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Ultrasensitive non-enzymatic glucose sensor based on three-dimensional network of ZnO-CuO hierarchical nanocomposites by electrospinning.

Zhou C, Xu L, Song J, Xing R, Xu S, Liu D, Song H - Sci Rep (2014)

Bottom Line: Three-dimensional (3D) porous ZnO-CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes.Moreover, a good synergetic effect between CuO and ZnO was confirmed.The nonenzymatic biosensing properties of as prepared 3D porous electrodes based on fluorine doped tin oxide (FTO) were studied and the results indicated that the sensing properties of 3D porous ZnO-CuO HNCs electrodes were significantly improved and depended strongly on the thickness of the HNCs.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, People's Republic of China.

ABSTRACT
Three-dimensional (3D) porous ZnO-CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes. The structural characterization revealed that the ZnO-CuO HNCs were composed of the ZnO and CuO mixed NWs trunk (~200 nm), whose outer surface was attached with small CuO nanoparticles (NPs). Moreover, a good synergetic effect between CuO and ZnO was confirmed. The nonenzymatic biosensing properties of as prepared 3D porous electrodes based on fluorine doped tin oxide (FTO) were studied and the results indicated that the sensing properties of 3D porous ZnO-CuO HNCs electrodes were significantly improved and depended strongly on the thickness of the HNCs. At an applied potential of + 0.7 V, the optimum ZnO-CuO HNCs electrode presented a high sensitivity of 3066.4 μAmM(-1)cm(-2), the linear range up to 1.6 mM, and low practical detection limit of 0.21 μM. It also showed outstanding long term stability, good reproducibility, excellent selectivity and accurate measurement in real serum sample. The formation of special hierarchical heterojunction and the well-constructed 3D structure were the main reasons for the enhanced nonenzymatic biosensing behavior.

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(a) Amperometric response of 3D porous ZnO–CuO HNCs (10, 15, 20, and 25 min) electrodes as well as 3D mixed ZnO/CuO, 3D pure CuO and ZnO NWs electrodes at an applied potential of 0.7 V upon successive additions of different concentration of glucose in a step of 10, 50, and 200 μM, respectively for each current step, inset is the current response of 3D porous ZnO–CuO HNCs (20 min) to 0.47 and 1 μM glucose). (b) The corresponding calibration curve of current vs. concentration of glucose. The error bars denote the standard deviation of triplicate determination of each concentration of glucose.
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f8: (a) Amperometric response of 3D porous ZnO–CuO HNCs (10, 15, 20, and 25 min) electrodes as well as 3D mixed ZnO/CuO, 3D pure CuO and ZnO NWs electrodes at an applied potential of 0.7 V upon successive additions of different concentration of glucose in a step of 10, 50, and 200 μM, respectively for each current step, inset is the current response of 3D porous ZnO–CuO HNCs (20 min) to 0.47 and 1 μM glucose). (b) The corresponding calibration curve of current vs. concentration of glucose. The error bars denote the standard deviation of triplicate determination of each concentration of glucose.

Mentions: Fig. 8a shows the I-t curve of different 3D electrodes performed at +0.7 V (vs. Ag/AgCl) in 0.1 M NaOH solution by addition of different concentration of glucose. It is clear that well-defined and fast amperometric responses are observed, except the pure ZnO NWs electrode which also has no response to glucose in I-t curve. The average times required approaching the steady-state current for the 3D pure CuO NWs electrode is 5 s, mixed ZnO/CuO NWs electrode is 3.4 s and 3D porous ZnO-CuO HNCs electrodes with electrospun time of 10, 15, 20, and 25 min were about 2.1, 1.6, 1.2, and 1.8 s, respectively, when the electrodes responded to 200 μM glucose. This indicates a rapid oxidative process in as-prepared 3D porous electrodes which is much faster than those in similar determination1235. Besides, the response times of the 3D porous electrodes modified by the samples which contain ZnO and CuO (mixed ZnO/CuO NWs and porous ZnO–CuO HNCs) are shorter than that of pure CuO NWs one and the corresponding responses are also higher, indicating that the interaction between ZnO and CuO in the composite structures are conducive to accelerate electron transport. Moreover, for the 3D porous ZnO–CuO HNCs electrodes, which has CuO NPs decorated on the surface of mixed ZnO/CuO NWs, they even show more faster response times and higher response, which further verify the advantage of ZnO–CuO HNCs structure. In our work, the I-t curves of the thinnest (10 min) and the thickest (25 min) 3D porous ZnO–CuO HNCs electrodes both show decreasing trend. This phenomenon reveals that the thickness of 3D structure has great influence on the performance of the electrodes. On the one hand, if the thickness is not thick enough it will lead to the electrode contain too little active ingredient content due to the lower combination rate of CuO as evidenced in XPS spectra and cause the suppression of I-t curve. On the other hand, if the thickness too thick it will result in too long electronic transmission path or the bad contact between FTO conducting substrate and upper 3D porous ZnO–CuO HNCs, then also cause the suppression of I–t curve. Note that a larger noise can be observed on the 3D porous ZnO-CuO HNCs electrode compared to the other contrastive electrodes in this study, this phenomenon can be ascribed to the formation of the hierarchical structure, which would increase the distance of each HNCs in 3D network to some extent and further work should be carried out to avoid this effect.


Ultrasensitive non-enzymatic glucose sensor based on three-dimensional network of ZnO-CuO hierarchical nanocomposites by electrospinning.

Zhou C, Xu L, Song J, Xing R, Xu S, Liu D, Song H - Sci Rep (2014)

(a) Amperometric response of 3D porous ZnO–CuO HNCs (10, 15, 20, and 25 min) electrodes as well as 3D mixed ZnO/CuO, 3D pure CuO and ZnO NWs electrodes at an applied potential of 0.7 V upon successive additions of different concentration of glucose in a step of 10, 50, and 200 μM, respectively for each current step, inset is the current response of 3D porous ZnO–CuO HNCs (20 min) to 0.47 and 1 μM glucose). (b) The corresponding calibration curve of current vs. concentration of glucose. The error bars denote the standard deviation of triplicate determination of each concentration of glucose.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4260231&req=5

f8: (a) Amperometric response of 3D porous ZnO–CuO HNCs (10, 15, 20, and 25 min) electrodes as well as 3D mixed ZnO/CuO, 3D pure CuO and ZnO NWs electrodes at an applied potential of 0.7 V upon successive additions of different concentration of glucose in a step of 10, 50, and 200 μM, respectively for each current step, inset is the current response of 3D porous ZnO–CuO HNCs (20 min) to 0.47 and 1 μM glucose). (b) The corresponding calibration curve of current vs. concentration of glucose. The error bars denote the standard deviation of triplicate determination of each concentration of glucose.
Mentions: Fig. 8a shows the I-t curve of different 3D electrodes performed at +0.7 V (vs. Ag/AgCl) in 0.1 M NaOH solution by addition of different concentration of glucose. It is clear that well-defined and fast amperometric responses are observed, except the pure ZnO NWs electrode which also has no response to glucose in I-t curve. The average times required approaching the steady-state current for the 3D pure CuO NWs electrode is 5 s, mixed ZnO/CuO NWs electrode is 3.4 s and 3D porous ZnO-CuO HNCs electrodes with electrospun time of 10, 15, 20, and 25 min were about 2.1, 1.6, 1.2, and 1.8 s, respectively, when the electrodes responded to 200 μM glucose. This indicates a rapid oxidative process in as-prepared 3D porous electrodes which is much faster than those in similar determination1235. Besides, the response times of the 3D porous electrodes modified by the samples which contain ZnO and CuO (mixed ZnO/CuO NWs and porous ZnO–CuO HNCs) are shorter than that of pure CuO NWs one and the corresponding responses are also higher, indicating that the interaction between ZnO and CuO in the composite structures are conducive to accelerate electron transport. Moreover, for the 3D porous ZnO–CuO HNCs electrodes, which has CuO NPs decorated on the surface of mixed ZnO/CuO NWs, they even show more faster response times and higher response, which further verify the advantage of ZnO–CuO HNCs structure. In our work, the I-t curves of the thinnest (10 min) and the thickest (25 min) 3D porous ZnO–CuO HNCs electrodes both show decreasing trend. This phenomenon reveals that the thickness of 3D structure has great influence on the performance of the electrodes. On the one hand, if the thickness is not thick enough it will lead to the electrode contain too little active ingredient content due to the lower combination rate of CuO as evidenced in XPS spectra and cause the suppression of I-t curve. On the other hand, if the thickness too thick it will result in too long electronic transmission path or the bad contact between FTO conducting substrate and upper 3D porous ZnO–CuO HNCs, then also cause the suppression of I–t curve. Note that a larger noise can be observed on the 3D porous ZnO-CuO HNCs electrode compared to the other contrastive electrodes in this study, this phenomenon can be ascribed to the formation of the hierarchical structure, which would increase the distance of each HNCs in 3D network to some extent and further work should be carried out to avoid this effect.

Bottom Line: Three-dimensional (3D) porous ZnO-CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes.Moreover, a good synergetic effect between CuO and ZnO was confirmed.The nonenzymatic biosensing properties of as prepared 3D porous electrodes based on fluorine doped tin oxide (FTO) were studied and the results indicated that the sensing properties of 3D porous ZnO-CuO HNCs electrodes were significantly improved and depended strongly on the thickness of the HNCs.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun, 130012, People's Republic of China.

ABSTRACT
Three-dimensional (3D) porous ZnO-CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes. The structural characterization revealed that the ZnO-CuO HNCs were composed of the ZnO and CuO mixed NWs trunk (~200 nm), whose outer surface was attached with small CuO nanoparticles (NPs). Moreover, a good synergetic effect between CuO and ZnO was confirmed. The nonenzymatic biosensing properties of as prepared 3D porous electrodes based on fluorine doped tin oxide (FTO) were studied and the results indicated that the sensing properties of 3D porous ZnO-CuO HNCs electrodes were significantly improved and depended strongly on the thickness of the HNCs. At an applied potential of + 0.7 V, the optimum ZnO-CuO HNCs electrode presented a high sensitivity of 3066.4 μAmM(-1)cm(-2), the linear range up to 1.6 mM, and low practical detection limit of 0.21 μM. It also showed outstanding long term stability, good reproducibility, excellent selectivity and accurate measurement in real serum sample. The formation of special hierarchical heterojunction and the well-constructed 3D structure were the main reasons for the enhanced nonenzymatic biosensing behavior.

Show MeSH