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Design of Nature-Inspired Multicolor Sensor for Detection and Discrimination of Biothiols based on Anti-Etching on Gold Nanorods

Akhondi, Golara | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56849 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Hormozinezhad, Mohammad Reza
  7. Abstract:
  8. Biological thiols are crucial substances that play an essential role in several biological processes and activities in the body. Hence, the fluctuation of their concentrations can be used as a diagnostic sign for numerous disorders. In contrast, the ratio of these thiols to their disulfide form within the cell is useful as an indicator for determining cytotoxicity. Hence, it is crucial for develop a simple yet efficient analytical technique for quickly recognizing and determining them. The purpose of this study is to develop a plasmonic colorimetric sensor by utilizing gold nanorods (AuNRs). This sensor aims to accurately measure and distinguish between cysteine (CYS) and glutathione (GSH), which are both essential biological thiols. Additionally, it aims to detect cystine (CYSS) and glutathione disulfide (GSSG), which are formed during the oxidation process of these biological thiols, resulting in the formation of disulfide bonds. The designed sensor operates by using the anti-etching mechanism of gold nanorods with varying aspect ratios (length/width) in a pH-stabilized glycine buffer. This mechanism is triggered in the presence of target biological thiols, resulting in distinct and specific color changes for each analyte. The study consisted of exploring the anti-etching mechanism by examining various influencing parameters. These parameters included the concentration of the corrosive agent (Hg2+), the concentration of ascorbic acid, the incubation time of thiols with mercury (II) ions, and the corrosion and anticorrosion kinetics of gold nanorods. The goal of this research was to gain a better understanding of these factors in order to enable visual detection. Ultimately, the suggested sensor's ability to detect and quantify the biological thiols was evaluated using advanced statistical techniques such as linear discriminant analysis (LDA) and partial least squares calibration (PLSR). The statistical results obtained at this stage clearly demonstrate the potential efficacy of the proposed sensor in accurately identifying and differentiating four biological thiols as individual components within the concentration range of 0.1-200 μM, as well as the ratio of thiols to their disulfide within the concentration range of 0.2-5.0 μM with The linear range is 1.9-40.0, 3.2-200, 2.0-70.0, 3.1-70.0, 0.4-5.0, 0.2-5.0 μM and detection limit is 0.6, 1.0, 0.6, 1.0, 0.1 and 0.09 µM respectively for cysteine, glutathione, cystine, glutathione disulfide and ratios of thiol to disulfide including (CYS:CYSS) and (GSH:GSSG) gives In addition, the efficiency of the designed sensor in the detection and measurement of biological thiols in real samples was investigated by detecting and measuring target analytes in the complex environment of plasma, and the obtained results indicate the possibility of using the designed sensor in the on-site measurements of biological thiols
  9. Keywords:
  10. Gold Nanorods ; Anticorrosive Coating ; Colorimetric Sensor ; Biothiols ; Cysteine

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