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    A highly sensitive and selective electrochemical sensor based on computer-aided design of molecularly imprinted polymer for the determination of leflunomide
    (Elsevier, 2022) Cetinkaya, Ahmet; Kaya, S. Irem; Corman, M. Emin; Karakaya, Mustafa; Atici, Esen Bellur; Ozkan, Sibel A.
    This study includes the electrochemical analysis of leflunomide (LEF), used in the treatment of rheumatoid arthritis, with a molecularly imprinted polymer (MIP) based sensor using different electroanalytical methods. In the design of MIPs, the choice of functional monomer is an important step in terms of the stability of the sensor. Based on the computational approach in this study, ortho-phenylenediamine (o-PD) was chosen as a functional monomer based on the comparison of interaction energies (delta E) between LEF and monomers, aniline (ANI) was chosen as a platform to develop MIP-based sensor. Morphological characterization of the developed p(ANI-o-PD) @MIP/GCE sensor was performed using Raman spectroscopy, surface electron microscopy (SEM), contact angle measurements, and electrochemical techniques. Quantitative analysis of LEF was performed using differential pulse voltammetry. Results showed that the p(ANI-o-PD)@MIP/GCE sensor has high selectivity and sensitivity. Under optimum conditions, the linear range was found to be 1 - 10 fM (r = 0.998) and the detection limit to be 0.291 fM. Also, the sensor was applied to pharmaceutical dosage form and serum samples to detect LEF, and satisfactory recovery results of 99.46% and 99.15% were obtained. Finally, the p(ANI-o-PD)@MIP/GCE sensor was evaluated using a non-imprinted polymer (NIP)-based electrochemical sensor. The proposed sensor with good reproducibility was effectively implemented for selective and sensitive detection of LEF in pharmaceutical and human serum samples. These results show that the molecular imprinting approach in detecting LEF is a highly effective technique in the potential of the newly developed sensor.
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    Öğe
    A porous molecularly imprinted nanofilm for selective and sensitive sensing of an anticancer drug ruxolitinib
    (Elsevier, 2021) corman, M. Emin; Cetinkaya, Ahmet; Ozcelikay, Goksu; Ozgur, Erdogan; Atici, Esen B.; Uzun, Lokman; Ozkan, Sibel A.
    A novel methodology has been applied to generate a porous molecularly imprinted material for highly selective and sensitive recognition of Janus kinase inhibitor ruxolitinib (RUX). The porous material-based nucleobase-derivative functional monomer was developed by a photopolymerization method. The thymine methacrylate (ThyM) as a functional monomer was synthesized and copolymerized with 2hydroxyethyl methacrylate (HEMA) in the presence of ethylene glycol dimethacrylate (EGDMA) onto the glassy carbon electrode [glassy carbon electrode/molecularly imprinted polymer@poly(2hydroxyethyl methacrylate-co-thymine methacrylate), (GCE/MIP@PHEMA-ThyM)] for the first time. The presence of ThyM results in the functional groups in imprinting binding sites, while the presence of poly(vinyl alcohol) (PVA) allows to generate porous materials for sensitive sensing. The characterization of GCE/MIP@PHEMA-ThyM was investigated by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy technique. Then, the porous MIP modified glassy carbon electrode was optimized with effecting parameters including removal agent, removal time, and incubation time to get a better response for RUX. Under well-controlled optimum conditions, the GCE/MIP@PHEMA-ThyM linearly responded to the RUX concentration up to 0.01 pM at the limit of detection (LOD) of 0.00191 pM. The non-imprinted polymer (NIP) was also prepared to serve as a control in the same way but without the template. The proposed method improves the accessibility of binding sites by generating the porous material resulting in highly selective and sensitive recognition of drugs in the pharmaceutical dosage form and synthetic human serum samples. (c) 2021 Elsevier B.V. All rights reserved.
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    Computational design and fabrication of a highly selective and sensitive molecularly imprinted electrochemical sensor for the detection of enzalutamide
    (Elsevier Science Sa, 2022) Kaya, S. Irem; Cetinkaya, Ahmet; Ozcelikay, Goksu; Corman, M. Emin; Karakaya, Mustafa; Atici, Esen Bellur; Ozkan, Sibel A.
    This study demonstrates the first electrochemical analysis of an anti-androgen drug enzalutamide with a molecularly imprinted polymer (MIP)-based sensor. An electrochemical sensor was developed through computational approaches for screening functional monomers in the rational design of MIPs. Based on the computational approach, ortho-phenylenediamine (o-PD) was selected as a functional monomer based on the comparison of interaction energies (Delta E) between enzalutamide and monomers. The characterization of the MIP-based sensor was investigated by Raman spectroscopy, surface electron microscopy (SEM), contact angle measurements, and electrochemical techniques. Different electrochemical techniques such as differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were utilized for the evaluation of MIP parameters (removal process, incubation time, monomer ratio etc.). MIP@ANI-co-o-PD/GCE showed a linear response in the concentration range between 1 x 10(-16) M and 1 x 10(-15) M with the limit of detection (LOD) and limit of quantification (LOQ) values of 0.019 fM and 0.065 fM, respectively. The application studies from human serum and pharmaceutical dosage form samples were concluded with good recovery results demonstrating the sensor's applicability, selectivity, precision, and accuracy. Furthermore, selectivity studies were carried out with similarly structured compounds teriflunomide and leflunomide. Lastly, the non-imprinted polymer (NIP) based electrochemical sensor was prepared and used for the performance evaluation of the MIP@ANI-co-o-PD/GCE sensor.