Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Lab Chip. 2019 Jan 29;19(3):484-492. doi: 10.1039/c8lc01015c.
High portability and environmental safety ("green") are two of the most important objectives pursued by microfluidic methods. However, there remain many challenges for the design of portable and visual microfluidic methods (e.g., chip electrophoresis) due to use of a cumbersome pump, power supply and detector. Herein, a facile double inner standard plot (DISP) model of electrophoresis titration (ET) was proposed for portable and visual assay of proteins in test milk samples without use of a pump, power supply or detector based on a moving reaction boundary (MRB) chip. The DISP-ET model predicted that: (i) by setting the upper limit (UL) and lower limit (LL) of double inner standard milk protein contents, points U and L were, respectively, achieved in the relationship D = -aC + b (D: MRB motion distance; C: protein content); and (ii) the two points divided both the C-axis and D-axis into "poor", "eligible" and "superior" rulers scaled for quantitative assay of test samples. To demonstrate the model of DISP-ET, an original portable device (120 mm × 78 mm × 30 mm, 341 g) was designed, which had a chip (25 mm × 25 mm × 4 mm) of three channels (15 mm × 200 μm × 80 μm), platinum electrodes, a lithium cell and touch screen. A series of experiments were undertaken based on the developed portable device. The relevant experiments demonstrated systemically the validity of the DISP-ET model, theory and method. In particular, the experiments clearly showed the advantages of the DISP-ET chip: portability, visuality, green use, rapidity, and flexibility for real-life use. Finally, the device was applied for a portable and visual assay of fresh milk from a cow on a dairy farm. The DISP-ET model opens a window for designing portable and visual quantitative methods of food-safety control and clinical diagnoses.
高便携性和环境安全性（“绿色”）是微流控方法追求的两个最重要目标。然而，由于使用繁琐的泵、电源和检测器，对于便携式和可视化微流控方法（例如芯片电泳）的设计仍然存在许多挑战。在此，提出了一种简单的电泳滴定双内标（DISP）模型，用于在无需使用泵、电源或检测器的情况下，基于移动反应边界（MRB）芯片对测试牛奶样品中的蛋白质进行便携式和可视化分析。DISP-ET 模型预测：（i）通过设置双内标牛奶蛋白含量的上限（UL）和下限（LL），在 D=-aC+b（D：MRB 运动距离；C：蛋白质含量）关系中分别达到点 U 和 L；（ii）这两个点将 C 轴和 D 轴分为“差”、“合格”和“优”标尺，用于定量分析测试样品。为了验证 DISP-ET 模型，设计了一种原始的便携式设备（120mm×78mm×30mm，341g），该设备具有一个三个通道的芯片（25mm×25mm×4mm），包括铂电极、锂电池和触摸屏。基于开发的便携式设备进行了一系列实验。相关实验系统地验证了 DISP-ET 模型、理论和方法的有效性。特别是，实验清楚地显示了 DISP-ET 芯片的优势：便携性、可视化、绿色使用、快速性和适用于实际生活的灵活性。最后，该设备用于对奶牛场的新鲜牛奶进行便携式和可视化分析。DISP-ET 模型为设计便携式和可视化食品安全控制和临床诊断定量方法开辟了一扇窗口。
