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Bioresorbable electronic stimulators are of rapidly growing interest as unusual therapeutic platforms, i.e., bioelectronic medicines, for treating disease states, accelerating wound healing processes and eliminating infections. Here, we present advanced materials that support operation in these systems over clinically relevant timeframes, ultimately bioresorbing harmlessly to benign products without residues, to eliminate the need for surgical extraction. Our findings overcome key challenges of bioresorbable electronic devices by realizing lifetimes that match clinical needs. The devices exploit a bioresorbable dynamic covalent polymer that facilitates tight bonding to itself and other surfaces, as a soft, elastic substrate and encapsulation coating for wireless electronic components. We describe the underlying features and chemical design considerations for this polymer, and the biocompatibility of its constituent materials. In devices with optimized, wireless designs, these polymers enable stable, long-lived operation as distal stimulators in a rat model of peripheral nerve injuries, thereby demonstrating the potential of programmable long-term electrical stimulation for maintaining muscle receptivity and enhancing functional recovery. Bioresorbable electronic stimulators can deliver electrical stimulation in rodents to enhance functional muscle recovery after nerve injury. Here, the authors present a bioresorbable dynamic covalent polymer that enables reliable, long-lived operation of soft, stretchable devices of this type.

Capabilities for continuous monitoring of pressures and temperatures at critical skin interfaces can help to guide care strategies that minimize the potential for pressure injuries in hospitalized patients or in individuals confined to the bed. This paper introduces a soft, skin-mountable class of sensor system for this purpose. The design includes a pressure-responsive element based on membrane deflection and a battery-free, wireless mode of operation capable of multi-site measurements at strategic locations across the body. Such devices yield continuous, simultaneous readings of pressure and temperature in a sequential readout scheme from a pair of primary antennas mounted under the bedding and connected to a wireless reader and a multiplexer located at the bedside. Experimental evaluation of the sensor and the complete system includes benchtop measurements and numerical simulations of the key features. Clinical trials involving two hemiplegic patients and a tetraplegic patient demonstrate the feasibility, functionality and long-term stability of this technology in operating hospital settings. Uninterrupted monitoring of pressure and temperature at skin interfaces can help to minimize the potential for pressure injuries in hospitalized or bedridden patients. Here, the authors introduce a soft, skin-mountable sensor that can continuously provide readings via antennas mounted under bedding, and demonstrate the functionality and robustness of the devices on patients.

Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections, thrombosis, and intimal lesions caused by surface friction. However, achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities, specifically regarding electrostatic interactions. This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan (ZW@CMC) with antibacterial and antithrombotic activities for use in catheters. The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties, which facilitate the formation of a stable hydration layer with low friction. The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group. This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer. This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation. Subsequently, the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity, hemolysis, and catheter friction. Furthermore, in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment. This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices. [Display omitted] •Zwitterionic carboxymethyl chitosan hydrogel was fabricated via water-based process.•Zwitterionic hydrogel improved the antimicrobial and antithrombotic performance.•Zwitterionic functionalization enhanced electrostatic repulsion for antifouling.•The hydrogel shows superior prevention of blood clotting in vivo catheterization test.•The Hydrogel coating supported sepsis curing by bacterial killing in sepsis model.

Individuals who are unable to walk independently spend most of the day in a wheelchair. This population is at high risk for developing pressure injuries caused by sitting. However, early diagnosis and prevention of these injuries still remain challenging. Herein, we introduce battery-free, wireless, multimodal sensors and a movable system for continuous measurement of pressure, temperature, and hydration at skin interfaces. The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity, a temperature sensor for measuring skin temperature, and a galvanic skin response sensor for measuring skin hydration levels. The movable system enables power harvesting, and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage. Experimental evaluations and numerical simulations of the devices, together with clinical trials for wheelchair patients, demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.

Through the direct decomposition of an Al precursor ink AlH 3 {O(C 4 H 9 ) 2 }, we fabricated an Al-coated conductive fiber filter for the efficient electrostatic removal of airborne particles (>99%) with a low pressure drop (~several Pascals). The effects of the electrical and structural properties of the filters were investigated in terms of collection efficiency, pressure drop, and particle deposition behavior. The collection efficiency did not show a significant correlation with the extent of electrical conductivity, as the filter is electrostatically charged by the metallic Al layers forming electrical networks throughout the fibers. Most of the charged particles were collected via surface filtration by Coulombic interactions; consequently, the filter thickness had little effect on the collection efficiency. Based on simulations of various fiber structures, we found that surface filtration can transition to depth filtration depending on the extent of interfiber distance. Therefore, the effects of structural characteristics on collection efficiency varied depending on the degree of the fiber packing density. This study will offer valuable information pertaining to the development of a conductive metal/polymer composite air filter for an energy-efficient and high-performance electrostatic filtration system.

Demand for augmented reality (AR) technology in the healthcare industry has gradually increased due to its immersive and interactive environment, which enhances the medical staff’s intuitive interpretation of sensing data during surgery, rehabilitation, diagnosis, education, and therapy. However, current skin-mountable, wearable sensors integrated with AR platforms mainly focus on Human-Machine Interface (HMI) for interactive experiences. Furthermore, most wearable sensors currently used in conjunction with AR systems are rigid and cumbersome, which hampers their application to the skin interfaces of patients for personalized healthcare. Herein, we developed a wireless, battery-free multi-axial sensor with a thin and small form factor and integrated it with the AR system to visualize sensing data (e.g., pressure, shear stress, and temperature) from the subjects. The overall system demonstrated efficacy in preventing pressure injuries, monitoring posture to prevent disc herniation, and intuitive AR monitoring of physical parameters for subjects sitting in wheelchairs and lying in bed.

Emerging freestanding membrane technologies, especially using inorganic thermoelectric materials, demonstrate the potential for advanced thermoelectric platforms. However, using rare and toxic elements during material processing must be circumvented. Herein, we present a scalable method for synthesizing highly crystalline CuS membranes for thermoelectric applications. By sulfurizing crystalline Cu, we produce a highly percolated and easily transferable network of submicron CuS rods. The CuS membrane effectively separates thermal and electrical properties to achieve a power factor of 0.50 mW m−1 K−2 and thermal conductivity of 0.37 W m−1 K−1 at 650 K (estimated value). This yields a record‐high dimensionless figure‐of‐merit of 0.91 at 650 K (estimated value) for covellite. Moreover, integrating 12 CuS devices into a module resulted in a power generation of ~4 μW at ΔT of 40 K despite using a straightforward configuration with only p‐type CuS. Furthermore, based on the temperature‐dependent electrical characteristics of CuS, we develop a wearable temperature sensor with antibacterial properties. Thermoelectric materials can efficiently generate electricity by recycling waste heat. This work designed a new thermoelectric model featuring thin and highly crystalline covellite (CuS) membrane through a solution‐based sulfurization on copper foils. The membrane enhances phonon scattering effects within nano‐sized pores in sub‐micron rods, maximizing thermoelectric properties.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20857-y

This paper presents a deterministic bead-in-droplet ejection (BIDE) technique that regulates the precise distribution of microbeads in an ejected droplet. The deterministic BIDE was realized through the effective integration of a microfluidic single-particle handling technique with a liquid dispensing system. The integrated bead dispenser facilitates the transfer of the desired number of beads into a dispensing volume and the on-demand ejection of bead-encapsulated droplets. Single bead–encapsulated droplets were ejected every 3 s without any failure. Multiple-bead dispensing with deterministic control of the number of beads was demonstrated to emphasize the originality and quality of the proposed dispensing technique. The dispenser was mounted using a plug-socket type connection, and the dispensing process was completely automated using a programmed sequence without any microscopic observation. To demonstrate a potential application of the technique, bead-based streptavidin–biotin binding assay in an evaporating droplet was conducted using ultralow numbers of beads. The results evidenced the number of beads in the droplet crucially influences the reliability of the assay. Therefore, the proposed deterministic bead-in-droplet technology can be utilized to deliver desired beads onto a reaction site, particularly to reliably and efficiently enrich and detect target biomolecules.