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  • Küçük Resim
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    Design of an electrochemical sensing platform based on MoS2-PEDOT:PSS nanocomposite for the detection of epirubicin in biological samples
    (Elsevier Inc., 2023) Er, Engin; Ateş, Ali Kemal
    Synthesizing of two dimensional (2D)-based nanomaterial and its sensing platform design is an attractive approach for quantitative purposed electrochemical applications. In this work, for the first time, we synthesized the molybdenum disulphide (CE-MoS2) nanosheets exfoliated by metal intercalation method and followed by the modification of their surfaces with Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as a conductive polymer. The structural, morphological, and electrochemical characterization of CE-MoS2/PEDOT: PSS nanocomposite were performed by XPS, TGA, TEM and EIS. The portable electrochemical sensing platform was fabricated by the modification of CE-MoS2/PEDOT:PSS nanocomposite on screen-printed carbon electrode (SPCE). The electrochemical behaviour of epirubicin (EPB) was examined on SPCE modified with CE-MoS2/ PEDOT:PSS nanocomposite using cyclic and differential pulse voltammetry. CE-MoS2/PEDOT:PSS/SPCE demonstrated a promising electrocatalytic activity towards the oxidation of EPB, and analytical performance in the concentration range of 0.06 – 9.30 µM with a low detection limit of 44.3 nM. The human plasma samples containing EPB were successfully analyzed using CE-MoS2/PEDOT:PSS/SPCE with the satisfactory recoveries. The proposed sensing design could be an alternative strategy to produce the 2D-based nanoplatforms for electroanalytical applications in clinical samples.
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    Öğe
    The fabrication of a highly sensitive electrochemical sensor based on AuNPs@graphene nanocomposite: Application to the determination of antidepressant vortioxetine
    (Elsevier, 2019) Ates, Ali Kemal; Er, Engin; Celikkan, Huseyin; Erk, Nevin
    This is the first report to development of a new generation and highly sensitive electrochemical sensing platform based on gold nanoparticles/graphene/(AuNPs@GRP) nanocomposite for the detection of vortioxetine (VOR). The electrochemical behavior of VOR has been investigated through adsorptive stripping differential pulse voltammetry (AdsDPV) on the proposed electrochemical sensor (AuNPs@GRP/GCE). The structural and morphological characterizations of fabricated AuNPs@GRP composite were performed by x-ray diffraction (XRD) and transmission electron microscopy (TEM) methods. A well-defined and irreversible oxidation peak at 972 mV was observed on the surface of AuNPs@GRP/GCE. The proposed electrochemical sensor exhibited outstanding electrocatalytic activity towards the electroxidation of VOR. Under the optimized conditions, the voltammetric response was linearly proportional to VOR concentration at two working range of 0.1-1.0 and 1.0-6.0 mu M with a low detection limit of 50.0 nM. The developed sensor was successfully carried out for reliable determination of VOR in pharmaceutical sample with satisfying recovery results. AuNPs@GRP/GCE could be utilized as a simple, inexpensive and reliable sensing platform for the routine analysis of VOR as an antidepressant drug in pharmaceutical samples.
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    Identification of major phenolic compounds of Aloe vera and its protective effect on ovaries under oxidative stress in diabetic rats
    (2023) Kurt, Serdal; Şeker, Uğur; Yazlık, Murat Onur; Hürkul, Muhammed Mesud; Er, Engin; Söker, Sevda
    The study investigated the major phenolic compounds of Aloe vera leaf (AVL) by the high-performance liquid chromatography (HPLC) method, and its protective effect on ovaries under oxidative stress of streptozotocin- induced diabetic rats. The study was conducted on control (untreated healthy rats; C), diabetes (untreated diabetic rats; D) and diabetes+A. vera treatment (diabetic rats treated with A. vera; D+A) groups. D+A group was given an ethanolic extract of A. vera (300 mg/kg) for 14 days. Major phenolic compounds of AVL were chlorogenic acid and rutin. alanine transaminase (ALT) and aspartate aminotransferase (AST) levels increased in D group compared to others groups (P<0.01). Alkaline phosphatase (ALP) and albumin levels were lower and higher in the C group than in other groups, respectively (P<0.01). In the D group compared to other groups, oxidative stress index (OSI) and total oxidant status levels increased, while total antioxidant status level decreased in both ovarian tissues and blood (P<0.01). Preantral and antral follicle counts decreased in the D group according to other groups (P<0.01) and atretic follicle count increased (P<0.05). Proliferating cell nuclear antigen (PCNA) expression level (P<0.01), and B-cell lymphoma-2-associated-X- protein (Bax; P<0.01) and tumor necrosis factor-alpha (TNF-α) expression levels (P<0.05) decreased and increased in group D according to other groups, respectively. In conclusion, treatment with AVL decreased OSI, improved follicular dynamics, and restored Bax, TNF-α and PCNA expression in diabetic rats.
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    Öğe
    Reduced graphene oxide/platinum nanoparticles/nafion nanocomposite as a novel 2D electrochemical sensor for voltammetric determination of aliskiren
    (Royal Soc Chemistry, 2017) Ates, Ali Kemal; Er, Engin; Celikkan, Huseyin; Erk, Nevin
    This study describes the fabrication of a sensitive and selective graphene-based electrochemical nanosensor for the detection of aliskiren (ALS). It is the first research study where the electrochemical oxidation and determination of ALS were investigated by cyclic voltammetry (CV) and adsorptive stripping differential pulse voltammetry (AdsDPV) using a 2D nanocomposite electrode modified with reduced graphene oxide/platinum nanoparticles/nafion (rGO/PtNPs/NFN/GCE). An rGO/PtNP nanocomposite was synthesized directly from graphene oxide (GO) and platinum salt using a single-step chemical reduction method. The synthesized rGO/PtNPs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The developed sensor exhibited excellent electrocatalytic activity (i.e. shifting the potential from 1225 to 1059 mV) towards the oxidation of ALS. The voltammetric responses of ALS presented a good linearity with an increase in concentration within two concentration ranges of 0.045-0.45 mu M and 0.45-2.70 mu M with a low detection limit of 8.2 nM. The analytical applicability of the proposed sensor was demonstrated by determining ALS with the recovery result of 97.0% in human blood plasma. The results strongly suggested that the proposed sensor could be promising as an alternative analytical approach for routine analysis of ALS in clinical samples.
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    Öğe
    Synthesis of Thioglycolic Acid-Modified Molybdenum Disulfide Nanosheets for Electrochemical Sensing and Its Application in Molnupiravir Detection
    (Electrochemical Soc Inc, 2024) Ates, Ali Kemal; Er, Engin
    In the modern world, population growth, industrialization, and lifestyle changes have led to a rise in existing and new diseases, increasing global drug consumption. Proper pharmaceutical dosage is vital since drugs are only effective within specific concentration ranges. Therefore, developing reliable analytical methods for drug analysis in pharmaceuticals and biological samples is essential. Electroanalytical methods are particularly advantageous due to their low cost, ease of use, and rapid response. This study introduces a highly sensitive electrochemical sensor based on thioglycolic acid (TA)-decorated metallic phase molybdenum disulfide (MP-MoS2) nanosheets for the selective detection of molnupiravir (MOL), an antiviral drug used in Covid-19 treatment. The TA@MP-MoS2 nanomaterial was characterized using FTIR, TEM, and EIS. Screen-printed carbon electrodes (SPCE) were modified with TA@MP-MoS2 nanosheets to evaluate their electro-chemical and catalytic behaviours towards MOL by cyclic voltammetry (CV) and square wave voltammetry (SWV). The sensor displayed a well-defined electro-oxidation signal for MOL at 0.534 V, with the linear responses in two concentration ranges: 0.50-3.40 mu M and 3.40-9.55 mu M, and a low detection limit of 22.6 nM. The proposed design that has promising results could be an alternative strategy to fabricate the sensitive sensor for the detection of antiviral agents in real samples.