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Thioglycolic Acid-Capped Cds Quantum Dots Conjugated to Α-Amylase As a Fluorescence Probe for Determination of Starch at Low Concentration Publisher Pubmed



Tayebi M1 ; Tavakkoli Yaraki M1 ; Mogharei A1 ; Ahmadieh M1 ; Tahriri M2, 3, 4 ; Vashaee D5 ; Tayebi L2, 6
Authors
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Authors Affiliations
  1. 1. Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
  2. 2. Marquette University School of Dentistry, Milwaukee, 53233, WI, United States
  3. 3. Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
  4. 4. Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
  5. 5. Electrical and Computer Engineering Department, North Carolina State University, Raleigh, 27606, NC, United States
  6. 6. Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, United Kingdom

Source: Journal of Fluorescence Published:2016


Abstract

In the present research, water soluble thioglycolic acid-capped CdS quantum dots (QDs) were synthesized by chemical precipitation method. The characteristics of prepared quantum dots were determined using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The obtained results revealed that CdS QDs have 5.60 nm crystallite size, hexagonal wurtzite structure and spherical morphology with less than 10 nm diameter. The photoluminescence (PL) spectroscopy was performed in order to study the effect of the presence of starch solutions. Blue emission peaks were positioned at 488 nm and its intensity quenched by increasing the concentration of starch solutions. The result of PL quenches in range of studied concentrations (0–100 ppm) was best described by Michaelis-Menten model. The amount of Michaelis constant (Km) for immobilized α-amylase in this system was about 68.08 ppm which showed a great tendency of enzyme to hydrolyze the starch as substrate. Finally, the limit of detection (LOD) was found to be about 2.24 ppm. © 2016, Springer Science+Business Media New York.