Browsing by Author "Sen, Fatih"

Now showing 1 - 20 of 39

Activity of Carbon-Supported Platinum Nanoparticles Toward Methanol Oxidation Reaction
(Amer Chemical Soc, 2007) Sen, Fatih; Gokagac, Gulsun
Two groups of carbon-supported platinum nanoparticle catalysts have been prepared. In group 1, catalysts I and 11 were prepared using PtCl4 and H2PtCI6 as starting materials and 1-hexanethiol, HSCH2CH2CH2CH2CH2CH3, as a surfactant. For group 11, the same platinum complexes were used as starting materials (catalyst III from PtCl4, catalyst IV from H2PtCl6) and tert-octanethiol, HSC(CH3)(2)CH2CH2CH2CH2CH3, was used as a surfactant for the first time. It has been found that the group II catalysts are between similar to 2 and similar to 3.3 times more active toward methanol oxidation reaction compared to other prepared and commercial catalysts. Transmission electron microscopy shows that the platinum nanoparticles are homogeneously dispersed on the carbon support and exhibit a narrow size distribution; the average particle size was found to be 2 +/- 0.4 and 3 +/- 0.4 nm in diameter for group I and group II catalysts, respectively. X-ray diffractogram analysis indicates that the platinum nanoparticles have a face centered cubic structure consistent with that of platinum metal itself., X-ray photoelectron spectra of the catalysts indicate two different types of platinum with the Pt 4f(7/2) binding energies of 71.1, 74.4 eV; 71.3, 74.3 eV; 71.0, 74.4 eV; and 71.5, 74.5 eV for catalysts I-IV, respectively. These have been identified as Pt(0O) and Pt(IV), which could be platinum oxide or hydroxide. By looking at the oxidation state data, we found that catalysts I-IV consist of 71% Pt(0) and 29% Pt(IV); 83% Pt(0) and 17% Pt(IV); 76% Pt(0) and 24% Pt(IV); and 65% Pt(0) and 35% Pt(IV), respectively.
Alterations in Quality Characteristics and Bioactive Compounds of Blackberry Fruits Subjected To Postharvest Salicylic Acid Treatment During Cold Storage
(Wiley, 2024) Sakaldas, Mustafa; Sen, Fatih; Gundogdu, Muttalip; Aglar, Erdal
Blackberry deteriorates rapidly after harvest due to its sensitive structure, limiting their storage time to about a week and resulting in significant economic losses. The study was conducted to determine the effects of salicylic acid applications on postharvest fruit quality in blackberries, the harvested fruit was immersed in salicylic acid solutions prepared at concentrations of 0.5, 1, and 1.5 mM for 15 min. Measurements and analyses such as weight loss, decay rate, soluble solids contents (SSC), pH, acidity, respiration rate, vitamin C, organic acids, and phenolic compounds were performed on fruits stored for 12 days with intervals of 4 days. Applying salicylic acid to fruits resulted in significantly less weight loss and decay rate. Salicylic acid application was effective in increasing SSC rate and decreasing titratable acidity with increasing storage time, and lower SSC and higher titratable acidity were measured with this application. Salicylic acid maintained organic acids and vitamin C postharvest. The decreases in individual phenolic compound levels occurred with extended storage time. Salicylic acid application generally was effective in maintaining concentrations of phenolic compounds during storage, and it was found to be effective on fruit quality, with effectiveness varying depending on application dosage. The study identified 1.5 mM as the most effective dosage of salicylic acid, which could be utilized to maintain postharvest quality and extend cold storage in blackberries. A study was conducted to assess the effects of salicylic acid on postharvest blackberry quality. Measurements such as weight loss, decay rate, soluble solids contents, pH, titratable acidity, respiration rate, vitamin C, organic acids, and phenolic compounds were taken over 12 days at 4-day intervals. Salicylic acid-treated fruits showed significantly less weight loss and decay. It also helped maintain organic acids, vitamin C, and phenolic compounds.image
Amylamine Stabilized Platinum(0) Nanoparticles: Active and Reusable Nanocatalyst in the Room Temperature Dehydrogenation of Dimethylamine-Borane
(Royal Soc Chemistry, 2014) Sen, Fatih; Karatas, Yasar; Gulcan, Mehmet; Zahmakiran, Mehmet
Herein, we report the preparation and characterization of platinum(0) nanoparticles stabilized by amylamine (C5H11NH2) ligands plus their catalytic use in the room temperature dehydrocoupling of dimethylamine-borane ((CH3)(2)NHBH3), which has attracted recent attention as a promising solid hydrogen storage material. Amylamine stabilized platinum(0) nanoparticles were reproducibly generated by an ethanol-superhydride reduction method and their preliminary characterization was done by ICP-OES, XRD, ATR-IR, TEM, HRTEM, and XPS spectroscopies. The sum of their results shows the formation of highly crystalline and colloidally stable platinum(0) nanoparticles. The catalytic performance of these new platinum(0) nanoparticles in terms of activity, isolability and reusability was investigated in the catalytic dehydrocoupling of dimethylamine-borane, in which they were found to be active and reusable heterogeneous catalysts even at room temperature.
Anom Approach for Statistical Evaluation of Some Antioxidant Enzyme Activities
(Frontiers Media Sa, 2022) Demir, Canan; Keskin, Siddik; Sen, Fatih
Free radicals are chemical molecules that are more reactive and have an unpaired electron. Free radicals formed inside the cell oxidize biomolecules, leading to cell death and tissue damage. Antioxidants are molecules that can stabilize or inactivate free radicals before they damage the cell. In this study; the availability of Malondialdehyde, Superoxide dismutase, Catalase and Reduced glutathione levels as markers for related diseases was evaluated by examining whether and in what range they may vary in some diseases. In study, nine groups consist of prostate cancer, cirrhosis, liver transplantation, chronic kidney damage, acute kidney injury, X-ray exposure, CT exposure, MR exposure and Osteonecrosis. Analysis of means is a method developed to compare group means with the overall mean and presents the results graphically in an easy-to-understand manner without the required for any post hoc test. In addition, related characteristics were categorized as "low and high" and Nonlinear Principal Component Analysis was conducted to visually present their relationship with related disease types in two-dimensional space. The upper and lower decision lines were found 3.123 and 2.794 mu mol/L, respectively for Malondialdehyde. Those with cirrhosis, chronic kidney disease, acute kidney disease and tomography exposure were included in the upper and lower decision lines. Those with prostate cancer, osteonecrosis, and X-ray exposure were above the upper decision line and are found higher than the overall mean. Those with lung transplantation and MR exposure appear to be below the lower decision line and lower than the overall mean. The present study provides the first comprehensive assessment of the availability of Malondialdehyde, Superoxide dismutase, Catalase and Reduced glutathione levels as markers for some related diseases. This study has shown that Analysis of means can be used as an alternative graphical procedure for multiple group comparisons with an overall mean in the studies regarding as biochemical characteristics and relating diseases. In addition, Nonlinear Principal Component Analysis can be useful aid for decision marker in some biochemical characteristics and related diseases.
Antioxidant, Antimicrobial, Cytotoxic and Protective Effects of Truffles
(Academic Press inc Elsevier Science, 2022) Fidan, Mehmet; Ali, Muhammad Muddassir; Erez, Mehmet Emre; Cigerci, Ibrahim Hakki; Ozdemir, Sadin; Sen, Fatih
Fungi can be used as a potent chemotherapeutic agent to treat various cancers. In current study acetone and methanol extracts of Terfezia claveryi, Terfezia boudieri, Terfezia olbiensis, Picoa lefebvrei, Picoa juniperi were used to assess total phenolic contents, antioxidant activity, ion-chelating impact, antimicrobial activity, the cytotoxic and protective effects. Both methanol and acetone extracts of T. boudieri had the highest FRAP and DPPH scavenging abilities. Dose-dependent increased ion-chelating impact of all tested truffles species was found. Extracts of T. boudieri, T. claveryi, and T. albiensis exhibited higher antimicrobial activities. T. claveryi and T. boudieri showed the highest protective effects against H2O2-induced genotoxicity (P < 0.05), in S. cerevisiae BY4741. The least protective effect was showed by the acetone extracts of T. olbiensis (144 +/- 8); methanol ex-tracts of P. lefebvrei (140 +/- 8) and P. juniperi (140 +/- 10). MCF 7 cells showed more sensitivity against to methanol extracts of T. boudieri at 10-100 mu g/mL concentrations. HepG2 cells showed more sensitivity against the methanolic extracts of T. boudieri at both doses. Overall, P. lefebvrei and P. juniperi extracts had the least cytotoxic effects. The species of Terfezia exhibit significant protective effects against DNA damage and also have the potential of cytotoxicity effects.
Assessment of Therapeutic Potential of Silver Nanoparticles Synthesized by Ferula Pseudalliacea Rech. F. Plant
(Elsevier, 2022) Kocak, Yilmaz; Oto, Gokhan; Meydan, Ismet; Seckin, Hamdullah; Gur, Tugba; Aygun, Aysenur; Sen, Fatih
Plant-mediated synthesis of silver nanoparticles (Ag NPs) has increased its use in various biomedical applications due to its cost-effectiveness, renewable and environmentally friendly properties. Therefore, the focus of the study was to synthesize Ag NPs and to evaluate their antibacterial, and antioxidant activities by using the aqueous root extract of Ferula pseudodalliacea plant as a reducing agent. In addition, the synthesis of nanoparticles was confirmed by performing Ag NPs/Fp characterization processes. According to the findings of our research, color change due to surface plasmon resonance was confirmed by UV-vis spectrometry. The crystal properties of Ag NPs/Fp were determined according to the XRD model. Phytochemicals responsible for coating and reduction of Ag NPs/Fp were observed by FT-IR analysis. It has been shown that the therapeutic effect of Ag NPs/Fp exhibits better antimicrobial and antioxidant activity than aqueous extract. In addition, it was determined that Ag NPs/Fp structures showed the best antifungal effect against Candida albicans ATTC 90028 pathogen and gave a better zone than Rifampicin antibiotic. Therefore, studies at the molecular level and more comprehensively are required to determine the bioactive components and pharmacological effects of Ferula pseudodalliacea plant to confirm our antibacterial, antioxidant, and antifungal activity results.
Atom Transfer Rearrangement Radical Polymerization of Diammine-Bis(2,4,6 Complexes in the Solid State
(Walter de Gruyter Gmbh, 2006) Goekagac, Guelsuen; Sonsuz, Muammer; Sen, Fatih; Kisakuerek, Duygu
The synthesis of the poly(dichloro- or dibromophenylene oxide)s was achieved by the thermal decomposition of diammine-bis(2,4,6-trihalophenolato)copper(II) complexes in the solid state by atom transfer rearrangement radical polymerization. The thermal decomposition was performed either at different temperature ranges, 110-250 degrees C, for 3 h, or at the maximum conversion temperature for different time intervals, 3-48 h. Maximum yields of polymers were obtained at 190 degrees C and 3 h. The polymers were characterized by FTIR, H-1 and C-13 NMR spectroscopy, SEM, TGA and molecular weight determination by viscometrical methods. All the polymers were rigid, having high T-g values between 178 and 189 degrees C. Only small amounts of Cu were detected by AAS.
Carbon-Nanotube Rhodium Nanoparticles as Highly-Active Catalyst for Hydrolytic Dehydrogenation of Dimethylamineborane at Room Temperature
(Academic Press inc Elsevier Science, 2018) Gunbatar, Serdar; Aygun, Aysenur; Karatas, Yasar; Gulcan, Mehmet; Sen, Fatih
In this study, we present a carbon nanotube-based Rh nanomaterial as a highly active catalyst for the hydrolytic dehydrogenation of dimethylamine - borane (DMAB) at room temperature. The prepared multi-walled carbon nanotube based Rh nanoparticles, called Rh NPs@ MWCNT, was readily prepared, stabilized and effectively used for the hydrolytic dehydrogenation of DMAB under ambient conditions. Monodisperse Rh NPs@ MWCNT nanocatalyst was characterized by using advanced analytical methods such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) etc. These analytical methods revealed that Rh nanoparticles on the surface of MWCNT were well dispersed and the average particle size was found to be 1.44 +/- 0.17 nm. The catalytic experiments revealed that the new Rh NPs@MWCNT nanocatalyst has a high catalytic effect to obtain hydrogen in 3.0 equation from DMAB, and the record catalytic TOF value for the catalytic reaction catalyzed by Rh NPs@MWCNT nanocatalyst was found to be 3010.47 h(-1) at room temperature. The current study presents the detailed kinetic studies of the hydrolytic dehydrogenation of DMAB catalyzed by Rh NPs@MWCNT, the results of catalytic experiments were performed at different temperatures, substrate and catalyst concentrations, the Rh NPs@MWCNT nanocatalyst was effectively used in the completion of the hydrolytic dehydrogenation of DMAB, and activation energy, enthalpy and entropy parameters. The experimental results showed that monodisperse Rh NPs@MWCNT nanocatalyst have record catalytic activity with TOF value of 3010.47 h(-1), and Rh(0) nanoparticles were well dispersed on the multi-walled carbon nanotubes. (C) 2018 Elsevier Inc. All rights reserved.
Catalytic Methanolysis and Hydrolysis of Hydrazine-Borane With Monodisperse Ru Nps@nano-Ceo2 Catalyst for Hydrogen Generation at Room Temperature
(Pergamon-elsevier Science Ltd, 2019) Karatas, Yasar; Gulcan, Mehmet; Sen, Fatih
Herein, we report metal catalyzed methanolysis and hydrolysis of hydrazine-borane as a fast hydrogen generation system under mild conditions. To the best of our knowledge, this is the first report that a monodisperse Ru NPs@nano-CeO2 catalyst can achieve a complete conversion of N2H4BH3 to H-2 with the assistance of both methanolysis and hydrolysis reactions. In order to achieve hydrolysis and methanolysis effectively, monodisperse Ru NPs@nano-CeO2 catalyst have been prepared by modifying the chemical reduction method which is a very simple and efficient method in room conditions. The synthesized Ru NPs@nano-CeO2 catalyst showed excellent catalytic activity, stability, and selectivity in the production of hydrogen by both hydrolysis and methanolysis of the hydrazine-borane. The results reported here also includes (i) identification of the prepared catalyst by using analytical techniques such as XRD, XPS, TEM, HR-TEM, (ii) determination of stoichiometry for methanolysis and hydrolysis reactions, (iii) determination of rate constants and laws for methanolysis and hydrolysis reactions, (iv) determination of kinetic parameters such as enthalpy, entropy and activation energy for methanolysis and hydrolysis reactions. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Characterization of Rheum Ribes With Zno Nanoparticle and Its Antidiabetic, Antibacterial, Dna Damage Prevention and Lipid Peroxidation Prevention Activity of in Vitro
(Academic Press inc Elsevier Science, 2022) Meydan, Ismet; Burhan, Hakan; Gur, Tugba; Seckin, Hamdullah; Tanhaei, Bahareh; Sen, Fatih
This study aims to investigate the antidiabetic, antimicrobial, DNA damage, and lipid peroxidation prevention activity of ZnO NPs/Rr formed as a result of the interaction of Rheum ribes (R.ribes) plant with ZnO. The ZnO NPs/Rr obtained as a result of the reaction were confirmed using high-reliability characterization methods. According to the data obtained as a result of the study, it is seen that the activity of ZnO NPs/Rr to prevent lipid peroxidation is quite strong. Lipid peroxidation inhibition activity of ZnO NPs/Rr at the highest concentration of 250 mu g/ml was calculated as % 89.1028. It was observed that ZnO NPs/Rr prevented DNA damage by % 92.1240 at the highest concentration of 100 mu g/ml. It was determined that the antidiabetic effect of ZnO NPs/Rr formed by ZnO of R. ribes plant, which is used as a medicinal plant as an antidiabetic, was significant. It appears to have a strong antidiabetic property compared to the positive control acarbose. In our current study, it was observed that ZnO NPs/Rr formed zones ranging from 8 +/- 3.0 to 21 +/- 4.5 against Gram-positive and Gram-negative microorganisms. It has been determined that ZnO nanoparticles have an antibacterial effect.
Chitosan/Pva-supported Silver Nanoparticles for Azo Dyes Removal: Fabrication, Characterization, and Assessment of Antioxidant Activity
(Royal Soc Chemistry, 2024) Meydan, Ismet; Aygun, Aysenur; Tiri, Rima Nour Elhouda; Gur, Tugba; Kocak, Yilmaz; Seckin, Hamdullah; Sen, Fatih
With the advancement of technology, studies in the field of nanotechnology have attracted great interest in recent years. The fact that nanomaterials have superior advantages over micromaterials provides a wide range of uses. Green synthesis is an effective way to prepare nanomaterials with an easy, fast, and environmentally friendly method. Within the scope of the study, AgNPs were synthesized using basil extract and combined with chitosan/PVA as a support material. By using chitosan/PVA support materials, the surface area of AgNPs was increased and it was aimed to improve their properties. The synthesized AgNPs@chitosan/PVA nanocomposite was characterized using various methods. In the UV-Vis spectrum, an absorbance peak was observed at 430 nm for the AgNPs@chitosan/PVA nanocomposite, and the particle size was determined as 25.10 nm according to TEM results. In addition, the photocatalytic and antioxidant activities of AgNPs@chitosan/PVA nanocomposite were investigated. The antioxidant activity of the AgNPs@chitosan/PVA (100 mu g mL-1) nanocomposite against DPPH and H2O2 was determined as 89.18% and 71.87%, respectively. The photocatalytic activity of the AgNPs@chitosan/PVA nanocomposite against methylene blue (MB), methylene red (MR), methylene orange (MO), safranin, and crystal violet (CV) dyes was 77%, 85%, 79%, 54%, and 9%, respectively. While the highest photocatalytic activity was observed against MR dye, very low photocatalytic activity was observed for CV. In light of the results obtained, it can be said that the AgNPs@chitosan/PVA nanocomposite has the potential to be used as an antioxidant agent and photocatalyst. The photocatalytic activity of AgNPs@chitosan/PVA nanocomposite was tested against different dyes such as methylene blue, methylene orange, and methylene red as an effective photocatalyst.
Efficiency Enhancement of Methanol/Ethanol Oxidation Reactions on Pt Nanoparticles Prepared Using a New Surfactant, 1,1-Dimethyl Heptanethiol
(Royal Soc Chemistry, 2011) Sen, Fatih; Sen, Selda; Gokagac, Gulsun
In this study, carbon-supported platinum nanoparticle catalysts were prepared using PtCl4 and H2PtCl6 as starting materials and 1-heptanethiol, 1,1-dimethyl heptanethiol, 1-hexadecanethiol and 1-octadecanethiol as surfactants. These nanoparticles can be used as catalysts for methanol and ethanol oxidation reactions in methanol and ethanol fuel cells. 1,1-Dimethyl heptanethiol was used for the first time in this type of synthesis; other surfactants were used to synthesize nanoparticles for comparison of the catalyst's performance. Cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to characterize the catalysts. It should also be stressed that AFM was employed for the first time in determining the surface topography of these catalysts. XRD, TEM and AFM height results indicate that the platinum crystallizes into a face-centered cubic structure and the surfactant plays an important role in determining the size of the platinum nanoparticles. XPS data revealed that the platinum was found in two different oxidation states, Pt(0) and Pt(IV) with a ratio of about 7.5 : 2.5, respectively. Electrochemical studies showed catalyst IIa to be the most active sample towards methanol/ethanol oxidation reactions (similar to 342 A g(-1) Pt at 0.612 V for methanol (4.6 times more active than the commercial catalyst), similar to 309 A g(-1) Pt at 0.66 V for ethanol, (15.4 times more active than the commercial catalyst)).
An Environmental Approach for the Photodegradation of Toxic Pollutants From Wastewater Using Pt-Pd Nanoparticles: Antioxidant, Antibacterial and Lipid Peroxidation Inhibition Applications
(Academic Press inc Elsevier Science, 2022) Seckin, Hamdullah; Tiri, Rima Nour Elhouda; Meydan, Ismet; Aygun, Aysenur; Gunduz, Meliha Koldemir; Sen, Fatih
Background: Green synthesis is an effective and friendly method for the environment, especially in recent years has been used in many areas. It finds application opportunities in many fields such as physics, chemistry, electronics, food, and especially health and is the subject of intensive studies in this field. Objectives: The synthesized Pt-Pd NPs were aimed to be used as a bio-based photocatalyst under sunlight to prevent wastewater pollution. In addition, it is aimed to use Pt-Pd NPs as biological agents in different applications in the future. Methods: In this study, the platinum-palladium nanoparticles were synthesized by the extract of Hibiscus sabdariffa, the characterization of the nanoparticles was carried out by different methods (ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), infrared transform spectroscopy atomic force microscopy (AFM), and ray diffraction (XRD) analysis). And we discussed several different parameters related to human health by obtaining platinum-palladium bimetallic nanoparticles (Pt-Pd NPs) with a green synthesis method. These parameters are antioxidant properties (total phenolic, flavonoid, and DPPH scavenging activity), antibacterial activity, and lipid peroxidation inhibition activity. Gallic acid was used as standard phenolic, and quercetin was used as standard flavonoid reagents. The newly synthesized Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs were compared with gram-positive and gram-negative bacteria, the high antibacterial activity was shown by gram-positive bacteria. The photodegradation of Pt-Pd NPs was carried out against MB dye for 180 min. Results: TEM results show that the average size of Pt-Pd NPs is around 4.40 nm. The total amount of phenolic compounds contained in 0.2 mg/ml of Pt-Pd NPs was equivalent to 14.962 +/- 7.890 mu g/ml gallic acid and the total amount of flavonoid component was found to be equal to 28.9986 +/- 0.204 mu g/ml quercetin. Hibiscus sabdariffa mediated green synthesized Pt-Pd NPs was found to have very effective for lipid pemxidation inhibition activity in the FeCl2-H2O2 system. The maximum DPPH scavenging activity was determined as 97.35% at 200 mu g/mi. The photocatalytic activity of Pt-Pd NPs was analysed against Methylene blue (MB) and the maximum degradation percentage was observed to be 83.46% at 180 min. Conclusions: The biogenic Pt-Pd NPs showed a high effective photocatalytic and biological activity.
Ex Situ Synthesis and Characterization of a Polymer-Carbon Nanotube-Based Hybrid Nanocatalyst With One of the Highest Catalytic Activities and Stabilities for the Hydrolytic Dehydrogenation of Hydrazine-Borane at Room Temperature Conditions
(Academic Press inc Elsevier Science, 2019) Demirkan, Buse; Kuyuldar, Esra; Karatas, Yasar; Gulcan, Mehmet; Sen, Fatih
In this study, a facile ex situ synthesis of a polyaniline-multiwalled carbon nanotube-based Pt nanocatalyst (Pt@PANI-MWCNT) with an average particle size of 3.18 +/- 0.12 nm was performed successfully. The obtained Pt@PANI-MWCNT nanocatalysts were isolated from the solution medium by centrifugation and then were characterized by spectroscopy and microscopy methods. The characterization studies showed that the prepared Pt nanoparticles were formed on PANI-MWCNT surface, and H-2 evolution was obtained by the dehydrogenation of hydrazine-borane in water as a model reaction under room temperature conditions, with the help of the synthesized nanocatalyst. It was observed that the Pt@PANI-MWCNT nanocatalyst had a very high catalytic activity for the hydrolytic dehydrogenation of hydrazine-borane and generated 2.95 mol of H-2 for 1 mol of hydrazine-borane. The initial turn-over frequency (TOFinitial) value of the prepared nanocatalyst for the model reaction at room temperature conditions was found to be 168.5 min(-1). The calculations for the kinetics of the hydrolytic dehydrogenation reaction showed that the hydrazine-borane catalytic reaction kinetics are first order, with respect to the catalyst concentration; several activation parameters, such as entropy (Delta S-#, (app) = -72.11 +/- 3 J/mol K), enthalpy (Delta S-#, (app) = 43.5 +/- 2 kJ/mol) and activation energy (E-a,E- app = 45.5 +/- 2 kJ/mol), of the catalytic reaction with the Pt@PANI-MWCNT nanocatalyst were calculated using these kinetic data. (C) 2019 Elsevier Inc. 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.
Green Synthesis and Characterization of Camellia Sinensis Mediated Silver Nanoparticles for Antibacterial Ceramic Applications
(Elsevier Science Sa, 2020) Gol, Fatma; Aygun, Aysenur; Seyrankaya, Abdullah; Gur, Tugba; Yenikaya, Cengiz; Sen, Fatih
This study focuses on the use of green synthesized silver nanoparticles (Ag-NPs) with the aid of Camellia sinensis (black tea) extract to provide antibacterial activity on ceramic structure. The synthesized Ag nanoparticles were added to the glaze used in the ceramic structures and mixed homogeneously. The homogeneous mixture was characterized by transmission electron microscopy (TEM), X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) techniques. The SPR band of the synthesized biogenic Ag NPs was observed as 422 nm during the reaction at mom temperature. TEM analysis revealed that Ag NPs were spherical and a particle size between 10 and 20 nm. Furthermore, the antibacterial properties of the homogeneous mixture (Ag NPs and glaze) were tested against Escherichia coli (E. coli, Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Biogenic Ag NPs at a concentration of 100 mu g/ml were observed to have 90%, 75%, 75%, 80% lethal effects against S. aureus, MRSA, B. Subtilis, and E. Coli bacteria, respectively. The antibacterial results of Ag NPs obtained with the help of Camellia sinensis show that they may have potential application and development in the field of ceramics. In addition, the antibacterial activity of commercially available antibiotics and the prepared Ag NPs were analyzed in ceramic glazes.
Green Synthesis and Characterization of Camellia Sinensis Mediated Silver Nanoparticles for Antibacterial Ceramic Applications (Vol 250, 123037, 2020)
(Elsevier Science Sa, 2021) Gol, Fatma; Aygun, Aysenur; Seyrankaya, Abdullah; Gur, Tugba; Yenikaya, Cengiz; Sen, Fatih
Green Synthesis of Palladium Nanoparticles: Preparation, Characterization, and Investigation of Antioxidant, Antimicrobial, Anticancer, and Dna Cleavage Activities
(Wiley, 2021) Gulbagca, Fulya; Aygun, Aysenur; Gulcan, Mehmet; Ozdemir, Sadin; Gonca, Serpil; Sen, Fatih
Green synthesis is considered to be one of the most suitable method because it enhances the therapeutic effects of palladium nanoparticles (Pd NPs). In this study, various biological activities such as antimicrobial, anticancer, antioxidant, and DNA cleavage activities of Urtica-mediated green synthesizing Pd NPs were investigated. The synthesized Pd NPs were characterized by using UV-vis, XPS, FT-IR, TEM, and XRD analyses. As a result of the TEM analysis of Pd NPs, the mean particle size was found to be 7.44 +/- 1.94 nm, and this result was supported by XRD analysis. The maximum DPPH scavenging activity was determined as 79.6% at 500 mg/L. The newly green synthesized Pd NPs exhibited high antimicrobial activity to gram-negative bacteria than gram-positive bacteria. Urtica-mediated green synthesized Pd NPs also showed double strain DNA cleavage activity. For the cytotoxic effects of Pd NPs, the MDA-MB-231 breast cancer cell line, HT-29 colon cancer cell line, Mia Paca-2 human pancreatic cancer cell line, and healthy cell line L929-Murine fibroblast cell line were used. IC50 values of Pd NPs against MDA-MB-231, HT-29, and MIA PaCa-2 cancer cell lines were calculated as 31.175, 20.383, and 29.335 mu g/ml, respectively. No significant cytotoxic effect was observed in the healthy lines L929.
Green Synthesis, Characterization and Bioactivity of Biogenic Zinc Oxide Nanoparticles
(Academic Press inc Elsevier Science, 2022) Gur, Tugba; Meydan, Ismet; Seckin, Hamdullah; Bekmezci, Muhammed; Sen, Fatih
In this study, we tried to enlighten the structure of zinc oxide nanoparticles (ZnO NPs) obtained from Thymbra Spicata L. plant by using green synthesis method in various ways. Some properties of zinc oxide nanoparticles were determined by using the characterization methods that scanning electron microscopy (SEM), Energy Dispersive X-ray analysis (EDX), fouirer transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet visible spectroscopy (UV-Vis) spectroscopy methods. The detected Zn nanoparticle sizes were determined to be between 6.5 nm and 7.5 nm. In addition to these studies, we investigated the antimicrobial effects of zinc oxide nanoparticles obtained by green synthesis against some pathogens. According to the results, it was seen that zinc oxide nanoparticles formed zones with a diameter of 16.3 mm, 10.25 mm, 13 mm and 10.2 mm, respectively, against Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25952, Pseudomonas aeruginosa ATCC 27853 bacteria and Candida albicans ATTC 90028 fungus, respectively. However, the radical quenching activity (DPPH) of the nanoparticles (Ts-ZnONP (79.67%)) was determined to be quite good compared to the positive control BHA. In addition, it is seen that the protective effect of ZnO NPs against DNA damage increases depending on the concentration. At a concentration of 100 mg/L, the DNA damage inhibitory effect was found to be maximum. In line with the comprehensive results, it was determined that the zinc oxide nanoparticles obtained with the green synthesis method have the potential of use in a wide variety of fields.
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.