Yazar "Colak, Suleyman Gokhan" seçeneğine göre listele

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    Enhanced bacterial uptake of 131I-labeled antimicrobial imidazolium bromide salts using fluorescent carbon nanodots
    (Elsevier, 2021) Duman, Ali Niyazi; Colak, Suleyman Gokhan; Alas, Melis Ozge; Er, Ozge; Tuncel, Ayca; Ozturk, Ismail; Yurt, Fatma
    Imidazolium bromide salts have been shown as potent antibiotic molecules that show structure-based bioactivity related to their cation alkyl side chain length. To enhance the bioavailability of lipophilic alkyl side chains herein, a 1,8-naphthalimide group containing imidazolium bromide salts bearing different lengths of alkyl chains (NIM1, 2, and 3) are coupled with fluorescent carbon dots (C-NIMs) through electrostatic and pi-pi interactions. Further, obtained nanocarriers were radio-labeled with iodine-131 (I-131) to track the bacterial uptake of them by Staphylococcus aureus and Escherichia coli. Antibacterial activities were also investigated by the microdilution method. Comparison studies showed that both radiolabeling efficiency and lipophilicity increased when NIMs were integrated onto the CDots. More importantly, CDots resulted in 4-fold enhanced uptake of NIM1 by S. aureus bacterium as compared to pristine imidazolium bromide salts while at a higher number of alkyl chain lengths enhancement was 2-fold.
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    Investigating the Immunostimulatory and Immunomodulatory Effects of cis and trans Isomers of Ruthenium Polypyridyl Complexes on the Mammalian Macrophage-Like Cells
    (Wiley-V C H Verlag Gmbh, 2020) Ayaz, Furkan; Colak, Suleyman Gokhan; Ocakoglu, Kasim
    Immunomodulatory and immunostimulatory compounds are drug candidates for the regulation of the function of immune system cells to fight against disease conditions including cancer to autoimmunity as well as inflammatory disorders. Due to the electron transfer capacity of photosensitizers in solar cell structures, we hypothesized that they can also be used to regulate the immune system cells' functions possibly through interfering with their electron transfer related activities. We examined thecisandtransisomers (cis-Ru andtrans-Ru) of ruthenium polypyridyl complex on the activated macrophage-like cellsin vitro. Our results suggest immunostimulatory and positive immunomodulatory roles for the ruthenium complex.These compounds increased the production of tumor necrosis factor (TNF) pro-inflammatory cytokine by macrophage-like cells. Therefore, bothcisandtransisomers can be used as a new generation of adjuvant candidates in the vaccine formulations to further boost the activity of immune cells against the disease agent or antigen.
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    Investigation of in vitro activities of Cu2ZnSnS4 nanoparticles in human non-small cell lung cancer
    (Elsevier, 2021) Colak, Suleyman Gokhan; Sezer, Canan Vejselova; Demirdogen, Ruken Esra; Ince, Mine; Emen, Fatih Mehmet; Ocakoglu, Kasim; Kutlu, Hatice Mehtap
    Cu2ZnSnS4 (CZTS) nanoparticles (NPs) were prepared by a simple hydrothermal method, and their cytotoxic, antiproliferative and proapoptotic activities on human non-small cell lung adenocarcinoma A549 cells were investigated for the first time, and the morphological and ultrastructural changes of these cells were monitored. The structural characterizations of the synthesized nanoparticles were made by using Field Emission-Scanning Electron Microscope (FE-SEM), X-Ray Powder Diffraction (XRD) and Raman techniques. Cytotoxicity and confocal microscopy studies revealed that the CZTS NPs effectively entered into the A549 cells in a dose-dependent not time-dependent manner over a period of 24 and 48 h. It was observed that the CZTS NPs had a negligible cytotoxic effect and considerable antiproliferative and pmapoptotic activities. The low cytotoxicity of the CSTZ NPs and their potent anticancer activity against A549 cells highlight their potential to be used as anticancer agents. This study may pave the way for designing and constructing various morphologically diverse, nanotextured materials with desired functional attributes.
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    Polyethersulfone membranes modified with CZTS nanoparticles for protein and dye separation: Improvement of antifouling and self-cleaning performance
    (Elsevier, 2021) Ocakoglu, Kasim; Dizge, Nadir; Colak, Suleyman Gokhan; Ozay, Yasin; Bilici, Zeynep; Yalcin, M. Serkan; Ozdemir, Sadin
    In this study, a novel polyethersulphone (PES) nanocomposite membrane incorporated with copper zinc tin sulfide (Cu2ZnSnS4) nanoparticles (CZTS NPs) was prepared through the phase inversion method. First, the samples containing different copper and zinc ratios in CZTS stoichiometry were prepared and characterized. The effect of copper and zinc ratio changes were examined on the photocatalytic properties of both NPs and nanocomposite membranes. The photocatalytic effect was tested and BR18 dye was degraded at 88.0% efficiency when exposed to visible light for 180 min in the presence of CZTS1.0 NPs catalyst. The results also exhibited that CZTS NPs blended membrane showed good self-cleaning performance. Second, we investigated the antioxidant, DNA cleavage, and biofilm inhibition activities of CZTS NPs. The antimicrobial activities of CZTS NPs were tested against seven microbial strains. The highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and chelating activities were found as 81.80 +/- 1.75% and 72.19 +/- 4.63%, respectively. CZTS NPs exhibited double-strand DNA cleavage activity at 500 mg/L. They showed significant biofilm inhibition as 92.15 +/- 5.67% against Staphylococcus aureus. CZTS NPs displayed moderate antimicrobial effects against tested microorganisms. Third, CZTS NPs were blended in polyethersulphone (PES) membrane and the morphology as well as performance of the fabricated nanocomposite membranes were systematically investigated by SEM-EDX, porosity, water contact angle, antifouling, and rejection measurements. The water flux of resulting nanocomposite membranes was markedly enhanced due to the introducing of CZTS NPs. Meanwhile, the nanocomposite membranes demonstrated remarkable antifouling properties (flux recovery ratio similar to 94%) in contrast with the bare PES (flux recovery ratio similar to 51%) when BSA was filtrated. The high retention of BSA (100%) as well as high permeation flux (73.8 +/- 9.8 L/m(2)/h) of the CZTS2.00 wt% membrane demonstrated that the constructed nanocomposite membrane possessed the characteristics of a promising membrane for purification of proteins.
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    Selective Photokilling of Human Pancreatic Cancer Cells Using Cetuximab-Targeted Mesoporous Silica Nanoparticles for Delivery of Zinc Phthalocyanine
    (Mdpi, 2018) Er, Ozge; Colak, Suleyman Gokhan; Ocakoglu, Kasim; Ince, Mine; Bresoli-Obach, Roger; Mora, Margarita; Lluisa Sagrista, Maria
    Background: Photodynamic therapy (PDT) is a non-invasive and innovative cancer therapy based on the photodynamic effect. In this study, we sought to determine the singlet oxygen production, intracellular uptake, and in vitro photodynamic therapy potential of Cetixumab-targeted, zinc(II) 2,3,9,10,16,17,23,24-octa(tert-butylphenoxy))phthalocyaninato(2-)-N-29,N-30,N-31,N-32 (ZnPcOBP)-loaded mesoporous silica nanoparticles against pancreatic cancer cells. Results: The quantum yield (Phi(Delta)) value of ZnPcOBP was found to be 0.60 in toluene. In vitro cellular studies were performed to determine the dark- and phototoxicity of samples with various concentrations of ZnPcOBP by using pancreatic cells (AsPC-1, PANC-1 and MIA PaCa-2) and 20, 30, and 40 J/cm(2) light fluences. No dark toxicity was observed for any sample in any cell line. ZnPcOBP alone showed a modest photodynamic activity. However, when incorporated in silica nanoparticles, it showed a relatively high phototoxic effect, which was further enhanced by Cetuximab, a monoclonal antibody that targets the Epidermal Growth Factor Receptor (EGFR). The cell-line dependent photokilling observed correlates well with EGFR expression levels in these cells. Conclusions: Imidazole-capped Cetuximab-targeted mesoporous silica nanoparticles are excellent vehicles for the selective delivery of ZnPcOBP to pancreatic cancer cells expressing the EGFR receptor. The novel nanosystem appears to be a suitable agent for photodynamic therapy of pancreatic tumors.
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    Synthesis of new water-soluble ionic liquids and their antibacterial profile against gram-positive and gram-negative bacteria
    (Elsevier Sci Ltd, 2019) Duman, Ali Niyazi; Ozturk, Ismail; Tuncel, Ayca; Ocakoglu, Kasim; Colak, Suleyman Gokhan; Hosgor-Limoncu, Mine; Yurt, Fatma
    A series of imidazolium bromide salts (NIM-Br 1a, 1b and 1c) bearing different lengths of alkyl chains were synthesized and theirin vitro antibacterial activities were determined by measuring the minimum inhibitory concentration (MIC) values for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis. In addition, these imidazolium derivatives were also evaluated against biofilm produced by these bacterial strains. All compounds were found to be effective against Gram-positive and Gram-negative bacteria, and also more effective on the S. aureus biofilm production than the others.
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    Water-Based Synthesis of Copper Chalcogenide Structures and Their Photodynamic Immunomodulatory Activities on Mammalian Macrophages
    (Springer, 2022) Ayaz, Furkan; Colak, Suleyman Gokhan; Ocakoglu, Kasim
    Generation of novel and versatile immunomodulatory agents that could suppress excessive inflammation has been crucial to fight against chronic inflammatory and autoimmune disorders. Immunomodulatory agents regulate the function of immune system cells to manage their activities. Current therapy regimens for the inflammatory and autoimmune disorders rely on immunomodulatory drug molecules but they are also associated with unwanted and severe side effects. In order to prevent the side effects associated with drug molecules, the field should generate novel immunomodulatory drug candidates and further test them. Moreover, the generation of photodynamic immunomodulatory molecules would also decrease possible side effects. Photodynamic activation enables specific and localized activation of the active ingredients upon exposure to a certain wavelength of light. In our study, we generated copper-based chalcogenide structures in gel and nanoparticle form by using a water-based method so that they are more biocompatible.After their chemical characterization, they were tested on mammalian macrophages in vitro. Our results suggest that these molecules were anti-inflammatory in dark conditions and their anti-inflammatory potentials significantly increased upon xenon light treatment. We are presenting novel photodynamic immunomodulatory agents that can be used to suppress excessive inflammation in disease conditions that have been associated with excessive inflammation.