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.
Complementary metal oxide semiconductor (CMOS) image sensors have received great attention for their high efficiency in biological applications. The present work describes a CMOS image sensor-based whole blood glucose monitoring system through a point-of-care (POC) approach. A simple poly-ethylene terephthalate (PET) chip was developed to carry out the enzyme kinetic reaction at various concentrations (110–586 mg/dL) of mouse blood glucose. In this technique, assay reagent is immobilized onto amine functionalized silica (AFSiO2) nanoparticles as an electrostatic attraction in order to achieve glucose oxidation on the chip. The assay reagent immobilized AFSiO2 nanoparticles develop a semi-transparent reaction platform, which is technically a suitable chip to analyze by a camera module. The oxidized glucose then produces a green color according to the glucose concentration and is analyzed by the camera module as a photon detection technique; the photon number decreases when the glucose concentration increases. The combination of these components, the CMOS image sensor and enzyme immobilized PET film chip, constitute a compact, accurate, inexpensive, precise, digital, highly sensitive, specific, and optical glucose-sensing approach for POC diagnosis.
Complementary metal oxide semiconductor (CMOS) image sensors are received great attention for their high efficiency in biological applications. The present work describes a CMOS image sensor-based whole blood glucose monitoring system through a point-of-care (POC) approach. A simple poly-ethylene terephthalate (PET) film chip was developed to carry out the enzyme kinetic reaction at various concentrations of blood glucose. In this technique, assay reagent was adsorbed onto amine functionalized silica (AFSiO<sub>2</sub>) nanoparticles in order to achieve glucose oxidation on the PET film chip. The AFSiO<sub>2</sub> nanoparticles can immobilize the assay reagent with an electrostatic attraction and eased to develop the opaque platform which was technically suitable chip to analyze by the camera module. The oxidized glucose then produces a green color according to the glucose concentration and is analyzed by the camera module as a photon detection technique. The photon number decreases with increasing glucose concentration. The simple sensing approach, utilizing enzyme immobilized AFSiO<sub>2</sub> nanoparticle chip and assay detection method was developed for quantitative glucose measurement.