کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5181336 | 1380959 | 2014 | 9 صفحه PDF | دانلود رایگان |
A functional polymer support was designed for covalent immobilization of enzyme uricase, which was further utilized in a single enzyme based silver nanoparticles (Ag-NPs)-optical biosensor system for estimation of uric acid. A carboxylic acid functionalized polymer support was fabricated via gamma radiation induced mutual-irradiation grafting of polyacrylic acid (PAA) on to non-woven polypropylene (PP) matrix. Grafting parameters, such as dose, monomer concentration, homopolymer inhibitor and inorganic acid concentration were studied to optimize the grafting process. PAA-g-PP samples were characterized by grafting yield measurement, water uptake, FTIR, TGA and SEM techniques. Uricase enzyme was immobilized on to the PAA-g-PP support via covalent amide linkage using coupling agents, namely N-hydroxysuccinimide (NHS) and N-ethyl-Nâ²-(3-(dimethylamino)propyl)carbodiimide (EDC). The catalytic activity of uricase was investigated spectrophotometrically using uric acid as a substrate. Study of kinetic parameters (Km, Vmax) revealed the value of Km for covalently immobilized uricase to be â¼1.2-fold higher than that of free enzyme. The uricase-immobilized-PAA-g-PP samples could be repeatedly used for â¼20 cycles over a period of 30 days when stored in phosphate buffer (pHâ¼7.4) at 4°C without significant decrease in the enzyme activity. The uricase immobilized samples were successfully used in conjunction with the radiolytically synthesized Ag-NPs as a LSPR-optical biosensor for estimation of uric acid.
Journal: Polymer - Volume 55, Issue 11, 27 May 2014, Pages 2652-2660