PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Nanostructured Ox-MWCNT-Ppy-Au Electrochemical Sensor for Ultralow Detection of Retrorsine and Evaluation of Its Cytotoxic Effects on Liver Cells(Taylor & Francis Ltd, 2025) Akturk, Ezgi Zekiye; Njjar, Muath; Ata, Melek Tunc; Kaya, Ahmet; Akdogan, Abdullah; Onac, CananThis study presents the development of a novel retrorsine (RTS)-imprinted sensor utilizing oxidized multi-walled carbon nanotubes (Ox-MWCNTs), polypyrrole (PPy), and gold nanoparticles (AuNPs), employing square wave voltammetry for the sensitive and selective detection of RTS which causes oxidative-stress and DNA damage. The fabricated Ox-MWCNT-PPy-AuNP sensor demonstrated a surface-area of (0.218 cm2) is 4.25 times larger than a bare glassy carbon electrode, with a low charge transfer resistance (10.9 Omega), enhancing electron transfer kinetics. The sensor showed excellent sensitivity in detecting retrorsine, with a limit of detection of 0.035 nM in synthetic matrices and -0.030 nM in HepaRG cell culture medium. Toxicity assays in HepaRG cells revealed dose-dependent oxidative-stress, with glutathione levels decreasing from 23.08 +/- 0.21 mu mol/109 to 21.21 +/- 0.02 mu mol/109 at 35 mu M retrorsine. Concurrently, GSSG levels increased from 1.32 +/- 0.26 mu mol/109 to 2.22 +/- 0.02 mu mol/109. DNA-damage assessed via comet assay, showed significant increases in tail-moment (2.53 mu m) and tail-migration (16.13 mu m). Oxidative DNA-damage, indicated by 8-OHdG levels, increased significantly from 0.29 +/- 0.02 ng.mL- (control) to 0.47 +/- 0.07 ng.mL- at 35 mu M retrorsine. These findings demonstrate the sensor's effectiveness for retrorsine detection and its applicability in toxicological studies. The integration of nanomaterial engineering and molecular imprinting provides a highly sensitive, selective, and eco-friendly solution for monitoring toxic agents and assessing their biological impacts.Article Citation - WoS: 3Citation - Scopus: 3A Novel MIP Electrochemical Sensor Based on a CuFe2O4NPs@rGO Nanocomposite and Its Application in Breast Milk Samples for the Determination of Fipronil(Royal Soc Chemistry, 2025) Njjar, Muath; Akturk, Ezgi Zekiye; Kaya, Ahmet; Onac, Canan; Akdogan, AbdullahBackground: fipronil, a widely utilized insecticide in agriculture, has been shown to have potential health implications as it can accumulate in the environment and affect human health. Electrochemical sensors, specifically those incorporating molecularly imprinted polymers (MIPs), provide an efficient way for the detection of fipronil because of their selectivity and specificity. The combination of CuFe2O4NPs and reduced graphene oxide (rGO) exhibits a synergistic effect that enhances sensitivity and selectivity. The composite's effective properties provide a robust platform for fipronil determination in various matrices. This study detected fipronil using an electrochemical sensor based on a glassy carbon electrode (GCE) modified with MIP@CuFe2O4NPs@rGO. Results: the synthesized MIP@CuFe2O4NPs@rGO material was characterized using various techniques such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (FESEM), X-ray diffraction (XRD) analysis, energy dispersive X-ray (EDX) analysis, Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS) analysis, and electrochemical impedance spectroscopy (EIS). The modified GCE showed enhanced electrochemical behavior for fipronil, as demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Optimization of parameters such as pH, pyrrole concentration, and template concentration further improved sensor performance. The sensor exhibited a linear dynamic range of 1 to 6 nM, with a limit of detection (LOD) of 0.30 nM (S/N = 3) and a limit of quantification (LOQ) of 1.08 nM (S/N = 10), highlighting its sensitivity and reliability. The precision of the method was excellent, with a relative standard deviation of less than 4.0%. When applied to quantify fipronil in breast milk samples, the sensor showed high accuracy and precision, with recoveries ranging from 96.24% to 97.75%. Significance: the sensor offers several advantages, including high sensitivity, specificity, and accuracy. Its ability to detect fipronil in complex matrices such as breast milk highlights its potential for real-world applications in environmental and health monitoring. Overall, this research paves the way for the development of efficient, rapid and eco-friendly sensors for detecting pesticide residues in various environmental and biological samples.Article Citation - WoS: 2Citation - Scopus: 2Determination of Retrorsine in Thyme Via Molecularly Imprinted Electrochemical Sensor: Validation and Comparison With Chromatographic Technique(Elsevier Sci Ltd, 2025) Tunc-Ata, Melek; Akturk, Ezgi Zekiye; Njjar, Muath; Kaya, Ahmet; Akdogan, Abdullah; Onac, CananPyrrolizidine alkaloid (PA) toxicity is a growing public health concern, especially with rising herbal product use during the pandemic, highlighting the need for accurate exposure data. Retrorsine (RTS), a retronecine-based PA, is highly toxic, causing liver damage, mutagenicity, and DNA cross-linking through metabolic activation. In the light of the need for a practical alternative to monitor pyrrolizidine alkaloid contamination in herbal products, a molecularly-imprinted-polymer sensor (MIPs-GCE) was used for exploring the electrochemical behavior of RTS electrochemical behavior using cyclic voltammetry and the selective detection of RTS using square wave voltammetry. The sensor demonstrated a linear-detection range of 0.05-2 nM, with a LOD of 0.02869 nM. The sensor's accuracy was validated by analyzing thyme samples, detecting RTS concentrations of 0.5168 and0.5345 nM with RSD of 2.4 % and 1.9 %. These results closely aligned LC-MS/MS values of 0.5142 and 0.5267 nM, confirming the sensor's precision. The sensor demonstrated high selectivity, low detection limits, and practical applicability, ensuring reliable and efficient RTS detection in the presence of twenty-eight different PA compounds. This study introduces a novel, reliable, and straightforward method for detecting PAs, with a specific focus on RTS, offering an enhancement to existing analytical techniques and presenting a complementary alternative in chromatographic applications such as LC-MS/MS, HPLC and GC-MS.