Simple monitoring of pH and urea in whole blood using wearable smart woman pad

In this work, we used a thread-paper microfluidic device (μTPAD) system, where a threaded part for the handling of the whole blood samples and a paper part for the reaction of plasma with immobilized bioreagents integrated into woman pad as a wearable sensing device namely as smart women pad. The μTPAD as a wearable smart woman pad is developed for the detection of pH and urea in mensuration blood as real samples.

This combined device was constructed to cover the elements required, that is, separation of red blood cell, conditioning, analyte reaction, and colorimetric detection. The color change in sensing areas was measured in the RGB values via a smartphone using the Color Grab after a smart woman pad was used. The thread allowed red blood cell sampling and separation, while the paper microfluidic device was used for conditioning, biorecognition, and colorimetric transduction of pH and urea as analytes.

The time needed for analysis was measured as 110 s using the equilibrium method for both analytes, with a limit of detection (LOD) of 72.55 μg/mL for urea, with precision around 1.68%, while for pH around 0.80%. The smart woman pad allowed rapid detection of pH and urea in menstruation blood as real samples for monitoring of the kidney functions, and the results showed an agreement with the conventional methods that have been generally used in the clinical laboratory.

The smart woman pad has the potential to be used as a wearable device to monitor the health status of the user via its blood mensuration analysis.