An ultrasimple and cost‐effective µPAD by pasting hydrophilic channels to a hydrophobic basement

The application of the paper‐based microfluidic device (µPAD) as a potentially significant platform for clinical diagnoses has gained a great interest during the recent years. This work presented a technically ultrasimple, low‐cost, effective, and rapid method for the µPADs fabrication by pasting a hydrophilic flower‐like paper mask to a hydrophobic PVC substrate, which was purchased with adhesive on it. The whole manufacture process could be implemented in a few seconds by untrained personnel. To demonstrate the feasibility of this method in real‐world situations, the developed paper device was employed for colorimetric assays of glucose in artificial urine and nitrite in artificial saliva. The main analysis parameters, for example, the optimum volumes of reagents, reaction time, and so forth, were seriatim optimized. Under optimal conditions, the detection limits were 0.9 mM and 19.5 µM for glucose and nitrite, respectively; the detection ranges were 0.9–30 mmol/L and 19.5–312.5 µmol/L for glucose and nitrite analyses, respectively. These results showed that this equipment‐free µPAD had great potentials for the qualitative or semiquantitative detection of glucose and nitrite in real samples.