Razvoj nanokompozitnih filmova na bazi kitozana s antimikrobnim djelovanjem

master's thesis

• Title (english): Development of chitosan-based nanocomposite films with antimicrobial activity
• Author: Dora Horvat
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Committee member: Dajana Kučić Grgić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Kitozan je biopolimer koji posjeduje izvrsna antimikrobna, biokompatibilna i biorazgradljiva svojstva, zbog čega nalazi primjenu u brojnim područjima, između ostalog i kao ambalaža za pakiranje hrane. Kako bi se poboljšala antimikrobna svojstva kitozanskih filmova za pakiranje hrane, a tako i produljio rok trajanja i kvaliteta zapakirane hrane, u ovom radu istraženi su kitozanski nanokompozitni filmovi s dodatkom aktivnih tvari. Nanokompozitni kitozanski filmovi pripremljeni su otapanjem kitozana (Cs) velikih molekulskih masa (100.000–300.000 Da) u razrijeđenoj 2 % (v/v) vodenoj otopini octene kiseline, uz dodatak nanočestica: kitozana (NCs), TiO2, Ti-Ag i Ti-Ag-h, ZnO, Zn-Ag i Zn-Ag-h. Nanočestice kitozana (NCs) pripremljene su iz kitozana niske molekulske mase (50.000–190.000 Da) otapanjem u 2 % (v/v) vodenoj otopini octene kiseline, te taloženjem dodatkom neotapala – natrijevog tripolifosfata (Na5P3O10). Dopiranje metalnih oksida (TiO2, ZnO) srebrovim ionima provedeno je miješanjem u suspenziji deionizirane vode gdje su dodane zadane odvage aktivnih tvari TiO2, ZnO i AgNO3. Dobiveni nanokompozitni filmovi karakterizirani su skenirajućom elektronskom mikroskopijom (SEM), difuznom refleksijskom spektroskopijom (DRS), infracrvenom spektroskopijom (FTIR), određivanjem površinskih svojstava mjerenjem kontaktnog kuta (θ) i određivanjem antimikrobnog djelovanja za pet bakterijskih kultura (Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Enterococcus faecalis i Pseudomonas aeruginosa). Analizom rezultata ustanovljeno je da su svi uzorci pokazali antimikrobno djelovanje na sve vrste ispitivanih bakterija, osim uzorka Cs/NCs/Ti-Ag-h, gdje je SEM analizom utvrđena loša dispergiranost nanočestica unutar polimerne matrice.

Abstract (english)

Chitosan is a biopolymer that has excellent antimicrobial, biocompatible and biodegradable properties and due to it has a wide range of the applications and one of them is food packaging. In order to improve the antimicrobial properties, and thus extend the shelf life and quality of packaged foods, chitosan nanocomposite films with active additives were studied in this work. Chitosan-based nanocomposite films were prepared by dissolving chitosan (Cs) of high molecular weight (100.000-300.000 Da) in a diluted 2 % (v/v) aqueous solution of acetic acid, with the addition of nanoparticles: nanochitosan (NCs), TiO2, Ti-Ag and Ti-Ag-h, ZnO, Zn-Ag and Zn-Ag-h. Chitosan nanoparticles (NCs) were prepared from chitosan of low molecular weight (50.000-190.000 Da) by dissolving it in a 2 % (v/v) aqueous solution of acetic acid and were precipitated by adding a non-solvent – sodium tripolyphosphate (Na5P3O10). The doping of metal oxides (TiO2, ZnO) with silver ions was carried out in ain deionized watersuspension where active substances TiO2, ZnO and AgNO3 were mixed in specified ratio. The obtained nanocomposite films were characterized by scanning electron microscopy (SEM), diffuse reflection spectroscopy (DRS), infrared spectroscopy (FTIR), determination of surface properties by measuring the contact angle (θ) and by determination of antimicrobial activity for five different bacterial cultures (Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Enterococcus faecalis i Pseudomonas aeruginosa). The results indicate that all samples showed antimicrobial activity against all types of tested bacteria, except for the Cs/NCs/Ti-Ag-h, where SEM analysis revealed poor dispersion of nanoparticles within the polymer matrix.

• Keywords: kitozan; biopolimeri; nanokompoziti; nanočestice; TiO2; ZnO; antimikrobna svojstva; ambalaža
• Keywords (english): chitosan; biopolymers; nanocomposites; nanoparticles; TiO2; ZnO; antimicrobial properties; packaging
• Language: croatian
• URN:NBN: urn:nbn:hr:149:416185
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-03-10 15:01:28