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Development of Biocompatible and Fluorescent Platforms Based on Carbon Dots and Deep Eutectic Solvents for Detection of Some Carcinogenic and Antidepressant Compounds

Manshaei, Faranak | 2023

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 55855 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagheri, Habib
  7. Abstract:
  8. The main focus of this thesis was on fluorescence sensors development based on carbon dots and deep eutectic solvents. Accordingly, an attempt was made to synthesize carbon dots and modified with deep eutectic solvents as biocompatible sensors. Eventually, development and application of these sensors in analytical systems ultimately led to satisfactory and comparable results with previous methods. In the first project, a rapid and miniaturized fluorescent probe based on the ultrasound‒assisted formation of carbon dots (CDs) in a metallic deep eutectic solvent (MDES) was developed and conveniently implemented to detect 4-MeI in commercial dark soft drinks. In-situ synthesis of CDs-chelated metals in the presence of the target analyte facilitates a kinetically fluorescence emission with no need to multi-step analysis. Simultaneous implementation of MDES as a green solvent and passivation agent also practically paves the way to minimize the hazardous chemicals consumption. Chelation of the divalent metal cations on the synthesized CDs and their strong interactions with the imidazole ring presumably provides a fluorescence quenching pathway induced by the model species. Accordingly, the calibration plot covers 0.6-320 ng mL-1 concentration range and the relative recoveries for eight real samples are in the range of 89-108%. The limit of detection and relative standard deviations (RSDs) of the developed method are 0.18 ng mL-1 and <11%, respectively. In the second project, a miniaturized probe based on the solublefluorescent surface molecularly imprinted polymer (S-FSMIP) was developed and conveniently implemented to detect sertraline (SER), as a model target, in human urine. The developed probe synthesis was conducted in two main steps: i) design of FSMIP with hydrophobic core and hydrophilic surface, ii) swelling process of FSMIP at a high temperature in the presence of a high boiling hydrophobic deep eutectic solvent (HDES). Employment of HDES as a green solvent for solvation of FSMIP minimizes the consumption of hazardous chemicals and also improves analyte transfer to surface of FMIP. There are two types of interactions which S-FSMIP could extract SER from urine sample. They involves: 1) specific interactions via cavities imprinted on FSMIP, and 2) non-specific interactions via hydrogen bond formation and hydrophobic interactions. In the present work, SER was detected by fluorescence quenching of S-FSMIP. In this work, the detection limit was 0.2 ng mL-1 and the relative standard deviation was less than 6% for inter- and intra-day. Absolute recovery values were also obtained for four patients (3 women and 1 man) treated with sertraline and a healthy individual in the range of 89-101%
  9. Keywords:
  10. Adsorption Isotherms ; Kinetics Study ; Chelate-Enhanced Fluorescence ; Biocompatible Carbon Dots ; Carcinogenic Compounds ; Antidepressants ; Deep Eutectic Solvent ; Fluorescent Molecularly Imprinted Polymer

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