A potentiometric indirect uric acid sensor based on ZnO nanoflakes and immobilized uricase.
In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of ~66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.
Department of Science and Technology, Linköping University, Campus Norrköping, Norrkoping, Sweden. syeal@itn.liu.se
Syed M Usman
SM
Ali
Zafar Hussain
ZH
Ibupoto
Muhammad
M
Kashif
Uda
U
Hashim
Magnus
M
Willander
D015374:Biosensing Techniques; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005465:Fluorocarbon Polymers / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D014503:Urate Oxidase / Q000737:chemistry / Q000378:metabolism*; D014527:Uric Acid / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
D004800:Enzymes, Immobilized; D005465:Fluorocarbon Polymers; D014527:Uric Acid; C040402:perfluorosulfonic acid; D014503:Urate Oxidase; D015034:Zinc Oxide