Flexible and Superwettable Bands as a Platform toward Sweat Sampling and Sensing

Abstract

Wearable biosensors as a user-friendly measurement platform have become a rapidly growing field of interests due to their possibility in integrating traditional medical diagnostics and healthcare management into miniature lab-on-body analytic devices. This paper demonstrates a flexible and skin-mounted band that combines superhydrophobic-superhydrophilic microarrays with nanodendritic colorimetric biosensors toward in situ sweat sampling and analysis. Particularly, on the superwettable bands, the superhydrophobic background could confine microdroplets into superhydrophilic microwells. On-body investigations further reveal that the secreted sweat is repelled by the superhydrophobic silica coating and precisely collected and sampled onto the superhydrophilic micropatterns with negligible lateral spreading, which provides an independent “vessel” toward cellphone-based sweat biodetection (pH, chloride, glucose and calcium). Such wearable, superwettable band-based biosensors with improved interface controllability could significantly enhance epidemical sweat sampling in well-defined sites, holding a great promise for facile and noninvasive biofluids analysis.

Flexible Multiplexed In2O3 Nanoribbon Aptamer-Field-Effect Transistors for Biosensing

“…Advances have been made in the areas of soft ( Kim et al., 2010 ; Minev et al., 2015 ; Wang et al., 2018 ) and minimally invasive bioelectronics ( Rim et al., 2015 ; Luan et al., 2017 ; Zhou et al., 2017 ). Wearable electronics enable sensor systems for monitoring vital signs from skin and biomarkers in sweat, such as ions, glucose, lactase, and cortisol ( Kim et al., 2016 ; Heo et al., 2018 ; Nyein et al., 2018 ; Chung et al., 2019 ; He et al., 2019 , 2020 ; Liu et al., 2020 ; Torrente-Rodriguez et al., 2020 ; Yang et al., 2020 ; Zhao et al., 2020 ). Efforts have been made toward bioelectronics for implantable devices, including liquid-metal- and hydrogel-based systems ( Yu et al., 2016 ; Fang et al., 2017 ; Liu et al., 2019 ; Wen et al., 2019 ).…”

Recent Advances in Skin Chemical Sensors

“…This strategy which consists in using colorimetric indicators integrated into sensing areas of a wearable patch, then taking a picture of the patch with a smartphone including picture treatment software able to translate the different color grades into quantitative values of analyte concentration has also been proposed by He et al [29] (for a glucose sensor). Here, fresh sweat is collected with the help of a large (the size of the patch) superhydrophobic surface which guide the liquid to the test area.…”

Advanced Wearable Microfluidic Sensors for Healthcare Monitoring

“…Semiquantitative colorimetric analysis based on a color chart can eliminate analyte concentrations, such as pH test paper. Quantitative colorimetric analysis utilizes external equipment to perform optical analysis of the color changes, which offers a precise and accurate analysis result . To date, quantitative colorimetric analysis has been widely used in wearable microfluidic sweat sensors for detecting electrolytes and metabolites, assisted by smart devices such as digital cameras or smartphones .…”

“…Quantitative colorimetric analysis utilizes external equipment to perform optical analysis of the color changes, which offers a precise and accurate analysis result . To date, quantitative colorimetric analysis has been widely used in wearable microfluidic sweat sensors for detecting electrolytes and metabolites, assisted by smart devices such as digital cameras or smartphones . In 2016, Koh et al first described a fully integrated, epidermal microfluidic system for sweat biomarker capture and multiple analyses by colorimetric detection, including the pH value, Cl − , glucose, lactate analysis, and sweat loss ( Figure a) .…”