Hossein Ebrahimi,1Hassan Baharloo,2Kiarash Alabakhshzadeh,3Amin Hajhosseini,4,*
1. Hamedan Medical Sciences University 2. Ahvaz Jundishapour university of medical sciences 3. Isfahan Medical Sciences University 4. Student Research Committee, Bushehr University of Medical Sciences, Bushehr, Iran
Introduction: After long-term high-intensity work, problems such as lack of concentration, fatigue, and suppression of the immune system occur, which reduce immunity, damage the nervous system, and slow alertness and coordination. This situation is summarized as fatigue. In addition, in manufacturing, physical fatigue is a challenging ergonomic/safety “issue” since it lowers productivity and increases the incidence of accidents. Therefore, physical fatigue should be controlled. Different measurement devices and techniques can be used to identify physical fatigue. Specially the wearable ones. Wearable biosensors are biosensing devices that can detect biomarkers accurately, instantly, and portable. In this field, Smart bracelets are popular today. While these wearables primarily monitor simple biometric signatures, new devices that can report human fitness levels by measuring molecular biomarkers are critical to human factor optimization in the commercial and DoD sectors.
Methods: In the upcoming systematic review, the required data were collected using keywords and also by using reliable databases such as PubMed, Scopus, ProQuest and Google Scholar. In this study, the statistical population includes all studies that have been conducted until 2022. After reviewing the relevant findings and also evaluating the quality of the data, 16 articles were analyzed.
Results: In the following we review 3 of new wearable biosensors:
1. wearable tear biosensors
One of the biological fluid that can be exploited for monitoring physiological status is tears. Not only are the biomarker molecules in tears directly released from the blood and show close tear-blood concentration correlations, but tear analysis also offers opportunities for the diagnosis of ocular disease. Tears are also less complex than blood and are part of the eye's anti-fouling mechanism. These properties make human tears an attractive diagnostic biofluid for healthcare monitoring applications that can be sampled without contact with blood. Wearable tear biosensors have been widely developed; The first samples were flexible strip-like devices which have been developed by using other materials to be more flexible and comfortable for users. Despite solving the comfort issues of wearable tear sensors, the possibility of eye diseases caused by the heating of the wireless transmission device should be considered. To prevent possible eye damage from wearable tear biosensors, the new ones ,that are frame-like, have been designed. This tear sensor are able to collect tears from the corners of eyes and could simultaneously detect glucose, vitamins, and extraocular tears via bioenzyme-substrate reaction without any direct contact with eyeball.
2. wearable saliva biosensors
The direct passage of a large number of saliva biomarkers through intercellular or paracellular pathways allows us to use saliva to investigate the physiological state of the body, and this method is a non-invasive alternative to blood analysis. Therefore, saliva can be a "mirror of the human body". The prototype of wearable saliva biosensors was the traditional paperbased saliva test strips, which collected saliva from subjects. To achieve continuous monitoring, paper-based saliva test strips were replaced with wearable 3D-printed microfluidic paper-based silicone braces. However, the brace required repeated removal from mouth for colorimetric analysis, which limited the widespread applicability of the braces. To improve The creation of wearable electrochemical sensor "Brace" improved these bottlenecks. These biosensors could analyze amount of glucose, cortisol, lactic acid, uric acid and etc.
3. wearable epidermal biosensors
Sweat is vigorously secreted to the skin surface during exercise and containing many biomarkers related to fatigue, and hence can be a satisfactory basis for fatigue diagnosis. For sweat analyzing, devices have been realized through direct transfer of sensors onto the (using E-skin or printed temporary tattoos), using sensors in wristbands and patches, or by embedding sensors directly into textiles to ensure firm contact with the skin while allowing the sensors to To withstand the mechanical pressures encountered during body movements. These sensors collect fatigue information by analyzing sweat’s biomarkers.
Conclusion: In conclusion, also these wearable biosensors are greatly high-tech, but they need to be more developed. For example, the fragility of wearable tear biosensors are hinder the widespread application by people who are prone to exercise fatigue, such as soldiers and athletes. And we have such these problems for the others. But these devises show considerable promise for noninvasive sensing of other physiologically important biomarkers.