Paper-Based and Time-Controlled Microfluidic Chip for Pesticide Detection

To realize the detection of pesticide, this study developed a paper-based chip involving a 2D to 3D flow channel and automatic time delay for detecting pesticides. The time delay was controlled by different pullulan concentrations. The 3D channel was fabricated by hot embossing (optimized printing parameters were 28 kg at 80°C, and Advantec No. 1 filter paper was used) and transfer printing the hydrophobic material into the paper. Finally, the limit of the detected concentration of the pesticide was 4 ng/mL, which was achieved using 250 U/mL of acetylcholinesterase (AChE) and 2.5% pullulan solution.