Stretchable electronics outperform existing rigid and bulky electronics and benefit a wide range of species, including humans, machines, and robots, whose activities are associated with large ...mechanical deformation and strain. Due to the nonstretchable nature of most electronic materials, in particular semiconductors, stretchable electronics are mostly realized through the strategies of architectural engineering to accommodate mechanical stretching rather than imposing strain into the materials directly. On the other hand, recent development of stretchable electronics by creating them entirely from stretchable elastomeric electronic materials, i.e., rubbery electronics, suggests a feasible a venue. Rubbery electronics have gained increasing interest due to the unique advantages that they and their associated manufacturing technologies have offered. This work reviews the recent progress in developing rubbery electronics, including the crucial stretchable elastomeric materials of rubbery conductors, rubbery semiconductors, and rubbery dielectrics. Thereafter, various rubbery electronics such as rubbery transistors, integrated electronics, rubbery optoelectronic devices, and rubbery sensors are discussed.
Compared to conventional rigid and bulky electronics, stretchable electronics have substantial advantages for various situations where large mechanical deformations are required. Recent progress shows stretchable electronics from all rubber‐like components are excellent candidates to substitute electronics developed using architectural engineering for eliminating strain. The current development in rubbery electronics is reviewed and future directions for the field are suggested.
An accurate extraction of physiological and physical signals from human skin is crucial for health monitoring, disease prevention, and treatment. Recent advances in wearable bioelectronics directly ...embedded to the epidermal surface are a promising solution for future epidermal sensing. However, the existing wearable bioelectronics are susceptible to motion artifacts as they lack proper adhesion and conformal interfacing with the skin during motion. Here, we present ultra-conformal, customizable, and deformable drawn-on-skin electronics, which is robust to motion due to strong adhesion and ultra-conformality of the electronic inks drawn directly on skin. Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors. Electrophysiological signal monitoring during motion shows drawn-on-skin electronics' immunity to motion artifacts. Additionally, electrical stimulation based on drawn-on-skin electronics demonstrates accelerated healing of skin wounds.
Organic solar cells (OSCs), particularly made based on solution processing methods, have made significant progress over the past decades through the concurrent evolution of organic photovoltaic ...materials and device engineering. Recently, high power conversion efficiencies around 18% and over 16% have been demonstrated in both rigid and flexible OSCs, respectively. While most of the OSC research has centered on efficiency and cost, their emerging and potential usages in many critical applications, particularly in biomedical fields have been rising. In this mini-review, we will briefly discuss the high-performance organic photovoltaic materials and the representative flexible OSCs to give a scope on the recent rapid development of OSCs. Besides, we will review some progress on the applications of OSCs in biomedical devices and integrated systems. The potential challenges associated with integrating OSCs for biomedical devices will be put forward.
Wearable human-machine interfaces (HMIs) are an important class of devices that enable human and machine interaction and teaming. Recent advances in electronics, materials, and mechanical designs ...have offered avenues toward wearable HMI devices. However, existing wearable HMI devices are uncomfortable to use and restrict the human body's motion, show slow response times, or are challenging to realize with multiple functions. Here, we report sol-gel-on-polymer-processed indium zinc oxide semiconductor nanomembrane-based ultrathin stretchable electronics with advantages of multifunctionality, simple manufacturing, imperceptible wearing, and robust interfacing. Multifunctional wearable HMI devices range from resistive random-access memory for data storage to field-effect transistors for interfacing and switching circuits, to various sensors for health and body motion sensing, and to microheaters for temperature delivery. The HMI devices can be not only seamlessly worn by humans but also implemented as prosthetic skin for robotics, which offer intelligent feedback, resulting in a closed-loop HMI system.
Wearable healthcare devices are mainly used for biosensing and transdermal delivery. Recent advances in wearable biosensors allow for long-term and real-time monitoring of physiological conditions at ...a cellular resolution. Transdermal drug delivery systems have been further scaled down, enabling wide selections of cargo, from natural molecules (e.g., insulin and glucose) to bioengineered molecules (e.g., nanoparticles). Some emerging nanopatches show promise for precise single-cell gene transfection in vivo and have advantages over conventional tools in terms of delivery efficiency, safety, and controllability of delivered dose. In this review, we discuss recent technical advances in wearable micro/nano devices with unique capabilities or potential for single-cell biosensing and transfection in the skin or other organs, and suggest future directions for these fields.
Current wearable sensors have allowed for long-term, real-time detection of specific biomarkers directly from patients.Miniaturized wearable biosensors with sensing elements interacting with skin or organs can capture target molecules from single cells, which results in significantly increased sensitivity, responding time, and precision.Emerging wearable devices based on novel nanomaterials or nanofabrication show potential for single-cell detection in cancer cell screening, cardiomyocyte detection, and optogenetics.Transdermal delivery devices have been scaled down to the micro- and/or nanoscale, and their applications have extended to wide selections of natural molecules and bioengineered molecules.Emerging nanodevices show unique capabilities in precise single-cell gene transfection in vivo, with improved delivery efficiency, safety, and dose controllability.
In recent years, wearable bioelectronics has rapidly expanded for diagnosing, monitoring, and treating various pathological conditions from the skin surface. Although the devices are typically ...prefabricated as soft patches for general usage, there is a growing need for devices that are customized in situ to provide accurate data and precise treatment. In this perspective, the state-of-the-art in situ fabricated wearable bioelectronics are summarized, focusing primarily on Drawn-on-Skin (DoS) bioelectronics and other in situ fabrication methods. The advantages and limitations of these technologies are evaluated and potential future directions are suggested for the widespread adoption of these technologies in everyday life.
Cardiovascular diseases are among the leading causes of death worldwide. Conventional technologies for diagnosing and treating lack the compliance and comfort necessary for those living with ...life-threatening conditions. Soft electronics presents a promising outlet for conformal, flexible, and stretchable devices that can overcome the mechanical mismatch that is often associated with conventional technologies. Here, we review the various methods in which electronics have been made flexible and stretchable, to better interface with the human body, both externally with the skin and internally with the outer surface of the heart. Then, we review soft, wearable, noninvasive heart monitors designed to be attached to the chest or other parts of the body for mechano-acoustic and electrophysiological sensing. A common method of treatment for various abnormal heart rhythms involves catheter ablation procedures and we review the current soft bioelectronics that can be placed on the balloon or head of the catheter. Cardiac mapping is integral to determine the state of the heart; we discuss the various parameters for sensing aside from electrophysiological sensing, such as temperature, pH, strain, and tactile sensing. Finally, we review the soft devices that harvest energy from the natural and spontaneous beating of the heart by converting its mechanical motion into electrical energy to power implants.
The need to develop wearable devices for personal health monitoring, diagnostics, and therapy has inspired the production of innovative on‐demand, customizable technologies. Several of these ...technologies enable printing of raw electronic materials directly onto biological organs and tissues. However, few of them have been thoroughly investigated for biocompatibility of the raw materials on the cellular, tissue, and organ levels or with different cell types. In addition, highly accurate multiday in vivo monitoring using such on‐demand, in situ fabricated devices has yet to be done. Presented herein is the first fully biocompatible, on‐skin fabricated electronics for multiple cell types and tissues that can capture electrophysiological signals with high fidelity. While also demonstrating improved mechanical and electrical properties, the drawn‐on‐skin ink retains its properties under various writing conditions, which minimizes the variation in electrical performance. Furthermore, the drawn‐on‐skin ink shows excellent biocompatibility with cardiomyocytes, neurons, mice skin tissue, and human skin. The high signal‐to‐noise ratios of the electrophysiological signals recorded with the DoS sensor over multiple days demonstrate its potential for personalized, long‐term, and accurate electrophysiological health monitoring.
Sensors fabricated directly on the skin are extremely promising for customized, on‐demand, and high‐quality physiological monitoring. However, the current literature does not thoroughly investigate the biocompatibility of the raw electronic materials deposited on skin. The development of a drawn‐on‐skin ink that is biocompatible on the cellular, tissue, and organ levels and can be used for multiday, high‐fidelity electrophysiology is presented.
Currently, there are no treatments that ameliorate cardiac cell death, the underlying basis of cardiovascular disease. An unexplored cell type in cardiac regeneration is cardiac Purkinje cells; ...specialized cells from the cardiac conduction system (CCS) responsible for propagating electrical signals. Purkinje cells have tremendous potential as a regenerative treatment because they may intrinsically integrate with the CCS of a recipient myocardium, resulting in more efficient electrical conduction in diseased hearts. This study is the first to demonstrate an effective protocol for the direct reprogramming of human cardiomyocytes into cardiac Purkinje-like cells using small molecules. The cells generated were genetically and functionally similar to native cardiac Purkinje cells, where expression of key cardiac Purkinje genes such as CNTN2, ETV1, PCP4, IRX3, SCN5a, HCN2 and the conduction of electrical signals with increased velocity was observed. This study may help to advance the quest to finding an optimized cell therapy for heart regeneration.
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•Small molecule treatment of human cardiomyocytes leads to Purkinje differentiation•Small molecule differentiation results in key Purkinje gene expression•Differentiated Purkinje cells can conduct fast electrical signals•Differentiated Purkinje cells are comparable to native Purkinje cells
Bioengineering; Cell biology; Stem cells research
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