Simultaneous lancet-free monitoring of alcohol and glucose from low-volumes of perspired human sweat

Ashlesha Bhide,Sriram Muthukumar,Shalini Prasad,Amreek Saini

doi:10.1038/s41598-018-24543-4

Ashlesha Bhide, Sriram Muthukumar + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-24543-4

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Abstract

A lancet-free, label-free biosensor for simultaneous detection of sweat glucose and alcohol was demonstrated using zinc oxide thin films integrated into a nanoporous flexible electrode system. Sensing was achieved from perspired human sweat at low volumes (1–3 μL), comparable to ambient conditions without external stimulation. Zinc oxide thin film electrodes were surface functionalized with alcohol oxidase enzyme and with glucose oxidase enzyme towards developing an affinity biosensor specific to the physiological relevant range of alcohol comprising of 0–2 drinks (0–50 mg/dl) and physiologically relevant range of glucose ranging from hypo- to hyper-glycaemia (50–130 mg/dl) in perspired human sweat. Sensing was achieved by measuring impedance changes associated with alcohol and glucose binding onto the sensor interface using electrochemical impedance spectroscopy with a dynamic range from 0.01–200 mg/dl and a limit of detection of 0.01 mg/dl for alcohol in human sweat. Sensor calibration in synthetic sweat containing interferents (25–200 mg/dl) and comparison using regression and Bland-Altman analysis of sweat sensor performance was done with BACtrack®. Combinatorial detection of glucose and ethanol in perspired human sweat and comparison of sweat sensor performance with Accu-Chek® blood glucose monitoring system that we expect would be relevant for pre-diabetics and diabetics for monitoring their glucose levels and alcohol consumption.

Highlights

® sensor performance with Accu-Chek blood glucose monitoring system that we expect would be relevant for pre-diabetics and diabetics for monitoring their glucose levels and alcohol consumption
Human eccrine glands secret sweat at the rate 5–10 nl/min/gland[13] typically which necessitates the use of low volumes for sensor functioning when it comes in contact with the skin
Nanoconfinement of biomolecules based on size offers an enhanced signal to noise ratio (SNR) which is feasible for detecting small analytes because human sweat consists of ions and lipids that would otherwise contribute to the noise factor[14,15,16,17]

Summary

Introduction

® sensor performance with Accu-Chek blood glucose monitoring system that we expect would be relevant for pre-diabetics and diabetics for monitoring their glucose levels and alcohol consumption. Wearable biosensing technologies that detect biomarkers from human sweat have evolved from this need of non-invasive monitoring of social lifestyle choices coupled with a view of chronic disease management. Human sweat is one such biomarker rich fluid containing valuable medical information that can be the key driver for developing sweat based point-of-care health management devices[5]. Diabetes Mellitus requires frequent monitoring of glucose levels with glucose being present in the range 0.1–50 mg/dl in human sweat[11]. The premise of this paper is to demonstrate a lifestyle monitor based on sweat alcohol detection designed on a flexible platform towards building a wearable, point-of-care diagnostic for: (1) Glucose management to monitor blood glucose levels after consumption of alcohol (2) addressing the rising need for controlling alcohol induced fatalities and damages

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