Diagnostics Devices for Improving the World: μPADs Integrated with Smartphone for Colorimetric Detection of Dopamine

In recent years, microfluidic paper-based analytical devices (μPADs ) were used; becuase of their low cost, ease of use, low sample consumption and reagent, and portability, specially in developing countries. In this research, colorimetric detection of dopamine (DA) was proposed on fast, simple, sensitive and low-cost μPADs, which is fabricated by using laser cutting technique. In paper-based microfluidic systems, wax printing is commonly used to create a hydrophobic barrier, but in this study, labels were used for the first time to create hydrophobic barriers due to their cost-effectiveness and easy access. Also in this study, the effect of various parameters on the performance improvement of developed μPADs such as DA volume, reaction time, drying time and volume ratio of ferric ion to DA was investigated. The results showed that the presence of DA made the red color bolder and a quantitative amount of DA was obtained by taking pictures of colored areas with a smartphone. Finally, after drawing the calibration curve, the limit of detection value 0.1 μM was defined.