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Owing to the unique combination of electrical conductivity and tissue-like mechanical properties, conducting polymer hydrogels have emerged as a promising candidate for bioelectronic interfacing with biological systems. However, despite the recent advances, the development of hydrogels with both excellent electrical and mechanical properties in physiological environments is still challenging. Here we report a bi-continuous conducting polymer hydrogel that simultaneously achieves high electrical conductivity (over 11 S cm−1), stretchability (over 400%) and fracture toughness (over 3,300 J m−2) in physiological environments and is readily applicable to advanced fabrication methods including 3D printing. Enabled by these properties, we further demonstrate multi-material 3D printing of monolithic all-hydrogel bioelectronic interfaces for long-term electrophysiological recording and stimulation of various organs in rat models.A bi-continuous hydrogel prepared from phase-separated PEDOT:PSS and polyurethane is 3D printed into soft biolelectronic devices with high electrical conductivity, stretchability and toughness for long-term in vivo electrophysiological monitoring and stimulation.

Hydrogels of conducting polymers, particularly poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), provide a promising electrical interface with biological tissues for sensing and stimulation, owing to their favorable electrical and mechanical properties. While existing methods mostly blend PEDOT:PSS with other compositions such as non-conductive polymers, the blending can compromise resultant hydrogels’ mechanical and/or electrical properties. Here, we show that designing interconnected networks of PEDOT:PSS nanofibrils via a simple method can yield high-performance pure PEDOT:PSS hydrogels. The method involves mixing volatile additive dimethyl sulfoxide (DMSO) into aqueous PEDOT:PSS solutions followed by controlled dry-annealing and rehydration. The resultant hydrogels exhibit a set of properties highly desirable for bioelectronic applications, including high electrical conductivity (~20 S cm −1 in PBS, ~40 S cm −1 in deionized water), high stretchability (> 35% strain), low Young’s modulus (~2 MPa), superior mechanical, electrical and electrochemical stability, and tunable isotropic/anisotropic swelling in wet physiological environments. Hydrogels of conducting polymers provide an electrical interface with biological tissues for sensing and stimulation, but currently have compromised mechanical and electrical properties. Here, the authors show a simple method to achieve pure PEDOT:PSS hydrogels that exhibit superior mechanical and electrical properties, stability, and tunable swelling.

Sensory (or afferent) nerves bring sensations of touch, pain, or temperature variation to the central nervous system and brain. Using the tools and materials of organic electronics, Kim et al. combined a pressure sensor, a ring oscillator, and an ion gel–gated transistor to form an artificial mechanoreceptor (see the Perspective by Bartolozzi). The combination allows for the sensing of multiple pressure inputs, which can be converted into a sensor signal and used to drive the motion of a cockroach leg in an oscillatory pattern. Science , this issue p. 998 ; see also p. 966 Organic flexible electronics mimic the functions of a biological afferent nerve and actuate muscles. The distributed network of receptors, neurons, and synapses in the somatosensory system efficiently processes complex tactile information. We used flexible organic electronics to mimic the functions of a sensory nerve. Our artificial afferent nerve collects pressure information (1 to 80 kilopascals) from clusters of pressure sensors, converts the pressure information into action potentials (0 to 100 hertz) by using ring oscillators, and integrates the action potentials from multiple ring oscillators with a synaptic transistor. Biomimetic hierarchical structures can detect movement of an object, combine simultaneous pressure inputs, and distinguish braille characters. Furthermore, we connected our artificial afferent nerve to motor nerves to construct a hybrid bioelectronic reflex arc to actuate muscles. Our system has potential applications in neurorobotics and neuroprosthetics.

Neurotransmitters play essential roles in regulating neural circuit dynamics both in the central nervous system as well as at the peripheral, including the gastrointestinal tract 1 – 3 . Their real-time monitoring will offer critical information for understanding neural function and diagnosing disease 1 – 3 . However, bioelectronic tools to monitor the dynamics of neurotransmitters in vivo, especially in the enteric nervous systems, are underdeveloped. This is mainly owing to the limited availability of biosensing tools that are capable of examining soft, complex and actively moving organs. Here we introduce a tissue-mimicking, stretchable, neurochemical biological interface termed NeuroString, which is prepared by laser patterning of a metal-complexed polyimide into an interconnected graphene/nanoparticle network embedded in an elastomer. NeuroString sensors allow chronic in vivo real-time, multichannel and multiplexed monoamine sensing in the brain of behaving mouse, as well as measuring serotonin dynamics in the gut without undesired stimulations and perturbing peristaltic movements. The described elastic and conformable biosensing interface has broad potential for studying the impact of neurotransmitters on gut microbes, brain–gut communication and may ultimately be extended to biomolecular sensing in other soft organs across the body. NeuroString, a tissue-like biological interface created by laser patterning of polyimide into a graphene/nanoparticle network embedded in an elastomer, is introduced, allowing in vivo real-time detection of neurotransmitters in the brain and gut.

Wearable bioelectronic sensors are often used for health monitoring but are typically limited to a few physical or chemical parameters, which hinders their ability to provide a complete health assessment. Recently, wearable sensor platforms have been developed that can simultaneously and continuously record multiple biophysical and biochemical signals. These devices take advantage of advances in electronic device fabrication and miniaturization, bioelectronic sensors, and flexible materials. However, compared with existing wearable systems, which mostly contain either biochemical or biophysical sensors, hybrid multimodal wearable patches present a number of distinct challenges for further advancement. Here, we examine the development of such hybrid multimodal wearable sensors and explore their potential applications in tracking the health and disease status of different users. We highlight the key biomarkers and vital signs (related to various pathophysiological conditions) that hybrid bioelectronic sensor systems must be designed around. We also explore how artificial intelligence could be integrated with these hybrid multimodal sensors to offer wearers the ability to assess their health status in real time. This Review examines the development and potential of wearable sensor systems that use multiple physical and chemical sensing modalities to assess human health.

Pure organic room temperature phosphorescence (RTP) materials become increasingly important in advanced optoelectronic and bioelectronic applications. Current phosphors based on small aromatic molecules show emission characteristics generally limited to short wavelengths. It remains an enormous challenge to achieve red and near-infrared (NIR) RTP, particularly for those from nonaromatics. Here we demonstrate that succinimide derived cyclic imides can emit RTP in the red (665, 690 nm) and NIR (745 nm) spectral range with high efficiencies of up to 9.2%. Despite their rather limited molecular conjugations, their unique emission stems from the presence of the imide unit and heavy atoms, effective molecular clustering, and the electron delocalization of halogens. We further demonstrate that the presence of heavy atoms like halogen or chalcogen atoms in these systems is important to facilitate intersystem crossing as well as to extend through-space conjugation and to enable rigidified conformations. This universal strategy paves the way to the design of nonconventional luminophores with long wavelength emission and for emerging applications. Pure organic room temperature phosphorescence (RTP) materials become increasingly important but achieving red and near-infrared (NIR) RTP remains challenging. Here, the authors demonstrate that succinimide derived cyclic imides can emit RTP in the red and NIR spectral range with outstanding efficiencies of up to 9.2%.

‘Smart’ bandages based on multimodal wearable devices could enable real-time physiological monitoring and active intervention to promote healing of chronic wounds. However, there has been limited development in incorporation of both sensors and stimulators for the current smart bandage technologies. Additionally, while adhesive electrodes are essential for robust signal transduction, detachment of existing adhesive dressings can lead to secondary damage to delicate wound tissues without switchable adhesion. Here we overcome these issues by developing a flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with skin-interfacing hydrogel electrodes capable of on-demand adhesion and detachment. In mice, we demonstrate that our wound care system can continuously monitor skin impedance and temperature and deliver electrical stimulation in response to the wound environment. Across preclinical wound models, the treatment group healed ~25% more rapidly and with ~50% enhancement in dermal remodeling compared with control. Further, we observed activation of proregenerative genes in monocyte and macrophage cell populations, which may enhance tissue regeneration, neovascularization and dermal recovery. A wireless ‘smart’ bandage stimulates wound healing.

Soft electronics are rising electronic technologies towards applications spanning from healthcare monitoring to medical implants. However, poor adhesion strength and significant mechanical mismatches inevitably cause the interface failure of devices. Herein we report a self-adhesive conductive polymer that possesses low modulus (56.1-401.9 kPa), high stretchability (700%), high interfacial adhesion (lap-shear strength >1.2 MPa), and high conductivity (1-37 S/cm). The self-adhesive conductive polymer is fabricated by doping the poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) composite with a supramolecular solvent (β-cyclodextrin and citric acid). We demonstrated the solution process-based fabrication of self-adhesive conductive polymer-based electrodes for various soft devices, including alternating current electroluminescent devices, electromyography monitoring, and an integrated system for the visualization of electromyography signals during muscle training with an array of alternating current electroluminescent devices. The self-adhesive conductive polymer-based electronics show promising features to further develop wearable and comfortable bioelectronic devices with the physiological electric signals of the human body readable and displayable during daily activities. Poor adhesion and mechanical mismatches may cause interface failure of soft devices. Here, authors report a supramolecular solvent-doped, soft, adhesive, yet conductive polymer composite for stretchable, wearable, and comfortable electronic devices.

We argue that development is not the outcome of genetic instructions or dynamics, but of biological agency embedded in a multi-scale coordination architecture characteristic of living systems. We outline the lack of a plausible mechanism by which semantic content about the phenotype could be encoded in, or retrieved from, the genotype or its patterns of expression per se, requiring the existence of some other process to govern development. Ample empirical evidence points to emergent bio-electrical morphogenetic fields as the locus of biological information shaping development. Indeed, they appear capable of defining architectural plans, computing an adequate developmental trajectory to realize those plans, and signalling appropriate actions to subsystems. We further suggest that such multi-scale coordination architectures display the physical property of contextuality, i.e. genuine emergence of observables (here, biological information) as a causal driver of system dynamics. This in turn explains the self-constructive aspect of biological intelligence, physically grounding it into a specific model of biological agency and information. This view reframes the relation between mind and body in developmental processes, suggesting that development is a fundamental expression of (embodied) intelligence.

The semiconductor industry is experiencing an accelerated transformation to overcome the scaling limits of the transistor and to adapt to new requirements in terms of data storage and computation, especially driven by artificial intelligence applications and the Internet of Things. In this process, new materials, devices, integration strategies and system architectures are being developed and optimized. Among them, memristive devices and circuits—memristors are two-terminal memory devices that can also mimic some basic bioelectronic functions—offer a potential approach to create more compact, energy-efficient or better-performing systems. The memristor industry is growing quickly, raising abundant capital investment, creating new jobs and placing advanced products in the market. Here we analyse the status and prospects of the memristor industry, focusing on memristor-based products that are already commercially available, prototypes with a high technological readiness level that might affect the market in the near future, and discuss obstacles and pathways to their implementation. The status and prospects of the memristor industry are analysed and the obstacles and pathways to their implementation are discussed.