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Effect of substrate (ZnO) morphology on enzyme immobilization and its catalytic activity.

Zhang Y, Wu H, Huang X, Zhang J, Guo S - Nanoscale Res Lett (2011)

Bottom Line: The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system.The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay.Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Key Laboratory of Micro/Nano Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, PR China. haixiawu@sjtu.edu.cn.

ABSTRACT
In this study, zinc oxide (ZnO) nanocrystals with different morphologies were synthesized and used as substrates for enzyme immobilization. The effects of morphology of ZnO nanocrystals on enzyme immobilization and their catalytic activities were investigated. The ZnO nanocrystals were prepared through a hydrothermal procedure using tetramethylammonium hydroxide as a mineralizing agent. The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system. The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay. Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker. The results showed that three-dimensional nanomultipod is more appropriate for the immobilization of enzyme used further in catalytic reaction.

No MeSH data available.


TEM images of amino group modified ZnO nanodisks. (a-c) TEM images of modified ZnO nanodisks with different TEOS:APTES ratios of 1:1, 1:4, and 1:10.
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Figure 4: TEM images of amino group modified ZnO nanodisks. (a-c) TEM images of modified ZnO nanodisks with different TEOS:APTES ratios of 1:1, 1:4, and 1:10.

Mentions: The amount of amino groups and the thickness of the coating layer can be controlled by adjusting the ratio of TEOS to APTES. When the ratio of TEOS to APTES was 1:1, a coating layer of approximately 2 nm can be generated on the surface of ZnO nanocrystal, but, at the same time, lots of isolated SiO2 nanocrystals were formed, as shown in Figure 4a. When the ratio of TEOS to APTES was 1:4, a layer with uniform thickness of about 2 nm was formed as shown in Figure 4b. When the ratio of TEOS to APTES was decreased to 1:10, no fully covered coating layer can be generated, as shown in Figure 4c. According to the standard curve of glycine obtained by Kaiser Assay, the amount of amino groups on the surface of ZnO nanocrystals was deduced. When the ratios of TEOS to APTES were 1:1, 1:4, and 1:10 used for the surface modification, the amounts of amino groups on the surface of ZnO nanodisks were 0.03, 0.07, and 0.02 mmol/g, respectively. These results show that the ratio of TEOS to APTES used for the surface modification determines the uniformity of the coating layer as well as the amount of amino groups.


Effect of substrate (ZnO) morphology on enzyme immobilization and its catalytic activity.

Zhang Y, Wu H, Huang X, Zhang J, Guo S - Nanoscale Res Lett (2011)

TEM images of amino group modified ZnO nanodisks. (a-c) TEM images of modified ZnO nanodisks with different TEOS:APTES ratios of 1:1, 1:4, and 1:10.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211870&req=5

Figure 4: TEM images of amino group modified ZnO nanodisks. (a-c) TEM images of modified ZnO nanodisks with different TEOS:APTES ratios of 1:1, 1:4, and 1:10.
Mentions: The amount of amino groups and the thickness of the coating layer can be controlled by adjusting the ratio of TEOS to APTES. When the ratio of TEOS to APTES was 1:1, a coating layer of approximately 2 nm can be generated on the surface of ZnO nanocrystal, but, at the same time, lots of isolated SiO2 nanocrystals were formed, as shown in Figure 4a. When the ratio of TEOS to APTES was 1:4, a layer with uniform thickness of about 2 nm was formed as shown in Figure 4b. When the ratio of TEOS to APTES was decreased to 1:10, no fully covered coating layer can be generated, as shown in Figure 4c. According to the standard curve of glycine obtained by Kaiser Assay, the amount of amino groups on the surface of ZnO nanocrystals was deduced. When the ratios of TEOS to APTES were 1:1, 1:4, and 1:10 used for the surface modification, the amounts of amino groups on the surface of ZnO nanodisks were 0.03, 0.07, and 0.02 mmol/g, respectively. These results show that the ratio of TEOS to APTES used for the surface modification determines the uniformity of the coating layer as well as the amount of amino groups.

Bottom Line: The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system.The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay.Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Key Laboratory of Micro/Nano Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Research Institute of Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, PR China. haixiawu@sjtu.edu.cn.

ABSTRACT
In this study, zinc oxide (ZnO) nanocrystals with different morphologies were synthesized and used as substrates for enzyme immobilization. The effects of morphology of ZnO nanocrystals on enzyme immobilization and their catalytic activities were investigated. The ZnO nanocrystals were prepared through a hydrothermal procedure using tetramethylammonium hydroxide as a mineralizing agent. The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system. The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay. Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker. The results showed that three-dimensional nanomultipod is more appropriate for the immobilization of enzyme used further in catalytic reaction.

No MeSH data available.