A novel method for enzyme immobilization: direct encapsulation of acid phosphatase in nanoporous silica host materials.
A novel method for enzyme immobilization: direct encapsulation of acid phosphatase in nanoporous silica host materials.
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DOI：
10.1166/jnn.2001.014
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发表时间：
2001-03
影响因子：
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通讯作者：
Y. Wei;J. Xu;Q. Feng;M. Lin;H. Dong;W. Zhang;C. Wang
中科院分区：
文献类型：
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作者：
Y. Wei;J. Xu;Q. Feng;M. Lin;H. Dong;W. Zhang;C. Wang
酸性磷酸酶（ACP）在介孔或更普遍的纳米孔二氧化硅中的固定化是通过正硅酸四甲基在ACP和d -葡萄糖（DG）存在下的溶胶-凝胶反应完成的，d -葡萄糖（DG）作为非表面活性剂模板，随后在形成纳米复合凝胶后通过水萃取去除。去除DG后二氧化硅载体的表征表明，随着DG含量的增加，二氧化硅载体的孔径和体积普遍增大。在高DG含量下，二氧化硅载体是纳米多孔的，具有相互连接的纳米级孔/通道，其直径为规则的（例如，3.4 nm）。与不含DG的微孔载体相比，纳米孔载体包封ACP的催化活性显著提高。在不同pH值和底物浓度下的表观酶活性与宿主基质的纳米结构密切相关。随着合成过程中DG含量的增加，活性有增加的趋势。DG含量为42-60 wt%时，样品的活性约为无模板对照的三倍。这些和其他来自酶动力学研究的结果表明，孔隙大小和体积的增加促进了底物和产物分子在宿主基质中的运输，导致观察到的活性增加。固定化后，ACP的热稳定性显著提高。宿主基质中没有检测到ACP的泄漏，生物凝胶是可重复使用的。该研究为纳米技术在各种生物催化剂和生物传感器领域的发展提供了一个有用的方案。
Immobilization of acid phosphatase (ACP) in mesoporous or, more generally, nanoporous silica has been accomplished via the sol-gel reactions of tetramethyl orthosilicate in the presence of ACP and of D-glucose (DG) as a nonsurfactant template, which is subsequently removed by water extraction after the formation of nanocomposite gels. Characterization of the silica host after the removal of DG shows that the pore size and volume generally increase with the DG content. At high DG contents, the silica hosts are nanoporous with interconnected nanoscaled pores/channels of regular diameter (e.g., 3.4 nm). Catalytic activity of ACP encapsulated in nanoporous hosts is significantly improved over that in microporous host prepared in the absence of DG. The apparent enzymatic activity at various pH values and substrate concentrations correlates well with the nanostructures of the host matrices. As the DG content is increased in the synthesis, the activity tends to increase. At a DG content of 42-60 wt%, the samples exhibit activities about triple that of the template-free control. These and other results from enzymatic kinetic studies suggest that the increase in the pore size and volume facilitates the transport of the substrate and product molecules in the host matrices, leading to the observed increase in activity. The thermal stability of ACP is remarkably improved upon immobilization. There is no detectable leakage of ACP from the host matrices and the biogels are reuseable. This study provides a useful protocol for the development of nanotechnology for various biocatalysts and biosensors.