Učinak stabilizacije nanočestica zlata i srebra tiolnim biomolekulama na njihovu toksičnost u vodenbuhi (Daphnia magna Straus, 1820)

master's thesis

• Title (english): Effect of thiol biomolecules stabilization of gold and silver nanoparticles toxicity to water flea (Daphnia magna Straus, 1820)
• Author: Ema Pasariček
• Mentor: Ivana Vinković Vrček (mentor)
• Mentor: Anamaria Štambuk (mentor)
• Committee member: Anamaria Štambuk (predsjednik povjerenstva)
• Committee member: Alan Moro (član povjerenstva)
• Committee member: Nenad Buzjak (član povjerenstva)
• Committee member: Sandra Radić Brkanac (član povjerenstva)
• Committee member: Ana Galov (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2017-02-14, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Vodenbuha (Daphnia magna Straus, 1820) je planktonski račić koji se koristi kao modelni organizam u validiranim metodama ekotoksikoloških testiranja. U ovom smo istraživanju koristili vodenbuhu kao testni organizam za ispitivanje ekotoksičnosti nanočestica zlata i srebra koje su bile stabilizirane tiolnim omotačima (glutation i/ili cistein). Učinke nanočestica srebra i zlata usporedili smo s ekotoksičnim učincima njihovih ionskih oblika (Ag+ i Au3+). Osim određivanja preživljenja vodenbuha nakon tretmana s nano i ionskim oblicima srebra i zlata, mjerili smo i razine biomarkera oksidativnog stresa (superoksid radikala, peroksidnog radikala i glutationa) primjenom fluorescentnih proba dihidroetidija, diklorodihidroflourescein diacetata i monoklorobimana. Cilj ovog rada bio je utvrditi smanjuje li tiolna stabilizacija nanočestica zlata i srebra njihov ekotoksični učinak. Akutni test toksičnosti je pokazao veću toksičnost ionskih oblika zlata i srebra u odnosu na nanozlato i nanosrebro. Ionsko srebro je najtoksičnija vrsta, u skladu s prijašnjim istraživanjima. Rezultati istraživanja pokazali su kako je glutationski omotač toksičniji od cisteinskog omotača. Nanozlato se nije pokazalo toksičnim. Rezultati upotrebe fluorescentnih proba ukazali su na prisutnost oksidativnog stresa u vodenbuhama. Vrsta Ag+ je pokazala višu razinu oksidativnog stresa od vrste Au3+. Opažena je dinamika između superoksidnih i peroksidnih radikala kod proba diklorodihidroflourescein diacetat i dihidroetidij. Naposljetku, nanosrebro stabilizirano glutationom pokazalo je najvišu razinu oksidativnog stresa.

Abstract (english)

Water flea (Daphnia magna Straus, 1820) is a planktonic crustacean used as a model organism in validated methods in ecotoxicology research. In this research, we used water flea as a test organism to assess ecotoxicity of gold and silver nanoparticles stabilized with thiol biomolecules (gluthatione and/or cysteine). We compared the effects of gold and silver nanoparticles with ecotoxicological effects of their ionic forms (Ag+ and Au3+). Besides determining the survival of water fleas after the treatment with nano and ionic forms of gold and silver we, also measured levels of oxidative stress biomarkers (superoxide radical, peroxide radical and gluthatione) by using fluorescent probes dihydroethidium, dichloro-dihydro-fluorescein diacetate and monochlorobimane. The aim of this study was to ascertain whether thiol stabilization of gold and silver nanoparticles decreases their ecotoxicological effect. Results obtained in acute toxicity testing showed greater toxicity when water fleas were exposed to ionic forms of gold and silver than when exposed to nanogold and nanosilver. Ionic silver exhibited the greatest toxicity which goes in accordance with previous research. Gluthatione coating showed greater toxicity than cysteine coating. However, nanogold showed no toxicity whatsoever. Results obtained in reactive oxygen species (ROS) assay indicated oxidative stress in water fleas when exposed to each fluorescent probe. Ionic silver showed greater level of oxidative stress than ionic gold. Furthermore, the dynamics between superoxide and peroxide radical were observed when using probes dichloro-dihydro-fluorescein diacetate and dihydroethidium. Finally, nanosilver stabilized with gluthatione showed the greatest level of oxidative stress.

• Keywords: nanočestice zlata; nanočestice srebra; Daphnia magna; oksidativni stres
• Keywords (english): gold nanoparticles; silver nanoparticles; Daphnia magna; oxidative stress
• Language: croatian
• URN:NBN: urn:nbn:hr:217:900689
• Study programme: Title: Enviromental Sciences; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra struke znanosti o okolišu (magistar/magistra struke znanosti o okolišu)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-05-22 10:32:49