Lan Ruyue, Liu Huijiao, Zhu Lin, Lu Fan, Wu Qingshi, Wu Weitai
State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
College of Chemical Engineering and Materials Science, Quanzhou Normal University Quanzhou Fujian 362000 China.
RSC Adv. 2020 Jul 15;10(44):26566-26578. doi: 10.1039/d0ra04339g. eCollection 2020 Jul 9.
Responsive fluorescent microgels, that can selectively, reversibly, and rapidly convert the fluctuation in intracellular glucose level into fluorescence signal, have the potential use for intracellular glucometry to promote the understanding of physiology. Herein, we report one-pot synthesis of such a responsive fluorescent composite microgels, which is made of a representative apo-enzyme, apo-glucose oxidase (apo-GOx), interpenetrated in a composite gel network that is comprised of ZnO quantum dots covalently bonded onto crosslinked poly(ethylene glycol) dimethacrylate. The key of this one-pot synthesis is applying a high-temperature short-time heating (HTST) method, so that the naturally dynamic profile of apo-GOx can be maintained and harnessed on the composite microgels to allow the highly selective response to glucose over a glucose concentration range of 0-20 mM. While the composite microgels can undergo volume phase transitions and convert both an increase and a decrease in glucose concentration into fluorescence signal shortly (<1 s), the changes in average hydrodynamic diameter and fluorescence of the composite microgels can be fully reversible even after twenty cycles of adding/removing glucose, indicating a reversible and rapid time response to the glucose concentration variations. With the composite microgels as biosensors, the fluorescence of the composite microgels embedded in the model cancer cells B16F10 can be modulated in response to intracellular glucose level variations, which are derived from a change in glucose concentration in the culture medium by an external supply, or that can be triggered by biochemical reactions (with the β-galactosidase catalysed hydrolysis of lactose as a model reaction for achieving increased glucose levels, and the GOx catalysed oxidation of glucose for achieving decreased glucose levels).
响应性荧光微凝胶能够选择性、可逆且快速地将细胞内葡萄糖水平的波动转化为荧光信号，在细胞内葡萄糖检测方面具有潜在应用价值，有助于增进对生理学的理解。在此，我们报告了这种响应性荧光复合微凝胶的一锅法合成，它由一种代表性的脱辅基酶——脱辅基葡萄糖氧化酶（apo-GOx）构成，该酶穿插于一个复合凝胶网络中，此网络由共价键合在交联聚乙二醇二甲基丙烯酸酯上的ZnO量子点组成。这种一锅法合成的关键在于采用高温短时加热（HTST）方法，从而使apo-GOx的天然动态特性得以维持并应用于复合微凝胶上，使其在0 - 20 mM的葡萄糖浓度范围内对葡萄糖具有高度选择性响应。虽然复合微凝胶能够经历体积相变，并在短时间内（<1秒）将葡萄糖浓度的升高和降低都转化为荧光信号，但即使在添加/去除葡萄糖二十个循环后，复合微凝胶的平均流体动力学直径和荧光变化仍可完全可逆，这表明其对葡萄糖浓度变化具有可逆且快速的时间响应。以复合微凝胶作为生物传感器，嵌入模型癌细胞B16F10中的复合微凝胶的荧光可根据细胞内葡萄糖水平的变化进行调节，这些变化源于通过外部供应改变培养基中的葡萄糖浓度，或者可由生化反应触发（以β-半乳糖苷酶催化乳糖水解作为实现葡萄糖水平升高的模型反应，以及以葡萄糖氧化酶催化葡萄糖氧化作为实现葡萄糖水平降低的模型反应）。
