Cnidarian tentacle-inspired microfluidic patch for improved analyte distribution in multiplex sweat sensing

Abstract A wearable multiplex sweat sensing patch with low sweat volume requirement and uniform distribution is highly desirable for noninvasive, real-time monitoring of various health-related biomarkers. The patch features a multi-channel microfluidic system inspired by cnidarians. It comprises of symmetric super-hydrophilic/super-hydrophobic patterned wedge channels allowing for simultaneous analysis of multiple analytes present in sweat. It ensures a uniform sweat transport and equal volume distribution across multiple sensing zones for a more accurate and reliable electrochemical sensing. As a proof of concept, a four-channel system housing sensors for glucose, lactate, urea, and pH was tested. The innovation lies in a unique surface design and electrode configuration utilizing PDMS-TiO 2 nanocomposite coating, integrating channels with electrodes, presenting a novel approach for accurate low-volume sweat analysis requiring a minimum of 4 µL. An on-body test was conducted to demonstrate the practical application of the patch. In addition, the physics of droplet splitting was explained through simulations.