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With advances in new materials and technologies, there has been increasing research focused on flexible sensors. However, in most flexible pressure sensors made using new materials, it is challenging to achieve high detection sensitivity across a wide pressure range. Although traditional silicon-based sensors have good performance, they are not for...
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... Silicon-based passive electronic devices, such as resistors and diodes, are drawn numerous attentions for applications in bioimplantable sensors. Utilizing piezoresistive, thermosensitive as well as bioabsorbable and biocompatible properties of silicon, various types of flexible transient sensors with appropriate structural designs can be prepared to detect temperature, pressure, stress, flow rate, pH value, and other related signals [92][93][94][95][96]. Reasonable structural design reduces the complexity of the fabrication process. ...
Recent advances in materials science, device designs and advanced fabrication technologies have enabled the rapid development of transient electronics, which represents a class of devices or systems that their functionalities and constitutions can be partially/completely degraded via chemical reaction or physical disintegration over a stable operation. Therefore, numerous potentials, including zero/reduced waste electronics, bioresorbable electronic implants, hardware security, and others, are expected. In particular, transient electronics with biocompatible and bioresorbable properties could completely eliminate the secondary retrieval surgical procedure after their in-body operation, thus offering significant potentials for biomedical applications. In terms of material strategies for the manufacturing of transient electronics, silicon nanomembranes (SiNMs) are of great interest because of their good physical/chemical properties, modest mechanical flexibility (depending on their dimensions), robust and outstanding device performances, and state-of-the-art manufacturing technologies. As a result, continuous efforts have been made to develop silicon-based transient electronics, mainly focusing on designing manufacturing strategies, fabricating various devices with different functionalities, investigating degradation or failure mechanisms, and exploring their applications. In this review, we will summarize the recent progresses of silicon-based transient electronics, with an emphasis on the manufacturing of SiNMs, devices, as well as their applications. After a brief introduction, strategies and basics for utilizing SiNMs for transient electronics will be discussed. Then, various silicon-based transient electronic devices with different functionalities are described. After that, several examples regarding on the applications, with an emphasis on the biomedical engineering, of silicon-based transient electronics are presented. Finally, summary and perspectives on transient electronics are exhibited.
... It is believed that a higher dielectric constant and material stability are the prerequisites for the achievement of higher pressure-sensing properties. [9][10][11][12] As a type of perovskite-type ceramic oxide, SeZnO 3 has attracted increasing attention for pressure sensing applications due to its special crystal structure, 13 large surface area, and abundant oxygen vacancies. 14 SeZnO 3 is a rare perovskite oxide with a valence combination of Se 4+ Zn 2+ -O 3 . ...
As a piezoelectric ceramic material, SeZnO3 has received increasing attention for pressure sensing. However, the poor conductivity and low dielectric constant of bare SeZnO3 severely limit its wide applications. Herein, to improve the pressure sensing properties of SeZnO3, SeZnO3 nanosheets composited with Ag nanoplates were synthesized via a dissolution coprecipitation method, which exhibited a higher sensitivity (54.8 kPa⁻¹) to external pressure with an excellent repeatability than that of bare SeZnO3 nanosheets (12.3 kPa⁻¹). The enhanced pressure sensing properties of Ag/SeZnO3 nanocomposites could be attributed to an increased dielectric constant and an enhanced charge output. Moreover, the nanocomposite-based pressure sensors showed an accelerated response/recovery rate (0.7 s/2.7 s) because of the effective charge transfer between SnZnO3 and Ag, which was confirmed by XPS results. This Ag/SeZnO3 composite nanosheet-based pressure sensor demonstrates a potential for practical monitoring of human movement.
... The photoresist-coated substrate is then placed under a photomask, which contains the desired pattern in opaque and transparent regions. When exposed to UV light, the photoresist in the transparent regions of the photomask becomes soluble and is removed during the development step, leaving behind the desired pattern on the substrate [100]. The photoresist in the opaque regions remains insoluble and acts as a protective mask during subsequent processing steps. ...
Flexible and stretchable electronics have emerged as highly promising technologies for the next generation of electronic devices. These advancements offer numerous advantages, such as flexibility, biocompatibility, bio-integrated circuits, and light weight, enabling new possibilities in diverse applications, including e-textiles, smart lenses, healthcare technologies, smart manufacturing, consumer electronics, and smart wearable devices. In recent years, significant attention has been devoted to flexible and stretchable pressure sensors due to their potential integration with medical and healthcare devices for monitoring human activity and biological signals, such as heartbeat, respiratory rate, blood pressure, blood oxygen saturation, and muscle activity. This review comprehensively covers all aspects of recent developments in flexible and stretchable pressure sensors. It encompasses fundamental principles, force/pressure-sensitive materials, fabrication techniques for low-cost and high-performance pressure sensors, investigations of sensing mechanisms (piezoresistivity, capacitance, piezoelectricity), and state-of-the-art applications.
... The most interesting use of nanobiosensors is in the diagnosis of Parkinson's disease and other clinical abnormalities (Perspectives 2022). For example, wearable devices based on silicon nanomembranes have been used to detect clinical abnormalities (Cheng et al. 2023). Nanofabrication enables the development of such sensors that can be used to improve the diagnostic accuracy of Parkinson's disease (Dixit et al. 2023). ...
In severe cases, Parkinson’s disease causes uncontrolled movements known as motor symptoms such as dystonia, rigidity, bradykinesia, and tremors. Parkinson’s disease also causes non-motor symptoms such as insomnia, constipation, depression and hysteria. Disruption of dopaminergic and non-dopaminergic neural networks in the substantia nigra pars compacta is a major cause of motor symptoms in Parkinson’s disease. Furthermore, due to the difficulty of clinical diagnosis of Parkinson’s disease, it is often misdiagnosed, highlighting the need for better methods of detection. Treatment of Parkinson’s disease is also complicated due to the difficulties of medications passing across the blood–brain barrier. Moreover, the conventional methods fail to solve the aforementioned issues. As a result, new methods are needed to detect and treat Parkinson's disease. Improved diagnosis and treatment of Parkinson's disease can help avoid some of its devastating symptoms. This review explores how nanotechnology platforms, such as nanobiosensors and nanomedicine, have improved Parkinson’s disease detection and treatment. Nanobiosensors integrate science and engineering principles to detect Parkinson’s disease. The main advantages are their low cost, portability, and quick and precise analysis. Moreover, nanotechnology can transport medications in the form of nanoparticles across the blood–brain barrier. However, because nanobiosensors are a novel technology, their use in biological systems is limited. Nanobiosensors have the potential to disrupt cell metabolism and homeostasis, changing cellular molecular profiles and making it difficult to distinguish sensor-induced artifacts from fundamental biological phenomena. In the treatment of Parkinson’s disease, nanoparticles, on the other hand, produce neurotoxicity, which is a challenge in the treatment of Parkinson’s disease. Techniques must be developed to distinguish sensor-induced artifacts from fundamental biological phenomena and to reduce the neurotoxicity caused by nanoparticles.
Implantable biosensors have evolved to the cutting-edge technology of personalized health care and provide promise for future directions in precision medicine. This is the reason why these devices stand to revolutionize our approach to health and disease management and offer insights into our bodily functions in ways that have never been possible before. This review article tries to delve into the important developments, new materials, and multifarious applications of these biosensors, along with a frank discussion on the challenges that the devices will face in their clinical deployment. In addition, techniques that have been employed for the improvement of the sensitivity and specificity of the biosensors alike are focused on in this article, like new biomarkers and advanced computational and data communicational models. A significant challenge of miniaturized in situ implants is that they need to be removed after serving their purpose. Surgical expulsion provokes discomfort to patients, potentially leading to post-operative complications. Therefore, the biodegradability of implants is an alternative method for removal through natural biological processes. This includes biocompatible materials to develop sensors that remain in the body over longer periods with a much-reduced immune response and better device longevity. However, the biodegradability of implantable sensors is still in its infancy compared to conventional non-biodegradable ones. Sensor design, morphology, fabrication, power, electronics, and data transmission all play a pivotal role in developing medically approved implantable biodegradable biosensors. Advanced material science and nanotechnology extended the capacity of different research groups to implement novel courses of action to design implantable and biodegradable sensor components. But the actualization of such potential for the transformative nature of the health sector, in the first place, will have to surmount the challenges related to biofouling, managing power, guaranteeing data security, and meeting today’s rules and regulations. Solving these problems will, therefore, not only enhance the performance and reliability of implantable biodegradable biosensors but also facilitate the translation of laboratory development into clinics, serving patients worldwide in their better disease management and personalized therapeutic interventions.
Flexible sensors have immense potential applications in fields like robot control, human interaction, and medical detection. However, obtaining sensors with excellent sensitivity and sensing range is a current challenge due to the limitations imposed by sensing principles and material characteristics. This paper proposes a flexible sensor with circumferential negative Poisson’s ratio characteristics, created by embedding a specific skeleton structure. Compared to pure foam, composite foam’s sensing range improves to 150kPa, a 2.06 times increase. Linear range and sensitivity of composite foam sensor also improves significantly, with linear sensitivities of 0.50 at 15%-40% strain and 1.17 at 65%-78%. The composite foam sensor also shows reliable stability and effective minimum load. The mechanical properties of the sensor materials were analyzed to obtain an explicit expression between the negative Poisson’s ratio structural parameters and compressive deformation, which is the theoretical basis for sensor structure design. Human interaction experiments demonstrate that the sensor has great potential for applications in human signal detection and intention recognition in medical detection.
