Lactate in sweat is an essential biomarker for health monitoring as it can provide information regarding the individual’s oxidative stress levels, cardiorespiratory performance, and muscle health. Although various wearable platforms have monitored sweat lactate in the past, most of these platforms’ function only with active perspiration, become inoperative at longer time periods (~ hours) due becoming saturated with sweat, and lack a mechanism to allow continuous flow of sweat. We will present a wearable, non-invasive, continuous sweat lactate monitoring platform, developed as an extension of our previously developed sweat sampling patch (Saha et al., ACS Appl. Mater. Interfaces, 13, 2021), which can withdraw sweat from subjects under rest. Our platform simultaneously uses osmosis (via a high solute containing hydrogel) for sweat withdrawal, a paper microfluidic channel for sweat transport and management, and enzymatic sensors for lactate detection. The key design feature includes sensor location directly at the sweat sampling site (for instantaneous sensing with low sweat volumes) and a paper channel with a tortuous path and large surface area (achieving delayed saturation). The fabricated enzymatic sensors possess a limit of detection, linear dynamic range, sensitivity, and stability of ~ 350 nM, 15 mM, 90 nA.mM-1.mm-2 and 4 days, respectively under in-vitro settings. The platform integration with our custom built flexible wireless potentiostat results in a wearable device that operates under low power consumption (~0.706 µW), while allowing real-time monitoring of sweat lactate trends on a wireless device (iPad). On-skin testing shows the potential of the integrated platform to continuously monitor sweat lactate trends from subjects at rest and at medium and high levels of physical exertion. Overall, this wearable system holds the potential of providing means of a comprehensive and long-term continuous analysis of sweat lactate trends in the human body.

Wearable platform for zero-power osmotic sweat extraction and continuous electrochemical lactate sensing

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.