State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, College of Chemistry and Pharmaceutical Science of Guangxi Normal University, Guilin 541004, PR China.
State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, College of Chemistry and Pharmaceutical Science of Guangxi Normal University, Guilin 541004, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Aug 5;219:240-247. doi: 10.1016/j.saa.2019.04.061. Epub 2019 Apr 23.
Zeolitic imidazolate framework-8 (ZIF-8) has become one of the most typical examples of nanostructures for multi-enzyme immobilization due to its economical, mild and easy synthesis process. However, ZIF-8 nanocrystals are easily decomposed under acidic conditions. To solve this problem, the Fe-polydopamine (Fe-PDA) was bonded with ZIF-8 surface to form ZIF-8@Fe-PDA hybrid shell with good stability. Based on this, we developed glucose oxidase@ZIF-8@Fe-PDA (GOx@ZIF-8@Fe-PDA) integrated nanozymes (INAzymes) with cascade reactions via a mild and environmentally friendly method. In order to synthesize the INAzymes, GOx was first embedded in ZIF-8 by coprecipitation (GOx@ZIF-8), and then GOx@ZIF-8 was bonded with Fe-PDA, which acted as a peroxidase mimic. The ZIF-8@Fe-PDA hybrid shell protected the INAzymes nanostructure from degradation under acidic conditions, which results in good chemical stability of the GOx@ZIF-8@Fe-PDA. In the INAzymes system, glucose is converted to gluconic acid by GOx in the presence of oxygen to produce HO as an intermediate. The HO reacts rapidly with Fe-PDA to generate OH, which oxidizes 3,3',5,5'-tetramethylbenzidine (TMB). The UV absorbance of oxidized TMB is directly proportional to the glucose concentration, and has a good linear relationship in the range of 5.0-100.0 μM glucose with detection limit of 1.1 μM. The INAzymes system has been successfully applied to rapid colorimetric detection of blood glucose levels. The INAzymes system exhibits high catalytic activity, excellent sensitivity, and enhanced chemical stability, playing great promise in clinical diagnosis and biosensing.
沸石咪唑酯骨架-8（ZIF-8）由于其经济、温和且易于合成的特点，已成为用于多酶固定化的最典型纳米结构之一。然而，ZIF-8 纳米晶体在酸性条件下容易分解。为了解决这个问题，将 Fe-聚多巴胺（Fe-PDA）键合到 ZIF-8 表面，形成具有良好稳定性的 ZIF-8@Fe-PDA 杂化壳。在此基础上，我们通过温和环保的方法，开发了基于级联反应的葡萄糖氧化酶@ZIF-8@Fe-PDA（GOx@ZIF-8@Fe-PDA）集成纳米酶（INAzymes）。为了合成 INAzymes，首先通过共沉淀将 GOx 嵌入 ZIF-8 中（GOx@ZIF-8），然后将 GOx@ZIF-8 与 Fe-PDA 键合，Fe-PDA 可作为过氧化物酶模拟物。ZIF-8@Fe-PDA 杂化壳保护 INAzymes 纳米结构在酸性条件下不降解，从而使 GOx@ZIF-8@Fe-PDA 具有良好的化学稳定性。在 INAzymes 体系中，GOx 在氧气存在下将葡萄糖转化为葡萄糖酸，产生 HO 作为中间产物。HO 与 Fe-PDA 快速反应生成 OH，OH 氧化 3,3',5,5'-四甲基联苯胺（TMB）。氧化 TMB 的紫外吸光度与葡萄糖浓度成正比，在 5.0-100.0 μM 葡萄糖范围内具有良好的线性关系，检测限为 1.1 μM。INAzymes 体系已成功应用于快速比色检测血糖水平。INAzymes 体系表现出高催化活性、优异的灵敏度和增强的化学稳定性，在临床诊断和生物传感方面具有广阔的应用前景。
