Use of CdSe/ZnS luminescent quantum dots incorporated within sol-gel matrix for urea detection |
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Authors: | Duong Hong Dinh Rhee Jong Il |
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Institution: | School of Applied Chemical Engineering, Research Center for Biophotonics, Chonnam National University, Yong-Bong dong 300, 500-757 Gwangju, Republic of Korea |
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Abstract: | In this work, urea detection techniques based on the pH sensitivity of CdSe/ZnS QDs were developed using three types of sol-gel membranes: a QD-entrapped membrane, urease-immobilized membrane and double layer consisting of a QD-entrapped membrane and urease-immobilized membrane. The surface morphology of the sol-gel membranes deposited on the wells in a 24-well microtiter plate was investigated. The linear detection range of urea was in the range of 0-10 mM with the three types of sol-gel membranes. The urea detection technique based on the double layer consisting of the QD-entrapped membrane and urease-immobilized membrane resulted in the highest sensitivity to urea due to the Michaelis-Menten kinetic parameters. That is, the Michaelis-Menten constant (Km =2.0745 mM) of the free urease in the QD-entrapped membrane was about 4-fold higher than that (Km =0.549 mM) of the immobilized urease in the urease-immobilized membrane and about 12-fold higher than that (Km =0.1698 mM) of the immobilized urease in the double layer. The good stability of the three sol-gel membranes for urea sensing over 2 months showed that the use of sol-gel membranes immobilized with QDs or an enzyme is suitable for biomedical and environmental applications. |
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Keywords: | Urea detection Quantum dots Sol-gel membranes Microtiter plate Urease Immobilization |
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