Université Grenoble Alpes, DCM UMR 5250, F-38000, Grenoble, France; CNRS, DCM UMR 5250, F-38000, Grenoble, France.
Université de Lorraine Institut Jean Lamour, UMR 7198, F-54000, Nancy, France; CNRS, Institut Jean Lamour, UMR, 7198, F-54000, Nancy, France.
Biosens Bioelectron. 2021 May 15;180:113137. doi: 10.1016/j.bios.2021.113137. Epub 2021 Mar 3.
A biosensor based on the release of the enzyme substrate from its structure was developed for the inhibitive detection of benzoic acid. A polyurethane support comprising two perforated microcapsules (800 μm in diameter) filled with methylene blue as a model compound and covered with a conductive deposit of multiwalled carbon nanotubes, continuously released this stored dye for 24 h. An increase in methylene blue concentration of 0.5-0.75 μmol L h and 1.5-2 μmol L h, in the presence and absence of the multiwalled carbon nanotube coating, respectively, was demonstrated by UV-vis spectroscopy in a 2 mL UV cuvette. The same configuration with microcapsules filled with catechol was modified by a laponite clay coating containing tyrosinase enzyme. The resulting biosensor exhibits a constant cathodic current at -0.155 V vs AgCl/Ag, due to the reduction of the ortho-quinone produced enzymatically from the released catechol. The detection of benzoic acid was recorded from the decrease in cathodic current due to its inhibiting action on the tyrosinase activity. Reagentless biosensors based on different deposited quantity of tyrosinase (100, 200, 400 and 600 μg) were investigated for the detection of catechol and applied to the detection of benzoic acid as inhibitor. The best performance was obtained with the 400 μg-based configuration, namely a detection limit of 0.4 μmol L and a sensitivity of 228 mA L mol. After the inhibition process, the biosensors recover 97-100% of their activity towards catechol, confirming a reversible inhibition by benzoic acid.
基于酶基质从其结构中释放的生物传感器被开发出来，用于对苯甲酸的抑制性检测。一种由两个穿孔微胶囊（直径 800μm）组成的聚氨酯载体，其中充满了亚甲基蓝作为模型化合物，并覆盖有一层多壁碳纳米管的导电沉积物，连续释放这种储存的染料长达 24 小时。在存在和不存在多壁碳纳米管涂层的情况下，通过在 2 mL UV 比色皿中进行的紫外可见光谱法，分别证明了 0.5-0.75μmol L h 和 1.5-2μmol L h 的亚甲基蓝浓度增加。用含有漆酶的膨润土粘土涂层修饰填充儿茶酚的微胶囊的相同配置。所得生物传感器在-0.155 V 相对于 AgCl/Ag 处表现出恒定的阴极电流，这是由于从释放的儿茶酚酶促产生的邻醌还原所致。由于其对漆酶活性的抑制作用，记录了苯甲酸的检测，这是由于阴极电流的减少。基于不同沉积量的漆酶（100、200、400 和 600μg）的无试剂生物传感器被用于检测儿茶酚，并应用于检测作为抑制剂的苯甲酸。基于 400μg 的配置获得了最佳性能，即检测限为 0.4μmol L，灵敏度为 228 mA L mol。在抑制过程之后，生物传感器对儿茶酚的活性恢复了 97-100%，证实了苯甲酸的可逆抑制。
