Silicon Micropillar Array-Based Wearable Sweat Glucose Sensor

Abstract

Wearable technologies have great potential in health monitoring and disease diagnostics. As a consequence, interest in the study of wearable sensors has dramatically increased over recent years. Successful translation of this technology from research prototypes to commercial products requires addressing some of the major challenges faced by wearable sensors such as loss of, and damage in, the biological recognition layer of the skin-interfaced sensors. In this work, we propose a solution to this challenge by integrating micropillar array (MPA) surfaces as part of the sensing layer with the aim to protect and prevent the loss of the enzyme layer from mechanical stress while the sensor is worn. The proposed wearable sensing patch is composed of reference, counter, and working electrodes, all made of MPAs and is designed for measuring glucose in sweat. MPA sensing patch has a wide linear range of 50 μM to 1.4 mM, a sensitivity of 4.7 ± 0.8 μA mM–1, and a limit of detection of 26 ± 5 μM. The glucose sensing patch was tested using human sweat where glucose-level changes were successfully measured before and after meal consumption. The developed patch provides an alternative solution to the problem of the damage to the sensor microenvironment upon wear. But in addition, it also offers a user-friendly, cost-effective, and reliable sweat analysis platform with significant potential in health monitoring applications.

Wearable Electrochemical Glucose Sensors in Diabetes Management: A Comprehensive Review

“…Glucose sensors have been developed on silicon-based micropillar arrays (MPAs) for noninvasive sweat glucose estimation. 152 A patch developed following this concept consisted about 72000 pillars/cm 2 and could directly interface the skin for sensing (Figure 5H). Each pillar was functionalized with electropolymerized Prussian blue (PB) catalyst, chitosangold nanoparticle composite, and a GOx enzymatic layer for selective glucose sensing.…”

Epidermal Wearable Biosensors for Monitoring Biomarkers of Chronic Disease in Sweat

“…In the second-generation biosensor, electron mediators are used to enhance the enzyme electrochemical reactions and to achieve efficient electron transfer from the enzyme’s activity center to the electrodes during sensing applications [ 127 , 128 ], resulting in better electrochemical performance. Carbon quantum dots (CQDs) and Prussian blue (PB) with high electron transfer rates are most commonly used to promote electron transfer and reduce interfacial impedance on the electrode surface ( Figure 6 A) [ 106 , 117 , 129 , 130 , 131 , 132 , 133 , 134 ]. However, the use of electron mediators not only increases the complexity of biosensors but also leads to low selectivity and instability due to cross-reactions and leakages of the electron mediators, respectively [ 121 , 135 ].…”

“…Copyright 2022, Elsevier), ( b ) second− (Reprinted with permission from Ref. [ 129 ]. Copyright 2022, American Chemical Society), and ( c ) third−generation (Reprinted with permission from Ref.…”

Wearable non-invasive glucose sensors based on metallic nanomaterials

“…1 (iii)). This sensor can prevent the loss of enzymes and settle the problem of damage to the sensor microenvironment after being worn on the body ([ 42 ]). In addition, a wearable, non-invasive, and biocompatible glucose sensor based on Au hydrogels to monitor the glucose concentration in sweat was developed in the study of Li et al.…”

“…(ii) Schematic illustration of the construction process of the gold electrode glucose sensor as well as the mechanism of amperometric detection towards glucose ([ 41 ]). (iii) Optical images illustrating the glucose detection device with reference (R), and counter (C), working (W) electrodes amounted on the arm ([ 42 ]). (iv) (a) Photographs of the wearable glucose sensor attached to the skin.…”