Wet‐Adhesive On‐Skin Sensors Based on Metal–Organic Frameworks for Wireless Monitoring of Metabolites in Sweat

Abstract

Metal–organic frameworks (MOFs) with well‐defined porous structures and tailored functionalities have been widely used in chemical sensing. However, the integration of MOFs with flexible electronic devices for wearable sensing is challenging because of their low electrical conductivity and fragile mechanical properties. Herein, a wearable sweat sensor for metabolite detection is presented by integrating an electrically conductive Ni‐MOF with a flexible nanocellulose substrate. The MOF‐based layered film sensor with inherent conductivity, highly porous structure, and active catalytic properties enables the selective and accurate detection of vitamin C and uric acid. More importantly, the lightweight sensor can conformably self‐adhere to sweaty skin and exhibits high water‐vapor permeability. Furthermore, a wireless epidermal nutrition tracking system for the in situ monitoring of the dynamics of sweat vitamin C is demonstrated, the results of which are comparable to those tested by high‐performance liquid chromatography. This study opens a new avenue for integrating MOFs as the active layer in wearable electronic devices and holds promise for the future development of high‐performance electronics with enhanced sensing, energy production, and catalytic capabilities through the implementation of multifunctional MOFs.

Electrochemical Nanosensors for Sensitization of Sweat Metabolites: From Concept Mapping to Personalized Health Monitoring

“…The sensor device can conformably self-adhere to human skin for monitoring changes in sweat vitamin C levels during daily activities. This study validates the expansion of MOF-based flexible electrochemical devices in the realm of healthcare [ 43 ]. Choi et al have developed a discerning non-enzymatic amperometric recognition technique for monitoring sweat lactic acid by using a multi-wall carbon nanotube (MWCNT)-polypyrrole core–shell nanowire ( Figure 5 c,d).…”

Nonenzymatic Sweat Wearable Uric Acid Sensor Based on N-Doped Reduced Graphene Oxide/Au Dual Aerogels

“…Here, the oxidation of UA probably follows the steps as below. 52,54 First, OH is adsorbed onto the with the experimental results, where the catalytic response of N-rGO/Au DAs to UA is more pronounced than those of pure N-rGO and Au gels, promising the high sensitivity in further sensing application.…”

“…It is of great significance to develop a UA sensor since it is an important biological molecule in many physiological metabolic processes of human beings. 52 We first investigated the electrocatalytic behavior of UA oxidation in 0.1 M PBS (pH 7.0). As seen from Figure 2C, the N-rGO/Au DAs/GCE displays an obvious catalytic oxidation toward UA with a peak current of 15.1 μA at 0.3 V and an onset potential of 0.196 V. The catalytic current is much larger than those of the other controlled aerogel material-modified GCEs, that is, 2.4 times of that of N-rGO/Au NPs/GCE (6.69 μA @ 0.3 V), 5.3 times of that of the Au aerogel/GCE (2.84 μA @ 0.3 V), and 2.6 times of that of the N-rGO/GCE (6.24 μA @ 0.3 V).…”

A Review on Electrochemical Microsensors for Ascorbic Acid Detection: Clinical, Pharmaceutical, and Food Safety Applications

“…Yang et al in 2022 presented a wet-adhesive epidermal sweat sensor for metabolite detection by integrating an electrically conductive Ni-MOF (Ni 3 HHTP 2 ) as the active layer with a flexible and breathable nanocellulose substrate ( Figure 8 ) [ 47 ]. The developed robust sensor can conformably self-adhere to sweaty skin and exhibits high water-vapor permeability.…”

“…( h ) The free energy diagrams for AA electrocatalytic oxidation on Ni−based cMOFs using DFT calculations. Reproduced with permission from [ 47 ]. Copyright 2022 John Wiley and Sons.…”