Makale Koleksiyonu
Bu koleksiyon için kalıcı URI
Güncel Gönderiler
Öğe Removal of anionic dyes with glycidyl methacrylate-grafted polyethylene terephthalate (PET) fibers modified with ethylenediamine(Springer, 2021) Bozkaya, Ogün; Günay, Kübra; Arslan, Metin; Gün Gök, ZehraIn this work, the epoxy groups of poly (ethylene terephthalate) PET copolymers grafted with glycidyl methacrylate (GMA) were modified with ethylenediamine (EDA) to form exclusive adsorbent for removal of congo red (CR) and acid violet7 (AV-7) in the aqueous environment. The graft copolymers (GMA-g-PET) were synthesized with different grafting yield by a radical polymerization process with using benzoyl peroxide (Bz(2)O(2)) as radical initiator. Amination of GMA-g-PET fibers using EDA was studied in different solvents, and maximum yield (w/w %) was obtained in the toluene. The grafted and modified fibers were analyzed by CHNS organic elemental analyzer, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (C-13-NMR). By SEM analysis, the morphological changes have been shown after grafting. The chemical changes after grafting and addition of EDA to the fibers have been proven with FTIR, NMR and elemental analysis. The thermal properties of the grafted and aminated fibers were researched with thermogravimetric analysis and differential scanning calorimeter analysis. The removal of dyes by the EDA-GMA-g-PET fibers was investigated in aqueous medium at different conditions. Optimum conditions of different parameters such as pH of medium, graft yield of GMA on the fibers, adsorption duration, initial concentration of dye molecules and effect of graft yield on amination reaction were examined. The optimum pH of CR and AV-7 removal was found 5 and 3, respectively. The removal yield was found about 100% for both dyes while initial concentration of dyes was changed from 10 to 400 mg/L. Adsorbed dyes with the fibers were desorbed with 1 M NaOH at room conditions.Öğe Production Sericin/Poly(Vinyl Alcohol) Blend Membranes Containing One-Step Synthesized Silver Nanoparticles by UV Radiation for Obtaining Versatile Antibacterial Materials(Wiley-V C H Verlag Gmbh, 2024) Temel, Aleyna; Doğan, Hatice Nuran; Yıldız, Emine; Yanık, Gizem; Gök, Zehra GünIn this study, silver nanoparticles (AgNPs) were in-situ synthesized in silk sericin/poly(vinyl alcohol) (SS/PVA) mixtures by an easy one-step synthesis method with the presence of ultraviolet (UV) radiation. Then, the SS/PVA composite membranes containing AgNPs were obtained by solvent casting method. The chemical structures of the membranes were investigated by fourier-transform infrared spectroscopy (FTIR) and results showed that the membranes were a mixture of silk sericin and PVA. The morphological features of the membranes were investigated by field emission scanning electron microscopy (FE-SEM) and it was seen that AgNPs containing membranes have heterogeneous structures. Energy dispersive spectroscopy (EDS) analysis revealed that the membranes contain carbon, oxygen, nitrogen, sulfur and silver. X-ray diffractometer (XRD) and thermogravimetric (TGA) analyses also proved the presence of AgNPs in the structure of membranes. The antibacterial activities of membranes containing AgNPs were investigated on Staphylococcus aureus and Escherichia coli bacteria with disk diffusion test and liquid culture medium incubation. It was found that SS/PVA membranes containing 5 and 10 mM AgNPs have quite high antibacterial activity on both types of bacteria. The functional SS/PVA membranes have capacity to be used in biomedical applications such as wound care materials. In this work, silver nanoparticles (AgNPs) are synthesized in-situ with UV light within silk sericin/poly(vinyl alcohol) (SS/PVA) polymer mixture and SS/PVA membranes containing AgNPs are obtained with solvent casting method. Various physical, chemical and morphological properties of membranes are examined. The antibacterial activity of the membranes is investigated on bacteria, and the membranes show high antibacterial activity. imageÖğe Production and characterization of hybrid nanofiber wound dressing containing Centella asiatica coated silver nanoparticles by mutual electrospinning method(Pergamon-Elsevier Science Ltd, 2022) Bozkaya, Ogün; Arat, Esra; Gök, Zehra Gün; Yiğitoğlu, Mustafa; Vargel, İbrahimThe aim of this work is to produce a therapeutic and antimicrobial nanofiber wound dressing material with suitable air permeability, water vapor transmission, water absorption, porosity, thermal and mechanical strength. For this purpose, first of all, Centella asiatica (CA) coated silver nanoparticles (CA-AgNPs) are synthesized with using CA extract as reducing and stabilizing agent. The green synthesized CA-AgNPs are characterized by UV-Vis spectroscopy, transmission electron microscope (TEM), zeta potential and fourier transform infrared (FTIR) spectroscopy measurements. The obtained CA-AgNPs give a single peak in the 420-430 nm range between 200 and 700 nm due to surface plasmon resonance (SPR). The average zeta potential and size of CA-AgNPs is found to be-30.4 mV and 14.8 +/- 7.3 nm, respectively. Then, poly caprolactone (PCL) and polyethylene oxide (PEO) nanofibers composition containing CA-AgNPs is synthesized by mutual electrospinning method. Before electrospinning, the PCL solution (12% w/v in chloroform/methanol (70%/30%, v/v)), PEO solution (3.5%, w/v in water) and PEO solutions containing 1%, 5% and 10% (v:v) of CA-AgNPs are prepared. In electrospinning experiments, to synthesis the PCL/PEO nanofibers containing CA-AgNPs, an electrospinning set-up consisting of two high voltage sources, an aluminum rotary roller collector and two syringe pumps (one with a double syringe and the other with a single syringe) is used. To produce the wound dressing materials, PEO solutions containing CA-AgNPs are placed on the double syringe pump and PCL solution is placed on the single syringe pump. The surface and physico-chemical properties of the produced hybrid nanofibers are characterized by field emission scanning electron microscopy (FESEM), energy dispersion spectrometry (EDS), FTIR, X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) surface area and porosity analyzer. Also, the thermal and mechanical properties of the obtained materials are investigated. In addition, the air permeability, water uptake capacity, water contact angle, water vapor transmission, in vitro degradation and silver release behavior of the samples are investigated. The results show that mutual dual-spinneret electrospinning technique combines the features of dissimilar components without corruption. Moreover, the in vitro degradation profile and silver release results show that these nanofibers could be used in wound dressing applications in the long term. With antimicrobial studies, PEO/ PCL nanofibers containing 5% and 10% CA-AgNPs are found to be effective against Staphylococcus aureus, Escherichia coli and Candida albicans. Also, the cytotoxic properties of nanofibers are investigated by MTT (3-[4,5dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay and results show the good biocompatibility for L929 fibroblast cells. Results reveal that CA-AgNPs loaded PCL/PEO hybrid nanofibers materials synthesized in this study has a promising potential for wound healing applications.Öğe Preparation of Poly(vinyl alcohol)/Silk Sericin Blend Membranes with Solvent Casting Method For Effective Removal of Remazol Black B(Korean Fiber Soc, 2023) Gök, Zehra GünIn the present work, poly(vinyl alcohol)/silk sericin (PVA/SS) membranes were obtained with an easily procedure and removal of remazol black B (RBB) by the membranes was investigated. To synthesize PVA/SS membranes by solvent casting method, 5% SS solution (g/mL) and 10% PVA solution (g/mL) were mixed one to one ratio by volume, the mixture was transferred to a petri dish and incubated at 25 oC for 24 h. Then, the obtained membranes were incubated at 150 oC for 1 h for physical crosslinking. The obtained membranes were characterized with fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA). Then, for adsorption experiments, firstly, RBB adsorption capabilities of PVA/SS membranes were tested at pH ranging from 2 to 7. After that, the removal experiments were carried out at different incubation time, initial dye concentration and PVA/SS membrane amount to optimize the conditions for removal of RBB with the PVA/SS membranes. The obtained membranes removed high amount of RBB when the solution pH was 2 and the adsorption of RBB to the membranes reached equilibrium within 10 h. The maximum RBB adsorption ability of the PVA/SS membranes was found to be 15.27 mg/g when the initial RBB amount of the solution was 200 mg/L. These results show that PVA/SS membranes, which can be easily synthesized for large applications, have the capacity to be used to remove negatively charged pollutants such as RBB from liquid solutions.Öğe Amino acid surface modified bioglass: A candidate biomaterial for bone tissue engineering1(Wiley, 2024) Özkabadayı, Yasin; Türk, Mustafa; Kumandaş, Ali; Karahan, SiyamiBioglasses are solid materials consisted of sodium oxide, calcium oxide, silicon dioxide and phosphorus in various proportions and have used in bone tissue engineering. There have been ongoing efforts to improve the surface properties of bioglasses to increase biocompatibility and performance. The aim of the present study is to modify the bioglass surface with an amino acid mixture consisting of arginine, aspartic acid, phenylalanine, cysteine, histidine and lysine, to characterize the surface, and to evaluate the performance and biocompatibility in vitro and in vivo. The untreated bioglass, bioglass kept in simulated body fluid (SBF), and modified bioglass were used in further evaluation. After confirmation of the surface modification with FT-IR analyses and SEM analyses, MC3T3-E1 preosteoblasts adhesion on the surface was also revealed by SEM. The modified bioglass had significantly higher ALP activity in colorimetric measurement, rate of calcium accumulations in Alizarin red s staining, lower rate of cell death in Annexin-V/PI staining to determine apoptosis and necrosis. Having higher cell viability rate in MTT test and absence of genotoxicity in micronucleus test (OECD 487), the modified bioglass was further confirmed for biocompatibility in vitro. The results of the rat tibial defect model revealed that the all bioglass treatments had a significantly better bone healing score compared to the untreated negative control. However, the modified bioglass exhibited significantly better bone healing efforts especially during the first and the second months compared to the other bioglass treatment treatments. As a result, the amino acid surface modification of bioglasses improves the surface biocompatibility and osteogenic performance that makes the amino acid modified bioglass a better candidate for bone tissue engineering. Research Highlights Bioglass surface modification with amino acids contributes to bioglass-tissue interaction with an improved cell attachment. Modified bioglass increases in vitro Alp activity and calcium accumulation, and also positively affects cell behavior by supporting cell adaptation. Bioglass exerts osteogenic potential in vivo especially during early bone healing.Öğe A detailed study on multifaceted bioactivities of the extracts and isolated compounds from truffle Reddellomyces parvulosporus(Wiley, 2022) Çayan, Fatih; Tel-Çayan, Gülşen; Deveci, Ebru; Duru, Mehmet Emin; Türk, MustafaMushrooms and truffles are attracting attention as a new generation of biotherapeutics. In the current study, isolation, phenolic and organic acid composition, and antioxidant, cytotoxic, anticholinesterase activities of truffle Reddellomyces parvulosporus were examined. Four known compounds (brassicasterol (1), ergosterol peroxide (2), fumaric acid (3) and mannitol (4)) were isolated with the combination of chromatographic techniques. Fumaric acid (54.74 +/- 0.85 mu g g(-1)) was found as the major compound by HPLC-DAD. All isolated compounds were bioassayed for antioxidant, cytotoxic, anticholinesterase, anti-tyrosinase, anti-urease, anti-alpha-glucosidase and anti-alpha-amylase activities. Compound 1 indicated notable cytotoxic activity on MCF-7 (IC50: 38.08 +/- 0.75 mu g mL(-1)) and compound 3 on H1299 (IC50: 62.37 +/- 0.75 mu g mL(-1)). Also, compounds 1 (84.55 +/- 1.14%) and 2 (84.90 +/- 0.10%) showed higher anti-urease activity than thiourea (78.57 +/- 0.22%), while compound 2 (66.31 +/- 0.08%) displayed near-standard anti-BChE activity. Also, being the first to emphasise the potential of R. parvulosporus as a natural food additive, this study evidenced its medicinal importance by revealing bioactive compounds and properties.Öğe The apoptotic and proliferative effects of tulathromycin and gamithromycin on bovine tracheal epithelial cell culture(Tubitak Scientific & Technological Research Council Turkey, 2022) Şahin, Yaşar; Yıldırım, Ebru; Yurdakök Dikmen, Begüm; Türk, MustafaGamithromycin and tulathromycin are commonly used in the treatment of bovine respiratory bacterial diseases. The current work was undertaken to establish the apoptotic, necrotic, and cytotoxic effects of these antibiotics in the target animal. Cells with apoptosis and necrosis were determined by dual staining method, cytotoxic effects were determined by MTT assay, cell proliferative effects were examined by XCelligence real-time cell analysis system (RTCA-SP). The comparison between gamithromycin and tulathromycin concentrations on tracheal cells in terms of % cell viability was found to be significantly different. While the cell viability percentage of gamithromycin was higher at 150 mu g/mL, 180 mu g/mL, and 240 mu g/mL than tulathromycin, and at 2 mu g/mL, 4 mu g/mL, 10 mu g/mL, 20 mu g/mL, and 50 mu g/mL concentrations tulathromycin cell viability was higher than gamithromycin (p < 0.05). When the staining method data were evaluated, the difference between the results of % apoptotic index at 20 mu g/mL concentration was significant and it was found that gamithromycin had more apoptotic effect than tulathromycin (p < 0.05). It was seen that tulathromycin and gamithromycin applied on tracheal epithelial cells at concentrations of 2 and 10 mu g/mL increased the viability depending on time. The increase in epithelial cell proliferation of gamithromycin and tulathromycin due to time shows that these antibiotics can maintain longterm prophylactic treatment against diseases.Öğe Investigation of the biocompatibility and in vivo wound healing effect of Cotinus coggygria extracts(Ankara Univ, 2024) Bozkaya, Esra; Türk, Mustafa; Ekici, Hüsamettin; Karahan, SiyamiCotinus coggygria is widely recognized its antiseptic, anti-inflammatory, antimicrobial, antihemorrhagic, and wound-healing properties. In this, aimed to evaluate the phenolic contents, cytotoxicity/proliferation, hemolytic, antimicrobial, genotoxic, apoptotic, necrotic activities, and in vivo wound healing effects of C. coggygria, , a plant species known to have beneficial effects on wound healing. TOF-LC/MS analyzes revealed that the methanol extract of C. coggygria leaves contained flavonoids and phenolic compounds such as gallic acid (18.5 mg/kg), catechin (4.6 mg/kg), protocatesic acid (0.6 mg/kg), vanillic acid (8.4 mg/kg), ellagic acid (0.1 mg/kg), rosmarinic acid (0.1 mg/kg), quercetin (15 ppb) and C. coggygria stems contained such as gallic acid (24.6 mg/kg), catechin (155.1 mg/kg), chlorogenic acid (1.9 mg/kg), 4hydroxybenzoic acid (383.3 mg/kg), rutin (2.5 mg/kg), ellagic acid (15.1 mg/kg), apigenin 7-glycoside (10.5 mg/kg), rosmarinic acid (0,4 mg/kg), quercetin (15.2 mg/kg), naringenin (279.1 mg/kg). Consequently, C. coggyria has a positive effect on wound healing with antibacterial properties, particularly against E. coli, and without cytotoxic, genotoxic, or hemolytic effects at test concentrations. In the in vivo burn model, wounds treated with leaf and stem extracts healed faster than the control group. Thus, C. coggygria is an effective plant for wound healing with antibacterial properties, particularly against E. coli, and without cytotoxic, genotoxic, and hemolytic effects.Öğe Effects of functional poly(ethylene terephthalate) nanofibers modified with sericin-capped silver nanoparticles on histopathological changes in parenchymal organs and oxidative stress in a rat burn wound model(Ankara Univ, 2023) Şahin, Yaşar; Gün Gök, Zehra; Alçığır, Mehmet Eray; Çınar, MiyasIn this study, it was aimed to investigate the effect of a poly(ethylene terephthalate)-g-poly(hydroxyethyl methacrylate) (PET-g-HEMA) nanofiber wound dressing modified with sericin-coated silver nanoparticles (S-AgNPs) on internal organs, oxidative stress, and biochemical parameters. To establish a burn model, the backs of anesthetized rats were shaved and then third-degree burns were created with a round-bottomed stainless steel rod 2 cm in diameter kept in 100 degrees C water for 20 seconds. The wounds of the negative control group (G1) were covered with standard bandages; the wounds of the positive control group (G2) were covered with silvercel, used as burn wound material; and the wounds of the experimental group (G3) were covered with PET-based dressing material. Histopathological changes in organs (liver, kidneys, heart, pancreas, lungs), total oxidant status (TOS), total antioxidant status (TAS), nitric oxide (NO), and biochemical parameters (serum aspartate aminotransferase [AST], alanine aminotransferase [ALT], gamma glutamyl transpeptidase [GGT], creatine kinase, lactate dehydrogenase [LDH], total protein, albumin, globulin, urea) were examined. Compared with the G1 group, plasma AST, ALT, and GGT levels were found to be significantly decreased in G2 and G3 (P<0.001). Plasma TAS was found to be significantly increased in G2 and G3 compared to G1 (P<0.05). Compared to the G1 group, degenerative and necrotic changes in the liver, kidneys, and pancreas were found to be significantly reduced in G2 and G3 (P<0.05). In conclusion, this work demonstrates that the synthesized PET-based wound dressing material has the capacity to be used commercially.Öğe Evaluation of photochemically cross-linked collagen/gold nanoparticle composites as potential skin tissue scaffolds(Tubitak Scientific & Technological Research Council Turkey, 2023) Yelkuvan, Evrim Meriç; Erdemli, Özge; Yılmaz, Bengi; Aktürk, ÖmerCollagen type I is the main structural unit in skin tissue and is therefore used preferentially in skin tissue scaffolds. However, collagen-based 3D scaffolds have weak aqueous stability and degradation profiles in their uncross-linked states and chemical cross -linking reagents arise toxicity concerns, which generally restrict the spectrum of their biomedical applicability. Here, the research goal is to photochemically cross-link collagen type I with rose bengal (RB) when subjected to green laser light and to investigate the effect of silk sericin-capped gold nanoparticles (S-AuNP) when incorporated into scaffolds on the cross-linking process and thus on the scaffold properties. All the collagen scaffolds, that is plain collagen (C), collagen/S-AuNP (C-Au), cross-linked collagen (C-RBL), and cross-linked collagen/S-AuNP (C-AuRBL) were characterized for their potential as skin tissue scaffolds. C-AuRBL group had the best thermal stability, resistance to enzymatic degradation, and more uniform pore size distribution. None of the groups had cytotoxicity (cell viability > 70%) regarding the microscopic observations and MTT cell viability assays for L929 fibroblasts. L929 fibroblasts and primary adult human epidermal keratinocytes (HEKa) were also separately seeded on C-AuRBL scaffolds and according to microscopy results, they could support the stimulation of adhesion, morphological changes, and spreading of both cells, thereby encouraging the usage of this fabrication strategy for prospective skin tissue scaffolds.Öğe Investigation of the in vitro antibacterial, cytotoxic and in vivo analgesic effects of silver nanoparticles coated with Centella asiatica plant extract(Ankara Univ, 2023) Bozkaya, Ogun; Ekici, Hüsamettin; Gün Gök, Zehra; Arat, Esra; Ekici, Seda; Yigitoglu, Mustafa; Vargel, İbrahimIn recent years, researchers have shown an increased interest in using medicinal plants for the synthesis of silver nanoparticles (AgNPs) having various therapeutic properties. Centella asiatica (CA), a medicinal plant, has been used to treat minor burn wounds, psoriasis, and hypertrophic wounds among many other pathological conditions. The current study aimed to synthesize CA coated AgNPs (CA-AgNPs) with appropriate biocompatibility and various therapeutic properties, including antimicrobial and analgesic activities. The synthesized CA-AgNPs were characterized by ultraviolet-visible (UV-Vis) spectroscopy, zeta potential measurements, and fourier transform infrared (FT-IR) spectroscopy. The formation of spherical CA-AgNPs was confirmed by a single surface plasmon resonance (SPR) peak emerging at 420 nm wavelength by UV-Vis. The average hydrodynamic diameter and zeta potential of the particles were found to be 29.5 nm and -24.5 mV, respectively. The FT-IR analyses showed that the AgNPs were coated and stabilized by bioactive compounds from the CA extract. MTT cytotoxicity assay revealed that CA-AgNPs at <= 1 mM concentrations exhibited biocompatibility for L929 fibroblast cells. The antimicrobial activity of CA-AgNPs was confirmed by significant inhibition of Staphylococcus aureus and Escherichia coli. In addition, the analgesic effect of CA-AgNPs was investigated for the first time in the literature by tail-flick and hot plate methods, and statistically significant results were obtained for both methods. Taken together, these results suggest that CA-AgNPs can be used as an effective antibacterial and analgesic agent in a variety of biomedical applications, including coating wound dressings.Öğe In vivo imaging/detection of MRSA bacterial infections in mice using fluorescence labelled polymeric nanoparticles carrying vancomycin as the targeting agent(TAYLOR & FRANCIS LTD, 2020) Dizaji, Araz Norouz; Ding, Dan; Kutsal, Tulin; Turk, Mustafa; Kong, Deling; Piskin, ErhanThis study aims to develop fluorescence labelled polymeric nanoparticle (NP) carrying vancomycin as the targeting agent for in vivo imaging of Methicillin-resistant Staphylococcus aureus bacterial infections in animal models. Maleimide functionalized 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[maleimide (polyethylene glycol)-2000] as the main was carrier matrix to prepare the NPs. A fluorescence probe, namely, poly[9,9 '-bis (6 ''-N,N,N-trimethylammonium) hexyl) fluorene-co-alt-4,7-(2,1,3-benzothiadiazole) dibromide] was encapsulated within these NPs by ultrasonication successfully. UV-Vis spectro- photometry of the NPs showed the characteristic shifting on the peak of conjugated polymers indicating successful packaging of this compound with lipid bilayers in nanoscales. Zeta-sizer and TEM analysis showed that the prepared NPs have a diameter of 80-100 nm in a narrow size distribution. Thiolated vancomycin was synthesized and attached to the NPs as the targeting agent. FTIR and MALDI-TOF spectroscopy analysis confirmed the immobilization. The specific targeting properties of the vancomycin conjugated NPs to the target bacteria were first confirmed in in vitro bacterial cultures in which Escherichia coli was the non-target bacteria - using confocal microscopy and TEM. Imaging of bacterial infections in vivo was investigated in mice model using a non-invasive live animal fluorescence imaging technique. The results confirmed that bacterial infections can be detected using these novel polymeric NPs carrying fluorescence probes for imaging and vancomycin as the targeting agent - in vivo successfully.Öğe Hydroxyapatite-based nanoparticles as a coating material for the dentine surface: An antibacterial and toxicological effect(ELSEVIER SCI LTD, 2020) Erdem, Umit; Dogan, Mustafa; Metin, Aysegul U.; Baglar, Serdar; Turkoz, Mustafa B.; Turk, Mustafa; Nezir, SaffetIn this study, nano sized hydroxyapatite (nHAp) and Ag(I) doped hydroxyapatite (Ag-nHAp) particles were synthesized by the precipitation method and used as a coating material for remineralization on caries-affected dentine samples. Characterization studies of both the synthesized hydroxyapatite-based particles and the coated dentine samples were performed using instrumental techniques such as SEM and FFIR, and then toxicity and antibacterial properties were also evaluated. It was observed that dentine samples were effectively coated by both nHAp and Ag center dot nHAp particles which have no toxic effects. Furthermore, the costing of nano-hydroxyapatite on dentine samples positively contributed to the viability of L929 fibroblast cells and also provided an antibacterial effect against to bacteria such as S. mutants, C. albicans and E. coli bacteria that are most frequently caused caries in the teeth. While all type of bacteria was eliminated by the nHAp coated dentine samples at 24th, Ag-nHAp coated dentine samples removed to all bacteria type at 1st.Öğe The Pimpled Gold Nanosphere: A Superior Candidate for Plasmonic Photothermal Therapy(DOVE MEDICAL PRESS LTD, 2020) Nasseri, Behzad; Turk, Mustafa; Kosemehmetoglu, Kemal; Kaya, Murat; Piskin, Erhan; Rabiee, Navid; Webster, Thomas J.Background: The development of highly efficient nanoparticles to convert light to heat for anti-cancer applications is quite a challenging field of research. Methods: In this study, we synthesized unique pimpled gold nanospheres (PGNSs) for plasmonic photothermal therapy (PPTT). The light-to-heat conversion capability of PGNSs and PPTT damage at the cellular level were investigated using a tissue phantom model. The ability of PGNSs to induce robust cellular damage was studied during cytotoxicity tests on colorectal adenocarcinoma (DLD-1) and fibroblast cell lines. Further, a numerical model of plasmonic (COMSOL Multiphysics) properties was used with the PPTT experimental assays. Results: A low cytotoxic effect of thiolated polyethylene glycol (SH-PEG400-SH-) was observed which improved the biocompatibility of PGNSs to maintain 89.4% cell viability during cytometry assays (in terms of fibroblast cells for 24 hrs at a concentration of 300 mu g/mL). The heat generated from the nanoparticle-mediated phantom models resulted in Delta T=30 degrees C, Delta T=23.1 degrees C and Delta T=21 degrees C for the PGNSs, AuNRs, and AuNPs, respectively (at a 300 mu g/mL concentration and for 325 sec). For the in vitro assays of PPTT on cancer cells, the PGNS group induced a 68.78% lethality (apoptosis) on DLD-1 cells. Fluorescence microscopy results showed the destruction of cell membranes and nuclei for the PPTT group. Experiments further revealed a penetration depth of sufficient PPTT damage in a physical tumor model after hematoxylin and eosin (H&E) staining through pathological studies (at depths of 2, 3 and 4 cm). Severe structural damages were observed in the tissue model through an 808-nm laser exposed to the PGNSs. Conclusion: Collectively, such results show much promise for the use of the present PGNSs and photothermal therapy for numerous anti-cancer applications.Öğe Synthesis and characterization of antibacterial drug loaded beta-tricalcium phosphate powders for bone engineering applications(SPRINGER, 2020) Topsakal, Aysenur; Ekren, Nazmi; Kilic, Osman; Oktar, Faik N.; Mahirogullari, Mahir; Ozkan, Ozan; Sasmazel, Hilal TurkogluPowders of beta-tricalcium phosphate [beta-TCP, beta-Ca-3(PO4)(2)] and composite powders of beta-TCP and polyvinyl alcohol (PVA) were synthesized by using wet precipitation methods. First, the conditions for the preparation of single phase beta-TCP have been delineated. In the co-precipitation procedure, calcium nitrate and diammonium hydrogen phosphate were used as calcium and phosphorous precursors, respectively. The pH of the system was varied in the range 7-11 by adding designed amounts of ammonia solution. The filtered cakes were desiccated at 80 degrees C and subsequently calcined at different temperatures in the range between 700-1100 degrees C. Later on, rifampicin form II was used to produce drug-loaded beta-TCP and PVA/beta-TCP powders. All the synthesized materials have been characterized from morphological (by scanning electron microscopy) and structural-chemical (by X-ray diffraction and Fourier transform infrared spectroscopy) point of view. The drug loading capacity of the selected pure beta-TCP powder has been assessed. The biological performance (cytocompatibility in fibroblast cell culture and antibacterial efficacy against Escherichia coli and Staphylococcus aureus) has been tested with promising results. Application perspectives of the designed drug-bioceramic-polymer blends are advanced and discussed. [GRAPHICS] .Öğe Production of 2-hydroxyethyl methacrylate-g-poly(ethylene terephthalate) nanofibers by electrospinning and evaluation of the properties of the obtained nanofibers(WILEY, 2020) Gok, Zehra Gun; Inal, Murat; Bozkaya, Ogun; Yigitoglu, Mustafa; Vargel, IbrahimNanofiber production was investigated from poly(ethylene terephthalate) (PET) polymers functionalized with hydroxyethyl methacrylate (HEMA) by grafting of HEMA monomers onto the PET fibers. HEMA grafted PET (PET-g-HEMA) copolymers were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy. PET and PET-g-HEMA were dissolved in trifluoroacetic acid and nanofibers were obtained by electrospinning. It was found that the PET and PET-g-HEMA polymers having grafting yield 20 and 55% could be converted to continuous, smooth, and beadles nanofibers. For characterization of the nanofiber membranes, thermogravimetric analysis, differential scanning calorimeter analysis, surface contact angle measurement, porosity analysis, and mechanical tests were applied. When compared with the original PET nanofibers, the thermal properties and degradation process of PET-g-HEMA nanofibers changed according to the amount of HEMA present in the structure of nanofibers. The contact angles of the nanofibers obtained from PET-g-HEMA polymers decreased whereas the water retention ability of the nanofibers increased compared to original PET nanofibers. The porosity of PET-g-HEMA nanofibers was found be high compared to PET nanofibers and whereas the mechanical properties of PET was higher than PET-g-HEMA nanofibers. The obtained nanofibers can be used in many fields such as biomaterial applications.Öğe Phosphorus-nitrogen compounds. Part 48. syntheses of the phosphazenium salts containing 2-pyridyl pendant arm: structural characterizations, thermal analysis, antimicrobial and cytotoxic activity studies(NATL INST SCIENCE COMMUNICATION-NISCAIR, 2020) Elmas, Gamze; Okumus, Aytug; Kilic, Zeynel; Ozbeden, Pelin; Acik, Leyla; Tunali, Beste Cagdas; Turk, MustafaThe phosphazenium salts (protic ionic liquids, PILs/protic molten salts, PMOSs) (6a-6d and 7a) of the free phosphazene bases (4a-4d and 5a) have been prepared by the reactions of the corresponding cyclotriphosphazenes with the bulky gentisic acid. The structures of the PMOS have been evaluated using the elemental analyses, FTIR, H-1, C-13{H-1} and P-31{H-1} NmR data. The molecular and crystal structures of 4a and 6c are established by X-ray crystallography. The thermal properties of the PMOS are determined using TG and DTA techniques. On the other hand, the antimicrobial activities of the free phosphazene bases (4a-4d and 5a-5d) and PMOSs (6a-6d and 7a) are screened against the selected bacteria and yeast strains. The antimicrobial activities of the free phosphazene bases and the PMOSs are compared. The interactions of the phosphazenes and their salts with plasmid DNA are elucidated by the agarose gel electrophoresis. The evaluations of the cytotoxic activities of these compounds are also studied against to L929 fibroblast and breast cancer cells (MDA-MB-231).Öğe Synthesis and biological evaluation of novel urea, thiourea and squaramide diastereomers possessing sugar backbone(ELSEVIER SCI LTD, 2020) Isilar, Ozer; Bulut, Adnan; Yaglioglu, Ayse Sahin; Demirtas, Ibrahim; Arat, Esra; Turk, MustafaA series of novel chiral 14 urea, thiourea and squaramide stereoisomers possessing carbohydrate backbones as well as amide functional groups was synthesized and characterized by their, H-1 NMR, C-13 NMR, FT-IR, HRMS, optical rotation, and melting points. Their antiproliferative activities were investigated against HeLa and PC3 cell lines. The compounds 9, 11 and 12 showed better activities at 25 mu M against PC3 cell line with respect to the standard 5-fluorouracil (5-FU). Especially, the compounds 9 and 11 showed higher activities than the standard 5-FU even at low concentration (5 mu M) against HeLa cell line. IC50 results also confirm these activities. The compounds 9, 10 and 11 have the IC50 values of 1.10 mu M, 1.51 mu M and 1.02 mu M, respectively while 5-FU has 2.51 mu M. Moreover, their cytotoxicity tests have proven that their viabilities were in between 50% and 100%.Öğe Synthesis of Bis(2,2,3,3-tetrafluoro-1,4-butanedialkoxy)-2-trans-6-bis(4-fluorobenzyl)spirocyclotetraphosphazene: Structural Characterization, Biological Activity and DFT Studies(SPRINGER/PLENUM PUBLISHERS, 2020) Elmas, Gamze; Kilic, Zeynel; Cosut, Bunyemin; Kesan, Gurkan; Acik, Leyla; Cam, Merve; Tunali, Beste CagdasThe Cl replacement reaction of octachlorocyclotetraphosphazene, N4P4Cl8 (1), with two equimolar amounts of N-(4-fluorobenzyl)-N'-methylpropane-1,3-diamine led to the formation of 4,4,8,8-tetrachloro-2-trans-6-bis-N-(4-fluorobenzyl)-N'-methylpropane-1,3-diamino-cyclotetraphosphazene (2). The reaction of 2 with excess sodium 2,2,3,3-tetrafluoro-1,4-butanedioxide afforded the bis(2,2,3,3-tetrafluoro-1,4-butanedialkoxy)-2-trans-6-bis(4-fluorobenzyespirocyclotetraphosphazene (2a). The elemental analyses, mass spectrum (ESI-MS), FTIR, HSQC, HMBC, H-1, C-13 and P-31 NMR spectral data of 2a were consistent with the proposed structure. The crystal structure of 2a was elucidated by X-ray diffraction method. The spectroscopic data of the molecules (2 and 2a) in the ground state were investigated by the Density Functional Theory (DFT) from the crystal structures. On the other hand, compound 2a was found to be the most active against S. aureus G(+) (MIC value: 125 mu M). Whilst, any antifungal activity of 2a was not observed against C. albicans and C. tropicalis. This compound also exhibits cytotoxic activity against L929 fibroblast and MCF-7 breast cancer cells. The interaction of 2a with pBR322 DNA was researched using gel electrophoresis. It is understood that the change in DNA conformation by interstrand of 2a with A/A and G/G nucleobases in DNA. [GRAPHICS] .Öğe Colloidal stability and biological activity evaluation of microbial exopolysaccharide levan-capped gold nanoparticles(ELSEVIER, 2020) Akturk, OmerThe main objectives of this study were to explore the suitability of the exopolysaccharide levan, biosynthesized by Bacillus subtilis, to aid in the formation of gold nanoparticles (AuNPs) and to investigate the colloidal stability and in vitro biological activity of this biopolymer-AuNPs complex. AuNPs (mainly spherical, 8-10 nm-sized, and monodispersed) were successfully synthesized in levan concentrations up to 0.5% w/v (L-AuNP0.5) while exposed to ultraviolet C (UVC) irradiation. The increase of levan quantity decreased the size of AuNPs according to Transmission Electron Microscopy (TEM) images and enhanced the colloidal stability significantly. The presence of L-AuNP0.5 at the highest treatment dose (1000 mu g/mL) exhibited substantial cytotoxicity towards L-929 mouse fibroblasts for all incubation periods. Dose-dependent toxicity was observed for the first day while, after this threshold value, medium (100 mu g/mL) and the lowest (10 mu g/mL) treatment doses were non-cytotoxic during 7 days of incubation, implying dose and time-independent cell viabilities ( > 95%) compared to the negative control (complete cell culture medium). There occurred a special surface interaction with cells and LAuNP0.5, especially when the cells were subjected to deliberate starvation periods to increase L-AuNP0.5 internalization via passive and active endocytosis. Scanning Electron Microscopy (SEM) images showed high accumulation of L-AuNP0.5 around or inside the cell membrane after 7 days. Overall, this attribute (high uptake of L-AuNP0.5) could make them promising candidates for prospective cancer therapeutics or drug delivery systems by enabling the cell internalization of anticancer drugs.
