Stabilnost nanočestica Fe3O4 u modelnim biološkim medijima

master's thesis

• Title (english): Stability of Fe3O4 nanoparticles in model biological media
• Author: Elizabeta Stojaković
• Mentor: Jelena Macan (mentor)
• Committee member: Jelena Macan (predsjednik povjerenstva)
• Committee member: Maja Dutour Sikirić (član povjerenstva)
• Committee member: Marica Ivanković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2016-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Physical Chemistry

Abstract

U novije vrijeme Fe3O4 nanočestice (NČ) privlače sve veću pažnju u različitim područjima primjene zbog svojih jedinstvenih fizikalno-kemijskih i magnetskih svojstava. Zbog svoje minimalne toksičnosti te NČ su posebno zanimljive u biomedicini. Za uspješnu primjenu NČ bitna je stabilnost, tj. agregacija u određenom mediju. Na proces agregacije utječe koncentracija samih NČ, ionska jakost, pH i sastav medija (ioni i organske tvari). Najčešće se stabilnost NČ određuje praćenjem promjene njihove veličine s vremenom. Kod većine metoda pomoću kojih se određuje veličina NČ potrebno je pripremiti suhi uzorak te se ne može odrediti utjecaj medija. Iz tog razloga, ali i jer je ta metoda nedestruktivna, brza i pouzdana, za određivanje veličine čestica u suspenziji se koristi dinamičko raspršenje svjetlosti. U ovom radu istražena je stabilnost Fe3O4 NČ u vodi te u modelnim biološkim medijima (fosfatnom puferu (Phosphate Buffered Saline, PBS), Dulbecco 's Modified Eagle Medium (DMEM) i DMEM/ITS (inzulin, transferin i selen)). Nanočestice magnetita su sintetizirane mokrom tehnikom mikroemulzije te karakterizirane difrakcijom rendgenskih zraka na prahu i pretražnom elektronskom mikroskopijom. Stabilnost Fe3O4 NČ u izabranim medijima istražena je mjerenjem veličine čestica metodom dinamičkog raspršenja svjetlosti tijekom 192 h za Mili Q vodu, 96 h za PBS i DMEM/ITS te 168 h za DMEM. Rezultati su pokazali da su glavni faktori koji utječu na stabilnost Fe3O4 NČ ionska jakost medija, što je u skladu s Derjaguin–Landau–Verwey–Overbeek (DLVO) teorijom, i prisutnost proteina koji mogu stabilizirati čestice adsorpcijom.

Abstract (english)

Recently, Fe3O4 nanoparticles, due to their unique physico-chemical and magnetic properties have attracted considerable interest for different applications. Due to their minimal toxecicity they are of particular interest in biomedicine. The success of nanoparticles applications depends on stability, i.e. agregation in a specific medium. Stability of nanoparticles is affected by concentration of the particles themselves, pH, ionic strength and composition of the medium (presence of the ions and organic matter). The stabiliy of particles is usually determined by measuring their size. Different methods are available for determination of size, but for most of them, nanoparticles should be deposited onto a surface and dried if a suspension is to be characterized. Sizes obtained with these methods do not reflect the influence of solvent. A method enabling determination of medium influence is dynamic light scattering (DLS). It is a nondestructive, fast and reliable method for determining the size of particles in the suspensions. Stability of Fe3O4 nanoparticles in Mili Q water and in biological media (Phosphate Buffered Saline (PBS), Dulbecco 's Modified Eagle Medium (DMEM) and DMEM/ITS (insulin, transferrin and selenium)) has been investigated. Magnetite nanoparticles were synthesized by wet microemulsion technique and characterized by powder X-ray diffraction and scanning electron microscopy. Stability of Fe3O4 nanoparticles has been monitored by dynamic light scattering during 192 h for Mili Q water, 96 h for PBS i DMEM/ITS and 168 h for DMEM. The results have shown that the main factors that affect the stability of Fe3O4 nanoparticle suspensions are ionic strength, which is in accordance with Derjaguin–Landau– Verwey–Overbeek (DLVO) theory, and the presence of proteins that may stabilize nanoparticles by adsorption.

• Keywords: dinamičko raspršenje svjetlosti; stabilnost; Fe3O4 nanočestice
• Keywords (english): dynamic light scattering; stability; Fe3O4 nanoparticles
• Language: croatian
• URN:NBN: urn:nbn:hr:149:304621
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Repository: Repository of Faculty of Chemical Engineering and Technology University of Zagreb
• Created on: 2017-11-09 13:33:30