. In this stuy, omine effet of ph n onentrtion of ZnO NP is investigte on Stphyloous ureus (ATCC:25923) s grm positive teri. Our results showe the ntimiroil effiy of ZnO NP ginst S.ureus. Antiteril tivity inrese with inresing nnoprtile onentrtion. Also it seems tht si ph improves ntiteril tivity of ZnO NP. So optimiztion of inviromentl ftors in orer to hieve mximum tivity of ZnO NP is very importnt. Experimentl: ZnO NP use for ntiteril ssy were prepre y therml eomposition metho[6]. Bteril strin n ulture meium: To investigte the effet of ph on ntiteril tivity of ZnO nnoprtiles, we use Stphyloous ureus (ATCC:25923) s grm positive teri.the teri is tken from Dr. Mohsenzeh (Veterinry fulty, Ferowsi University of Mshh).TSB(tripti soy roth) is use s ulture mei. Effet of ph n Zno onentrtion: Conentrtion of 15 CFU/ml of teril suspension from logrithmi phse ws e to ifferent roth meium with onentrtions of 1.5,.75,.375,.187,n.92g/ml of ZnO NP. After 24 hours the visile turiity of ifferent ultures were ompre with positive ontrol (ulture without ZnO NP). Sine, no visile growth of teril ells ws oserve t onentrtions of 1.5,.75, n.375 2g/ml, MIC (minimum inhiitory onentrtion) of ZnO NP ginst S. ureus is.375 2g/ml. Hene onentrtions of.375,.187, n.9 2g/ml of ZnO NP were hoose to investigte the omine effet of ph n onentrtion on the ntiteril tivity. The onentrtion of 15 CFU/ml from logrithmi phse teril ells were e to ifferent roth meium with onentrtions of.375,.187, n.9 2g/ml of ZnO NP n ph rnge from 7-1. Two negtive ontrols were use:i)-broth meium with ph rnge of 7-1 n onentrtions of 1.5,.75,.375,.187, n.9 2g/ml of ZnO NP.ii)-Broth meium with ph onitions from

3 Different ultures with ph rnge of 7-1 were use s positive ontrols. Finlly, fter preprtion ll of the smples, 152l of eh one ws trnsferre to every well of 96-well miroplte. Then the miroplte ws lote in shker inutor n OD6 ws reen y Elizreer in ext times n growth urve of eh smple ws rwn. Derese growth of teril ells in the presene of ZnO NP ws ompre with the norml growth of teril ells in sene of ZnO NP. Results: Bteril growth ws inhiite in the presene of ZnO NP t onentrtions of.375 n.187 2g/ml (s ompre with positive ontrol) with the lowest growth in.375 2g/ml. But there ws no signifint ifferene t teril growth etween onentrtion of.9 2g/ml n positive ontrol (Fig. 1). ph: 7.8 OD6.6 Fig. 1: Effet of ZnO NP onentrtion on the growth urve of S.ureus t ph:7. D).3752g/ml, E).1872g/ml, F).92g/ml n G) positive ontrol Bteril growth ws ompletely inhiite in onentrtion of.375 2g/ml of ZnO NP in ph 8. Also teril growth is reue in onentrtion of.187 2g/ml in omprison with positive ontrol. There ws ely time out 8 hours in growth urve of teri in onentrtion of.187 2g/ml. When the onentrtion of ZnO NP es.9 2g/ml, teril growth reue in 8 n 1 hours fter ultivtion in omprison with positive ontrol (Fig.2). 887

4 OD Fig. 2: Effet of ZnO NP onentrtion on the growth urve of S.ureus t ph:8. D).3752g/ml, E).1872g/ml, F).92g/ml n G) positive ontrol ZnO NP inhiite the teril growth ompletely t onentrtion of.375 n t ph 9. Also, teril growth reue in onentrtion of.187 2g/ml in omprison with positive ontrol. The ely time of the growth urve of teri in ph 9 ws out 1 hours, whih ws more thn the mount t ph 8. There ws no signifint ifferene for teril growth etween onentrtion of.9 2g/ml n positive ontrol (Fig. 3)..8 OD 6.6 Fig. 3 : Effet of ZnO NP onentrtion on the growth urve of S.ureus t ph:9. D).3752g/ml, E).1872g/ml, F).92g/ml n G) positive ontrol At ph 1 n the.375 2g/ml of ZnO NPs, 1% inhiition of teril growth ws oserve. At onentrtion of.187 2g/ml, reution of teril growth n ely time of out 1 hours ws 888

5 eliite.at.9 2g/ml, teril growth reue in ph:1 in omprison with positive ontrol fter 6 hours of ultivtion. Also, the ely time of out 1 hours ws oserve t onentrtion of.9 2g/ml n t ph:1 (Fig. 4). 1 OD Fig. 4: Effet of ZnO NP onentrtion on the growth urve of S.ureus t ph:1. D).3752g/ml, E).1872g/ml, F).92g/ml n G) positive ontrol Disussion: Our results showe s the onentrtion of ZnO NPs inrese, the ntiteril tivity improve (Fig. 1-4). Aoring to the growth urves of S.ureus t.3752g/ml of ZnO NPs, no teril growth ws oserve t ph rnge of 8-1, however teril ells grew t ph:7. At the onentrtion of.187 2g/ml of ZnO NP, the ely time inrese s the ph enhne. Also, t.9 2g/ml, more reution of teril growth ws oserve s the ph inrese, so s t ph 1 fter 6 hours, signifint ifferene of teril growth etween positive ontrol n growth urve of teri ws oserve. So, it seems tht in si ph, the ntiteril tivity of ZnO NP inreses. Zin oxie is phototlyst; one it is illuminte y light with energy higher thn its n gps, the eletrons in ZnO will jump from the vlene n to the onution n, n the eletron (e - ) n eletri hole (h+) pirs will form on the surfe of the phototlyst. The negtive eletrons n oxygen will omine into O2-; the positive eletri holes n wter will generte hyroxyl rils. Sine oth re unstle hemil sustnes, when the orgni ompoun flls on the surfe of the phototlyst it will omine with O2- n OH respetively, n turn into ron ioxie (CO2) n wter (H2O)[7]. As the ph inreses, the onentrtion of hyroxyl nione inrese too. So these nions n positive eletri holes omine into hyroxyl rils, so the ntiteril tivity of ZnO NPs enhnes t si ph. 889

6 Colusions: Overll, the finings suggest tht ZnO nnoprtiles n e use externlly to ontrol the spreing of teril infetions. It seems tht optimiztion of environmentl ftors, oul hnge the ioil properties of ZnO NP ginst S.ureus. Therefore, in the future, ZnO nnoprtiles ontining formultions my e utilize for externl uses s ntiteril gents in ointments, lotions, mouthwshes, n surfe otings on vrious sustrtes to prevent miroorgnisms from tthing, olonizing, spreing, n forming iofilms in inwelling meil evies. Refferenes: [1] N. Jones, B. Ry, K. T. Rnjit2 & A. C. Mnn, Antiteril tivityof ZnO nnoprtile suspensions on ro spetrum of miroorgnisms. FEMS Miroiol Lett 279 (28) [2]Toxiologil Review of Nno Zin Oxie. Prospet glol nnomteril sfety. 8 Septemer 29. [3]Swi J, Igrshi H, Hshimoto A, Kokugn T, Shimizu M. Evlution of growth inhiitory effet of ermi power slurry on teri y onutne metho. J Chem Eng Jpn 28 (1995) [4] Swi J, Shoji S, Igrshi H, Hshimoto A, Kokugn T, Shimizu M, Kojim H. Hyrogen peroxie s n ntiteril ftor in zin oxie power slurry. J Ferment. 86 (1998) [5] Swi J. Quntittive evlution of ntiteril tivities of metlli oxie powers (ZnO, MgO n CO) y onutimetri ssy. J Miroiol Methos 54 (23) [6] R. Jll, E. K. Gohrshi, M. Areshi, M. Moosvi, A. Yousefi, P. Nnrrow, ZnO nnofluis: Green synthesis, hrteriztion, n ntiteril tivity. Mterils Chemistry n Physis 121 (21) [7] T. Jin, D. Sun, J.Y. SU, H. Zhng, H.-J. Sue. Antimiroil Effiy of Zin Oxie Quntum Dots ginst Listeri monoytogenes, Slmonell Enteritiis, n Esherihi oli O157:H7. J Foo Si. 74(29) M [8] Y. W. H. Wong, C. W. M. Yuen, M. Y. S. Leung, S. K. A. Ku1, n H. L. I. Lm. Selete Applitions of Nnotehnology in Textiles. AUTEX Reserh Journl, 6 (26)