Browsing by Author "Dilmac, Yusuf"

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Fabrication of Non-Enzymatic Glucose Sensor Dependent Upon Au Nanoparticles Deposited on Carboxylated Graphene Oxide
(Elsevier Science Sa, 2020) Dilmac, Yusuf; Guler, Muhammet
In this article, Au nanoparticles (AuNPs) were deposited on carboxylated graphene oxide (GO-COOH) for the electrochemical oxidation and enzyme-free voltammetric and amperometric determination of glucose. The GO-COOAu modified glassy carbon electrode (GCE) exhibited good sensitivity and stability toward glucose electro-oxidation in alkaline media. The surface morphology of the as-prepared nanocomposite was investigated by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The electrochemical characterization of theworking electrodes was evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry. The GO-COOAu/GCE sensor provided excellent electro-catalytic performance for glucose oxidation with a linear range from 0.02 to 4.48 mM (R-2 = 0.9919) at +0.35 V, a low limit of detection (LOD) of 6 mu M, and a high sensitivity of 20.218 mu A mM(-1) cm(-2). The GO-COOAu nanocompositemodified working electrode with high sensitivity, repeatability, reproducibility, and quantification of glucose in human serumsamples made it a promising material for the development of non-enzymatic sensors.
Palladium Nanoparticles Decorated (3-Aminopropyl)triethoxysilane Functionalized Reduced Graphene Oxide for Electrochemical Determination of Glucose and Hydrogen Peroxide
(Elsevier Science Sa, 2019) Guler, Muhammet; Dilmac, Yusuf
This study presents the fabrication of a glucose biosensor based on the immobilization of glucose oxidase (GOx) on Pd nanoparticles (PdNPs) loaded (3-aminopropyl)triethoxysilane (APTES) functionalized reduced graphene oxide (rGO-APTES) and non-enzymatic H2O2 sensor based on Pd@rGO-APTES nanocomposite modified glassy carbon electrode (GCE). Also, Nafion (Nf) was used as a protective membrane for the sensor and biosensor. The electrocatalytic properties of the sensor and biosensor were investigated using electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The Nf/Pd@rGO-APTES/GOx/GCE biosensor sensitively measured glucose and showed a linear range from 3 mu M to 4.57 mM with a detection limit (LOD) of 0.91 mu M. The biosensor had a sensitivity of 234.1 mu A mM(-1) cm(-2) and an acceptable selectivity for glucose. The Nf/Pd@rGO-APTES/GCE nanocomposites had an excellent electrochemical response to the reduction of H2O2. The linear range of the sensor for the detection of H2O2 concentration was from 0.7 mu M to 13.5 mM with 0.21 mu M of LOD. The sensitivity was calculated to be 1164.3 mu A mM(-1) cm(-2). In addition, the sensor and biosensor showed excellent sensitivity, selectivity, response time, linear range, LOD, repeatability, reproducibility, and storage stability when compared with reported sensors and biosensors.