Chen Hongxia, Zhang Jiangjiang, Wu Heng, Koh Kwangnak, Yin Yongmei
Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
Institute of General Education, Pusan National University, Pusan 609-735, Republic of Korea.
Anal Chim Acta. 2015 May 22;875:92-8. doi: 10.1016/j.aca.2015.02.022. Epub 2015 Feb 12.
A colorimetric sensor has been developed in this work to sensitively detect α-glucosidase activity and screen α-glucosidase inhibitors (AGIs) utilizing unmodified gold nanoparticles (AuNPs). The sensing strategy is based on triple-catalytic reaction triggered by α-glucosidase. In the presence of α-glucosidase, aggregation of AuNPs is prohibited due to the oxidation of cysteine to cystine in the system. However, with addition of AGIs, cysteine induced aggregation of AuNPs occurs. Thus, a new method for α-glucosidase activity detection and AGIs screening is developed by measuring the UV-vis absorption or visually distinguishing. A well linear relation is presented in a range of 0.0025-0.05 U mL(-1). The detection limit is found to be 0.001 U mL(-1) for α-glucosidase assay, which is one order of magnitude lower than other reports. The IC50 values of four kinds of inhibitors observed with this method are in accordance with other reports. The using of unmodified AuNPs in this work avoids the complicated and time-consuming modification procedure. This simple and efficient colorimetric method can also be extended to other enzymes assays.
在这项工作中，已开发出一种比色传感器，用于利用未修饰的金纳米颗粒（AuNPs）灵敏地检测α-葡萄糖苷酶活性并筛选α-葡萄糖苷酶抑制剂（AGIs）。传感策略基于α-葡萄糖苷酶触发的三催化反应。在α-葡萄糖苷酶存在的情况下，由于系统中半胱氨酸被氧化为胱氨酸，AuNPs的聚集被抑制。然而，加入AGIs后，半胱氨酸诱导AuNPs发生聚集。因此，通过测量紫外可见吸收或目视辨别，开发了一种检测α-葡萄糖苷酶活性和筛选AGIs的新方法。在0.0025 - 0.05 U mL(-1)范围内呈现良好的线性关系。发现α-葡萄糖苷酶测定的检测限为0.001 U mL(-1)，比其他报道低一个数量级。用该方法观察到的四种抑制剂的IC50值与其他报道一致。这项工作中使用未修饰的AuNPs避免了复杂且耗时的修饰过程。这种简单有效的比色法也可扩展到其他酶的测定。
