Highly-sensitive cholesterol biosensor based on well-crystallized flower-shaped ZnO nanostructures |
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Authors: | Ahmad Umar M.M. Rahman Y.-B. Hahn |
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Affiliation: | a Department of Chemistry, Faculty of Science, Najran University, P.O. Box 1988, Najran 11001, Kingdom of Saudi Arabia b School of Semiconductor and Chemical Engineering, BK21 Centre for Future Energy Materials and Devices, Nanomaterials Research Processing Centre, Chonbuk National University, 664-14, 6 Duckjin Dong, 1 Ga Jeonju, Choella-Bukto, Jeonju 561-756, South Korea c Department of Physics, Faculty of Science, Najran University, P.O. Box 1988, Najran 11001, Kingdom of Saudi Arabia |
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Abstract: | This paper reports the fabrication of highly-sensitive cholesterol biosensor based on cholesterol oxidase (ChOx) immobilization on well-crystallized flower-shaped ZnO structures composed of perfectly hexagonal-shaped ZnO nanorods grown by low-temperature simple solution process. The fabricated cholesterol biosensors reported a very high and reproducible sensitivity of 61.7 μA μM−1 cm−2 with a response time less than 5 s and detection limit (based on S/N ratio) of 0.012 μM. The biosensor exhibited a linear dynamic range from 1.0-15.0 μM and correlation coefficient of R = 0.9979. A lower value of apparent Michaelis-Menten constant (Kmapp), of 2.57 mM, exhibited a high affinity between the cholesterol and ChOx immobilized on flower-shaped ZnO structures. Moreover, the effect of pH on ChOx activity on the ZnO modified electrode has also been studied in the range of 5.0-9.0 which exhibited a best enzymatic activity at the pH range of 6.8-7.6. To the best of our knowledge, this is the first report in which such a very high-sensitivity and low detection limit has been achieved for the cholesterol biosensor by using ZnO nanostructures modified electrodes. |
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Keywords: | 62.23.Hj 82.45.Yz 87.85.Rs 81.05.Dz 81.07.&minus b 81.10.Bk |
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