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Topçu, Aykut Arif ( Aksaray, Yazar ) Yılmaz, Erkut ( Aksaray, Yazar ), Tailor-made Escherichia coli (E. coli) receptors were created with microcontact imprinted technique and binding events of E. coli were carried out by a surface plasmon resonance (SPR) sensor in aqueous solution and in urine mimic in real time and label-free. N-methacryloyl-(L)-histidine methyl ester (MAH) was selected as a functional monomer to design tailor-made E. coli receptors on the polymeric film and during the formation of the polymeric film on a chip surface, Ag nanoparticles (AgNPs) were entrapped into the polymer mixture in order to lower the detection limit of biomimetic SPR based sensor. The polymeric film was characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM), ellipsometer and contact angle measurements. Limit of detection (LOD) was found 0.57 CFU/mL and feasibility of the biomimetic sensor was investigated in urine mimic.

WOS: 000400822900032, PubMed: 28350333, Producing molecular imprinting-based materials has received increasing attention due to recognition selectivity, stability, cast effectiveness, and ease of production in various forms for a wide range of applications. The molecular imprinting technique has a variety of applications in the areas of the food industry, environmental monitoring, and medicine for diverse purposes like sample pretreatment, sensing, and separation/purification. A versatile usage, stability and recognition capabilities also make them perfect candidates for use in forensic sciences. Forensic science is a demanding area and there is a growing interest in molecularly imprinted polymers (MIPs) in this field. In this review, recent molecular imprinting applications in the related areas of forensic sciences are discussed while considering the literature of last two decades. Not only direct forensic applications but also studies of possible forensic value were taken into account like illicit drugs, banned sport drugs, effective toxins and chemical warfare agents in a review of over 100 articles. The literature was classified according to targets, material shapes, production strategies, detection method, and instrumentation. We aimed to summarize the current applications of MIPs in forensic science and put forth a projection of their potential uses as promising alternatives for benchmark competitors.

WOS: 000404553900191, PubMed: 28608810, Identification of pathogenic microorganisms by traditional methods is slow and cumbersome. Therefore, the focus today is on developing new and quicker analytical methods. In this study, a Surface Plasmon Resonance (SPR) sensor with a microcontact imprinted sensor chip was developed for detecting Salmonella paratyphi. For this purpose, the stamps of the target microorganism were prepared and then, microcontact S. paratyphi-imprinted SPR chips were prepared with the functional monomer N-methacryloyl-L-histidine methyl ester (MAH). Characterization studies of the SPR chips were carried out with ellipsometry and scanning electron microscopy (SEM). The real-time Salmonella paratyphi detection was performed within the range of 2.5 x 10(6)-15 x 10(6) CFU/mL. Selectivity of the prepared sensors was examined by using competing bacterial strains such as Escherichia coli, Staphylococcus aureus and Bacillus subtilis. The imprinting efficiency of the prepared sensor system was determined by evaluating the responses of the SPR chips prepared with both molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs). Real sample experiments were performed with apple juice. The recognition of Salmonella paratyphi was achieved using these SPR sensor with a detection limit of 1.4 x 10(6) CFU/mL. In conclusion, SPR sensor has the potential to serve as an excellent candidate for monitoring Salmonella paratyphi in food supplies or contaminated water and clearly makes it possible to develop rapid and appropriate control strategies.

WOS: 000394064800071, PubMed: 28183651, This 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., Ministry of Food, Agriculture and Livestock, of Republic of Turkey [TAGEM 12/AR-GE/35], This research has been carried out with supports from the Ministry of Food, Agriculture and Livestock, of Republic of Turkey with grant number TAGEM 12/AR-GE/35.

WOS: 000389909100106, PubMed ID: 27979281, Herein, we focused on developing a new generation of monolithic columns for extracting aflatoxin from real food samples by combining the superior features of molecularly imprinted polymers and cryogels. To accomplish this, we designed multiclonal plastic antibodies through simultaneous imprinting of aflatoxin subtypes B1, B2, G1, and G2. We applied Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and spectrofluorimetry to characterize the materials, and conducted selectivity studies using ochratoxin A and aflatoxin M1 (a metabolite of aflatoxin B1), as well as other aflatoxins, under competitive conditions. We determined optimal aflatoxin extraction conditions in terms of concentration, flow rate, temperature, and embedded particle amount as up to 25 ng/mL for each species, 0.43 mL/min, 7.0, 30 degrees C, and 200 mg, respectively. These multiclonal plastic antibodies showed imprinting efficiencies against ochratoxin A and aflatoxin M1 of 1.84 and 26.39, respectively, even under competitive conditions. Finally, we tested reusability, repeatability, reproducibility, and robustness of columns throughout inter- and intra- column variation studies, Ministry of Food Agriculture and Livestock, General Directorate of Agricultural Research and Policies [TAGEM/10/AR-GE/09], The study was financially supported by the Ministry of Food Agriculture and Livestock, General Directorate of Agricultural Research and Policies, grant number TAGEM/10/AR-GE/09.

WOS: 000407478900004, PubMed: 28322473, Diagnostic biomarkers such as proteins and enzymes are generally hard to detect because of the low abundance in biological fluids. To solve this problem, the advantages of surface plasmon resonance (SPR) and nanomaterial technologies have been combined. The SPR sensors are easy to prepare, no requirement of labelling and can be detected in real time. In addition, they have high specificity and sensitivity with low cost. The nanomaterials have also crucial functions such as efficiency improvement, selectivity, and sensitivity of the detection systems. In this report, an SPR-based sensor is developed to detect lysozyme with hydrophobic poly (N-methacryloyl-(L)-phenylalanine) (PMAPA) nanoparticles. The SPR sensor was first characterized by attenuated total reflection-Fourier transform infrared, atomic force microscope, and water contact angle measurements and performed with aqueous lysozyme solutions. Various concentrations of lysozyme solution were used to calculate kinetic and affinity coefficients. The equilibrium and adsorption isotherm models of interactions between lysozyme solutions and SPR sensor were determined and the maximum reflection, association, and dissociation constants were calculated by Langmuir model as 4.87, 0.019nM(-1), and 54nM, respectively. The selectivity studies of SPR sensor were investigated with competitive agents, hemoglobin, and myoglobin. Also, the SPR sensor was used four times in adsorption/desorption/recovery cycles and results showed that, the combination of optical SPR sensor with hydrophobic ionizable PMAPA nanoparticles in one mode enabled the detection of lysozyme molecule with high accuracy, good sensivity, real-time, label-free, and a low-detection limit of 0.66nM from lysozyme solutions. Lysozyme detection in a real sample was performed by using chicken egg white to evaluate interfering molecules present in the medium.

The 17β-estradiol (E2), natural steroid hormone, is one of the most potent endocrine disrupting compounds even at ng L−1 levels. Its rapid, selective and sensitive detection is intensively required. In this study, quartz crystal microbalance (QCM) sensor was prepared for real-time monitoring of E2 in water samples, through the attachment of E2 imprinted nanoparticles, synthesized by mini-emulsion polymerization, on the gold surface of QCM sensor. QCM sensor surface was characterized by atomic force microscopy (AFM), ellipsometer, and contact angle measurements. The specificity of the QCM nanosensor was shown by competitive adsorption of E2, stigmasterol and cholesterol. The results showed that QCM nanosensor has high selectivity and sensitivity for E2 even in a wide range of 3.67 nM–3.67 pM. The detection and quantification limits were calculated as 613 fM and 2.04 pM, respectively. According to the results, the proposed molecular imprinted QCM nanosensor is promising cost-friendly alternative for quantification of E2 from ground water. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1164–1169, 2013

Poly(hydroxyethyl methacrylate) (PHEMA) nanobeads with an average size of 300 nm in diameter and with a polydispersity index of 1.156 were produced by a surfactant free emulsion polymerization. Specific surface area of the PHEMA nanobeads was found to be 996 m 2 /g. Imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was used as a metal-chelating ligand. IMEO was covalently attached to the nanobeads. PHEMA-IMEO nanobeads were used for the removal of copper(II) ions from aqueous solutions. To evaluate the degree of IMEO loading, the PHEMA nanobeads were subjected to Si analysis by using flame atomizer atomic absorption spectrometer and it was estimated as 973 µmol IMEO/g of polymer. The PHEMA nanobeads were characterized by transmission electron microscopy and fourier transform infrared spectroscopy. Adsorption equilibrium was achieved in about 8 min. The adsorption of Cu 2+ ions onto the PHEMA nanobeads was negligible (0.2 mg/g). The IMEO attachment into the PHEMA nanobeads significantly increased the Cu 2+ adsorption capacity (58 mg/g). Adsorption capacity of the PHEMA-IMEO nanobeads increased significantly with increasing concentration. The adsorption of Cu 2+ ions increased with increasing pH and reached a plateau value at around pH 5.0. Competitive heavy metal adsorption from aqueous solutions containing Cu + , Cd 2+ , Pb 2+ and Hg 2+ was also investigated. The adsorption capacities are 61.4 mg/g (966.9 µmol/g) for Cu 2+ ; 180.5 mg/g (899.8 µmol/g) for Hg 2+ ; 34.9 mg/g (310.5 µmol/g) for Cd 2+ and 14.3 mg/g (69 µmol/g) for Pb 2+ . The affinity order in molar basis is observed as Cu 2+ > Hg 2+ > Cd 2+ > Pb 2+ . These results may be considered as an indication of higher specificity of the PHEMA-IMEO nanobeads for the Cu 2+ comparing to other ions. Consecutive adsorption and elution operations showed the feasibility of repeated use for PHEMA-IMEO nanobeads.

The aim of this study was to investigate the performance of monoliths composed of hydroxyethyl methacrylate (HEMA) to which N -methacryloyl-(L)-cysteine methyl ester (MAC) was polymerized for removal of heavy metal ions. Poly(HEMA-MAC) monolith was produced by bulk polymerization. Poly(HEMA-MAC) monolith was characterized by FTIR and scanning electron microscopy (SEM). The poly(HEMA-MAC) monolith with a swelling ratio of 89%, and containing 69.4 μmol MAC/g were used in the adsorption studies. Adsorption capacity of the monolith for the metal ions, i.e., Cu 2+ , Cd 2+ , Zn 2+ , Hg 2+ , and Pb 2+ were investigated in aqueous media containing different amounts of the ions (10–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(HEMA-MAC) monolith were 68.2 mg/g for Zn 2+ , 129.2 mg/g for Cu 2+ , 245.8 mg/g for Pb 2+ , 270.2 mg/g for Hg 2+ , and 284.0 mg/g for Cd 2+ . pH significantly affected the adsorption capacity of MAC incorporated monolith. The competitive adsorption capacities were 587 μmol/g for Zn 2+ , 1646 μmol/g for Cu 2+ , 687 μmol/g for Pb 2+ , 929 μmol/g for Hg 2+ , and 1993 μmol/g for Cd 2+ . The chelating monolith exhibited the following metal ion affinity sequence on molar basis: Cd 2+ > Cu 2+ > Hg 2+ > Pb 2+ > Zn 2+ . The formation constants of MAC–metal ion complexes have been investigated applying the method of Ruzic. The calculated values of stability constants were 5.28 × 10 4 L/mol for Cd 2+ , 4.16 × 10 4 L/mol for Cu 2+ , 2.27 × 10 4 L/mol for Hg 2+ , 1.98 × 10 4 L/mol for Pb 2+ , and 1.25 × 10 4 L/mol for Zn 2+ . Stability constants were increased with increasing binding affinity. The chelating monoliths can be easily regenerated by 0.1 M HNO 3 with higher effectiveness. These features make poly(HEMA-MAC) monolith a potential adsorbent for heavy metal removal.

WOS: 000349082200095, The detection of pathogenic bacteria is essential for a sustainable prevention of water quality and by this way prevention of life threatening illnesses. It is important to use rapid methods for pathogenic bacteria detection but traditional detection methods may take up to a whole week. In this report, we describe a molecular imprinting based bacteria sensor via whole cell imprinting for rapid detection of bacteria from water sources. Here, Escherichia coli (E. coli) is selected as model bacteria because of it is one of the most abundant pathogenic bacteria in ground water sources and may cause severe illnesses. The presence of E. coli in the water sources is an indicator of urban and agricultural runoffs, so monitoring E. coli contamination is important to preserve quality of the water sources. Traditional detection methods for E. coli include genomic analysis, antibody based assays, culture methods, fluorescence and microscopy. Disadvantages of traditional bacteria detection methods induce many researches on other detection methods like biosensors. In this study, a new label-free rapid and selective detection method was developed via micro contact imprinting of whole cell on both optical and mass sensitive devices. The amino acid based recognition element, N-methacryloyl-L-histidine methylester (a polymerizable form of histidine) was used in this study to obtain similar recognition as in natural antibodies., Ministry of Science, Industry and Technology of Republic of Turkey [1236.TGSD.2013]; Scientific and Technological Research Council (TUBITAK) of Republic of Turkey [2216], This research has been carried out with supports from the Ministry of Science, Industry and Technology of Republic of Turkey with grant number 1236.TGSD.2013 and 2216 program of Scientific and Technological Research Council (TUBITAK) of Republic of Turkey.

In this work, Cibacron Blue F3GA (CB) modified pencil graphite electrodes (PGEs) were prepared and their affinities to bovine serum albumin were investigated. Preparation of the PGEs was performed using cyclic voltammetry (CV) and passive adsorption techniques. Improved electrochemical results were obtained with the PGEs prepared by CV technique compared to the PGEs prepared by passive adsorption technique. In order to obtain more sensitive results number of scans used in CV technique and the effect of concentration of CB were studied. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) were used for the characterization of modified electrodes. The modified PGEs were then used for the electrochemical monitoring of affinity interaction between CB and bovine serum albumin. The effect of BSA concentration and interfering species (tryptophan, glucose and immunoglobulin G) on the response of the electrode were examined. The aim of this study was to prepare an easy, fast, stable and cheap modified electrode for the investigation of the well-known affinity of CB to serum albumin. The electrochemistry can provide alternative routes for dye-protein interaction instead of using classical time-consuming methods.

WOS: 000283804400082, PubMed ID: 20605089, The aim of this study is to prepare quartz crystal microbalance (QCM) nanosensor for the real-time detection of lysozyme. In the first part, the lysozyme imprinted (MIP) nanoparticles were prepared by mini-emulsion polymerization. The MIP nanoparticles were characterized by TEM, zeta-sizer and FTIR-ATR measurements. Particle size was found around 50 nm. The MIP nanoparticles were attached by dropping of nanoparticle solution to gold surface and then, dried at 37 degrees C for 6 h. QCM nanosensor was characterized with AFM and ellipsometer. The observations indicated that the nanoparticle film was almost monolayer. The detection limit was found as 1.2 ng/mL. The specificity of the QCM nanosensor was shown by using albumin as a competitor molecule. The results show that the QCM nanosensor has high selectivity and sensitivity with a wide range of lysozyme concentrations in both aqueous solutions (0.2-1500 mu g/mL) and natural sources (egg white) (460-1500 ng/mL)

Poly(hydroxyethyl methacrylate) (PHEMA) nanoparticles with an average size of 300 nm in diameter and with a polydispersity index of 1.156 were produced by surfactant free emulsion polymerization. Specific surface area of the PHEMA nanoparticles was found to be 996 m(2)/g. Metal-chelating ligand 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was covalently attached to the PHEMA nanoparticles. IMEO content was 0.97 mmol IEMO/g. The morphology and properties of these nanoparticles were characterized with scanning electron microscopy, Fourier transform infrared spectroscopy and atomic force microscopy. The Cu2+-chelated PHEMA-IMEO nanoparticles were used in the adsorption-elution studies of human serum albumin (HSA) in a batch system. Maximum HSA adsorption amount of the Cu2+ chelated nanoparticles was 680 mg HSA/g. The PHEMA-IMEO-Cu2+ nanoparticles exhibited a quite high adsorption capacity and fast adsorption rate due to their high specific surface area and the absence of internal diffusion resistance.

The aim of this study was to prepare magnetic beads that could be used for the removal of heavy-metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate-1-vinyl-1,2,4-triazole) [m-poly (EGDMA-VTAZ)] beads were produced by suspension polymerization in the presence of a magnetite Fe3O4 nanopowder. The specific surface area of the m-poly(EGDMAVTAZ) beads was 74.8 m(2)/g with a diameter range of 150-200 mu m, and the swelling ratio was 84%. The average Fe3O4 content of the resulting m-poly(EGDMA-VTAZ) beads was 14.8%. The maximum binding capacities of the m-poly (EGDMA-VTAZ) beads from aquous solution were 284.3 mg/g for Hg2+, 193.8 mg/g for Pb2+, 151.5 mg/g for Cu2+, 128.1 mg/g for Cd2+, and 99.4 mg/g for Zn2+. The affinity order on a mass basis was Hg2+ > Pb2+ > Cu2+ > Cd2+> Zn2+. The binding capacities from synthetic waste water were 178.1 mg/g for Hg2+, 132.4 mg/g for Pb2+, 83.5 mg/g for Cu2+, 54.1 mg/g for Cd2+, and 32.4 mg/g for Zn2+. The magnetic beads could be regenerated (up to ca. 97%) by a treatment with 0.1 M HNO3. These features make m-poly(EGDMA-VTAZ) beads potential supports for heavy-metal removal under a magnetic field. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 2246-2253, 2009

Rheumatoid arthritis is characterized by chronic polyarthritis and destruction of multiple joints. In this study, poly(hydroxyethyl methacrylate-N-methacryloyl-(L-histidine)-methylester) (PHEMAH) beads were used in the removal of pathogenic antibodies from rheumatoid arthritis patient plasma in a packed bed column. PHEMAH beads, in the size range of 80-120 mum, were produced by suspension polymerization. The beads were contacted with blood in an in vitro system. Loss of blood cells and clotting times were followed. PHEMAH beads were characterized by scanning electron microscopy. We found that PHEMAH beads had a spherical shape and porous structure. Loss of cells in the blood contacting with PHEMAH beads was negligible. IgM-antibody adsorption capacity decreased significantly with the increase of the plasma flow-rate. With increasing IgM-antibody concentration, the amount of IgM-antibody adsorbed per unit mass increased and then reached saturation. Maximum IgM-antibody adsorption amount was 69.2 mg/g. IgM-antibody molecules could be repeatedly adsorbed and desorbed without noticeable loss in the IgM-antibody adsorption amount.