title: Thioglycolic Acid-Capped CdS Quantum Dots Conjugated to α-Amylase as a Fluorescence Probe for Determination of Starch at Low Concentration.
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.
authors.affiliation: Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
authors.forename: Mahnoush
authors.initials: M
authors.lastname: Tayebi
authors.affiliation: Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran. mty2016@aut.ac.ir.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Tavakkoli Yaraki
authors.affiliation: Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Mogharei
authors.affiliation: Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Ahmadieh
authors.affiliation: Marquette University School of Dentistry, Milwaukee, WI, 53233, USA. mohammadreza.tahriri@marquette.edu.|Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. mohammadreza.tahriri@marquette.edu.|Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran. mohammadreza.tahriri@marquette.edu.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Tahriri
authors.affiliation: Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC, 27606, USA.
authors.forename: Daryoosh
authors.initials: D
authors.lastname: Vashaee
authors.affiliation: Marquette University School of Dentistry, Milwaukee, WI, 53233, USA.|Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK.
authors.forename: Lobat
authors.initials: L
authors.lastname: Tayebi
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D057230:Limit of Detection; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D013213:Starch / Q000032:analysis*; D013440:Sulfides / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry*; D000516:alpha-Amylases / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D013440:Sulfides; D013864:Thioglycolates; C034939:cadmium sulfide; C017487:2-mercaptoacetate; D013213:Starch; D000516:alpha-Amylases
keywords: CdS QDs; Photoluminescence; Starch; Synthesis; Thioglycolic acid; α-amylase