We developed the acetylcholinesterase detection system using paper hybrid centrifugal fluidic disc platform. A new method of metering using paper was applied to disk platforms. After the solution is applied to the paper, a certain amount of solution flows to the detection zone according to the rotation speed and rotation time of the disc. Detection zones contain various concentrations of pesticide and material for colorimetric detection. Therefore, the buffer-injected through the inlet is distributed in the same amount in 6 detection zones to activate the pre-contained enzyme. The disk platform was configured to obtain a calibrated curve for the concentration of acetylcholinesterase. Pesticides inhibit acetylcholinesterase and cause a cholinergic overdose. Blood pesticide detection is a method of measuring acetylcholinesterase activity. Therefore, a calibration curve that is detected in the same environment is needed to diagnose the activity of the enzyme due to pesticide poisoning of blood. The assay consists of acetylthiocholine and ELLMAN reagent. Acetylcholinesterase decomposes acetylthiocholine into thiocholine and ELLMAN reagent develops yellow color by the product. The color change of the detection zone was obtained through scanner after 2 minutes of buffer injection. In this study, the concentration of the enzyme was detected by metering through paper without any elaborate plastic processing or chemical treatment of the channel. The platform can provide a suitable standard for detecting suspected blood and pesticide substances on the same disk platform.
In this study, we demonstrate a novel wax-patterned paper-polymer centrifugal optical system for performing multiple biomedical tests. The system consists of a detector (photodiode, LED), a diagnostic disc (paper, plastic) and a DC motor, allowing monitoring of changes in real time absorbance. Here, a wax printer was used to form hydrophobic channels on paper. The diagnostic disc can be prepared by attaching wax-patterned paper to a plastic disc. After the diagnostic disc is mounted on the dc motor, the fluid first wets the wax-patterned paper by centrifugal force, slowly moves by capillary action, and the reaction proceeds in the reaction zone with enzyme and color indicator. Microfluidic devices prepared in the wax-patterned paper have several attractive features such as low cost, ease of use, disposability and portability. In addition, the centrifugal disk-based platform can provide a solution for high-efficiency analysis that can process multiple reactions in parallel and monitor reactions in real time. To demonstrate the usability of this system, we performed realtime monitoring of glucose, an important indicator of blood glucose. The detection results could be delivered with the calibration curve within 10 seconds and no complex image analysis was required. The developed wax-patterned paperpolymer centrifugal optical system is promising for clinical multianalyte point-of-care testing due to its ease of manufacture, ease of operation, low cost and high sensitivity.