| Summary: | 碩士 === 明志科技大學 === 機械工程系機械與機電工程碩士班 === 106 === In pesticide detection, the activity of acetylcholinesterase (AChE) is inhibited, causing AChE to lose its ability to hydrolyze by combining with pesticides. The activity of AChE is reduced when the pesticide concentration is increased. Therefore, yellow 5-thio-2-nitrobenzoate (TNB) products are reduced and the color of the reaction becomes brighter. The toxicity of the pesticide depends on the inhibition of AChE, and such detection methods require the sample to have a fixed reaction time, resulting in a complicated procedure if traditional technology is used. To reduce the operating steps in and cost incurred by pesticide detection processes, this study was conducted to develop a paper-based chip for pesticide detection with automatic time delay and transfer printing the three-dimensional flow channel on the paper. In the proposed design, pullulan and AChE are mixed and placed on the chip. When the pesticides pass through the channel, pullulan is dissolved to delay the time of reaction and simultaneously inhibit AChE. In this design,different delay times can be adjusted depending on the concentration of the pullulan solution.
A change in color is induced by the chemical reaction and recorded using a color spectrometer. The measured RGB values are transferred to the Yxy and Lab color spaces by using a color conversion formula. This conversion can allow users to easily observe the trend of the color change. In the future, color information will be recognized by using a chroma card. In this study, a pesticide at a concentration of 0.0004 μg/mL could be detected using 250 U/mL AChE and 2.5% pullulan solution. The flow time of this process was 128 s.
The chip was fabricated by transfer printing the Teflon hydrophobic material to create a hydrophobic barrier on filter paper by using an imprint machine, which was developed in our laboratory. This study also optimizing the parameters of printing pressure, mold, temperature and filter papers. For avoiding test solution was not diffused due to the capillary force. The lowest dimension error was obtained using Advantec No.1 filter paper and a printing force of 28 kg at 80°C. The fabrication steps are rapid and inexpensive because special equipment is not required in this design. Therefore, the chip has potential for mass manufacturing and also has excellent market value.
|
|---|
