Stress Dissipation Encoded Silk Fibroin Electrode for the Athlete-Beneficial Silk Bioelectronics

Transforming Healthcare: Intelligent Wearable Sensors Empowered by Smart Materials and Artificial Intelligence

Intelligent wearable sensors, empowered by machine learning and innovative smart materials, enable rapid, accurate disease diagnosis, personalized therapy, and continuous health monitoring without disrupting daily life. This integration facilitates a shift from traditional, hospital-centered healthcare to a more decentralized, patient-centric model, where wearable sensors can collect real-time physiological data, provide deep analysis of these data streams, and generate actionable insights for point-of-care precise diagnostics and personalized therapy. Despite rapid advancements in smart materials, machine learning, and wearable sensing technologies, there is a lack of comprehensive reviews that systematically examine the intersection of these fields. This review addresses this gap, providing a critical analysis of wearable sensing technologies empowered by smart advanced materials and artificial Intelligence. The state-of-the-art smart materials-including self-healing, metamaterials, and responsive materials-that enhance sensor functionality are first examined. Advanced machine learning methodologies integrated into wearable devices are discussed, and their role in biomedical applications is highlighted. The combined impact of wearable sensors, empowered by smart materials and machine learning, and their applications in intelligent diagnostics and therapeutics are also examined. Finally, existing challenges, including technical and compliance issues, information security concerns, and regulatory considerations are addressed, and future directions for advancing intelligent healthcare are proposed.

A Soft Patch for Dynamic Myocardial Infarction Monitoring

Wearable electronics for cardiac monitoring have been widely developed in the field of routine vital sign monitoring and arrhythmia determination due to their convenience and continuity. However, there are very few reports on the demonstration of a stretchable multilead electrocardiogram (ECG) patch integrated with myocardial infarction (MI) location capability. Here, we first propose a wearable dynamic cardiac monitoring patch, which can acquire seven-lead ECG signals continuously. A novel stretchable bioelectrode is mounted on the patch, which is strain-insensitive in the 100% tensile strain range. Moreover, the bioelectrode maintains good adhesion to the skin at more than 0.4 N/cm. This soft and wireless multilead ECG patch is designed for long-term, all-round real-time cardiac monitoring. For MI classification, a machine learning model for MI identification and location is trained with accuracy (99.93%) and sensitivity (99.98%). In addition, we also propose a new framework for the automated annotation of MI abnormal segments, which simultaneously addresses the recognition of abnormal waveforms and the integration of interlead relationships. This study contributes to the realization of personalized medical monitoring and intervention as well as early warning for MI.

Spider Silk-Inspired Hyaluronic Acid-Based Hydrogels with Superior Self-Healing Capability and Enhanced Strength

Hyaluronic acid hydrogels are promising materials for diverse applications, yet their potential is hampered by limitations such as low self-healing efficiency and insufficient mechanical strength. Inspired by the heterogeneous structures of spider silk, we introduce a novel dual dynamically crosslinked network hydrogel. This hydrogel comprises an acylhydrazone-crosslinked network, utilizing aldehyde hyaluronic acid (AHA) and 3,3'-dithiobis (propionohydrazide) (DTP) as a first network, and a secondary network formed by hydrogen bonds-crosslinked network between tannic acid (TA) and silk fibroin (SF) with β-sheet formation. The hydrogel exhibits exceptional self-healing ability due to the dynamic and reversible nature of Schiff base bonds, disulfide bonds, and hydrogen bonds, achieving complete healing within 5 minutes. Additionally, the spider silk-inspired heterogeneous structures enhance mechanical properties. Furthermore, the incorporation of TA provides enhances adhesion, as well as remarkable antibacterial and antioxidant properties. This innovative hyaluronic acid-based hydrogel, inspired by spider silk, offers a promising avenue to fortify both the mechanical strength and self-healing capabilities of hydrogels, thus expanding opportunities for applications in tissue engineering and biomedicine.

Viscoelastic and antimicrobial dental care bioplastic with recyclable life cycle

Medical plastic-appliance-based healthcare services, especially in dentistry, generate tremendous amounts of plastic waste. Given the physiological features of our mouth, it is desirable to substitute dental care plastics with viscoelastic and antimicrobial bioplastics. Herein, we develop a medical-grade and sustainable bioplastic that is viscoelastic enough to align the tooth positions, resists microbial contamination, and exhibits recyclable life cycles. In particular, we devise a molecular template involving entanglement-inducing and antimicrobial groups and prepare a silk fibroin-based dental care bioplastic. The generated compactly entangled structure endows great flexibility, toughness, and viscoelasticity. Therefore, a satisfactory orthodontic outcome is accomplished, as demonstrated by the progressive alignment of male rabbit incisors within the 2.5 mm range. Moreover, the prepared bioplastic exhibits resistance to pathogenic colonization of intraoral microbes such as Streptococcaceae and Veillonellaceae. Because the disentanglement of entangled domains enables selective separation and extraction of the components, the bioplastic can be recycled into a mechanically identical one. The proposed medical-grade and sustainable bioplastic could potentially contribute to a green healthcare future.

Self-healing and adhesive MXene-polypyrrole/silk fibroin/polyvinyl alcohol conductive hydrogels as wearable sensor

Conductive hydrogels become increasing attractive for flexible electronic devices and biosensors. However, challenges still remain in fabrication of flexible hydrogels with high electrical conductivity, self-healing capability and adhesion property. Herein, a conductive hydrogel (PSDM) was prepared by solution-gel method using MXene and dopamine modified polypyrrole as conductive enhanced materials, polyvinyl alcohol and silk fibroin as gel networks, and borax as cross-linking agent. Notably, the PSDM hydrogels not only showed high permeability (13.82 mg∙cm-2∙h-1), excellent stretch ability (1235 %), high electrical conductivity (11.3 S/m) and long-term stability, but also exhibited high adhesion performance and self-healing properties. PSDM hydrogels displayed outstanding sensing performance and durability for monitoring human activities including writing, finger bending and wrist bending. The PSDM hydrogel was made into wearable flexible electrodes and realized accurate, sensitive and reliable detection of human electromyographic and electrocardiographic signals. The sensor was also applied in human-computer interaction by collecting electromyography signals of different gestures for machine learning and gesture recognition. According to 480 groups of data collected, the recognition accuracy of gestures by the electrodes was close to 100 %, indicating that the PSDM hydrogel electrodes possessed excellent sensing performance for high precision data acquisition and human-computer interaction interface.

Recent advance of high-quality perovskite nanostructure and its application in flexible photodetectors

Flexible photodetectors (PDs) have garnered increasing attention for their potential applications in diverse fields, including weather monitoring, smart robotics, smart textiles, electronic eyes, wearable biomedical monitoring devices, and so on. Notably, perovskite nanostructures have emerged as a promising material for flexible PDs due to their distinctive features, such as a large optical absorption coefficient, tunable band gap, extended photoluminescence decay time, high carrier mobility, low defect density, long exciton diffusion lengths, strong self-trapped effect, good mechanical flexibility, and facile synthesis methods. In this review, we first introduce various synthesis methods for perovskite nanostructures and elucidate their corresponding optical and electrical properties, encompassing quantum dots, nanocrystals, nanowires, nanobelts, nanosheets, single-crystal thin films, polycrystalline thin films, and nanostructured arrays. Furthermore, the working mechanism and key performance parameters of optoelectronic devices are summarized. The review also systematically compiles recent advancements in flexible PDs based on various nanostructured perovskites. Finally, we present the current challenges and prospects for the development of perovskite nanostructures-based flexible PDs.

Cultured meat with enriched organoleptic properties by regulating cell differentiation

Research on cultured meat has primarily focused on the mass proliferation or differentiation of muscle cells; thus, the food characteristics of cultured meat remain relatively underexplored. As the quality of meat is determined by its organoleptic properties, cultured meat with similar sensory characteristics to animal-derived meat is highly desirable. In this study, we control the organoleptic and nutritional properties of cultured meat by tailoring the 2D differentiation of primary bovine myoblasts and primary bovine adipose-derived mesenchymal stem cells on gelatin/alginate scaffolds with varying stiffness. We assess the effect of muscle and adipose differentiation quality on the sensory properties of cultured meat. Thereafter, we fabricate cultured meat with similar sensory profiles to that of conventional beef by assembling the muscle and adipose constructs composed of highly differentiated cells. We introduce a strategy to produce cultured meat with enriched food characteristics by regulating cell differentiation with scaffold engineering.

Quasi-Homogeneous and Hierarchical Electronic Textiles with Porosity-Hydrophilicity Dual-Gradient for Unidirectional Sweat Transport, Electrophysiological Monitoring, and Body-Temperature Visualization

On-skin electronics based on impermeable elastomers and stacking structures often suffer from inferior sweat-repelling capabilities and severe mechanical mismatch between sub-layers employed, which significantly impedes their lengthy wearing comfort and functionality. Herein, inspired by the transpiration system of vascular plants and the water diode phenomenon, a hierarchical nonwoven electronic textile (E-textile) with multi-branching microfibers and robust interlayer adhesion is rationally developed. The layer-by-layer electro-airflow spinning method and selective oxygen plasma treatment are utilized to yield a porosity-hydrophilicity dual-gradient. The resulting E-textile shows unidirectional, nonreversible, and anti-gravity water transporting performance even upon large-scale stretching (250%), excellent mechanical matching between sub-layers, as well as a reversible color-switching ability to visualize body temperature. More importantly, the conducting and skin-conformal E-textile demonstrates accurate and stable detecting capability for biomechanical and bioelectrical signals when applied as an on-skin bioelectrode, including different human activities, electrocardiography, electromyogram, and electrodermal activity signals. Further, the E-textile can be efficiently implemented in human-machine interfaces to build a gesture-controlled dustbin and a smart acousto-optic alarm. Hence, this hierarchically-designed E-textile with integrated functionalities offers a practical and innovative method for designing comfortable and daily applicable on-skin electronics.

Regulation of the Inevitable Water-Responsivity of Silk Fibroin Biopolymer by Polar Amino Acid Activation

In nature, water is vital for maintaining homeostasis. Particularly, organisms (e.g., plant leaf, bird feather) exploit water fluidics for motions. Hydration-adaptive crystallization is the representative water-responsive actuation of biopolymers. This crystallization has inspired the development of intelligent human-robot interfaces. At the same time, it hinders the consistent adhesion of tissue adhesive. As hydration-adaptive crystallization is inevitable, the on-demand control of crystallization is desirable in the innovative biopolymeric biomedical systems. To this end, this study developed an amino acid-based technology to artificially up- or down-regulate the inevitable crystallization of silk fibroin. A case II diffusion model was constructed, and it revealed that the activity of polar amino acid is related to crystallization kinetics. Furthermore, the water dynamics study suggested that active amino acid stabilizes crystallization-triggering water molecules. As a proof-of-concept, we verified that a 30% increase in the activity of serine resulted in a 50% decrease in the crystallization rate. Furthermore, the active amino acid-based suppression of hydration-adaptive crystallization enabled the silk fibroin to keep its robust adhesion (approximately 160 kJ m^-3) by reducing the water-induced loss of adhesive force. The proposed silk fibroin was demonstrated as a stable tissue adhesive applied on ex vivo porcine mandible tissue. This amino acid-based regulation of hydration-adaptive crystallization will pioneer next-generation biopolymer-based healthcare.

An All-in-One, Bioderived, Air-Permeable, and Sweat-Stable MXene Epidermal Electrode for Muscle Theranostics

Muscle fatigue is a common symptom experienced by many people and associated with less maximal force production of fatigued muscle. It is highly desirable to simultaneously and imperceivably diagnose muscle fatigue and restore muscle function using one skin electrode, yet no such electrode has been developed so far. Herein, we report an all-in-one, bioderived, air-permeable, and sweat-stable MXene electrode that can concurrently and comfortably record electromyographic (EMG) signals and achieve electrostimulation and electrothermal therapy for muscle theranostics. Leveraging the structural arrangement of perennial herbs and ion cross-linking of MXene in sweat, MXene-based electrodes (MBE) exhibit high breathability, are ultralightweight (∼0.25 mg/cm³), and have low and stable electrode-skin interfacial impedance at a variety of environments, facilitating the long-term reliable monitoring of electrophysiology. Taken together with electrostimulation and electrothermal therapy at the skin surface, MBE can diagnose muscle fatigue and restore muscle function by stimulating blood circulation. In addition, it can also be used for muscle rehabilitation training and prosthesis control via human-computer interaction. Our all-in-one, bioderived, air-permeable, and sweat-stable MXene electrode has a great potential for daily wearable healthcare of muscle fatigue.

Surface Wrinkling for Flexible and Stretchable Sensors

Recent advances in nanolithography, miniaturization, and material science, along with developments in wearable electronics, are pushing the frontiers of sensor technology into the large-scale fabrication of highly sensitive, flexible, stretchable, and multimodal detection systems. Various strategies, including surface engineering, have been developed to control the electrical and mechanical characteristics of sensors. In particular, surface wrinkling provides an effective alternative for improving both the sensing performance and mechanical deformability of flexible and stretchable sensors by releasing interfacial stress, preventing electrical failure, and enlarging surface areas. In this study, recent developments in the fabrication strategies of wrinkling structures for sensor applications are discussed. The fundamental mechanics, geometry control strategies, and various fabricating methods for wrinkling patterns are summarized. Furthermore, the current state of wrinkling approaches and their impacts on the development of various types of sensors, including strain, pressure, temperature, chemical, photodetectors, and multimodal sensors, are reviewed. Finally, existing wrinkling approaches, designs, and sensing strategies are extrapolated into future applications.