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Huskić M, Kepić D, Kleut D, Mozetič M, Vesel A, Anžlovar A, Bogdanović DB, Jovanović S. The Influence of Reaction Conditions on the Properties of Graphene Oxide. Nanomaterials (Basel) 2024; 14:281. [PMID: 38334554 PMCID: PMC10856647 DOI: 10.3390/nano14030281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/10/2024]
Abstract
The present study focuses on correlations between three parameters: (1) graphite particle size, (2) the ratio of graphite to oxidizing agent (KMnO4), and (3) the ratio of graphite to acid (H2SO4 and H3PO4), with the reaction yield, structure, and properties of graphene oxide (GO). The correlations are a challenge, as these three parameters can hardly be separated from each other due to the variations in the viscosity of the system. The larger the graphite particles, the higher the viscosity of GO. Decreasing the ratio of graphite to KMnO4 from 1:4 to 1:6 generally leads to a higher degree of oxidation and a higher reaction yield. However, the differences are very small. Increasing the graphite-to-acid-volume ratio from 1 g/60 mL to 1 g/80 mL, except for the smallest particles, reduced the degree of oxidation and slightly reduced the reaction yield. However, the reaction yield mainly depends on the extent of purification of GO by water, not on the reaction conditions. The large differences in the thermal decomposition of GO are mainly due to the bulk particle size and less to other parameters.
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Affiliation(s)
- Miroslav Huskić
- Faculty of Polymer Technology, 2380 Slovenj Gradec, Slovenia
| | - Dejan Kepić
- Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia (S.J.)
| | - Duška Kleut
- Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia (S.J.)
| | - Miran Mozetič
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.M.); (A.V.)
| | - Alenka Vesel
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia; (M.M.); (A.V.)
| | - Alojz Anžlovar
- National Institute of Chemistry, 1000 Ljubljana, Slovenia;
| | | | - Svetlana Jovanović
- Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia (S.J.)
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Krunić M, Ristić B, Bošnjak M, Paunović V, Tovilović-Kovačević G, Zogović N, Mirčić A, Marković Z, Todorović-Marković B, Jovanović S, Kleut D, Mojović M, Nakarada Đ, Marković O, Vuković I, Harhaji-Trajković L, Trajković V. Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death. Free Radic Biol Med 2021; 177:167-180. [PMID: 34678419 DOI: 10.1016/j.freeradbiomed.2021.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/13/2021] [Accepted: 10/18/2021] [Indexed: 01/18/2023]
Abstract
We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP). GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•-), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagy-limiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.
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Affiliation(s)
- Matija Krunić
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia
| | - Biljana Ristić
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia
| | - Mihajlo Bošnjak
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia
| | - Verica Paunović
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia
| | - Gordana Tovilović-Kovačević
- Department of Biochemistry, Institute for Biological Research, "Siniša Stanković"- National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11000, Belgrade, Serbia
| | - Nevena Zogović
- Department of Neurophysiology, Institute for Biological Research "Siniša Stanković" - National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11000, Belgrade, Serbia
| | - Aleksandar Mirčić
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia
| | - Zoran Marković
- Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade P.O. Box 522, 11000, Belgrade, Serbia
| | - Biljana Todorović-Marković
- Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade P.O. Box 522, 11000, Belgrade, Serbia
| | - Svetlana Jovanović
- Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade P.O. Box 522, 11000, Belgrade, Serbia
| | - Duška Kleut
- Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade P.O. Box 522, 11000, Belgrade, Serbia
| | - Miloš Mojović
- Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, 11000, Belgrade, Serbia
| | - Đura Nakarada
- Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, 11000, Belgrade, Serbia
| | - Olivera Marković
- Department of Chemistry, Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000, Belgrade, Serbia
| | - Irena Vuković
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia
| | - Ljubica Harhaji-Trajković
- Department of Neurophysiology, Institute for Biological Research "Siniša Stanković" - National Institute of the Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11000, Belgrade, Serbia.
| | - Vladimir Trajković
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Dr. Subotića 1, 11000, Belgrade, Serbia.
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