Yazar "Odaci D." seçeneğine göre listele
Listeleniyor 1 - 11 / 11
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Bacterial sensors based on chitosan matrices(2008) Odaci D.; Timur S.; Telefoncu A.Bacterial cells were entrapped together with chitosan matrix onto the surface of graphite electrode to form microbial biosensors. Two types of bacterial sensors were constructed by using Pseudomonas fluorescens (Pseudomonas putida DSM 6521) and P. putida DSM 50026 cells as the biological components and the measurements were based on the respiratory activity of the cells. Carbon nanotube (CNT)-modified chitosan membrane was also prepared to test nanoparticle effect on the efficiency of biosensor performances. As well as the response characteristics, stabilities and substrate specificities were investigated. Data were given as the comparison of CNT-modified and -unmodified systems. © 2008 Elsevier B.V. All rights reserved.Öğe Construction and comparison of trametes versicolor laccase biosensors capable of detecting xenobiotics(2010) Sezgintrk M.K.; Odaci D.; Pazarliolu N.; Pilloton R.; Dinçkaya E.; Telefoncu A.; Timur S.Amperometric biosensors using laccase from Trametes versicolor as a bioelement were developed for 2,4-dichloro phenoxy acetic acid (2,4-D). Laccase enzyme was immobilized by gelatin and glutaraldehyde onto a Clark oxygen probe and screen printed electrodes (SPEs). Amperometric and chronoamperometric measurements were carried out with the biosensors. First, the effect of laccase activity on the biosensor performances was investigated for both biosensors, and then optimum pH and temperature and also thermal stability of the biosensors were tested. In addition, the detection ranges of some phenolic compounds were obtained by the help of calibration graphs of them. In repeatability studies, variation coefficients and standard deviations for both biosensors were also calculated by the studies done for this purposes. Finally, the biosensors were applied to the determination of 2,4-D in a real herbicide sample. © 2010 Informa UK Ltd.Öğe Design and application of a sol-gel based fluorescent glucose arrays [Sol-gel tabanli floresans glukoz arrayleri'nin hazirlanmasi ve uygulamalari](2009) Yildirim N.; Odaci D.; Öztürk G.; Alp S.; Ergun Y.; Feller K.-H.; Dornbusch K.; Timur S.Here we present a new sol-gel based fluorescent glukoz biosensor. The sensor is based on the pH sensitive fluorescent dye entrapped in a tetraethoxysilane (TEOS) based sol-gel together with glukoz oxidase. Micro-analytic sustem which can measure the pH induced chance in the fluorescens intensity due to the enzymatic reaction in spotted layer on the glass surface was used as a measuring system. The system was calibrated to glukoz. As well as characterization, glukoz biosensing in such fruit juice samples were carried out. ©2009 IEEE.Öğe Detection of toxic metals using nanostructured biosensing platforms(Elsevier, 2023) Alhardan R.; Kilic N.M.; Cevher S.C.; Soylemez S.; Odaci D.; Kurbanoglu S.Toxic metals accumulate in living things without any degradation or catabolism. Trace elements are necessary for the continuation of life’s activities. Toxic and trace element levels in all living things in the biological system interact and correlate with each other due to exposure to heavy metals caused by environmental pollution. On the other hand, it is known that trace elements and toxic metals compete with each other in the stages of absorption, distribution, and accumulation in mammals. In recent years, the importance of heavy metals in public health has increased as a result of technological development all over the world. Especially the deterioration of the food chain caused by environmental pollution and heavy metal contamination has increased the need to control the use of metals. Moreover, improving the quality of life is one of the most important goals of global research efforts. Naturally, quality of life is closely related to disease control, food quality and safety, and the quality of our environment. A continuous, fast, and precise monitoring system is needed to control critical parameters in all these areas. In this context, biosensors combine a biological recognition element with a suitable transducer. This article attempts to discuss the design, characterization, reliability tests, and usability of biosensors, which were prepared quickly and cost-effectively and developed for the analysis of toxic metals in water, soil, and agricultural products, as well as from biological samples. Further, the description of some important toxic metals and the types of nanomaterials used as a detection platform were also considered. The review mainly focuses on the application of nanostructured biosensing platforms for toxic metal detections, their advantages and disadvantages, and offers a roadmap for future development to improve their usefulness in pollution monitoring. In light of this, this chapter will provide an overview of different types of biosensors being used, ranging from different electrochemical tags and nanomaterials for various biomedical and environmental applications, with an outlook on biosensor technology. © 2024 Elsevier Inc. All rights reserved.Öğe Electrochemical glucose biosensing by pyranose oxidase immobilized in gold nanoparticle-polyaniline/AgCl/gelatin nanocomposite matrix(2010) Ozdemir C.; Yeni F.; Odaci D.; Timur S.A novel pyranose oxidase (PyOx) biosensor based on gold nanoparticles (AuNPs)-polyaniline(PANI)/AgCl/gelatin nanocomposite has been developed for the glucose detection. PyOx was immobilized on the surface of glassy carbon electrode (GCE) via the nanocomposite matrix. The electrode surface was imaged by scanning electron microscopy (SEM). Amperometric detection of the consumed oxygen during the enzymatic reaction was monitored at -0.7 V. After optimization studies, analytical characterization of the biosensor was carried out. The linear response of the AuNPs-AgCl/PANI/gelatin modified PyOx biosensor is found to be from 0.05 to 0.75 mM glucose with the equation of y = 2.043x + 0.253; R2 = 0.993. Finally, proposed biosensor was used to analyze glucose content in real samples. Obtained data from the biosensing system was compared with a commercial enzyme assay kit based on spectrophotometric Trinder reaction as a reference method. © 2009 Elsevier Ltd. All rights reserved.Öğe Maltose biosensing based on co-immobilization of ?-glucosidase and pyranose oxidase(2010) Odaci D.; Telefoncu A.; Timur S.A new bi-enzymatic system was designed by co-immobilization of ?-glucosidase (AG) and pyranose oxidase (PyOx) for maltose analysis. The immobilization was carried out by cross-linking enzyme mixture, chitosan (CHIT) and carbon nanotube (CNT) via glutaraldehyde. The structure of biosensor including enzyme, CHIT, glutaraldehyde and CNT amount together with operational conditions like pH, temperature and applied potential were optimized. Then analytical characterization was performed. A fast linear response of the biosensor was observed for maltose in the concentration range from 0.25 to 2.0 mM at 35 °C and pH 6.0. The effect of CNT addition into the immobilization matrix was also investigated. The linear relationships between sensor response (y; µA/cm2) and substrate concentration (x; mM) were defined by the equations of y = 0.844x + 0.029 (R2 = 0.999) and y = 0.882x + 0.0625 (R2 = 0.996) for AG/PyOx/CHIT and AG/PyOx/CHIT-CNT biosensors, respectively. All other data were also given as comparison of two systems one with CNT-modified and CNT-free. Finally, for the sample application, maltose was analyzed in beer samples. As a result, it has been found that; complex matrix of natural beer samples had no influence on the biosensing response. Also the results were in good agreement with those obtained by spectrophotometric measurements. © 2009 Elsevier B.V. All rights reserved.Öğe A new approach for in vitro imaging of breast cancer cells by anti-metadherin targeted PVA-pyrene(Wiley-VCH Verlag, 2010) Medine E.I.; Odaci D.; Gacal B.N.; Gacal B.; Sakarya S.; Unak P.; Timur S.; Yagci Y.Poly(vinyl alcohol)-pyrene-anti-metadherin (PVA-Py-(Anti-MTDH)), a novel antibody based water soluble probe containing both fluorescent and target sites in the structure for in vitro imaging of breast cancer cells is reported here. Since breast cancer cells have an excess of MDTH protein expressed on the surface, a PVA-Py prepared by "Click chemistry" approach is targeted by Anti-MTDH antibody and applied to the MCF-7 cell line. After characterization, the designed architecture was evaluated in terms of cell incorporation efficiency and compared with a non-targeted structure (PVA-Py). Atomic force microscopy (AFM) and fluorescence microscopy images of cells after incubation of the probe molecules were also obtained to monitor the interaction of the probes with the cancerous cells. (Figure Presented). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.Öğe Pyranose oxidase biosensor based on carbon nanotube (CNT)-modified carbon paste electrodes(2008) Odaci D.; Telefoncu A.; Timur S.Pyranose oxidase (POx) biosensor based on carbon nanotube (CNT)-modified carbon paste electrode (CNTPE) was developed and characterized using glucose as a substrate. As well as, POx-CNTPEs, unmodified carbon paste electrodes (POx-CPE) were also prepared to examine the effect of CNT addition to the efficiency of the biosensing system and results were given as a comparison of two systems. Apart from analytical characterization, optimization studies and stability tests were carried out. Finally, proposed systems were applied to glucose analysis in wine samples. © 2008 Elsevier B.V. All rights reserved.Öğe Recent advances in development of surfactant-based electrochemical sensors and biosensors(Elsevier, 2024) Kilic N.M.; Alhardan R.; Kurbanoglu S.; Odaci D.Surfactants are widely used chemical compounds with hydrophobic and hydrophilic groups, playing indispensable roles in various daily life applications. Biosurfactant technology contributes to sustainable advancements in industries like bioremediation, health, food processing, and cosmetics. Surfactants can be categorized into anionic, cationic, nonionic, and amphoteric, with anionic surfactants being the most widely used. Surfactant-based electrochemical techniques have gained importance for their benefits. These techniques are being highly used in electrochemical biosensors to accelerate electron transfer and enhance analyte adsorption. The use of amphiphilic ionic surfactants in liquid membrane-type sensors has shown promising results, with solid-state surfactant sensors being a recent exception. In biomedicine and pharmaceutical analysis, surfactant-based electrochemical biosensors have found a lot of applications for detecting diverse biomolecules with high sensitivity and selectivity. © 2024 Elsevier Inc. All rights reserved.Öğe Use of a thiophene-based conducting polymer in microbial biosensing(2008) Odaci D.; Kiralp Kayahan S.; Timur S.; Toppare L.Immobilization of whole viable Pseudomonas fluorescens cells was achieved on a graphite electrode modified with a thiophene-based conducting polymer. Microbial electrodes were constructed by the entrapment of bacterial cells on conducting copolymer matrix using a dialysis membrane. The biosensor was characterized using glucose as the substrate. As well as analytical characterization, effects of electropolymerization time, pH and temperature on the sensor response were examined. Finally, operational stability was also tested. © 2008 Elsevier Ltd. All rights reserved.Öğe Use of eggshell membrane as an immobilization platform in microbial sensing(2008) Yeni F.; Odaci D.; Timur S.A new microbial biosensor was developed by immobilizing Pseudomonas fluorescens cells on eggshell membrane via physical adsorbtion. Bacteria-modified eggshell membrane was fixed tightly onto the surface of a carbon paste electrode (CPE) with a silicone rubber o-ring to construct a microbial biosensor. The measurements were based on the respiratory activity of the cells caused by oxygen consumption during bacterial metabolism. A mediated biosensor was also developed by ferrocene. As well as the response characteristics, stabilities and substrate specificities were investigated. Data were given as the comparison of mediated and unmediated systems. Copyright © Taylor & Francis Group, LLC.
