Noninvasive Sweat-Lactate Biosensor Emplsoying a Hydrogel-Based Touch Pad

Kuniaki Nagamine,Hiroyuki Furusawa,Hiroyuki Matsui,Taisei Mano,Ayako Nomura,Ryota Izawa,Yusuke Ichimura,Shizuo Tokito,Daisuke Kumaki

doi:10.1038/s41598-019-46611-z

Abstract

This study is the first report demonstrating proof-of-concept for a hydrogel-based touch sensor pad used for the non-invasive extraction and detection of sweat components. The sensor device was composed of an electrochemical L-lactate biosensor covered with an agarose gel in a phosphate buffer saline. When human skin contacts the agarose gel, L-lactate in sweat was continuously extracted into the gel, followed by in-situ potentiometric detection without controlled conditions. This novel type of sweat sensor is expected to enable the simple, non-invasive daily periodic monitoring of sweat biomarkers for advanced personal healthcare methods in the future.

Highlights

Tsuda et al proposed a straightforward and periodic sweat sampling method[19,20]
We first carried out a study to replicate the sweat extraction methods proposed by Tsuda et al.[19,20,25] in order to optimize the composition of the sweat extraction solution
The L-lactate concentration in the Dulbecco’s Phosphate Buffer Saline (DPBS) collected from the skin surface was quantified using a commercially-available L-lactate sensor

Summary

Introduction

Human skin was exposed to 1 vol% aqueous ethanol to extract the sweat component into aqueous ethanol They emphasized that the addition of ethanol into water induces a smaller surface tension of the solution to the skin allowing the solution to penetrate the sweat gland effectively. This study reports on a hydrogel-based touch sensor pad for the non-invasive extraction and detection of sweat components (Fig. 1). The sweat components can be and continuously extracted from human skin contacted with the agarose hydrogel, followed by in-situ detection. This new type of touch sensor pad integrated with biosensors will enable non-invasive and daily periodic monitoring of sweat biomarkers without harsh exercise-, environmental temperature control, and cholinergic agonist-assisted perspiration

Objectives

Methods

Results

Conclusion