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Über dieses Buch

This book describes the fabrication of a frequency-based electronic tongue using a modified glassy carbon electrode (GCE), opening a new field of applying organic precursors to achieve nanostructure growth. It also presents a new approach to optimizing nanostructures by means of statistical analysis.
The chemical vapor deposition (CVD) method was utilized to grow vertically aligned carbon nanotubes (CNTs) with various aspect ratios. To increase the graphitic ratio of synthesized CNTs, sequential experimental strategies based on response surface methodology were employed to investigate the crystallinity of CNTs. In the next step, glucose oxidase (GOx) was immobilized on the optimized multiwall carbon nanotubes/gelatin (MWCNTs/Gl) composite using the entrapment technique to achieve enzyme-catalyzed oxidation of glucose at anodic potentials, which was drop-casted onto the GCE. The modified GCE’s performance indicates that a GOx/MWCNTs/Gl/GC electrode can be utilized as a glucose biosensor with a high direct electron transfer rate between GOx and MWCNTs/Gl. It was possible to use the fabricated biosensor as an electronic tongue thanks to a frequency-based circuit attached to the electrochemical cell. The results indicate that the modified GCE (with GOx/MWCNTs/Gl) holds promising potential for application in voltammetric electronic tongues.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract
Glucose monitoring is one of the main targets of biosensing studies, as 5% of the populations of developed countries are suffering from diabetes. Therefore, an accurate monitoring of the blood glucose level seems to play a major role in the diagnosis and management of diabetes mellitus. Carbon nanotube (CNT) is one of the most promising materials widely used in this area due to its electrical properties. Beside glucose monitoring for diabetes, the biosensors array for the electronic tongue has also become an important area of research. Generally, an electronic tongue is a single or multisensory device dedicated to the automated analysis of complex composition samples and recognizes their characteristic taste properties. This chapter introduces the synthesis method, optimization approach, properties, and electrochemical applications of the CNTs-based glucose biosensor. Furthermore, the significance of the electrochemical glucose biosensor in both medical application and glucose-based electronic tongue is discussed in detail.
Amin TermehYousefi

Chapter 2. Background of the Study

Abstract
CNTs are allotropes of carbon in the nano form of a cylinder. In this chapter, the history of generating CNTs, the applications, and chemical properties of CNTs are reviewed. Also, the different generation of glucose biosensors as well as CNTs-based nanocomposite for electrochemical detection of glucose are highlighted. Generally, nanostructures have great potential to explore as simple and easy blood glucose checking medical tools. Electrochemical based oxidation of the immobilized enzymes (glucose oxidase) on CNTs has opened exciting opportunities for the determination of glucose. According to the previous publication related to the CNTs-based biosensor, CNTs display a perfect combination of electrical properties which enhance the sensitivity and selectivity of the fabricated amperometric glucose biosensors.
Amin TermehYousefi

Chapter 3. Experimental Procedures and Materials

Abstract
In this chapter, the main experimental steps used for synthesis, optimization, characterization, applications of CNTs, and preparation of CNTs-based nanocomposites electrode by drop-casting technique, and electrochemical measurements are discussed in detail. Furthermore, the equipment used to characterize grown CNTs as well as amperometric glucose biosensors are discussed. The mechanism of CNTs growth and glucose detection is also schematically illustrated. All the discussed methods are reproducible within the given experimental limitations.
Amin TermehYousefi

Chapter 4. Results and Discussions

Abstract
This chapter indicates that the vertically aligned MWCNTs were successfully synthesized on a silicon substrate via the CVD method with different morphological properties. The crystallinity of synthesized MWCNTs was also optimized using statistical analysis to control the growth condition and defect amount of CNTs. In line with the previous chapter, the optimized MWCNT was used to obtain the MWCNT/GL matrix to improve the direct electron transfer processes between GOx and modified GCE through hydrophobic-hydrophobic interactions in forming stable dispersions of MWCNTs. The GCE modified by GOx/MWCNTs/Gl was used for glucose detection approaches based on the electrochemical method. Furthermore, the GOx/MWCNTs/Gl/GCE was employed to fabricate an electronic tongue for sweetness diagnoses by recording frequency response of the glucose biosensor. The frequency results recorded by oscilloscope indicate that, by adding different glucose concentrations to electrochemical cells connected to the circuit, the output oscillation frequency changes.
Amin TermehYousefi

Chapter 5. Conclusion

Abstract
In this chapter, a summary of the results are presented in brief. Based on results, major fundamental and technological advances have been made for enhancing the capabilities and improving the reliability of glucose measuring devices trough electrochemical glucose monitoring which has contributed significantly to improve the lives of diabetic people. Membrane, mediator, and electrocatalyst were some of the modified activities used to improve the second generation of biosensors based on mediator modified GOx sensors which are still gaining the huge attract by the market leaders.
Amin TermehYousefi

Backmatter

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