Browsing by Author "Aktas, N."

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Degradable Natural Phenolic Based Particles With Micro-And Nano-Size Range
(Bentham Science Publishers B.V., 2018) Sahiner, N.; Sagbas, S.; Sahiner, M.; Aktas, N.
Background: Degradable polymeric particles derived from phenolic compounds are promising materials for biomedical applications due to their inherently antioxidant, antimicrobial, and anticancerogenic properties. We revise all the patent regarding to the biomedical and food additive formulations of Rutin (RT) and Quercetin (QC) as phenolic compounds. Objective: Prepare degradable Poly(Rutin) (p(RT)) and Poly(Quercetin) (p(QC)) particles from natural phenolic compounds, Rutin (RT) and Quercetin (QC). Method: P(RT), and p(QC) particles were prepared using microemulsion crosslinking method employing phenolic compounds such as RT and QC as monomer and poly(ethylene glycol) diglycidyl ether (PEGGE) as a crosslinker in a single step. The degradability of these particles was investigated at physiological conditions, pH 5.4, 7.4, and 9 at 37.5°C. The antioxidant capacity of RT, QC and their corresponding particles was determined by means of total phenol content and ABTS + scavenging assay. The blood compatibility of the particles is determined with hemolysis and blood clotting tests, and the cytotoxicity of the particles on L929 fibroblast cell and A549 cancer cells was done by WST-1 tests. Results: The size of the prepared phenolic particles was in the size range of 0.4-4 μm with negative zeta potentials,-20.29±1.7 and-31.31±2.0 mV for p(RT) and p(QC) particles, respectively. The highest amount of degradation was obtained for p(QC) particles in almost a linear profile with relatively longer time degrading kinetics at pH 9, e.g., 197±23 mg/g QC was released up to 130 h. The antioxidant capacities of phenolic compounds were decreased about ten-fold upon the particle formations of the phenolic compound, and the antioxidant capacity of p(QC) particles was found to be better than p(RT) particles with 0.22±0.01 and 0.05±0.001 μmol trolox equivalent g -1 , respectively. The blood compatibility test of p(RT) and p(QC) particles revealed that both particles are blood compatible up to 1 mg/mL concentration and possess clotting of blood over 1 mg/mL concentrations. Furthermore, the cytotoxicity tests showed that p(RT) particles are more biocompatible than p(QC) on the fibroblast cell as 91% cell viability versus 50% for p(QC) was observed at 75 μg/mL particle concentrations. Additionally, at this concentration 42.3% of cancer cells were inhibited by p(RT) particles. Conclusion: Degradable p(RT) and p(QC) particles that are prepared in a single step offer great avenue for biomedical applications as highly antioxidant materials and with good biocompatibility in contact with blood and fibroblast cells, as well as great anticancerogenic capability against the cancer cells. © 2018 Bentham Science Publishers.
Halloysite-Carboxymethyl Cellulose Cryogel Composite From Natural Sources
(Elsevier Ltd, 2017) Sengel, S.B.; Sahiner, M.; Aktas, N.; Sahiner, N.
In this work, novel superporous composite cryogel using natural source such as carboxymethyl cellulose (CMC) and halloysite nanotubes (Hal nanotubes) was prepared. The composite was prepared via cryogelation method including the Hal nanotubes within polymeric matrices before cryogelation. A series of the Hal nanotubes/carboxymethyl cellulose composite were prepared by varying the used amounts of crosslinker, and Hal nanotubes amounts. Additionally, Hal nanotubes were modified with different modifying agent such as (3-aminopropyl)triethoxysilane (APTES), (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTACI), polyethylenimine (PEI), epichlorohydrin (ECH), diethylenetriamine (DETA), taurine (TA), and tris(2-aminoethyl)amine (TAEA), these modified Hal nanotubes were used in CMC cryogel composite preparation. Characterization of the synthesized materials was performed by Scanning and Transmission Electron Microscopy (SEM and TEM), Zeta Potential (ZP) measurement, Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR) spectroscopic measurement and Surface area and Porosity Analyzer. © 2017 Elsevier B.V.
Magnetic Co-Fe Bimetallic Nanoparticle Containing Modifiable Microgels for the Removal of Heavy Metal Ions, Organic Dyes and Herbicides From Aqueous Media
(Royal Soc Chemistry, 2015) Ajmal, M.; Siddiq, M.; Aktas, N.; Sahiner, N.
Poly(methacrylic-co-acrylonitrile) (p(MAc-co-AN)) microgels were prepared and nitrile groups were converted to amidoxime groups by chemical modification. Amidoximated microgels, amid-p(MAc-co-AN) microgels were used for in situ synthesis of cobalt-iron (Co-Fe) bimetallic magnetic nanoparticles by simultaneous reduction of Co(II) and Fe(II) ions within microgel. The prepared magnetic microgels as amid-mag-p(MAc-co-AN) microgel were found to be very effective adsorbents for the removal of metal ion such as Cd(II), Cr(III), and organic dyes e.g., methylene blue (MB), rhodamine 6G (R6G) and a herbicide, paraquat (PQ). A tremendous increase in the adsorption capacities of amid-p(MAc-co-AN) microgels was found as 88.1, 89.9, 190.0, 334.5 and 166.5 mg g(-1) from 40.2, 37.4, 75.3, 57.4, and 56.3 for MB, R6G, PQ, Cd(II), and Cr(III), respectively. Moreover, a further increase in adsorption capacity of amid-mag-p(MAc-co-AN) microgel composites were also accomplished with the existence of magnetic particles. Adsorption of these contaminants from tap, river and seawater was also studied. The effects of different parameters i.e., pH, concentration of adsorbent solution and amount of adsorbate was also studied. Langmuir, Freundlich and Temkin adsorption models were applied, and the adsorption of Cd(II) and Cr(III) was found to obey Langmuir adsorption isotherm better.
P(Thyme Oil) and P(Clove Oil) Organo-Particles With Biocompatible, Anticancer, Antioxidant, and Antibacterial Properties Against Capan-1 and L-929 Cells
(John Wiley and Sons Inc, 2024) Alpaslan, D.; Ersen Dudu, T.; Moran Bozer, B.; Aktas, N.; Turk, M.
The synthesis of p(ClO) and p(TO) organo-particles from clove oil and thyme oil is the first in the literature. The particles were tested against the L-929 cell line for cell viability/cytotoxicity. The anticancer activity was studied against the Capan-1 pancreatic cancer cell line. p(ClO) and p(TO) organo-particles were featured by thermogravimetry (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), particle size (DLS), and particle charge (zeta potential, Zeta) analyses. Antioxidant, biocompatible, antimicrobial, and in vitro cytotoxicity specialties were investigated. p(ClO) and p(TO) organo-particles were found to be effective on the L-929 fibroblast cell line and Capan-1 pancreatic cancer cell line in research on Capan-1 and L-929 cell lines. Additionally, it was shown that large dosages of p(ClO) organo-particles were not hazardous to L-929 cell lines. A difference was found between the rates of cell viability and apoptosis and necrosis when the MTT study findings of p(ClO) and p(TO) organo-particles were studied in Capan-1 cell line. The p(TO) organo-particle had the highest % apoptosis rate. At the 100 g mL−1 concentration, the fibroblast cell viability of p(ClO) and p(TO) organo-particles was 176.46% and 107.78%, respectively. The IC50 value derived for the decrease in viability was determined as (2.22 mg mL−1) and it was calculated that it would kill the pancreatic cancer cells by 50% when doxorubicin and p(ClO) were administered combined. © 2023 Canadian Society for Chemical Engineering.
Quantum Size Effect of Cadmium-Doped Titanium Dioxide Photocatalysts Towards Methylene Blue Degradation and Electrooxidation
(Springer, 2022) Kivrak, H.; Saleh, D., I; Alpaslan, D.; Caglar, A.; Selcuk, K.; Dudu, T. E.; Aktas, N.
At present, titanium dioxide supported cadmium catalysts were prepared at 0.5-5% cadmium loading by impregnation method. 0.5% Cd/TiO2 catalyst was characterized with scanning electron microscopy-energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Characterization results revealed that by cadmium doping to titanium dioxide, surface electronic properties and crystal structure of Cd/TiO2 catalysts changed as obtained from SEM-EDX, XRD, and XPS. Following this, methylene blue degradation and electrochemical oxidation measurements were examined under UV light. Electrooxidation measurements were investigated to determine the methylene blue electrooxidation activities of titanium dioxide supported cadmium catalysts prepared at 0.5-5% cadmium loading with the cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy in 1 M KOH + 0.1875 M Methylene blue solution at 100 mV s(-1) in the dark and under UV light. Methylene blue oxidation measurements revealed that 0.5% Cd/TiO2 had the highest catalytic activity and stability in the dark and under UV illumination. 0.5% Cd/TiO2 electrode exhibited enhanced electrocatalytic activity under UV illumination. Photocatalytic methylene blue oxidation enhanced for 0.5% Cd/TiO2 by altering the surface electronic structure and crystal properties of titanium dioxide, assigned to structure sensitivity. As a result, this electrode production method is promising for the photocatalytic water remediation.
The Utilization Smart Hydrogels and Composites With Controllable Porosity in the Preparation of Metal Nanocatalyst
(Crc Press-taylor & Francis Group, 2012) Sahiner, N.; Ozay, O.; Sagbas, S.; Yasar, A.; Aktas, N.
The hydrogels from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS), 2-acrylamido glyconic acid (AAGA), N-vinyl imidazole (VI), and sulfopropylmethacrylate (SPM) that can absorb metal ions such as Co, Ni, Rh, Ru ye Pt from aqueous media were used in the preparation of homo or copolymeric hydrogels and their organic-inorganic composites with tetraethoxy silane (TEOS), tertamethoxysilane (TMOS) and vinyltriethoxysilane (VTEOS), or vinyltrimethoxyilane (VTMOS) as hydrogel-silica composites. The prepared hydrogel and their silica composites were used as template in Cu, Ag, Co, Ni, Fe etc, and magnetic ferrite particle preparation. The prepared hydrogel metal composites were used as a smart catalyst system with controllable porosity for the production of hydrogen in the hydrolysis of different hydrites such as NaBH4 is a novel concept and a smart approach.