Epidermal Patch with Glucose Biosensor: pH and Temperature Correction toward More Accurate Sweat Analysis during Sport Practice

TLDR

Reliable enzymatic sweat sensors require pH and temperature correction because sensor activity depends strongly on these factors. The study aims to develop an epidermal glucose sensor patch that incorporates real‑time pH and temperature correction to enable reliable sweat glucose monitoring during sport. The patch is a flexible microfluidic skin device containing glucose, pH, and temperature sensors, and its performance was validated by comparing on‑body measurements with UV–vis spectrometry and ion chromatography. The sensor shows a 10–200 μM linear response, fast kinetics, good selectivity, and excellent reversibility, and nine on‑body tests confirm its potential for reliable sweat glucose monitoring during sport.

Abstract

We present an epidermal patch for glucose analysis in sweat incorporating for the first time pH and temperature correction according to local dynamic fluctuations in sweat during on-body tests. This sort of correction is indeed the main novelty of the paper, being crucial toward reliable measurements in every sensor based on an enzymatic element whose activity strongly depends on pH and temperature. The results herein reported for corrected glucose detection during on-body measurements are supported by a two-step validation protocol: with the biosensor operating off- and on-bodily, correlating the results with UV–vis spectrometry and/or ion chromatography. Importantly, the wearable device is a flexible skin patch that comprises a microfluidic cell designed with a sweat collection zone coupled to a fluidic channel in where the needed electrodes are placed: glucose biosensor, pH potentiometric electrode and a temperature sensor. The glucose biosensor presents a linear range of response within the expected physiological levels of glucose in sweat (10–200 μM), and the calibration parameters are dynamically adjusted to any change in pH and temperature during the sport practice by means of a new "correction approach". In addition, the sensor displays a fast response time, appropriate selectivity, and excellent reversibility. A total of 9 validated on-body tests are presented: the outcomes revealed a great potential of the wearable glucose sensor toward the provision of reliable physiological data linked to individuals during sport activity. In particular, the developed "correction approach" is expected to impact into the next generation of wearable devices that digitalize physiological activities through chemical information in a trustable manner for both sport and healthcare applications.