**3.2 Wearable biosensors**

The primary use of biological information detection technology is the detection of physiological and biochemical data, such as biomarkers, that are strongly associated to abnormalities in human tissues and organs. This technique is essential for the early clinical diagnosis and management of chronic disorders. The Internet of Things (IoT) and Big Data (BD) can be used with wearable biosensors to enable the detection, transmission, storage, and thorough analysis of human physiological and biochemical data. In frontier industries like home healthcare, chronic illness diagnosis and treatment, and personal health monitoring, this technology has incredibly broad applications and promising business prospects. Mobile devices, telemedicine, and wearable biosensors are revolutionizing clinical research. For managing diabetes, modern continuous glucose monitoring (CGM) devices provide precise interstitial glucose measurement. Smartphone apps for health are widely used for self-care and self-monitoring. To assess the effect of a synbiotic medicinal food on glucose regulation, meal-tolerance tests were performed as part of a pilot study. Over the course of 40 days, an average of 3000 data points per patient were obtained using CGM devices and a smartphone app for diet tracking. Participants expressed great satisfaction with the sensors, product, and app, and no negative incidents were noted. The need for larger research in the future is indicated by the considerable alterations in postprandial glucose response that were found in real-world settings, even though statistical

### *Applications of Cutting-Edge Biosensors in Healthcare and Biomedical Research DOI: http://dx.doi.org/10.5772/intechopen.112693*

significance could not be reached [41]. For noninvasive interstitial fluid (ISF) extraction and real-time glucose testing, a screen-printed iontophoretic biosensing system has been created. The technique supports glucose oxidase (GOx) immobilization by using a three-dimensional graphene aerogel paired with Prussian blue (GA@PB) as an electron mediator, improving detection sensitivity. Reverse iontophoresis-based ISF extraction is shown to be effective by utilizing an *ex vivo* model and a synthetic diffuse cell. The device detects ISF glucose with great sensitivity and accuracy in the range of 0 to 15 mM, with a detection limit of 0.26 mM. The viability of this system, which offers adaptability, biocompatibility, and promise for the development of wireless wearable biosensors for continuous blood glucose monitoring, has been tested on healthy volunteers [42].

Flexible and stretchable biosensors, which can provide smooth and conformable biological-electronic interfaces for continuously gathering high-fidelity signals, are opening up a wide range of new applications. Organic thin film transistors (OTFTs) are the ideal transducers for flexible and stretchable biosensing because of their softness, inherent function of amplification, biocompatibility, simplicity of functionalization, low cost, and diversity of the device. Wearable biosensors provide a noninvasive way to continuously measure biochemical parameters, measure biochemical parameters continually, allowing for the identification of medical hazards and the prediction of physiological status. Few commercial wearable sensors can diagnose health issues through perspiration, despite the fact that they detect physical activities. With its adaptability, affordability, integration, and unobtrusiveness, electronic textile (e-textile) biosensors provide prospects in this area. There are significant challenges in the development of textile-based sensing materials, skin interfaces, and embedded data transmission. For lactate and salt detection during physical activity, a novel wearable electrochemical sweat biosensor using zinc-oxide nanowires (ZnO NWs) has been introduced. The wearable headband that houses this sweat biosensor, which is entirely integrated, accurately, and wirelessly measures human perspiration. On-body measurements during exercise show high testing accuracy and signal stability during movement [43]. Due to its breathability, flexibility, softness, and comfort, textiles present a viable substrate for the integration of wearable chemical sensors. Dry-spinning has been used to create extremely conductive, stretchable, and straininsensitive gold fibers. These fibers can be used to make lactate-sensing electrodes for a typical three-electrode setup. Textiles can be made from these gold fibers. High sensitivity can be seen in the textile lactate biosensors. Furthermore, the sensors do not require any additional structural design to maintain their sensitivity even under the high tensile strain of up to 100%. These results demonstrate the possibility of noninvasive lactate monitoring offered by wearing smart textiles [44]. Wearable energy storage and flexible body biomolecular detection are two crucial elements for real-time monitoring of human health in a practical situation. It would be fantastic if a single wearable could be used for both energy storage and biomolecular detection. Despite recent major developments in biosensor technology, there are still a number of issues that need to be resolved before they can reach their full potential. One of these difficulties is the protracted manufacturing process for biosensors, which may prevent their general adoption. To enhance the functionality and precision of biosensors, a greater comprehension of molecular biological processes is also required. Problems with biocompatibility are also a major obstacle because it is essential for the long-term use of biosensors that they are compatible with the human body. Finally, preserving the sterility of implantable sensors is still a problem that needs to be solved in order to stop infections and guarantee their dependability. Future biosensing

devices will be more effective and trustworthy if these problems are resolved through additional study and technical improvements. Exciting developments in biosensors have been made possible by the quick improvements in artificial intelligence, semiconductor technology, and 3D printing. New chances and possibilities are presented using polymeric nanoparticles in miniaturization processes, such as silicon and fiber optics. Additionally, the combination of cutting-edge 2D materials like graphene [45], borophene [46], and phosphorene [47] with biosensors has the potential to lead to sizable advancements in biotechnology and medicine. Graphene, a single layer of carbon atoms structured in a honeycomb lattice structure, borophene, a single layer of boron atoms in various configurations, and phosphorene, a single layer of phosphorus atoms arranged in a puckered honeycomb lattice, are examples of cutting-edge 2D materials that can be combined with biosensors to produce significant improvements in biotechnology and medical treatment. These outstanding 2D materials are wellsuited for boosting the sensitivity and effectiveness of biosensors due to their extraordinary features like high surface-to-volume ratio, exceptional electrical conductivity, and variable band gaps. These developments will transform the way diseases are diagnosed and help save countless lives.
