Yazar "Onur, Mehmet Ali" seçeneğine göre listele

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    Anti-proliferative effects of gold nanoparticles functionalized with Semaphorin 3F
    (Springer, 2017) Tan, Gamze; Onur, Mehmet Ali
    The 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.
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    Cellular localization and biological effects of 20nm-gold nanoparticles
    (Wiley, 2018) Tan, Gamze; Onur, Mehmet Ali
    Gold 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.
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    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]
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    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, Beatriz
    The 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.
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    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 Cem
    Objectives: 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.