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Öğe Indian saffron - Turmeric (Curcuma longa) embedded supermacroporous cryogel discs for heavy metal removal(Biointerface Research Applied Chemistry, 2019) Aslıyüce, Sevgi; Bereli, Nilay; Topçu, Aykut; Ramteke, Pramod W.; Denizli, AdilCryogels are used in a variety of environmental and biotechnological processes. Cryogels are polymeric materials with large pores and open flow channels. Turmeric is a very popular spice, especially in India, which has been shown to contain curcumin alkaloids to treat a variety of many diseases. Playing a protective and therapeutic role against the diseases results from being able to bind to various targets. In this study, Indian saffron (Turmeric) embedded poly(2-hydroxyethyl methacrylate) cryogel discs (Tur-PHEMA/CDs) have been prepared to remove heavy metal ions from waste-water, which is a major environmental problem by utilizing the heavy metal binding property of turmeric. Tur-PHEMA/CDs were used to remove Cu(II), Pb(II), Cd(II) ions. Poly(2-hydroxyethyl methacrylate) cryogel discs (PHEMA/CDs) were also used as control polymer. The prepared cryogels are characterized by multiple experimental tests. The Tur-PHEMA/CDs and PHEMA/CDs with respectively swelling ratio of 83.6% and 71.2% were used in heavy metal ions adsorption studies. pH values of the solution were changed in the range of 3.0-6.0 to determine optimum pH. Maximum adsorption capacities of the Tur-PHEMA/CDs from aqueous solution were 18.36 mg/g for Cu(II), 8.99 mg/g for Pb(II) and 5.76 mg/g for Cd(II). The affinity order of heavy metal ions on mass basis was Cu(II) > Pb(II) > Cd(II) from synthetic wastewater. EDTA solution (0.5 M) was used for desorbing of heavy metal ions.Öğe Nanobiosensors for mycotoxins detection in foodstuff: Qualitative and quantitative assessments(Elsevier, 2024) Çalışır, Merve; Özgür, Erdoğan; Çimen, Duygu; Topçu, Aykut Arif; Erkek, Muhammed; Bereli, Nilay; Denizli, AdilMycotoxins are naturally toxic compounds with low molecular weight and formed as a result of the secondary metabolism of fungi (mold) species. Since they are harmful to many living organisms, cost-effective, sensitive, and reliable detection methods are crucial for preventing the unwanted side effects of these toxic metabolites. Enzyme-linked immunoassay (ELISA), chromatographic methods like thin layer chromatography (TLC), and biosensors are often used as analytical approaches for the detection of mycotoxins. In this context, we summarized the traditional methods for mycotoxin detection and focused on the potential use of nanobiosensor platforms for mycotoxin sensing in foodstuffs.Öğe Plastic antibody based surface plasmon resonance nanosensors for selective atrazine detection(Elsevier, 2017) Yılmaz, Erkut; Özgür, Erdoğan; Bereli, Nilay; Türkmen, Deniz; Denizli, AdilThis study reports a surface plasmon resonance (SPR) based affinity sensor system with the use of molecular imprinted nanoparticles (plastic antibodies) to enhance the pesticide detection. Molecular imprinting based affinity sensor is prepared by the attachment of atrazine (chosen as model pesticide) imprinted nanoparticles onto the gold surface of SPR chip. Recognition element of the affinity sensor is polymerizable form of aspartic acid. The imprinted nanoparticles were characterized via FTIR and zeta-sizer measurements. SPR sensors are characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectrophotometry (FTIR) and contact angle measurements. The imprinted nanoparticles showed more sensitivity to atrazine than the non-imprinted ones. Different concentrations of atrazine solutions are applied to SPR system to determine the adsorption kinetics. Langmuir adsorption model is found as the most suitable model for this affinity nanosensor system. In order to show the selectivity of the atrazine-imprinted nanoparticles, competitive adsorption of atrazine, simazine and amitrole is investigated. The results showed that the imprinted nanosensor has high selectivity and sensitivity for atrazine. (C) 2016 Elsevier B.V. All rights reserved.Öğe Poly(Hydroxyethyl methacrylate) immunoaffinity cryogel column for the purification of human immunoglobulin M(MDPI Multidisciplinary Digital Publishing Institute, 2020) Bakhshpour, Monireh; Topçu, Aykut Arif; Bereli, Nilay; Alkan, Hüseyin; Denizli, AdilHuman immunoglobulin M (hIgM) antibodies are considered as hopeful tools for diseases therapy. Therefore, chromatography approaches are used to purify hIgM with a single step. In this study, we prepared a poly(hydroxyethyl methacrylate) based immunoaffinity p(HEMA-I) cryogel column by using cyanamide to immobilize antihuman immunoglobulin on the p(HEMA) cryogel for purification of hIgM in aqueous solution and artificial human plasma. The characterization of the p(HEMA) cryogel column was performed by using a scanning electron microscope (SEM), micro-computerized tomography (µ-CT), Fourier transform infrared spectroscopy (FTIR), swelling degree and macro-porosity. Further, the optimizations of various parameters were performed such as, pH, ionic strength, temperature and concentration of hIgM in aqueous solutions. In addition, the Langmuir adsorption model was supported by experimental results. Maximum adsorbed amount of hIgM corresponded to 11.1 mg/g at pH 5.75 [morpholino ethanesulfonic acid (MES buffer)]. Our results indicated that the p(HEMA-I) cryogel column can be reused at least 10 times without significant loss in adsorption capacity. As a natural source, artificial human plasma was selected for hIgM adsorption and the purity of hIgM was evaluated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Öğe Preparation of cryogel columns for depletion of hemoglobin from human blood(Taylor & Francis, 2016) Derazshamshir, Ali; Baydemir, Gözde; Yılmaz, Fatma; Bereli, Nilay; Denizli, AdilIn this study, we aimed to prepare the metal chelate affinity cryogels for the hemoglobin (Hb) depletion. Poly(2-hydroxyethyl methacrylate) (PHEMA) cryogels were selected as base matrix because of their blood compatibility, osmotic, chemical, and mechanical stability. Cryogels are also useful when working with the viscous samples such as blood, because of their interconnected macroporous structure. Iminodiacetic acid (IDA), the chelating agent, was covalently coupled with PHEMA cryogels after activation with the epichlorohydrin and then the Ni(II) ions were chelated to the IDA-bound cryogels. The depletion of the Hb from hemolysate was shown by SDS-PAGE.Öğe Protein C recognition by ion-coordinated imprinted monolithic cryogels(Wiley-VCH, 2017) Demirci, Binnaz; Bereli, Nilay; Aslıyüce, Sevgi; Baydemir, Gözde; Denizli, AdilThe protein C imprinted monolithic cryogel was synthesized using 2-hydroxyethyl methacrylate by redox cryo-polymerization method. The prepared monolithic cryogel was characterized by Fourier transform infrared spectroscopy, swelling test, surface area measurements, and scanning electron microscopy. The nonimprinted cryogel was prepared as well for control. Adsorption of protein C from aqueous solutions was investigated in a continuous mode and several parameters affecting adsorption performance were optimized. The maximum protein C adsorption amount was 30.4 mg/g. The selectivity studies were performed by monolithic column studies and fast protein liquid chromatography, using hemoglobin and human serum albumin as competing proteins. The relative selectivity coefficients were 2.37 and 8.89 for hemoglobin and human serum albumin, respectively. Reusability was tested for ten consecutive adsorption-desorption cycles, and no significant change in adsorption capacity was recorded. A pseudo-second-order model was suitable to interpret kinetic data, and the Langmuir model suited the adsorption isotherms well.Öğe Real time monitoring and label free creatinine detection with artificial receptors(ELSEVIER SCIENCE BV, 2019) Topçu, Aykut Arif; Özgür, Erdo?an; Yılmaz, Fatma; Bereli, Nilay; Denizli, AdilMolecular imprinting technique is used to design artificial creatinine receptor on the gold surface of surface plasmon resonance (SPR) chip using N-methacryloyl-(L)-histidine methyl ester (MAH), as a functional monomer. Surface characterization of SPR sensor chip is performed with atomic force microscope (AFM), ellipsometry and contact angle measurements. Creatinine imprinted SPR sensor is characterized with a linear range between 1 and 100 mM and limit of detection (LOD) and limit of quantification (LOQ) of creatinine are found 57 mu M and 190 mu M, respectively. N-hydroxysuccinimide (NHS) and creatine molecules are selected to examine the selectivity of creatinine imprinted SPR sensor. Reusability studies of SPR sensor is determined in urine mimic samples.Öğe Surface plasmon resonance sensors for medical diagnosis(Springer Berlin Heidelberg, 2018) Yeşeren, Saylan; Yılmaz, Fatma; Özgür, Erdoğan; Derazshamshir, Ali; Bereli, Nilay; Yavuz, Handan; Denizli, Adil[No abstract available]Öğe Surface plasmon resonance-based immunosensor for igm detection with gold nanoparticles(MDPI, 2021) Bereli, Nilay; Bakhshpur, Monireh; Topçu, Aykut Arif; Denizli, AdilIn this work, a surface plasmon resonance (SPR) based immunosensor was prepared by the immobilization of the amine-functionalized gold nanoparticles (N-AuNPs) on the sensing surface to sense immunoglobulin M (IgM) antibodies in the aqueous solution and artificial plasma. The characterization studies of SPR based immunosensor for IgM detection were performed with scanning electron microscope (SEM), contact angle measurements, and ellipsometry. Kinetic studies for the IgM immunosensor were carried out in the range of 1.0 to 200 ng/mL IgM concentrations in an aqueous solution. The total IgM analysis time including adsorption, desorption, and regeneration cycles was nearly 10 min for the prepared immunosensor. The limit of detection (LOD) and limit of quantification (LOQ) were found as 0.08 and 0.26 ng/mL, respectively. The reusability of the proposed immunosensor was tested with 6 consecutive adsorption-desorption, and regeneration cycles. Also, enzyme-linked immunosorbent assay (ELISA) method was utilized in the validation of the immunosensor.
