Dual-signal readout paper-based wearable biosensor for multiplexed analyte detection in sweat with 3D origami structure

In this research, we designed and implemented a small, convenient, and non-invasive paper-based microfluidic sweat sensor that can simultaneously detect multiple key biomarkers in human sweat. The origami structure of the chip includes colorimetric and electrochemical sensing regions. Different colorimetric sensing regions are modified with specific chromogenic reagents to selectively identify glucose, lactate, uric acid, and magnesium ions in sweat, as well as its pH value. The regions of electrochemical sensing identify cortisol in sweat by molecular imprinting. The entire chip is composed of hydrophilic- and hydrophobically-treated filter paper, and 3D microfluidic channels are constructed by using folding paper. The thread-based channels formed after hydrophilic and hydrophobic modifications are used to control the rate of flow of sweat, which in turn can be used to control the sequence of reactions in the differently colored regions of development to ensure that signals of the best color can be captured simultaneously in the colorimetric sensing regions. Finally, the results of on-body experiments verified the reliability of the proposed sweat sensor and its potential for the non-invasive identification of a variety of sweat biomarkers.