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Öğe Antibody purification from human plasma by metal-chelated affinity membranes(Wiley, 2012) Yavuz, Handan; Bereli, Nilay; Armutçu, Canan; Yılmaz, Fatma; Denizli, AdilThe aim of this study is to investigate in detail the feasibility of poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methyl ester), PHEMAH membranes for purification of immunoglobulin G (IgG) from human plasma. PHEMAH membranes were prepared by photo-polymerization technique. Then, Zn2+, Ni2+, Co2+, and Cu2+ ions were chelated directly on the PHEMAH membranes. Elemental analysis assay was performed to determine the nitrogen content and polymerized MAH was calculated as 168.5 mu mol/g. The nonspecific IgG adsorption onto the plain PHEMA membranes was negligible (about 0.25 mg/mL). A remarkable increase in the IgG adsorption capacities were achieved from human plasma with PHEMAH membranes (up to 68.4 mg/mL). Further increase was observed with the metal-chelated PHEMAH membranes (up to 118 mg/mL). The metal-chelate affinity membranes allowed the one-step separation of IgG from human plasma. The binding range of metal ions for surface histidines from human plasma followed the order: Cu2+ > Ni2+ > Zn2+ > Co2+. Adsorbed IgG was eluted using 250 mM EDTA with a purity of 94.1%. IgG molecules could be repeatedly adsorbed and eluted with the metal-chelated PHEMAH membranes without noticeable loss in their IgG adsorption capacity. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3476-3484, 2012Öğe Antibody Purification from Human Plasma by Metal-Chelated Affinity Membranes(Humana Press Inc, 2015) Yavuz, Handan; Bereli, Nilay; Yilmaz, Fatma; Armutcu, Canan; Denizli, AdilImmobilized metal ion affinity chromatography (IMAC) has been used for purification of proteins. IMAC introduces a new approach for selectively interacting biomolecules on the basis of their affinities for metal ions. The separation is based on different binding abilities of the proteins to the chelated metal ions on support. Here, N-methacryloyl-(L)-histidine methyl ester (MAH) is used as the metal-chelating ligand. Poly(hydroxyethyl methacrylate) Poly(HEMA) based membranes were prepared by photo-polymerization technique. Then, Zn2+, Ni2+, Co2+, and Cu2+ ions were chelated directly on the poly(HEMA-MAH) membranes for purification of immunoglobulin G (IgG) from human plasma.Öğe Electrochromatographic separation of hydrophobic amino acid enantiomers by molecularly imprinted capillary columns(Elsevier Sci Ltd, 2020) Şarkaya, Koray; Asır, Süleyman; Göktürk, Ilgım; Yılmaz, Fatma; Yavuz, Handan; Denizli, AdilIn the present study, the enantiomeric forms of hydrophobic amino acids (L-tryptophan, L-tyrosine, and L-phenylalanine) were separated by molecularly imprinted capillary columns (MICC) via Capillary Electrochromatography (CEC) for the first time. The monomer ratio, crosslinker ratio, template molecule ratio, the porogen ratio and type, polymerization time, and also the effect of temperature were examined to increase the permeability properties of MICC. FTIR, SEM and BET analyses were realized for the characterization of MICC. The effect of the electric field, organic solvent ratio, and pressure were carried out experimentally to determine the optimum conditions. The separation performances of MICC and the non-imprinted capillary columns (NICC) were compared electrochromatographically.Öğe Molecular imprinting of macromolecules for sensor applications(Mdpi, 2017) Saylan, Yeşeren; Yılmaz, Fatma; Özgür, Erdoğan; Derazshamshir, Ali; Yavuz, HandanMolecular recognition has an important role in numerous living systems. One of the most important molecular recognition methods is molecular imprinting, which allows host compounds to recognize and detect several molecules rapidly, sensitively and selectively. Compared to natural systems, molecular imprinting methods have some important features such as low cost, robustness, high recognition ability and long term durability which allows molecularly imprinted polymers to be used in various biotechnological applications, such as chromatography, drug delivery, nanotechnology, and sensor technology. Sensors are important tools because of their ability to figure out a potentially large number of analytical difficulties in various areas with different macromolecular targets. Proteins, enzymes, nucleic acids, antibodies, viruses and cells are defined as macromolecules that have wide range of functions are very important. Thus, macromolecules detection has gained great attention in concerning the improvement in most of the studies. The applications of macromolecule imprinted sensors will have a spacious exploration according to the low cost, high specificity and stability. In this review, macromolecules for molecularly imprinted sensor applications are structured according to the definition of molecular imprinting methods, developments in macromolecular imprinting methods, macromolecular imprinted sensors, and conclusions and future perspectives. This chapter follows the latter strategies and focuses on the applications of macromolecular imprinted sensors. This allows discussion on how sensor strategy is brought to solve the macromolecules imprinting.Öğe Molecularly Imprinted Quartz Crystal Microbalance Sensor (QCM) for Bilirubin Detection(Mdpi Ag, 2016) Çicek, Çiğdem; Yılmaz, Fatma; Özgür, Erdoğan; Yavuz, Handan; Denizli, AdilThis study aims the preparation of a QCM sensor for the detection of bilirubin in human plasma. Bilirubin-imprinted poly-(2-hydroxyethyl methacrylate-N-methacryloyl-l-tryptophan methyl ester) (PHEMATrp) nanofilm (MIP) on the gold surface of a QCM chip was synthesized by the molecular imprinting technique. Meanwhile, the non-imprinted PHEMATrp (NIP) nanofilm was synthesized by the same experimental technique to examine the imprinting effect. Characterization of MIP and NIP nanofilms on the QCM chip surface was achieved by atomic force microscopy (AFM), ellipsometry, Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR) and contact angle measurements (CA). The observations indicated that the nanofilm was almost in a monolayer. Thereinafter, the imprinted and the non-imprinted QCM chips were connected to the QCM system to investigate kinetic and affinity properties. In order to examine the selectivity of the MIP-PHEMATrp nanofilm, competitive adsorption of bilirubin with cholesterol and estradiol was performed. Limit of detection (LOD) and limit of quantitation (LOQ) values were calculated as 0.45 g/mL and 0.9 g/mL, respectively.Öğe Quartz crystal microbalance based biosensors for detecting highly metastatic breast cancer cells via their transferrin receptors(Royal Soc Chemistry, 2016) Atay, Seda; Pişkin, Kevser; Yılmaz, Fatma; Çakır, Canan; Yavuz, HandanA quartz crystal microbalance (QCM) biosensor was developed to detect highly metastatic breast cancer cells by functionalizing the gold sensor surface with transferrin attachment. MDA-MB 231 breast cancer cells with high and MCF 7 cells with low metastatic potential and transferrin expression were used. Serum starved MDA-MB-231 cells were used as control cells. First, poly(2-hydroxyethyl methacrylate) (PHEMA) nanoparticles were prepared by mini-emulsion polymerization of hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA). Nanoparticles were characterized with a zeta-sizer and then their suspension is dropped on the surface of the QCM and the dried QCM surface was modified further by activation with carbodiimide and transferrin attachment. The QCM biosensor was analyzed by using atomic force microscopy (AFM), ellipsometry, Fourier transform infrared spectrophotometry (FTIR) and contact angle measurements. The cells were applied to the derivatized QCM sensor to investigate the affinity and binding kinetics. The nanoparticles and transferrin were found to form a monolayer on the QCM surface. Binding kinetics were best fitted to the Langmuir-Freundlich adsorption model. The QCM signal was correlated well with the number of transferrin receptors on cells. It is concluded that the QCM biosensor functioning via transferrin receptor interactions may be used to detect breast cancer cells with high metastatic potential.Öğe Separation of histidine enantiomers by capillary electrochromatography with molecularly imprinted monolithic columns(Wiley-V C H Verlag Gmbh, 2020) Şarkaya, Koray; Aşır, Süleyman; Göktürk, Ilgım; Ektirici, Sisem; Yılmaz, Fatma; Yavuz, Handan; Denizli, AdilIn this study, we aimed to separate the enantiomeric forms of d,l-histidine, one of the essential amino acids, through molecular imprinted monolithic capillary electrochromatography columns prepared using hydrophobic N-methacryloyl-(l)-phenylalanine methyl ester as the functional monomer, and l-histidine as the template molecule. We investigated the effect of monomer ratio, temperature, template molecule mole ratio, crosslinker ratio, and porogen ratio to improve the permeability properties of the monolithic column. Characterization studies of the column were evaluated by attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer-Emmett-Teller analysis. The chromatographic performance of the column was investigated using alkylbenzene-derived compounds. We evaluated some parameters to determine the optimum conditions for electrochromatographic studies such as electric field, organic solvent ratio, and pressure effect. The calculated imprinting factor (2.18) proved that the l-histidine imprinted amino acid-based monolithic column separated d,l-histidine molecules efficiently (percent relative standard deviation < 1.5) from each other using molecular imprinting technique with high-resolution values (resolution value > 1.5). As a result, selective d,l-histidine separation was achieved in less than 10 min at pH 7.0 without using a ligand or extra modification step for the first time.Öğe Surface plasmon resonance sensors for medical diagnosis(Springer Berlin Heidelberg, 2018) Saylan, Yeşeren; Yılmaz, Fatma; Özgür, Erdogan; Derazshamshir, Ali; Bereli, Nilay; Yavuz, Handan; Denizli, AdilSurface plasmon resonance (SPR) sensors have fascinated impressive attention to detect clinically related analytes in recent years. SPR sensors have also multiple advantages over existing conventional diagnostic tools such as easy preparation, no requirement of labeling, and high specificity and sensitivity with low cost, and they provide real-time detection capability. There are some articles and reviews in literature focusing on the applications of SPR-based sensors for the diagnosis of medically important entities such as proteins, cells, viruses, disease biomarkers, etc. These articles generally give information on the determination of such structures merely, whereas this presented manuscript combines recent literature for most of the medically important structures together including proteins, hormones, nucleic acids, whole cells, and drugs that especially the latest applications of SPR sensors for medical diagnosis to follow up new strategies and discuss how SPR strategy is brought to solve the medical problems.
