Yazar "Tan, Gamze" seçeneğine göre listele
Listeleniyor 1 - 19 / 19
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Anti-proliferative effects of gold nanoparticles functionalized with Semaphorin 3F(Springer, 2017) Tan, Gamze; Onur, Mehmet AliThe new vessel formations play a vital role in growth and spread of cancer. Current anti-angiogenic therapies, predominantly based on vascular endothelial growth factor (VEGF) inhibition, can inhibit vascular development; however, they are usually ineffective against the primary tumor occurrence. The aim of this study was to assess anti-angiogenic effects of gold nanoparticles (AuNPs) functionalized with Semaphorin (Sema) 3F protein. The polyethylene glycol (PEG)-coated AuNPs were covalently functionalized with Sema 3F and labeled with the TAMRA fluorescent dye. The effect of the NPs on human umbilical vein endothelial cells (HUVECs) is probed in the way of internalization and viability assays. AuNP-Sema 3F bioconjugates showed great endothelial cell uptake. AuNP-Sema 3F bioconjugates reduced VEGF(165)-induced endothelial cell proliferation more effectively than Sema 3F alone, suggesting that the therapeutic effects of Sema 3F can be improved by conjugation to AuNPs. Also, no significant toxicity effect was induced by bioconjugates. This is the first study that reports a covalent binding of full length Sema 3F to NPs. The exogenously administration of Sema 3F, which has both anti-angiogenic and antitumoral activity, to tumor vasculature via a carrying platform may not only lead to more effective antiangiogenic treatment but also may make current approach more applicable in clinical use like drug delivery system.Öğe Anti-vascular effects of 4 nm and 20 nm PMA coated gold nanoparticles on CAM model(Wiley, 2018) Tan, Gamze[Abstract Not Available]Öğe Antioxidative and antiproliferative effects of propolis-reduced silver nanoparticles(Techno Press, 2021) Tan, Gamze; İlk, Sedef; Foto, Fatma Z.; Foto, Egemen; Sağlam, NecdetIn this study, phytochemicals present in Propolis Extract (PE) were employed as reducing and stabilizing reagents to synthesize silver nanoparticles. Three propolis-reduced silver nanoparticles (P-AgNPs1-3) were synthesized using increasing amounts of PE. P-AgNPs were treated with different cancer cells -lung (A549), cervix (HeLa) and colon (WiDr) for 24, 48 and 72 h to evaluate their anti -proliferative activities. A non-cancerous cell type (L929) was also used to test whether suppressive effects of P-AgNPs on cancer cell proliferation were due to a general cytotoxic effect. The characterization results showed that the bioactive contents in propolis successfully induced particle formation. As the amount of PE increased, the particle size decreased; however, the size distribution range expanded. The antioxidant capacity of the particles increased with increased propolis amounts. P-AgNP1 exhibited almost equal inhibitory effects across all cancer cell types; however, P-AgNP2 was more effective on HeLa cells. P-AgNPs3 showed greater inhibitory effects in almost all cancer cells compared to other NPs and pure propolis. Consequently, the biological effects of P-AgNPs were highly dependent on PE amount, NP concentration, and cell type. These results suggest that AgNPs synthesized utilizing propolis phytochemicals might serve as anti -cancer agents, providing greater efficacy against cancer cells.Öğe Antitumor activity of chitosan from mayfly with comparison to commercially available low, medium and high molecular weight chitosans(Springer, 2018) Tan, Gamze; Kaya, Murat; Tevlek, Atakan; Sargın, İdris; Baran, TalatInsects' cuticles have a potential to be evaluated as a chitin source. Especially adults of aquatic insects like mayflies (order Ephemeroptera) swarm in enormous numbers in artificially lit areas while mating in spring and then die by leaving huge amounts of dead insects' bodies. Here in this study, mayfly corpses were harvested and used for production of low MW chitosan. Dried mayfly bodies had 10.21% chitin content; mayfly chitin was converted into chitosan with efficiency rate of 78.43% (deacetylation degree, 84.3%; MW, 3.69 kDa). Cytotoxicity and anti-proliferative activity of mayfly and commercially available shrimp chitosans (low, medium, and high MW) were determined on L929 fibroblast and three different cancer types including HeLa, A549, and WiDr. Apoptosis and necrosis stimulating potential of mayfly and commercial chitosans were also evaluated on A549 and WiDr cells using acridine orange and propidium iodide dual staining to observe morphological changes in nuclei and thus to reveal the predominant cell death mechanism. The effects of chitosans have varied depending on cell types, concentration, and chitosan derivatives. Mayfly and low MW chitosans had a cytotoxic effect at a concentration of 500 mu g mL(-1) on non-cancer cells. At concentrations below this value (250 mu g mL(-1)), mayfly and commercial chitosans except high MW one exhibited strong inhibitory activity on cancer cells especially A549 and WiDr cells. Mayfly chitosan induced early and late apoptosis in A549 cells, but late apoptosis and necrosis in WiDr cells. This study suggests that dead bodies of mayflies can be used for production of low MW chitosan with anti-proliferative activity.Öğe Cellular localization and biological effects of 20nm-gold nanoparticles(Wiley, 2018) Tan, Gamze; Onur, Mehmet AliGold nanoparticles (AuNPs) have recently emerged as prominent vehicles for many biomedical applications from sensing to delivery. The relevant literature contains conflicting data about the effects of AuNPs on living cells. The aim of present study is the synthesis and characterization of AuNPs at nanoscale, tracking their cellular localization and determining their effects on cell viability, migration and angiogenesis. Within this scope, 20 nm AuNPs were synthesized and characterized using various spectrometric techniques to determine their size, shape and surface properties such as charge and texture. Two main cell types including mouse fibroblast (L929) and human cervix adenocarcinoma (HeLa) were used in the study to compare the biological effects of colloidal gold on both non-cancer and cancer cells. AuNPs were allowed to interact with HeLa cells to determine their intracellular localization. AuNPs were mainly attached to the cell membrane/membranous compartments and to be captured in small amounts in cytoplasmic vacuoles or to be distributed freely in the cytosol. Scratch assay results showed that AuNPs reduced cancer cell migration especially at increasing concentrations. According to the chick chorioallantoic membrane assay, AuNPs exhibited strong anti-angiogenetic properties and can inhibit vascularization during angiogenesis. In addition, the MTT assay confirmed that AuNP-treated cells caused concentration dependent cytotoxic effects on both cell types. As a result, AuNPs not only have inhibitory effects on cancer cells, but also possess antiangiogenic activity, thus making them a multipotent agent for cancer therapy.Öğe Cellular uptake and bioactivity of antibody-gold nanoparticle bioconjugates(Elsevier Science Bv, 2016) Tan, Gamze; Kantner, Karsten; Zhang, Qian; Soliman, Mahmoud G.; Del Pino, Pablo; Parak, Wolfgang J.; Onur, Mehmet Ali; Valdeperez, Daniel; Rejman, Joanna; Pelaz, Beatriz[Abstract Not Available]Öğe Chitosan nanofiber production from Drosophila by electrospinning(Elsevier Science Bv, 2016) Kaya, Murat; Akyüz, Bahar; Bulut, Esra; Sargın, İdris; Eroğlu, Fatma; Tan, GamzeDrosophila melanogaster is one of the important test organisms in genetics thanks to its fast growth rate in a culture. This study demonstrates that the fly D. melanogaster can also be exploited as a source for nanofiber production in biotechnical applications. First, its chitin content was determined (7.85%) and then high molecular weight chitosan (141.4 kDa) was synthesized through deacetylation of chitin isolates. Chitosan nanofibers with the diameter of 40.0073 +/- 12.347 nm were produced by electrospinning of Drosophila chitosan. The physicochemical properties of obtained chitin and chitosan from D. melanogaster were determined by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The study demonstrated that the fly D. melanogaster can be utilized for production of chitosan.nanofiber concerning its cultivability and low-cost culture requirements.Öğe Comparison of garlic and onion extract-derived gold nanoparticles: Characterization and anticancer activity(Editions de Sante, 2023) Tan, Gamze; Tevlek, Atakan; Aydın, Halil MuratThe present study aims to probe the antioxidative and anticancer activities of gold nanoparticles (AuNPs) reduced by Allium cepa L. (onion-O) and Allium sativum L. (garlic-G) extracts. Versatile analyzes were employed to evaluate the morphological and hydrodynamic properties of the particles, as well as to determine their bioactive components and radical scavenging activities. The biological effects of particles such as toxicity, proliferation, motility, and cell-death mechanism were tested in vitro on fibroblast (L929) and different cancer cell lines. The size range of the spherical particles prepared in three groups for each plant extract was found to vary between 5-10 nm and 7–18 nm for garlic and onion respectively, depending on the extract amount. The particles were also found to be well-dispersed and colloidally stable in aqueous media. Gallic acid was the common phenolic compound in the extracts. The radical scavenging properties of the particles increased depending on the extract amount, and the effect was greater in those synthesized with onion extract. When comparing different types of AuNPs, garlic-reduced AuNPs (GAuNPs) had a more stable effect on cancer cells than onion-reduced AuNPs (OAuNPs). Fluorescence staining showed that nanoparticles caused relatively similar necrotic responses in WiDr cells. However, OAuNPs triggered apoptosis to a greater extent in MCF-7 cells than GAuNPs. Both types of particles inhibited cell migration in both healthy and cancerous cells. In sum, both AuNPs exhibited cytotoxicity through their ability to modulate proliferation, apoptosis, and motility. ©Öğe Conjugation of polymer-coated gold nanoparticles with antibodies—synthesis and characterization(mdpi, 2015) Tan, Gamze; Kantner, Karsten; Zhang, Qian; Soliman, Mahmoud G.; Del Pino, Pablo; Parak, Wolfgang Johann; Onur, Mehmet Ali; Valdeperez, Daniel; Rejman, Joanna; Pelaz, BeatrizThe synthesis of polymer-coated gold nanoparticles with high colloidal stability is described, together with appropriate characterization techniques concerning the colloidal properties of the nanoparticles. Antibodies against vascular endothelial growth factor (VEGF) are conjugated to the surface of the nanoparticles. Antibody attachment is probed by different techniques, giving a guideline about the characterization of such conjugates. The effect of the nanoparticles on human adenocarcinoma alveolar basal epithelial cells (A549) and human umbilical vein endothelial cells (HUVECs) is probed in terms of internalization and viability assays.Öğe Controlled release and anti-proliferative effect of imatinib mesylate loaded sporopollenin microcapsules extracted from pollens of Betula pendula(Elsevier Science, 2017) Sargın, İdris; Akyüz, Lalehan; Kaya, Murat; Tan, Gamze; Çeter, Talip; Yıldırım, Keyser; Ertosun, Şeymanur; Aydın, Gözde Hatun; Topal, MügeSporopollenin is a promising material for drug encapsulation due to its excellent properties; uniformity in size, non-toxicity, chemically and thermally resilient nature. Herein, morphologically intact sporopollenin microcapsules were extracted from Betula pendula pollens. Cancer therapeutic agent (imatinib mesylate) was loaded into the microcapsules. The encapsulation efficiency by passive loading technique was found to be 21.46%. Release behaviour of the drug from microcapsules was found to be biphasic, with an initial fast release followed by a slower rate of release. Imatinib mesylate release from the drug itself (control) was faster than from imatinib mesylate-loaded sporopollenin microcapsules. The release profiles for both free and entrapped drug samples were significantly slower and more controlled in PBS buffer (pH 7.4) than in HCl (pH 1.2) buffer. Cumulative drug release from IM-MES-loaded sporopollenin microcapsules was found to be 65% within 24 h for PBS, whereas release from the control was completed within 1 h. Also, a complete dissolution of control in HCl buffer was observed within first 30 min. MTT assay revealed that drug-loaded microcapsules were effective on WiDr human colon carcinoma cell line. B. pendula sporopollenin can be suggested as an effective carrier for oral delivery of imatinib mesylate.Öğe DNA interaction, antitumor and antimicrobial activities of three-dimensional chitosan ring produced from the body segments of a diplopod(Elsevıer Scı Ltd, 2016) Kaya, Murat; Akyüz, Bahar; Bulut, Esra; Sargın, İdris; Tan, Gamze; Erdönmez, Demet; Maheta, Mansi; Satkauskas, SauliusCommercially available chitins and the chitin isolated from mushrooms, insect cuticles, shells of shrimp, crab and crayfish reported in the literature are in forms of powder, flake or granule. Three-dimensional chitins have been only known from the sponges but still three-dimensional chitosan has not been reported yet. In this study, we produced three-dimensional chitin and chitosan rings from the body segments of a diplopod species (Julus terrestris). Obtained chitin and chitosan rings were characterized (by FT-IR, SEM, TGA, XRD, dilute solution viscometry and EA) and compared with commercial chitin and chitosan. The interactions with plasmid DNA was studied at varying concentrations of chitosan (0.04, 0.4 and 4 mg/mL). Antitumor activity tests were conducted (L929 and HeLa), low cytotoxicity and high antiproliferative activity was observed. Antimicrobial activities of J. terrestris chitosan were investigated on twelve microorganisms and maximum inhibition (15.6 +/- 1.154 mm) was recorded for common human pathogen Staphylococcus aureus. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Effects of calcium silicate cements on neuronal conductivity(PMC, 2022) Sungur, Derya Deniz; Onur, Mehmet Ali; Akbay, Esin; Tan, Gamze; Dağlı Cömert, Fügen; Sayın, Taner CemObjectives: This study evaluated alterations in neuronal conductivity related to calcium silicate cements (CSCs) by investigating compound action potentials (cAPs) in rat sciatic nerves. Materials and methods: Sciatic nerves were placed in a Tyrode bath and cAPs were recorded before, during, and after the application of test materials for 60-minute control, application, and recovery measurements, respectively. Freshly prepared ProRoot MTA, MTA Angelus, Biodentine, Endosequence RRM-Putty, BioAggregate, and RetroMTA were directly applied onto the nerves. Biopac LabPro version 3.7 was used to record and analyze cAPs. The data were statistically analyzed. Results: None of the CSCs totally blocked cAPs. RetroMTA, Biodentine, and MTA Angelus caused no significant alteration in cAPs (p > 0.05). Significantly lower cAPs were observed in recovery measurements for BioAggregate than in the control condition (p < 0.05). ProRoot MTA significantly but transiently reduced cAPs in the application period compared to the control period (p < 0.05). Endosequence RRM-Putty significantly reduced cAPs. Conclusions: Various CSCs may alter cAPs to some extent, but none of the CSCs irreversibly blocked them. The usage of fast-setting CSCs during apexification or regeneration of immature teeth seems safer than slow-setting CSCs due to their more favorable neuronal effects.Öğe Green synthesis of silver nanoparticles using Allium cepa and Allium sativum extract: A comparative characterization study(Elsevier Science Bv, 2017) Tan, Gamze[Abstract Not Available]Öğe In vitro cytotoxicity of gold ions and gold nanoparticles on human bone marrow-derived mesenchymal stem cells(Elsevier, 2015) Tan, Gamze; Yaman, Melek; Oruklu, Nihan; Sağlam, Necdet; Bağrıaçık, Emin Ümit[Abstract Not Available]Öğe Inhibitory effects of Semaphorin 3F as an alternative candidate to anti-VEGF monoclonal antibody on angiogenesis(Springer New York LLC, 2019) Tan, GamzeVascular endothelial growth factor (VEGF) inhibition forms the basis for anti-angiogenic therapies. With the methods based on the monoclonal antibody-mediated typical VEGF blockade, pathological angiogenesis in the tumor microenvironment is inhibited and the limitation of tumor growth is provided; however, the existing tumor tissue cannot be intervened. In this study, the anti-angiogenic effects of Semaphorin (SEMA) 3F, which has frequently been reported to have tumor suppressive properties, on a chick chorioallantoic membrane model as well as in vitro cell-cell interactions were investigated and comparatively assessed using anti-VEGF antibody. Vascular endothelial cells and chick embryos were stimulated with 10–16 ng/mL VEGF165 prior to SEMA 3F administration in order to generate pathological vascularization conditions. Both in vitro and in ovo results revealed that SEMA 3F suppressed VEGF165-induced abnormal vascularization more effectively than anti-VEGF. Moreover, the required dose of SEMA 3F was significantly lower than that of anti-VEGF (103 times less under in ovo conditions). In light of these results, SEMA 3F is recommended as an important therapeutic agent for the prevention of pathological angiogenesis. SEMA 3F may offer an effective and efficient anti-angiogenic intervention that can be administered at a lower dose alternative to typical VEGF blocking agents.Öğe Investigation the potential use of silver nanoparticles synthesized by propolis extract as N-acyl-homoserine lactone-mediated quorum sensing systems inhibitor(TÜBİTAK, 2020) İlk, Sedef; Tan, Gamze; Emul, Ezgi; Sağlam, NecdetBackground/aim: Quorum sensing (QS) is a chemical communication process that bacteria use to regulate virulence. Inhibition of QS (antiQS) overcomes the pathogenicity of bacteria. Silver nanoparticles (AgNPs) have been used as antimicrobials against pathogens, but have not been used against QS-mediated bacterial infection. Also, studies have been carried out on the inhibitory effects of propolis based structures on pathogen growth, but no studies have been found on their potential use as QS inhibitor. The present study aims to investigate the synthesis and characterization of silver nanoparticles (AgNPs) reduced with propolis extract (P–AgNPs) and evaluation of their antimicrobial and, for the first time, antiQS activity. Materials and methods: P–AgNPs were synthesized using with different volumes (1, 2.5 and 5 mL) of propolis extract (PE) by biological method via reduction of silver nitrate. Synthesized P–AgNPs were characterized in terms of hydrodynamic, chemical, morphological, physical, and antioxidant properties. Disc diffusion and flask incubation assays were used to evaluate the antimicrobial effect against Gram–negative bacteria (Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella typhimurium, Enterobacter aerogenes, Pseudomonas aeruginosa) and Gram–positive bacteria (Staphylococcus aureus, Streptococcus mutans, Bacillus thuringiensis) and QS– regulated biofilm activity against biosensor strain Chromobacterium violaceum CV026. Results: AgNPs were successfully synthesized by biological method via PE. The violacein pigment production based on the QS system was greatly inhibited by the P–AgNPs (inhibition zones: 16.22-21.48 mm and violacein inhibition: 63.16 ± 2.4-75.24 ± 3.5 %) without interfering with the growth of bacteria, which is the first report on the antiQS effect of P–AgNPs. Conclusion: Our results suggest that P–AgNPs may be potentially used to inhibit bacterial physiological processes due to the signal molecules regulates important collective behavior of bacteria. The development of such nontoxic biomaterials may have great potential to evaluate for the new medicinal substance that inhibits the pathogenic biofilms.Öğe Photoacoustic analysis and imaging techniques: Sound of light(Taylor & Francis, 2018) Tan, GamzeAn unusual form of imaging and analysis applications combines optics and acoustics to probe the features and behaviors of materials. The name of photoacoustic like all other techniques of spectroscopy reveals underlying its theoretical basis. Even if the prefix "photo" makes sense for a spectroscopy, acoustic may be initially amazing. Photoacoustic technique is extension of the photothermal effect, which is based on light beam hitting the sample and altering its thermal status. More precisely, photoacoustic effect is a transformation between light, heat, and sound caused by light absorption. After the successful formulation of general theoretical model, photoacoustic technique, which initially was only used for the analysis of gas samples, has been efficiently extended to analysis of condensed matters. Variety of samples, nondestructive analysis and imaging, depth profiling, high specificity and sensitivity, analysis of opaque samples are the most important advantages of photoacoustic technique. As of today, many researchers have performed in vitro and in vivo analysis and imaging application using photoacoustic technique; moreover, increasing number of companies are manufacturing biomedical imaging devices based on this effect. If the obstacles to experimental restrictions are removed, we will begin to hear the sound of light as more powerfully in many applications, particularly physics, materials science, and medicine.Öğe Synthesis and characterization of silver nanoparticles integrated in polyvinyl alcohol nanofibers for bionanotechnological applications(TÜBİTAK, 2016) Tan, Gamze; Sağlam, Semran; Emül, Ezgi; Erdönmez, Demet; Sağlam, NecdetCharacterization and microbial growth activity of polyvinyl alcohol (PVA) nanofibers (NFs) produced by an electrospinning technique containing different amounts of silver nanoparticles (AgNPs) was investigated. AgNPs were synthesized by chemical reduction of silver nitrate (AgNO3 ) (in different weight ratios) in PVA solution followed by electrospinning to produce PVA/AgNPs NFs. The properties of PVA/AgNPs NFs were studied as a function of the silver content. The morphology and distribution of NFs and AgNPs were characterized by transmission and scanning electron microscopy. The size of NFs was 135–160 nm, and the size of AgNPs was 15–27 nm. TEM images clearly showed that spherical AgNPs were homogeneously integrated in PVA NFs. The microbial activity of NFs containing different amounts of AgNPs was examined against both Gram-negative (Pseudomonas aeruginosa and Escherichia coli) and Gram-positive (Bacillus megaterium and Staphylococcus aureus) bacteria and against Candida albicans. PVA NFs containing AgNPs exhibited increasing inhibitory effects against microbial pathogenic strains with increasing AgNPs amounts. The results suggest that PVA/AgNPs NFs could be used for wound dressing components, protective coatings, biomedical devices, and water purification.Öğe Toxic effects of gold nanoparticles and gold ions in human umbilical cord derived mesenchymal stem cells(Elsevier, 2015) Tan, Gamze; Sağlam, Necdet; Yaman, Melek; Oruklu, Nihan; Bağrıaçık, Emin Ümit[Abstract Not Available]
