End-to-end design of wearable sensors

Abstract

Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.

A Comprehensive Review of the Recent Developments in Wearable Sweat-Sensing Devices

“…A growing number of research studies that have been reported on analyzing various sweat biomarkers for use in a broad range of clinical diagnostic purposes, including health concerns, nutritional imbalance, drug abuse, and many more [ 1 , 2 , 3 , 4 ], have seen a ten-fold rise in this field, as shown in Figure 1 . However, there are still gaps in the structured content on related SSD applications based on the current existing review articles, such as insufficient information about a few sweat biomarkers, especially hormones, drugs, nicotine, and vitamin C, and inadequate detailed explanation of the respective application concepts related to these biomarkers and a lack of a fundamental response mechanism of chemical sensors that enable users to understand the process of the target analyte’s detection for various sweat compositions [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Despite these limitations, the existing reviews seemed to disregard addressing issues such as an analysis effect formation mixing new and old sweat samples, which can be a daunting challenge for acquiring a high precision in sweat analysis.…”

A Soft Wearable Microfluidic Patch with Finger-Actuated Pumps and Valves for On-Demand, Longitudinal, and Multianalyte Sweat Sensing

“…Wearable sensors represent a unique class of diagnostic tools for real-time, noninvasive, or minimally invasive investigation of human physiology. − Engineering advances in materials, design, electronics, and data analysis form the basis for a rich variety of wearable sensors that conformally mount on soft biological tissues and offer unprecedented insights into various biological processes. , Examples include devices integrated on the skin, − eye, − and mouth − to measure a wide range of biochemical and biophysical parameters. Among these, wearable sweat sensors are of particular interest due to the physiological significance of sweat, ease of sample collection, and availability of a large area for device integration.…”

Face masks as a platform for wearable sensors

“…Unlike conventional diagnostic testing, which takes place at a centralized clinical laboratory, wearable sensors can provide continuous physiological information about the health of an individual 1 . The sensors thus have the potential to personalize the diagnosis of diseases, that is, abnormal conditions could be identified -practically in real time -by measuring deviations (or patterns of deviations) from healthy baselines.…”