Browsing by Author "Altuner, Elif Esra"

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Biogenic Platinum-Based Bimetallic Nanoparticles: Synthesis, Characterization, Antimicrobial Activity and Hydrogen Evolution
(Pergamon-elsevier Science Ltd, 2023) Darabi, Rozhin; Alown, Fadaa E. D.; Aygun, Aysenur; Gu, Qiang; Gulbagca, Fulya; Altuner, Elif Esra; Karimi-Maleh, Hassan
In this study, platinum-based silver nanoparticles (Pt@Ag NPs) were synthesized by the green synthesis method, and their catalytic effects on hydrogen production were investi-gated. The characterization measurements of the synthesized NPs were performed by TEM, UV-Vis, XRD, and FTIR. According to TEM characterization results, Pt@Ag NPs had an average size of 5.431 nm. In experiments based on catalytic reactions for hydrogen pro-duction, test measurements were made at different parameters. It was observed that as the concentrations of the substrate and catalysts increased, the catalytic reaction accelerated, and the hydrogen release increased. Likewise, it was determined that hydrogen production increased with increasing temperature in different temperature experiments. The turnover frequency, entropy, activation energy, and enthalpy values are calculated as 702.38 h-1,-160.5 J/mol.K, 32.48 kJ/mol, and 29.94 kJ/mol, respectively. According to the reusability test results, it was observed that the average reusability was found to be 85% after 5 cycles and it was confirmed that the NPs showed high-catalytic activity. In addition, the biological activities of Pt@Ag NPs, including antimicrobial, antioxidant and anticancer were tested. Pt@Ag NPs synthesized using Hibiscus sabdariffa (Hs) extract are thought to have the po-tential to be used in both biomedical and catalytic applications. The use of Pt@Ag NPs in the hydrogen production process shows great promise for green energy studies because it is environmentally friendly, non-toxic, and low cost. & COPY; 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Facile Bio-Fabrication of Pd-Ag Bimetallic Nanoparticles and Its Performance in Catalytic and Pharmaceutical Applications: Hydrogen Production and In-Vitro Antibacterial, Anticancer Activities, and Model Development
(Elsevier, 2022) Gulbagca, Fulya; Aygun, Aysenur; Altuner, Elif Esra; Bekmezci, Muhammed; Gur, Tugba; Sen, Fatih; Vasseghian, Yasser
The production of nanoparticles by the biosynthesis method attracts great attention due to their environmentally friendly structure and biocompatibility. In this study, a green method for the synthesis of Palladium-Silver nanoparticles (Pd-Ag NPs) using the extract of Nigella satioa seeds is reported. Pd-Ag NPs obtained by the green synthesis method were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), UV-vis spectrometry, and X-Ray diffraction patterns (XRD). Pd-Ag NPs were seen to have a spherical structure in the TEM analysis image and the average particle size was found to be 6.80 nm. In addition, the anticancer and antibacterial activities of Pd-Ag NPs synthesized by the green synthesis method were investigated. Pd-Ag NPs had lethality of 69.26%, 52.28%, 76.90%, and 57.49% respectively, against Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Bacillus subtilis, and Escherichia coli bacteria at 200 mu g/mL. Besides, the antibacterial activity of Pd-Ag NPs against B. subtilis, S. aureus, and MRSA bacteria was developed by the Neuro-fuzzy (ANFIS) model. The minimum inhibitory concentration (IC50) values of Pd-Ag NPs against human breast cancer cells, human endometrial carcinoma cells, and human cervical cancer cell lines were determined as 12.4384 +/- 0.39 mu g/mL, 13.5043 +/- 0.539 mu g/mL, 17.7172 +/- 0.782 mu g/mL, respectively. The catalytic activity of Pd-Ag NPs was investigated by sodium borohydride (NaBH4) hydrolysis. Enthalpy, entropy, turner of frequency (TOF), and activation energy values were calculated as 24.51 kJ/mol, -183.15 J/mol.K, 1387.29 h(-1), 27.01 kJ/mol, respectively. In the light of the obtained results, it promises that Pd-Ag NPs may play a therapeutic role in complications related to cancer and bacterial infections. The use of Pd-Ag NPs as catalysts will contribute to the development and application of new nano-catalysts to reduce environmental pollution. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Highly Active Pdpt Bimetallic Nanoparticles Synthesized by One-Step Bioreduction Method: Characterizations, Anticancer, Antibacterial Activities and Evaluation of Their Catalytic Effect for Hydrogen Generation
(Pergamon-elsevier Science Ltd, 2023) Aygun, Aysenur; Gulbagca, Fulya; Altuner, Elif Esra; Bekmezci, Muhammed; Gur, Tugba; Karimi-Maleh, Hassan; Sen, Fatih
Metallic nanoparticles (MNPs) have important applications in medicine and technology. Bimetallic NPs, which are among the metallic nanoparticles, are of great interest due to their properties. An innovative method by green synthesis has been developed to obtain bimetallic NPs. Aromatic plants are used in this synthesis method. One of the plants used for green synthesis is Nigella sativa and it has a unique place among plants for use as medicine. In this study, the synthesis of Palladium-Platinum bimetallic nanoparticles (PdPt NPs) and the catalytic, antibacterial, and anticancer activity of synthesized PdPt NPs by green synthesis method using Nigella sativa seed extract are reported. The synthesized PdPt NPs were characterized by Fourier Transform Infrared Spectrophotometer (FTIR), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and UV-Vis spectrom-etry techniques. The catalytic activity of PdPt NPs was determined by performing sodium borohydride (NaBH4) hydrolysis experiments. According to the results obtained, Turnover Frequency (TOF), activation energy, entropy, and enthalpy values were found to be 1664.76 h-1, 13.93 kJ/mol,-119.02 J/mol.K, and 11.43 kJ/mol, respectively. It was determined that PdPt NPs are highly effective catalysts for hydrogen production. PdPt NPs (200 mu g/mL) were determined to have antibacterial activity of 57.58%, 64.42%, 48.68%, and 58.77% against Escherichia coli, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, and Bacillus subtilis bacteria, respectively. In addition, the cytotoxic effects of PdPt NPs, MTT against human breast cancer cell line (MDA-MB-231), human endometrial carcinoma cell line (Ishikawa, ISH), human cervical cancer cell line (HeLa), L929-Murine fibroblast cell line test, and IC50 values were calculated. The IC50 values of PdPt NPs applied against MDA-MB-231, ISH, and HeLa cancer cell lines were calculated as 9.1744 +/- 1.566 mu g/mL, 12.2431 +/- 1.132 mu g/ mL, 18.1963 +/- 1.730 mu g/mL, respectively. No significant cytotoxic effect was observed in healthy L929-murine fibroblasts. Green synthesis of PdPt NPs was determined to have significant advantages over chemical approaches. The biogenic PdPt NPs synthesized in this study suggest the design of bio-based bimetallic catalysts with high catalytic perfor-mance to prevent environmental pollution. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Palladium Based Bimetallic Nanocatalysts: Synthesis, Characterization and Hydrogen Fuel Production
(Elsevier Sci Ltd, 2023) Ni, Kaijie; Wu, Yingji; Karimi, Fatemeh; Gulbagca, Fulya; Seyrankaya, Abdullah; Altuner, Elif Esra; Sen, Fatih
In this study, Palladium dopped Copper oxide nanoparticles (CuO@Pd NPs) were synthesized by an environmentally friendly green synthesis method for hydrogen production experiments. Characterizations of synthesized nanoparticles; UV-vis Spectroscopy to characterize the optical properties, Scanning Electron Microscopy (SEM) to determine the morphology and particle size of the particles, Fourier Transform Infrared Spectroscopy (FTIR) for the analysis of organic groups, and X-ray Diffraction Spectroscopy (XRD) for the crystal lattice type analysis were used. As a result of the UV-vis Spectroscopy characterization of the synthesized nanoparticles, an absorption peak compatible with metals visible at 422 nm was observed. According to the XRD analysis results, the crystal size observed in the cubic phase was calculated as approximately 4.426 nm. According to the results of the SEM analysis the average particle size of the cubic nanoparticles was seen as 26.2 nm. The catalytic properties of CuO@Pd NPs were determined by the sodium borohydride hydrolysis reaction. As a result of catalyst, substrate, temperature, and reusability experiments, some activation parameters required for a catalytic reaction of nanoparticles were calculated. The activation energy of CuO@Pd NPs was calculated as 37.39 kJ/mol, enthalpy change as 34.84 kJ/mol, and entropy change as -189.8 J/mol.K. TOF, which is an indicator of hydrogen efficiency, was calculated as 1513.4 h-1. Reusability experiments were carried out in 4 cycles and the catalytic activity of CuO@Pd NPs was measured as 70 %. In light of these results, it was seen that nanoparticles provide optimal conditions for a catalytic reaction.