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Fabrication of Applied Electrode Materials based on Metal-Organic Frameworks to Design Non-Enzymatic Electrochemical Sensing Platforms for Measuring of Glucose in Physiological Samples

Ezzati, Milad | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52651 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Shahrokhian Dehkordi, Saeed
  7. Abstract:
  8. In the first work, the method of direct growth was used to grew MOFs based on cobalt, as electroactive centers, for preparing electrochemical sensors for the determination of glucose. In comparison to most of the electrochemical sensing platforms based on MOFs for determining glucose, which suffer from some disadvantages like time-consuming synthesis procedures and using hazardous organic solvents, the proposed in situ growth method is much faster and no need to toxic organic solvents. Herein, cobalt-based MOFs were grown on the surface of the reduced graphene oxide modified glassy carbon electrode by the direct and rapid conversion of cobalt hydroxide nanosheets intermediates. The electrochemical behavior of the as prepared MOFs via in situ method toward glucose electrooxidation was evaluated and compared to those attained by conventional hydrothermal methods. The results show that the modified electrode via in situ based MOFs show better lectrochemical responses against electrooxidation of glucose, which can be attributed to uniform structure of these MOFs and better accessibility of the electrolyte ions and analyte molecules to the surface of the electrode in comparison to hydrothermal based MOFs modified electrodes. The capability of the in situ based MOFs modified electrode for quantitative determination of glucose was evaluated via amperometry technique. Finally, in order to examine the ability of the modified electrode in practical applications, the human blood serum sample was analyzed and results show that the fabricated electrode can be used as a reliable and applicable sensing platform for the determination of glucose in physiological samples. In the second work, the in situ growth method was used to direct growth of bimetallic MOFs based on nickel and cobalt electroactive centers without any organic binder or excess layer, on the surface of carbonaceous substrates such as glassy carbon electrode and graphitic screen printed electrode to design nonenzymatic glucose sensing platforms. The electrochemical behavior of the NiCo-BTC MOFs was evaluated toward glucose electrooxidation and the obtained results compared to those attained from hydrothermal method and corresponding mono metallic MOFs (cobalt based and nickel based MOFs) were synthesized via same in situ growth method. The results obviously showed that the electrochemical responses of in situ based bimetallic MOFs against electrooxidation of glucose was much better than other modified electrodes, which can be attributed to synergistic effects between Ni and Co metallic centers in comparison to mono metallic MOFs and better accessibility of the electrolyte ions and analyte molecules to the electroactive sites on the electrode’s surface and larger electroactive surface area in compared to hydrothermal based MOFs. The capability of the in situ based bimetallic MOFs modified electrode for determining glucose was evaluated via amperometry technique. Finally, the ability of this modified electrode for measuring glucose in physiological samples such as human blood serum sample was evaluated and outcomings confirm that this modified electrodes can be used as a reliable and applicable sensing platform for measuring glucose in practical applications. Moreover, in order to miniaturization and extend the applications of such sensors from “lab-to-market”, the same strategy was used to the modification of the graphitic screen printed electrode’s surface. The capability of this modified toward glucose electrooxidation was evaluated via chronoamperometry technique. The obtained results obviously revealed that this sensing platform can be used as a in situ and efficient sensor for accurate measurement of glucose
  9. Keywords:
  10. Metal-Organic Framework ; Modified Electrodes ; Glassy Carbon Electrode ; Nonenzymatic Sensor ; Graphitic Screen-Printed Electrodes

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