Yazar "Yilmaz, Tulay" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Complex Structured Fluorescent Polythiophene Graft Copolymer as a Versatile Tool for Imaging, Targeted Delivery of Paclitaxel, and Radiotherapy
    (Amer Chemical Soc, 2016) Guler, Emine; Akbulut, Huseyin; Geyik, Caner; Yilmaz, Tulay; Gumus, Z. Pinar; Barlas, F. Baris; Ahan, Recep Erdem; Demirkol, Dilek Odaci; Yamada, Shuhei; Endo, Takeshi; Timur, Suna; Yagci, Yusuf
    Advances in polymer chemistry resulted in substantial interest to utilize their diverse intrinsic advantages for biomedical research. Especially, studies on drug delivery for tumors have increased to a great extent. In this study, a novel fluorescent graft copolymer has been modified by a drug and targeting moiety and the resulting structure has been characterized by alterations in fluorescent intensity. The polythiophene based hybrid graft copolymer was synthesized by successive organic reactions and combination of in situ N-carboxy anhydride (NCA) ring opening and Suzuki coupling polymerization processes. Initially, targeted delivery of the graft copolymer was investigated by introducing a tumor specific ligand, anti-HER2/neu antibody, on the structure. The functionalized polymer was able to differentially indicate HER2-expressing A549 human lung carcinoma cells, whereas no signal was obtained for Vero, monkey kidney epithelial cells, and HeLa, human cervix adenocarcinoma cells. After integrating paclitaxel into the structure, cell viability, cell cycle progression, and radiosensitivity studies demonstrate HER2/neu targeting polymers inhibit cell proliferation. Importantly, the graft copolymer used had no cytotoxic effects to cells, as evidenced by cell viability and cell cycle analysis. This work clearly confirms that a specially designed and fabricated graft copolymer with a highly complex structure is a promising theranostic agent capable of targeting tumor cells for diagnostic and therapeutic purposes.
  • Küçük Resim Yok
    Öğe
    Polypeptide with electroactive endgroups as sensing platform for the abused drug 'methamphetamine' by bioelectrochemical method
    (Elsevier Science Bv, 2016) Demir, Bilal; Yilmaz, Tulay; Guler, Emine; Gumus, Z. Pinar; Akbulut, Huseyin; Aldemir, Ebru; Coskunol, Hakan; Colak, Demet Goen; Cianga, Ioan; Yamada, Shuhei; Timur, Suna; Endo, Takeshi; Yagci, Yusuf
    Affinity-type sensors have emerged as outstanding platforms in the detection of diagnostic protein markers, nucleic acids and drugs. Thus, these novel platforms containing antibodies could be integrated into the monitoring systems for abused drugs. Herein, we established a novel detection platform for the analysis of a common illicit drug; methamphetamine (METH). Initially, a fluorescent-labeled polypeptide (EDOT-BTDA-Pala), derived from L-alanine N-carboxyanhydride (L-Ala-NCA) via ring-opening polymerization using 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)benzo[c][1,2,5]thiadiazole-5,6-diamine (EDOT-NH2-BTDA) as initiator, was employed as a glassy carbon electrode (GCE) covering host, in order to immobilize the METH selective antibody. Prior to the examination of analytical features, GCE/EDOT-BTDA-Pala/Antibody surface was successfully characterized in the way of electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy) and microscopic techniques (scanning electron microscopy and fluorescence microscopy). As for the analytical characterization, linearity and limit of detection (LOD) were found as 10-100 mu g/mL with an equation of y=0.0429x-0.2347, (R-2=0.996) and 13.07 mu g/mL, respectively. Moreover, sample application using artificial urine, saliva and serum samples spiked with METH (10, 25, 50 mu g/mL) were performed and LC-MS/MS system was used for further confirmation. The described platform can be adapted to monitor the other types of abused drugs by using suitably selected biorecognition elements.
  • Küçük Resim Yok
    Öğe
    Synthesis and application of a novel poly-L-phenylalanine electroactive macromonomer as matrix for the biosensing of 'Abused Drug' model
    (Royal Soc Chemistry, 2016) Yilmaz, Tulay; Guler, Emine; Gumus, Z. Pinar; Akbulut, Huseyin; Aldemir, Ebru; Coskunol, Hakan; Colak, Demet Goen; Cianga, Ioan; Yamada, Shuhei; Timur, Suna; Endo, Takeshi; Yagci, Yusuf
    Polypeptide-functionalized macromonomers are very fascinating candidates for the modification of various surfaces of different sizes as well as geometry, and have attracted considerable attention for biomolecule stabilization, biomedical device fabrication and bioanalytical applications. In the present work, synthesis and characterization of a novel poly-L-phenylalanine-bearing electroactive macromonomer (EDOT-BTDA-PPhe) were carried out. In the following steps, a glassy carbon electrode was covered with this material, and then cocaine aptamer was immobilized to obtain a biofunctional surface for the biosensing of ` Abused Drug' model. Aptamers attached to polypeptide side chains on the macromonomer with good orientation are induced for conformational change into three-way junction form as a result of selective binding of cocaine or its metabolite. This aptamer folding-based conformational response provides detectable signals due to formation of a compact interface which restricts electron transfer of redox probe. The stepwise modification of the surface was confirmed by electrochemical techniques. At the final step, the aptasensor was applied for the electrochemical detection of cocaine and its major metabolite, benzoylecgonine (BE), which exhibited a linear correlation between 1.0 and 10 nM and between 0.5 and 10 mu M respectively. The proposed methods were successfully employed for the analysis of synthetic biological fluids.