Browsing by Author "Ozdemir, S."
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Article Characterization and Antioxidant-Antimicrobial Activity of Silver Nanoparticles Synthesized Using Punica Granatum Extract(Springer, 2022) Aygun, A.; Ozdemir, S.; Gulcan, M.; Yalcin, M. S.; Ucar, M.; Sen, F.In this study, low-cost, simple, and eco-friendly green synthesis of silver nanoparticles was performed using pomegranate extract (Ag NPs/PG). Punica granatum extract acts as a reducing agent and capping agent in the synthesis of Ag NPs. The presence of Ag NPs/PG was analyzed using characterization methods such as UV-Vis absorption spectroscopy (UV-Vis), Fourier transform infrared spectrophotometer (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). XRD, TEM, and XPS analysis showed the presence elements, surface morphology, various shapes, and the presence of Ag NPs in the sample. The Ag NPs/PG particle sizes were found to be 5-45 nm in TEM analysis. By using the XRD technique, Ag NPs were determined to be a cubic crystal structure with face-centered. Furthermore, the antioxidant and antibacterial properties of Ag NPs/PG were also investigated. The enhanced biological activity of Punica granatum-mediated green synthesized Ag NPs was investigated based on antioxidant, antimicrobial, and DNA cleavage studies. The Ag NPs showed 91.6% DPPH (2,2-diphenyl-1-picrylhydrazyl) radical inhibition rate activity at the highest concentration (500 mg mL(-1)). It exhibited significant chemical nuclease activity. Ag NPs/PG had significant antibacterial activity against gram-positive and gram-negative bacteria, but gram-negative bacteria more susceptible than gram-positive. Biogenic synthesis of Ag NPs with the help of Punica granatum extract is a useful and environmentally safe synthesis technique. It is thought that Ag NPs obtained using Punica granatum may have potential use in the fields of nanomedicine, nanobiosensor, and nanobiotechnology in the near future.Article Eco-Friendly Production of Platinum Nanoparticles: Physicochemical Properties, Evaluation of Biological and Catalytic Activities(Springer, 2024) Kocak, Y.; Aygun, A.; Altuner, E. E.; Ozdemir, S.; Gonca, S.; Berikten, D.; Sen, F.In this research, Vitis vinifera extract was used as a reducing molecule for the biogenic synthesis of platinum nanoparticles (Vv-Pt NPs). Vv-Pt NPs were extensively characterized by various methods. It has been determined that Pt NPs were spherical shaped and 1.513 +/- 0.35 nm in size with TEM analysis. The biological activity of synthesized Pt NPs using Vitis vinifera extract was investigated such as antimicrobial, antioxidant, and DNA cleavage studies. Pt NPs exhibited the highest 2,2-Diphenyl-1-picrylhydrazil (DPPH) radical scavenging activity at 200 mg/L. The synthesized Pt NPs were observed to have significant chemical nuclease activity. Pt NPs were found to have significant antibacterial activity against Gram (-) and Gram (+) bacteria, and the highest antimicrobial activity was observed against E. coli. Then, hydrogen production was investigated due to the catalytic effects of Vv-Pt NPs on the hydrolysis of sodium borohydride (NaBH4). Turnover of frequency (TOF), enthalpy (triangle H), entropy (triangle S), and activation energy (Ea) values were determined as 1217.20 h(-1), 37.70 kJ/mol, -153.66 kJ/mol K, and 40.24 kJ/mol, respectively. It has been observed that synthesized Vv-Pt NPs will be used as nano-drugs and will guide sustainable, renewable, and clean energy studies.Article Synthesis of Bis(Thiosemicarbazone) Derivatives: Definition, Crystal Structure, Biological Potential and Computational Analysis(Taylor & Francis Ltd, 2018) Ates, D.; Gulcan, M.; Gumus, S.; Sekerci, M.; Ozdemir, S.; Sahin, E.; Colak, N.(2-(2-(2-methoxyphenyl)hydrazono)cyclohexane-1,3-diylidene) bis(hydrazine carbothioamide) (L-1), 4-(2-(-2,-6-bis(2-carbamothioylhydrazono) cyclohexylidene) hydrazinyl)benzoic acid (L-2), and (2-(2-(4-bromophenyl) hydrazono) cyclohexane-1,3-diylidene) bis(hydrazinecarbothioamide) (L-3) bis(thiosemicarbazone) derivative compounds were synthesized by the condensation reaction of thiosemicarbazide and various ketone compounds. The structures of synthesized compounds were characterized by using FT-IR, H-1 and C-13-NMR spectra, elemental analysis and mass spectra. Also, the structure of L-1 has been determined by X-ray crystallographic analysis. Additionally, the antioxidant activities (free radical (DPPH) scavenging, iron chelating and reducing power) of compounds were evaluated. Especially, L-3 displayed good DPPH activity (84.13%) at 100mg/L. Moreover, pBR322 plasmid DNA cleavage activity was examined and all of the compounds were able to cleave the plasmid DNA. Finally, the ground state geometries of the thiosemicarbazone derivatives were optimized using Density Functional Theory applications at B3LYP/6-31G (d,p) level in order to obtain information about the 3D geometries and electronic structure.