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A potentiometric indirect uric acid sensor based on ZnO nanoflakes and immobilized uricase.

Ali SM, Ibupoto ZH, Kashif M, Hashim U, Willander M - Sensors (Basel) (2012)

Bottom Line: 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 sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.

View Article: PubMed Central - PubMed

Affiliation: Department of Science and Technology, Linköping University, Campus Norrköping, Norrkoping, Sweden. syeal@itn.liu.se

ABSTRACT
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.

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(a) AFM image of deposited gold thin film on glass substrate showing a flat surface with a surface roughness of Ra = 10 nm and (b) AFM image of grown ZnO-NFs arrays.
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f1-sensors-12-02787: (a) AFM image of deposited gold thin film on glass substrate showing a flat surface with a surface roughness of Ra = 10 nm and (b) AFM image of grown ZnO-NFs arrays.

Mentions: To fabricate the sensor electrodes, glass substrates were used after being cleaned with acetone and de-ionized water then we affixed the glass substrate on a flat support inside the vacuum chamber of an evaporation system (Evaporator Satis CR725). In the first step, a thin film of titanium (Ti) with 20 nm thickness was evaporated as an adhesive layer then gold (Au) thin film with 100 nm thickness was evaporated. An AFM image showing the surface roughness of deposited gold films is shown in Figure 1(a).


A potentiometric indirect uric acid sensor based on ZnO nanoflakes and immobilized uricase.

Ali SM, Ibupoto ZH, Kashif M, Hashim U, Willander M - Sensors (Basel) (2012)

(a) AFM image of deposited gold thin film on glass substrate showing a flat surface with a surface roughness of Ra = 10 nm and (b) AFM image of grown ZnO-NFs arrays.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376584&req=5

f1-sensors-12-02787: (a) AFM image of deposited gold thin film on glass substrate showing a flat surface with a surface roughness of Ra = 10 nm and (b) AFM image of grown ZnO-NFs arrays.
Mentions: To fabricate the sensor electrodes, glass substrates were used after being cleaned with acetone and de-ionized water then we affixed the glass substrate on a flat support inside the vacuum chamber of an evaporation system (Evaporator Satis CR725). In the first step, a thin film of titanium (Ti) with 20 nm thickness was evaporated as an adhesive layer then gold (Au) thin film with 100 nm thickness was evaporated. An AFM image showing the surface roughness of deposited gold films is shown in Figure 1(a).

Bottom Line: 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 sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.

View Article: PubMed Central - PubMed

Affiliation: Department of Science and Technology, Linköping University, Campus Norrköping, Norrkoping, Sweden. syeal@itn.liu.se

ABSTRACT
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.

Show MeSH