Flexible bioelectronic systems with large-scale temperature sensor arrays for monitoring and treatments of localized wound inflammation.

Continuous monitoring and closed-loop therapy of soft wound tissues is of particular interest in biomedical research and clinical practices. An important focus is on the development of implantable bioelectronics that can measure time-dependent temperature distribution related to localized inflammation over large areas of wound and offer in situ treatment. Existing approaches such as thermometers/thermocouples provide limited spatial resolution, inapplicable to a wearable/implantable format.

Wearable Applicability of Respiratory Airflow Transducers: Current Approaches and Future Directions.

Advanced technologies employed in modern respiratory airflow transducers have exhibited powerful capabilities in accurately measuring respiratory flow under controlled and sedentary conditions, particularly in clinical settings. However, the wearable applicability of these transducers as face-mounted electronics for use in occupational and sporting activities remains unexplored. The present review addresses the critical wearability issue associated with current respiratory airflow transducers, including pneumotachographs, orifice flowmeters, turbine flowmeters, hot wire anemometers, ultrasound flowmeters, and piezoelectric airflow transducers.

Multi-functional, conformal systems with ultrathin crystalline-silicon-based bioelectronics for characterization of intraocular pressure and ocular surface temperature.

Technologies that established in vivo evaluations of soft-tissue biomechanics and temperature are essential to biological research and clinical diagnostics, particularly for a wide range of eye-related diseases such as glaucoma. Of importance are advanced bioelectronic devices for high-precise monitoring of intraocular pressure (IOP) and various ocular temperatures, as clinically proven uses for glaucoma diagnosis. Existing characterization methods are temporary, single point, and lack microscale resolution, failing to measure continuous IOP fluctuation across the long-term period.

Multilevel design and construction in nanomembrane rolling for three-dimensional angle-sensitive photodetection.

Releasing pre-strained two-dimensional nanomembranes to assemble on-chip three-dimensional devices is crucial for upcoming advanced electronic and optoelectronic applications. However, the release process is affected by many unclear factors, hindering the transition from laboratory to industrial applications. Here, we propose a quasistatic multilevel finite element modeling to assemble three-dimensional structures from two-dimensional nanomembranes and offer verification results by various bilayer nanomembranes.

Anti-friction gold-based stretchable electronics enabled by interfacial diffusion-induced cohesion.

Stretchable electronics that prevalently adopt chemically inert metals as sensing layers and interconnect wires have enabled high-fidelity signal acquisition for on-skin applications. However, the weak interfacial interaction between inert metals and elastomers limit the tolerance of the device to external friction interferences. Here, we report an interfacial diffusion-induced cohesion strategy that utilizes hydrophilic polyurethane to wet gold (Au) grains and render them wrapped by strong hydrogen bonding, resulting in a high interfacial binding strength of 1017.

Ultrathin, Transferred Layers of Silicon Oxynitrides as Tunable Biofluid Barriers for Bioresorbable Electronic Systems.

Bio/ecoresorbable electronic systems create unique opportunities in implantable medical devices that serve a need over a finite time period and then disappear naturally to eliminate the need for extraction surgeries. A critical challenge in the development of this type of technology is in materials that can serve as thin, stable barriers to surrounding ground water or biofluids, yet ultimately dissolve completely to benign end products. This paper describes a class of inorganic material (silicon oxynitride, SiON) that can be formed in thin films by plasma-enhanced chemical vapor deposition for this purpose.

One-step rolling fabrication of VO tubular bolometers with polarization-sensitive and omnidirectional detection.

Uncooled infrared detection based on vanadium dioxide (VO) radiometer is highly demanded in temperature monitoring and security protection. The key to its breakthrough is to fabricate bolometer arrays with great absorbance and excellent thermal insulation using a straightforward procedure. Here, we show a tubular bolometer by one-step rolling VO nanomembranes with enhanced infrared detection.

Self-Rolled-Up Ultrathin Single-Crystalline Silicon Nanomembranes for On-Chip Tubular Polarization Photodetectors.

Freestanding single-crystalline nanomembranes and their assembly have broad application potential in photodetectors for integrated chips. However, the release and self-assembly process of single-crystalline semiconductor nanomembranes still remains a great challenge in on-chip processing and functional integration, and photodetectors based on nanomembrane always suffer from limited absorption of nanoscale thickness. Here, a non-destructive releasing and rolling process is employed to prepare tubular photodetectors based on freestanding single-crystalline Si nanomembranes.

Ultrathin, Soft, Bioresorbable Organic Electrochemical Transistors for Transient Spatiotemporal Mapping of Brain Activity.

A critical challenge lies in the development of the next-generation neural interface, in mechanically tissue-compatible fashion, that offer accurate, transient recording electrophysiological (EP) information and autonomous degradation after stable operation. Here, an ultrathin, lightweight, soft and multichannel neural interface is presented based on organic-electrochemical-transistor-(OECT)-based network, with capabilities of continuous high-fidelity mapping of neural signals and biosafety active degrading after performing functions. Such platform yields a high spatiotemporal resolution of 1.

Nanomembrane-assembled nanophotonics and optoelectronics: from materials to applications.

Nanophotonics and optoelectronics are the keys to the information transmission technology field. The performance of the devices crucially depends on the light-matter interaction, and it is found that three-dimensional (3D) structures may be associated with strong light field regulation for advantageous application. Recently, 3D assembly of flexible nanomembranes has attracted increasing attention in optical field, and novel optoelectronic device applications have been demonstrated with fantastic 3D design.

Self-rolling of vanadium dioxide nanomembranes for enhanced multi-level solar modulation.

Thermochromic window develops as a competitive solution for carbon emissions due to comprehensive advantages of its passivity and effective utilization of energy. How to further enhance the solar modulation ([Formula: see text]) of thermochromic windows while ensuring high luminous transmittance ([Formula: see text]) becomes the latest challenge to touch the limit of energy efficiency. Here, we show a smart window combining mechanochromism with thermochromism by self-rolling of vanadium dioxide (VO) nanomembranes to enhance multi-level solar modulation.

Mapping of Spatiotemporal Auricular Electrophysiological Signals Reveals Human Biometric Clusters.

Underneath the ear skin there are rich vascular network and sensory nerve branches. Hence, the 3D mapping of auricular electrophysiological signals can provide new biomedical perspectives. However, it is still extremely challenging for current sensing techniques to cover the entire ultra-curved auricle.

Implantable Electronic Medicine Enabled by Bioresorbable Microneedles for Wireless Electrotherapy and Drug Delivery.

A combined treatment using medication and electrostimulation increases its effectiveness in comparison with one treatment alone. However, the organic integration of two strategies in one miniaturized system for practical usage has seldom been reported. This article reports an implantable electronic medicine based on bioresorbable microneedle devices that is activated wirelessly for electrostimulation and sustainable delivery of anti-inflammatory drugs.

Recent advances in microsystem approaches for mechanical characterization of soft biological tissues.

Microsystem technologies for evaluating the mechanical properties of soft biological tissues offer various capabilities relevant to medical research and clinical diagnosis of pathophysiologic conditions. Recent progress includes (1) the development of tissue-compliant designs that provide minimally invasive interfaces to soft, dynamic biological surfaces and (2) improvements in options for assessments of elastic moduli at spatial scales from cellular resolution to macroscopic areas and across depths from superficial levels to deep geometries. This review summarizes a collection of these technologies, with an emphasis on operational principles, fabrication methods, device designs, integration schemes, and measurement features.

Transient, Implantable, Ultrathin Biofuel Cells Enabled by Laser-Induced Graphene and Gold Nanoparticles Composite.

Transient power sources with excellent biocompatibility and bioresorablility have attracted significant attention. Here, we report high-performance, transient glucose enzymatic biofuel cells (TEBFCs) based on the laser-induced graphene (LIG)/gold nanoparticles (Au NPs) composite electrodes. Such LIG electrodes can be easily fabricated from polyimide (PI) with an infrared CO laser and exhibit a low impedance (16 Ω).

Stretchable Sweat-Activated Battery in Skin-Integrated Electronics for Continuous Wireless Sweat Monitoring.

Wearable electronics have attracted extensive attentions over the past few years for their potential applications in health monitoring based on continuous data collection and real-time wireless transmission, which highlights the importance of portable powering technologies. Batteries are the most used power source for wearable electronics, but unfortunately, they consist of hazardous materials and are bulky, which limit their incorporation into the state-of-art skin-integrated electronics. Sweat-activated biocompatible batteries offer a new powering strategy for skin-like electronics.

Miniaturized electromechanical devices for the characterization of the biomechanics of deep tissue.

Evaluating the biomechanics of soft tissues at depths well below their surface, and at high precision and in real time, would open up diagnostic opportunities. Here, we report the development and application of miniaturized electromagnetic devices, each integrating a vibratory actuator and a soft strain-sensing sheet, for dynamically measuring the Young's modulus of skin and of other soft tissues at depths of approximately 1-8 mm, depending on the particular design of the sensor. We experimentally and computationally established the operational principles of the devices and evaluated their performance with a range of synthetic and biological materials and with human skin in healthy volunteers.

Recent advances in biofluid detection with micro/nanostructured bioelectronic devices.

Most biofluids contain a wide variety of biochemical components that are closely related to human health. Analyzing biofluids, such as sweat and tears, may deepen our understanding in pathophysiologic conditions associated with human body, while providing a variety of useful information for the diagnosis and treatment of disorders and disease. Emerging classes of micro/nanostructured bioelectronic devices for biofluid detection represent a recent breakthrough development of critical importance in this context, including traditional biosensors (TBS) and micro/nanostructured biosensors (MNBS).

Bioresorbable Multilayer Photonic Cavities as Temporary Implants for Tether-Free Measurements of Regional Tissue Temperatures.

. Real-time monitoring of the temperatures of regional tissue microenvironments can serve as the diagnostic basis for treating various health conditions and diseases. .

Catheter-integrated soft multilayer electronic arrays for multiplexed sensing and actuation during cardiac surgery.

The rigidity and relatively primitive modes of operation of catheters equipped with sensing or actuation elements impede their conformal contact with soft-tissue surfaces, limit the scope of their uses, lengthen surgical times and increase the need for advanced surgical skills. Here, we report materials, device designs and fabrication approaches for integrating advanced electronic functionality with catheters for minimally invasive forms of cardiac surgery. By using multiphysics modelling, plastic heart models and Langendorff animal and human hearts, we show that soft electronic arrays in multilayer configurations on endocardial balloon catheters can establish conformal contact with curved tissue surfaces, support high-density spatiotemporal mapping of temperature, pressure and electrophysiological parameters and allow for programmable electrical stimulation, radiofrequency ablation and irreversible electroporation.

Silicon nanomembrane phototransistor flipped with multifunctional sensors toward smart digital dust.

The sensing module that converts physical or chemical stimuli into electrical signals is the core of future smart electronics in the post-Moore era. Challenges lie in the realization and integration of different detecting functions on a single chip. We propose a new design of on-chip construction for low-power consumption sensor, which is based on the optoelectronic detection mechanism with external stimuli and compatible with CMOS technology.