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Öğe Application of disposable biosensor for nivolumab–DNA interaction using pencil graphite electrode(Pleiades Publishing, 2023) Aslan, Mehmet; Aydın, Fırat; Aslan, Ferhat; Levent, AbdulkadirAbstract: In this study, the interaction of the anticancer drug Nivolumab (NIVO) with dsDNA was investigated using differential pulse (DPV) technique by monitoring the changes in the oxidation signal of adenine and guanine bases on PG electrode. Surface characterization of the PG (pencil graphite) electrode was carried out using cyclic voltammetry, electrochemical impedance spectrometry techniques and scanning electron microscope, Energy Dispersive X-ray. DPV parameters, the effect of pH on the electrode surface, stirring speed, dsDNA immobilization time, immobilized dsDNA concentrations, NaCl concentration, NIVO concentration interacting with dsDNA were optimized with PG electrode. With the determined parameters, NIVO–dsDNA interaction in PBS (pH 3.0) supporting electrolyte solution was elucidated. In the NIVO–dsDNA interaction using UV technique, the K binding constant and free energy of binding value was found to be 8.93 × 104 and 6.754 kcal mol–1, respectively. It was determined that the data obtained by electrochemical method were in parallel with the data obtained by spectrometric method. The results obtained electrochemically with high sensitivity, low cost, fast, simple, low detection limit will be the first example of NIVO–dsDNA interaction using PG electrode.Öğe Electrochemical evaluation of nivolumab used in cancer treatment with differential pulse voltammetry: A novel approach with single-use pencil graphite electrode(Springer Int Publ Ag, 2023) Aslan, Mehmet; Aydın, Fırat; Levent, AbdulkadirObjectivesNivolumab is used in a treatment called immunotherapy, which helps the immune system cells to attack cancer cells. The electrochemical properties and quantification of this drug were performed using single-use pencil tips.Evidence acquisitionHere, a selective voltammetric method for the determination and electrochemical characterization of Nivolumab used in cancer therapy was developed for the first time using a disposable pencil electrode by cyclic voltammetry and differential pulse voltammetry techniques. Nivolumab exhibited an anodic signal at +0.879 V (vs. Ag/AgCl) in PBS (pH 3.0, 0.02 M NaCl) medium.ResultsThis procedure showed a linear response in phosphate buffer solutions (pH 3.0, 0.02 M NaCl) media within the concentration range of 0.01 mg mL-1 to 0.07 mg mL-1 and limit of detection and the limit of quantification values were determined to be 2.49 mu g mL-1 and 8.30 mu g mL-1, respectively.ConclusionsThe developed method offers an important analytical approach for the detection and characterization of NIVO. Precisely measuring and monitoring the levels of such drugs in real sample analyses or biological samples is critical for evaluating response to treatment, optimizing treatment strategies. Therefore, the method was applied to real sample analyses. Voltammetric results developed using PG electrode were compared with UV-Vis results. It has been determined that the results obtained are compatible with each other.Öğe Firstly electrochemical examination of vildagliptin at disposable graphite sensor: Sensitive determination in drugs and human urine by square-wave voltammetry(Elsevier, 2021) Altunkaynak, Yalçın; Yavuz, Ömer; Levent, AbdulkadirThe work describes the determination of vildagliptin at the pencil graphite electrode using cyclic voltammetry and square-wave voltammetry. Vildagliptin yielded a well-defined irreversible peak response in phosphate buffer (PBS 9.0) medium, at about +1.13 V by cyclic voltammetry. Using optimum square-wave voltammetry condi-tions, a good linear correlation was obtained between the anodic current signal and concentration, in the range of 2.94-49.98 mu M in PBS (pH 9.0) medium, the limit of detection and relative standard deviation were calculated as 82 nM (24.88 ng L-1) and 2.95%, respectively. The developed voltammetric method was successfully applied for vildagliptin determination without any separation in pharmaceutical preparations and urine samples.Öğe Firstly electrochemical investigetions and determination of anticoagulant drug edoxaban at single-use pencil graphite electrode: an eco-friendly and cost effective voltammetric method(Springer Science and Business Media Deutschland GmbH, 2023) Kılıç, Abdulkadir; Aslan, Mehmet; Önal, Günay; Levent, AbdulkadirObjectives: The anticoagulant drug edoxaban has a blood thinning mechanism of action. In this study, a pencil graphite electrode was electrochemically activated at + 1.4 V for 60 s. in a Britton-Robinson (pH 9.0) supporting electrolyte solution. Evidence acquisition: A simple, fast, and sensitive electrochemical procedure was developed using cyclic voltammetry and square wave voltammetry techniques. It was observed that edoxaban gave a good oxidation signal with cyclic voltammetry technique at a potential of + 0.98 V (vs. Ag/AgCl). Results: This procedure showed a linear response in a Britton-Robinson (pH 9.0) media within the concentration range of 0.2–1.8 µM and limit of detection (LOD) and the limit of quantification (LOQ) values were determined to be 0.073 μM (0.133 μg mL−1) and 0.243 μM (0.443 μg mL−1), respectively. Conclusion: The method developed in this study was successfully applied to drug and urine samples. The developed voltammetric method was highly selective and gave satisfactory recovery results in urine and pharmaceutical samples. The results of the voltammetric method were compared with the spectroscopic method and it was determined that the results were compatible.Öğe Investigation of the electrochemical properties of edoxaban using glassy carbon and boron-doped diamond electrodes and development of an eco-friendly and cost effective voltammetric method for its determination(Academic Press Inc., 2024) Kılıç, Abdulkadir; Aslan, Mehmet; Levent, AbdulkadirIn this study, the highly risky drug Edoxaban (EDX), which can threaten life and cause bleeding, was electro analytically evaluated. The electrochemical behavior of EDX was investigated using glassy carbon electrode (GCE) and boron-doped diamond electrode (BDDE). In this study, for the first time, a simple, rapid, sensitive, and selective voltammetric technique was developed by using different electrodes for the electrochemical characterization and detection of EDX. The optimized voltammetric technique showed anodic signals of EDX at +1.09 V and +1.08 V on GCE and BDDE, respectively, in BR (pH 5.0) solution. The developed voltammetric method provided a very good analytical working range for EDX in BR (pH 5.0) solution on GCE and BDDE, covering concentration ranges from 1.84 μM to 12.88 μM and from 3.68 μM to 14.72 μM, respectively. The limits of detection for EDX on GCE and BDDE under these experimental conditions were calculated as 0.24 μM and 0.57 μM, respectively. The developed voltammetric methods on both electrodes were successfully applied to urine and tablet samples. Additionally, the obtained voltammetric results were compared with UV–Vis spectroscopy results.Öğe Separation, optimization, and quantification of cytokinins by a recently developed amide-embedded stationary phase(Taylor & Francis Inc, 2017) Aral, Hayriye; Hasimi, Duygu; Aral, Tarik; Levent, Abdulkadir; Ziyadanogullari, BerrinIn this study, some plant growth regulators known as cytokinins [kinetin (K), zeatin (Z), thidiazuron (TDZ), benzylaminopurine (BAP), and dimethylallylaminopurine (AAP)] were separated by HPLC using an amide-embedded mixed-mode stationary phase which was synthesized by Aral et al. in recent years. The effect of mobile phase content, mobile phase pH, buffer concentration, and temperature on separation process was studied. In addition, a quantitative determination of cytokinins from Salvia limbata extract was studied, and some validation parameters such as limit of detection (LOD), limit of quantification (LOQ), and relative standard deviation (RSD) were calculated as a range of 0.03-0.1, 0.1-0.26mg/L, and 0.03-0.08, respectively. [GRAPHICS] .Öğe Voltammetric studies and spectroscopic investigations of the interaction of an anticancer drug bevacizumab-DNA and analytical applications of disposable pencil graphite sensor(Elsevier B.V., 2023) Aslan, Mehmet; Aydın, Fırat; Levent, AbdulkadirA sensitive, simple, fast electrochemical biosensor for the DNA interaction of bevacizumab (BEVA), which is used as a targeted drug in cancer treatment, was developed using the differential pulse voltammetry (DPV) technique with pencil graphite electrode (PGE). In the work, PGE was electrochemically activated in a supporting electrolyte medium of +1.4 V/60 s (PBS pH 3.0). Surface characterization of PGE was carried out by SEM, EDX, EIS, and CV techniques. Determination and electrochemical properties of BEVA were examined with CV and DPV techniques. BEVA gave a distinct analytical signal on the PGE surface at a potential of +0.90 V (vs. Ag/AgCl). In the procedure proposed in this study, BEVA gave a linear response on PGE in PBS (pH 3.0 containing 0.02 M NaCl) (0.1 mg mL−1 – 0.7 mg mL−1) with LOD and LOQ values of 0.026 mg mL−1 and 0.086 μg mL−1, respectively. BEVA was reacted with 20 μg mL−1 DNA in PBS for 150 s and analytical peak signals for adenine and guanine bases were evaluated. The interaction between BEVA-DNA was supported by UV–Vis. Absorption spectrometry and the binding constant was determined as 7.3 × 104.
