Browsing by Author "Sazaklioglu S.A."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Calibration Curve Approaches for Nonlinear Data Points Obtained in Colo 320 Exosomes Determination
    (Center of Excellence in Electrochemistry, Univ. of Tehran, 2022) Sazaklioglu S.A.; Torul H.; Kabadayi H.; Vatansever H.S.; Tamer U.; Celikkan H.
    The limit of detection (LOD) is defined as the lowest quantity or concentration of a component that can be reliably distinguished from the limit of blank (LOB). LOD value is one of the most important parameters considered for many determination methods and is usually calculated on the linear correlation between signal and concentration. However, the linear correlation may not always be obtained in experimental studies. We claim that data with low linear correlation have meaning, and we present such a study because analytical studies based on these data are not easily understood in the literature. In this manuscript, we suggest that a calibration curve can be obtained from nonlinear data points and the LOD value can be calculated. We tested this approach for the determination of exosomes and supported it with mathematical calculations. We produced a label-free sensor using anti-CD63 on the gold electrode for selective and reliable impedimetric detection of the exosomes obtained from Colo 320 cell lines in data points that are high concentrations and out of linearity. We characterized in detail what each calculation means. This sensor with a LOD value of 3.90×1011 exosome particles µL-1 and with a cubic polynomial model for the calibration curve was considered sensitive and reliable, especially for high vesicle content of samples such as cell culture medium. © 2022 by CEE (Center of Excellence in Electrochemistry).
  • No Thumbnail Available
    Item
    Sensitive and reliable lab-on-paper biosensor for label-free detection of exosomes by electrochemical impedance spectroscopy
    (Springer, 2024) Sazaklioglu S.A.; Torul H.; Tamer U.; Ensarioglu H.K.; Vatansever H.S.; Gumus B.H.; Çelikkan H.
    A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified with gold particles (AuPs@PE) and then conjugated with anti-CD9 (Anti-CD9/AuPs@PE) for the detection of exosomes. Variables involved in the biosensor design were optimized with the univariate mode. The developed method presents the limit of detection of 8.7 × 102 exosomes mL−1, which is lower than that of many other available methods under the best conditions. The biosensor was also tested with urine samples from cancer patients with high recoveries. Due to this a unique, low-cost, biodegradable technology is presented that can directly measure exosomes without labeling them for early cancer or metastasis detection. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2024.