Utjecaj ishodnog sloja i ionske jakosti na nastajanje i svojstva polielektrolitnog višesloja kitozan/pektin

master's thesis

• Title (english): The influence of a precursor layer and ionic strength on the formation and properties of chitosan/pectin polyelectrolyte multilayer
• Author: Ana Ivančić
• Mentor: Davor Kovačević (mentor)
• Mentor: Juraj Nikolić (komentor)
• Committee member: Davor Kovačević (predsjednik povjerenstva)
• Committee member: Marijana Đaković (član povjerenstva)
• Committee member: Ivan Nemet (član povjerenstva)
• Committee member: Tajana Begović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2024-02-16, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Polielektrolitni višeslojevi su tanki filmovi koji nastaju naizmjeničnom adsorpcijom suprotno nabijenih polielektrolita na čvrstu površinu. Filmovi izgrađeni od prirodnih polielektrolita, poput kitozana i pektina, posebno su zanimljivi zbog biokompatibilnosti i netoksičnosti, ali i antimikrobnih svojstava što ih čini pogodnim kandidatima za primjenu kao zaštita površine voća. U prvom dijelu ovog diplomskog rada istraživan je utjecaj ionske jakosti i ishodnog sloja na nastajanje i svojstva polielektrolitnog višesloja kitozan/pektin, dok je u drugom dijelu ispitana adhezija bakterije Staphylococcus aureus na njegovu površinu. Površinska svojstva poput debljine, hrapavosti, morfologije i močivosti pripravljenih višeslojeva određena su korištenjem elipsometrije, tenziometrije i mikroskopije atomskih sila. Nadalje, pretražnom elektronskom mikroskopijom određena je prekrivenost površine višeslojeva bakterijama nakon inkubacije. Rezultati pokazuju na to da ionska jakost te ishodni sloj utječu na svojstva višesloja kitozan/pektin, dok istraživanja adhezije bakterija ukazuju da je višesloj kojem je završni sloj kitozan učinkovitiji protiv adhezije bakterije S. aureus od višesloja koji završava pektinom.

Abstract (english)

Polyelectrolyte multilayers are thin films prepared by alternating adsorption of oppositely charged polyelectrolytes to a solid surface. Such materials, when prepared out of biocompatible and non-toxic polyelectrolytes, for instance chitosan and pectin, have shown to be suitable as protective coatings on fruits due to their antimicrobial properties. The first part of this thesis focuses on the influence of ionic strength and the precursor layer on the formation and properties of the chitosan/pectin multilayer, while the second part covers bacterial adhesion of Staphylococcus aureus to the multilayer. The surface properties and thickness of the multilayer were investigated by ellipsometry, tensiometry and atomic force microscopy. In addition, surface coverage of the film with S. Aureus after adhesion experiments was determined with scanning electron microscopy. The results have shown that both ionic strength and the precursor layer influence the multilayer properties. Finally, adhesion experiments indicate that the chitosan-terminating multilayer is more efficient against adhesion than the pectin-terminating one.

• Keywords: adhezija bakterija; elipsometrija; ionska jakost; ishodni sloj; mikroskopija atomskih sila; polielektrolit; polielektrolitni višesloj
• Keywords (english): atomic force microscopy; bacterial adhesion; ellipsometry; ionic strength; polyelectrolyte; polyelectrolyte multilayer; precursor layer
• Language: croatian
• URN:NBN: urn:nbn:hr:217:368612
• Project: Number: IPS-2020-01-6126; Title: Modulacija polifenolnog profila voća uslijed fizikalnih tretmana nakon branja; Title: Modulation of fruit polyphenolic profile by sustainable postharvest physical treatments; Leader: Davor Kovačević; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IPS
• Study programme: Title: Graduate university studies in chemistry; specializations in: Graduate university studies in chemistry; Course: Graduate university studies in chemistry; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra kemije (sveučilišni/a magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2026-02-16
• Created on: 2024-03-12 12:05:05