Antimikrobni učinak koloidnih otopina nanočestica elementarnoh metala i metalnih oksida na E.coli

master's thesis

• Title (english): Antimicrobial efficiency of metal and metal oxide colloidal nanoparticles against E.coli
• Author: Filip Penava
• Mentor: Ivan Kosalec (mentor)
• Mentor: Iva Rezić (mentor)
• Committee member: Ivan Kosalec (predsjednik povjerenstva)
• Committee member: Davor Šakić (član povjerenstva)
• Committee member: Josipa Vlainić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of microbiology); Zagreb
• Defense date and country: 2018-09-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Medical Biochemistry

Abstract

Koloidne nanočestice metala i metalnih oksida se sve više upotrebljavaju kao alternativa antibioticima zbog
njihovih brojnih prednosti u svrhu liječenja i sprječavanja bakterijskih infekcija, a osobito su popularne
koloidne nanočestice srebra, titanova dioksida i cinkova oksida zbog svoje široke primjene u biomedicini,
industriji i biotehnologiji. Escherichia coli vrlo je zanimljiv modelni organizam za proučavanje jer pripada
najviše istraženim bakterijama na svijetu, no i dalje je vrlo čest uzročnik bakterijskih infekcija raznih
organskih sustava koje mogu biti i životno ugrožavajuće. Stalnom borbom protiv infekcija uzrokovanih
E.coli raznim načinima, primjerice antibioticima, došlo je do razvitka otpornih sojeva protiv kojih se vrlo
teško boriti uobičajenim načinima pa se stoga treba okrenuti i novim sredstvima. Upravo je to i cilj ovog
rada, pokazati da su koloidne nanočestice ta nova opcija, tj. sredstvo borbe protiv bakterijskih infekcija. MIK
i MBK vrijednostima koloidnih nanočestica srebra, cinkova oksida i titanova dioksida na E.coli ATCC
10536 pokazano je kako su one vrlo potentno antimikrobno sredstvo, a među njima najpotentniji baktericidni
učinak imaju koloidne nanočestice srebra. U svrhu ispitivanja mogućeg postojanja sinergizma navedenih
koloidnih nanočestica, pripremljena je optimirana smjesa koja se sastojala od 0.794 ppm nanočestica srebra,
683.217 ppm nanočestica titanova dioksida i 15.989 ppm nanočestica cinkova oksida što ukupno čini smjesu
od 700.000 ppm. Rezultati govore u prilog antagonizmu, ali i da nema statistički značajne razlike u
antimikrobnoj aktivnosti na sojeve ATCC 10536 i ESBL+ MFBF 12794 bakterijske vrste E.coli. Zadnji
korak je ispitati antimikrobnu aktivnost tkanine impregnirane slojem navedene smjese koloidnih nanočestica,
a rezultati govore da kod oba soja dolazi do potpune odnosno stopostotne redukcije broja kolonija nakon 12
sata inkubacije tkanine na koju su inokulirani ispitivani sojevi. Međutim, nema statistički značajne razlike u
postotku redukcije broja kolonija između ispitivanih sojeva sojeva.

Abstract (english)

Metal and metal oxide colloidal nanoparticles are increasingly used as an alternative to antibiotics because of
their many advantages (in comparison to antibiotics) for treatment and prevention of bacterial infections. The
most popular colloidal nanoparticles are silver, zinc oxide and titanium dioxide nanoparticles because they
are used in various fields such as biotechnology and biomedicine. Escherichia coli (E.coli) is the most finely
understood and extensively studied free-living organism on our planet. However, despite being the most
extensively studied organism, E.coli is still to this day a very common cause of diseases of various organs
and therefore E.coli is a very interesting model organism for this study. Resistance to antibiotics emerges in
bacteria due to genetic mutations and consecutive selection of resistant mutants through selective pressure of
antibiotics and because of that antibiotic resistance has become one of the leading problems in modern
medicine. Therefore, currently available options (such as antibiotics) against bacterial infections are limited
and it is advised to turn to new and improved antimicrobial agents. Metal and metal oxide colloidal
nanoparticles are exactly that, the new and improved antimicrobial agents. MIC and MBC values of silver,
zinc oxide and titanium colloidal nanoparticles against E.coli ATCC 10536 suggest that these nanoparticles
are very potent antimicrobial agents with silver nanoparticles being the most potent of them. A mixture of
nanoparticles (0.794 ppm of silver, 683.217 ppm of titanium dioxide and 15.989 ppm of zinc oxide) was
prepared to determine a possible synergism between them. Results suggest that there is no synergism
observed between silver, zinc oxide and titanium colloidal nanoparticles in the mixture and that there is no
statistically significant difference in terms of antimicrobial efficiency against the two E.coli strains (ATCC
10536 i ESBL+ MFBF 12794). Lastly, antimicrobial efficiency of a textile fabric impregnated with the
mixture of nanoparticles was evaluated using the time-kill method. Results suggest that after 12 hours of
incubation there were no growth of bacterial colonies observed (complete reduction of bacterial colonies) for
both E.coli strains. However, no statistically significant difference in terms of reduction of bacterial colonies
was observed between the two E.coli strains.

• Keywords: antibakterijski učinak; koloidne nanočestice; Escherichia coli
• Keywords (english): antibacterial efficiency; colloidal nanoparticles; Escherichia coli
• Language: croatian
• URN:NBN: urn:nbn:hr:163:911731
• Study programme: Title: Medical biochemistry; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra medicinske biokemije (magistar/magistra medicinske biokemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-12-18 10:06:00