Gu Zhen, Wu Ming-Lei, Yan Bing-Yong, Wang Hui-Feng, Kong Cong
Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of Education, East China University of Science and Technology, Shanghai 200237, P. R. China.
Shanghai Key Laboratory of Forensic Medicine (Academy of Forensic Science), Shanghai 200063, P. R. China.
ACS Omega. 2020 May 4;5(19):11196-11201. doi: 10.1021/acsomega.0c01274. eCollection 2020 May 19.
In this paper, a palm-size digital microfluidic (DMF) platform integrated with colorimetric analysis was developed for quantifying the concentration of nitrite. To realize the on-chip repeatable colorimetric analysis, a novel printed circuit board (PCB)-based DMF chip was designed with an embedded aperture on the actuator electrode, forming a vertical light path for online measurement of the droplets. The capabilities of the DMF platform enable automatic manipulation of microliter-level droplets to implement Griess assay without the use of external systems such as syringe, pump, or valve, which provides the benefits including high flexibility, portability, miniature size, and low cost. Results indicated the characteristics of good linearity ( = 0.9974), the ignorable crosstalk for reusability, and the limit of detection (LOD) of nitrite as low as 5 μg/L. Furthermore, the presented platform was successfully applied to determine nitrite levels in food products with reliable results and satisfactory recoveries. This integrated DMF platform can be a promising new tool for a wide range of applications involving step-by-step solution mixing and optical detection in environmental monitoring, food safety analysis, and point-of-care testing.
本文开发了一种集成比色分析的手掌大小的数字微流控（DMF）平台，用于定量亚硝酸盐浓度。为实现芯片上的可重复比色分析，设计了一种基于新型印刷电路板（PCB）的DMF芯片，在致动器电极上设有嵌入式孔，形成垂直光路以在线测量液滴。DMF平台的功能能够自动操控微升级液滴，无需使用诸如注射器、泵或阀门等外部系统即可实施格里斯试剂比色法，具有高灵活性、便携性、尺寸小巧和低成本等优点。结果表明该平台具有良好的线性（ = 0.9974）、可重复使用时可忽略不计的串扰以及低至5 μg/L的亚硝酸盐检测限（LOD）。此外，该平台成功应用于测定食品中的亚硝酸盐含量，结果可靠，回收率令人满意。这种集成的DMF平台有望成为一种新型工具，广泛应用于环境监测、食品安全分析和即时检测等领域中涉及逐步溶液混合和光学检测的各种应用。
