PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection

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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, Canan
    This 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.
  • Review
    Citation - WoS: 5
    Citation - Scopus: 5
    Development and Functionalization of Electrospun Fiber Coated Thin Film Microextraction Devices for Rapid Mass Spectrometric Determination of Biologically Important Polar Molecules
    (Elsevier B.V., 2024) Öztürk,M.; Salih,B.; Eroğlu,A.E.; Boyaci,E.
    Rapid diagnosis of diseases is one of the challenging areas in clinical research. From the analytical chemist's perspective, the main challenges are isolating the compounds from the bio-specimen and lengthy analysis times. In this regard, solid phase microextraction offers a platform to address the abovementioned challenges. Moreover, its sharp tip-thin film geometry, known as coated blade spray (CBS), can enhance the extraction and act as an ionization source in direct mass spectrometric analysis. In this study, a new CBS device specifically designed for polar analytes was prepared and optimized to determine urinary metabolites. For this purpose, polyacrylonitrile (PAN) was selected as a base polymer as it can be electrospun to form a nanofibrous structure, and it can be modified with weak ion exchange moieties to interact with polar analytes. Following the electrospinning of PAN, hydrolysis was optimized, and conditions leading to sufficient extraction enhancement without dissolving the polymer were obtained when probes were treated with 5.0 M of NaOH for 2.5 h. Using the coated blades prepared as explained, the evaluation of various extraction conditions showed that 5 min is sufficient for equilibrium extraction. In addition, the solution's ionic strength and pH significantly affect the extraction. Optimum sorption was obtained at no salt added and pH 7.0 conditions. The CBS-MS optimization showed that 10.0 µL of ACN/MeOH/H2O (40:40:20, v/v/v) with formic acid kept for 15 seconds on the blade before voltage application leads to the highest signal. The limits of quantification of the analytes are between 50 and 100 ng/mL. © 2024 Elsevier B.V.