Self-Evolving Hierarchical Hydrogel Fibers with Circadian Rhythms and Memory Functions.

The fusion of hierarchical tissues at interfaces, incorporating ultrafast selective transport channels, enables efficient matter exchange and energy transfer across multiscale structures in living organisms. However, achieving these characteristics simultaneously in an artificial multimaterial system is challenging. Here, this work presents a multimaterial hydrogel fiber with a hierarchical structure of interface fusion, which forms spontaneously through in situ hierarchy evolution induced by ionic cross-linking and molecular shear flow. Water transport occurs in the angstrom-scale confined slits created by aligned cellulose nanocrystals (CNCs) by direct Coulomb knock-on, resembling Newton's cradle motion. The fusion of interfaces enables high-efficiency water transport across multiscale layers, combined with Newton's cradle-like collective water motion, creating a highly sensitive negative feedback loop within the fiber. These fibers exhibit integrated behaviors of time-space perception, short-term memory and adaptive changes in shape. Additionally, they demonstrate rhythm characteristics, changing periodically in a 24-h day-night cycle. Composed of natural building blocks, these hierarchical hydrogel fibers exhibit a memristor effect similar to that of an elementary neuron, making them promising for applications in seamless on-skin and implantable bioelectronics.

Constructing Lysozyme Protective Layer via Conformational Transition for Aqueous Zn Batteries.

The practical applications for aqueous Zn ion batteries (ZIBs) are promising yet still impeded by the severe side reactions on Zn metal. Here, a lysozyme protective layer (LPL) is prepared on Zn metal surface by a simple and facile self-adsorption strategy. The LPL exhibits extremely strong adhesion on Zn metal to provide stable interface during long-term cycling. In addition, the self-adsorption strategy triggered by the hydrophobicity-induced aggregation effect endows the protective layer with a gap-free and compacted morphology which can reject free water for effective side reaction inhibition performance. More importantly, the lysozyme conformation is transformed from α-helix to ß-sheet structure before layer formation, thus abundant functional groups are exposed to interact with Zn2+ for electrical double layer (EDL) modification, desolvation energy decrease, and ion diffusion kinetics acceleration. Consequently, the LPL renders the symmetrical Zn battery with ultra-long cycling performance for more than 1200 h under high Zn depth of discharge (DOD) for 77.7%, and the Zn/Zn0.25V2O5 pouch cell with low N/P ratio of 2.1 at high Zn utilization of 48% for over 300 cycles. This study proposes a facile and low-cost method for constructing a stable protective layer of Zn metal for high Zn utilization aqueous devices.

Hydrogen Bonding Competition Mediated Phase Separation with Abnormal Moisture-Induced Stiffness Boosting.

Moisture usually deteriorates polymers' mechanical performance owing to its plasticizing effect, causing side effects in their practical load-bearing applications. Herein, a simple binary ionogel consisting of an amphiphilic polymer network and a hydrophobic ionic liquid (IL) is developed with remarkable stiffening effect after moisture absorption, demonstrating a complete contrast to water-induced softening effect of most polymer materials. Such a moisture-induced stiffening behavior is induced by phase separation after hydration of this binary ionogel. Specifically, it is revealed that hydrogen (H)-bonding structures play a dominant role in the humidity-responsive behavior of the ionogel, where water will preferentially interact with polymer chains through H-bonding and break the polymer-IL H-bonds, thus leading to phase separation structures with modulus boosting. This work may provide a facile and effective molecular engineering route to construct mechanically adaptive polymers with water-induced dramatic stiffening for diverse applications.

Exploring the interplay between core and mood symptoms in schizophrenia: A network analysis.

BACKGROUND: Schizophrenia is a complex neuropsychiatric disorder characterized by positive symptoms, negative symptoms, cognitive deficits, and co-occurring mood symptoms. Network analysis offers a novel approach to investigate the intricate relationships between these symptom dimensions, potentially informing personalized treatment strategies. METHODS: A cross-sectional study was conducted from November 2019 to October 2021, involving 1285 inpatients with schizophrenia in Liaoning Province, China. Symptom severity was assessed using the Positive and Negative Syndrome Scale (PANSS), Hamilton Depression Rating Scale (HAMD-17), Hamilton Anxiety Rating Scale (HAMA-14), and Montreal Cognitive Assessment (MoCA). Network analysis was conducted to investigate the network structure, central symptoms, and bridge symptoms. RESULTS: The network analysis uncovered profound interconnectivity between core symptoms and the anxiety-depression community. Central symptoms, such as psychic anxiety, poor rapport, delusions, and attention, were identified as potential therapeutic targets. Bridge symptoms, including insomnia, depressed mood, anxiety-somatic, conceptual disorganization, and stereotyped thinking, emerged as key nodes facilitating interactions between symptom communities. The stability and reliability of the networks were confirmed through bootstrapping procedures. DISCUSSION: The findings highlight the complex interplay between schizophrenia symptoms, emphasizing the importance of targeting affective symptoms and cognitive impairment in treatment. The identification of central and bridge symptoms suggests potential pathways for personalized interventions aimed at disrupting self-reinforcing symptom cycles. The study underscores the need for a transdiagnostic, personalized approach to schizophrenia treatment.

A Solid-Liquid Bicontinuous Fiber with Strain-Insensitive Ionic Conduction.

Stretchable ionic conductors are crucial for enabling advanced iontronic devices to operate under diverse deformation conditions. However, when employed as interconnects, existing ionic conductors struggle to maintain stable ionic conduction under strain, hindering high-fidelity signal transmission. Here, it is shown that strain-insensitive ionic conduction can be achieved by creating a solid-liquid bicontinuous microstructure. A bicontinuous fiber from polymerization-induced phase separation, which contains a solid elastomer phase interpenetrated by a liquid ion-conducting phase, is fabricated. The spontaneous partitioning of dissolved salts leads to the formation of a robust self-wrinkled interface, fostering the development of highly tortuous ionic channels. Upon stretch, these meandering ionic channels are straightened, effectively enhancing ionic conductivity to counteract the strain effect. Remarkably, the fiber retains highly stable ionic conduction till fracture, with only 7% resistance increase at 200% strain. This approach presents a promising avenue for designing durable ionic cables capable of signal transmission with minimal strain-induced distortion.

Small Ionic-Liquid-Based Molecule Drives Strong Adhesives.

Nature has inspired scientists to fabricate adhesive materials for applications in many burgeoning areas. However, it is still a significant challenge to develop small-molecule adhesives with high-strength, low-temperature and recyclable properties, although these merits are of great interest in various aspects. Herein, we report a series of strong adhesives based on low-molecular-weight molecular solids driven by the terminal modification of ionic liquids (ILs) and subsequent supramolecular self-assembly. The emergence of high strength and liquid-to-solid transitions for these supramolecular aggregates relies on modifying IL with a high melting point motif and enriching the types of noncovalent interactions in the original ILs. Using this strategy, we demonstrate that our IL-based molecular solids can efficiently obtain a high adhesion strength (up to 8.95 MPa). Importantly, we elucidate the mechanism underlying the reversible and strong adhesion enabled by monomer-to-polymer transitions. These fundamental findings provide guidance for the design of high-performance supramolecular adhesive materials.

Entropy-Driven Design of Highly Impact-Stiffening Supramolecular Polymer Networks with Salt-Bridge Hydrogen Bonds.

Impact-stiffening materials that undergo a strain rate-induced soft-to-rigid transition hold great promise as soft armors in the protection of the human body and equipment. However, current impact-stiffening materials, such as polyborosiloxanes and shear-thickening fluids, often exhibit a limited impact-stiffening response. Herein, we propose a design strategy for fabricating highly impact-stiffening supramolecular polymer networks by leveraging high-entropy-penalty physical interactions. We synthesized a fully biobased supramolecular polymer comprising poly(α-thioctic acid) and arginine clusters, whose chain dynamics are governed by highly specific guanidinium-carboxylate salt-bridge hydrogen bonds. The resulting material exhibits an exceptional impact-stiffening response of ∼2100 times, transitioning from a soft dissipating state (21 kPa, 0.1 Hz) to a highly stiffened glassy state (45.3 MPa, 100 Hz) with increasing strain rates. Moreover, the material's high energy-dissipating and hot-melting properties bring excellent damping performance and easy hybridization with other scaffolds. This entropy-driven approach paves the way for the development of next-generation soft, sustainable, and impact-resistant materials.

Hydrogels with Differentiated Hydrogen-Bonding Networks for Bioinspired Stress Response.

Stress response, an intricate and autonomously coordinated reaction in living organisms, holds a reversible, multi-path, and multi-state nature. However, existing stimuli-responsive materials often exhibit single-step and monotonous reactions due to the limited integration of structural components. Inspired by the cooperative interplay of extensor and flexor cells within Mimosa's pulvini, we present a hydrogel with differentiated hydrogen-bonding (H-bonding) networks designed to enable the biological stress response. Weak H-bonding domains resemble flexor cells, confined within a hydrophobic network stabilized by strong H-bonding clusters (acting like extensor cells). Under external force, strong H-bonding clusters are disrupted, facilitating water diffusion from the bottom layer and enabling transient expansion pressure gradient along the thickness direction. Subsequently, water diffuses upward, gradually equalizing the pressure, while weak H-bonding domains undergo cooperative elastic deformation. Consequently, the hydrogel autonomously undergoes a sequence of reversible and pluralistic motion responses, similar to Mimosa's touch-triggered stress response. Intriguingly, it exhibits stress-dependent color shifts under polarized light, highlighting its potential for applications in time-sensitive "double-lock" information encryption systems. This work achieves the coordinated stress response inspired by natural tissues using a simple hydrogel, paving the way for substantial advancements in the development of intelligent soft robots.

High-yield BMP2 expression in rice cells via CRISPR and endogenous αAmy3 promoter.

Plant cells serve as versatile platforms for the production of high-value recombinant proteins. This study explored the efficacy of utilizing an endogenous αAmy3 promoter for the expression of a bioactive pharmaceutical protein, specifically the mature region of human bone morphogenetic protein 2 (hBMP2m). Utilizing a refined CRISPR/Cas9-mediated intron-targeting insertion technique, which incorporates an artificial 3' splicing site upstream of the target gene, we achieved a transformation efficiency of 13.5% in rice calli that carried the rice-codon optimized mature region of hBMP2 cDNA (rhBMP2m) in the αAmy3 intron 1. Both homozygous and heterozygous rhBMP2m knock-in rice suspension cell lines were generated. These lines demonstrated the endogenous αAmy3 promoter regulated rhBMP2m mRNA and rhBMP2m recombinant protein expression, with strongly upregulation in respond to sugar depletion. The homozygous rhBMP2m knock-in cell line yielded an impressive 21.5 µg/mL of rhBMP2m recombinant protein, accounting for 1.03% of the total soluble protein. The high-yield expression was stably maintained across two generations, indicating the genetic stability of rhBMP2m gene knock-in at the αAmy3 intron 1 locus. Additionally, the rice cell-derived rhBMP2m proteins were found to be glycosylated, capable of dimer formation, and bioactive. Our results indicate that the endogenous rice αAmy3 promoter-signal peptide-based expression system is an effective strategy for producing bioactive pharmaceutical proteins. KEY POINTS: • The endogenous αAmy3 promoter-based expression system enhanced the yield of BMP2 • The increased yield of BMP2 accounted for 1.03% of the total rice-soluble proteins • The rice-produced BMP2 showed glycosylation modifications, dimer formation, and bioactivity.

Strong, tough and anisotropic bioinspired hydrogels.

Soft materials are widely used in tissue engineering, soft robots, wearable electronics, etc. However, it remains a challenge to fabricate soft materials, such as hydrogels, with both high strength and toughness that are comparable to biological tissues. Inspired by the anisotropic structure of biological tissues, a novel solvent-exchange-assisted wet-stretching strategy is proposed to prepare anisotropic polyvinyl alcohol (PVA) hydrogels by tuning the macromolecular chain movement and optimizing the polymer network. The reinforcing and toughening mechanisms are found to be "macromolecule crystallization and nanofibril formation". These hydrogels exhibit excellent mechanical properties, such as extremely high fracture stress (12.8 ± 0.7 MPa) and fracture strain (1719 ± 77%), excellent modulus (4.51 ± 0.76 MPa), high work of fracture (134.47 ± 9.29 MJ m-3), and fracture toughness (305.04 kJ m-2) compared with other strong hydrogels and even natural tendons. In addition, excellent conductivity, strain sensing capability, water retention, freezing resistance, swelling resistance, and biocompatibility can also be achieved. This work provides a new and effective method to fabricate multifunctional anisotropic hydrogels with high tunable strength and toughness with potential applications in the fields of regenerative medicine, flexible sensors, and soft robotics.

Self-compliant ionic skin by leveraging hierarchical hydrogen bond association.

Robust interfacial compliance is essential for long-term physiological monitoring via skin-mountable ionic materials. Unfortunately, existing epidermal ionic skins are not compliant and durable enough to accommodate the time-varying deformations of convoluted skin surface, due to an imbalance in viscosity and elasticity. Here we introduce a self-compliant ionic skin that consistently works at the critical gel point state with almost equal viscosity and elasticity over a super-wide frequency range. The material is designed by leveraging hierarchical hydrogen bond association, allowing for the continuous release of polymer strands to create topological entanglements as complementary crosslinks. By embodying properties of rapid stress relaxation, softness, ionic conductivity, self-healability, flaw-insensitivity, self-adhesion, and water-resistance, this ionic skin fosters excellent interfacial compliance with cyclically deforming substrates, and facilitates the acquisition of high-fidelity electrophysiological signals with alleviated motion artifacts. The presented strategy is generalizable and could expand the applicability of epidermal ionic skins to more complex service conditions.

Piezoionic Elastomers by Phase and Interface Engineering for High-Performance Energy-Harvesting Ionotronics.

Piezoionic materials play a pivotal role in energy-harvesting ionotronics. However, a persistent challenge lies in balancing the structural requirements for voltage generation, current conduction, and mechanical adaptability. The conventional approach of employing crystalline heterostructures for stress concentration and localized charge separation, while effective for voltage generation, often compromises the stretchability and long-range charge transport found in homogeneous quasisolid states. Herein, phase and interface engineering strategy is introduced to address this dilemma and a piezoionic elastomer is presented that seamlessly integrates ionic liquids and ionic plastic crystals, forming a finely tuned microphase-separated structure with an intermediate phase. This approach promotes charge separation via stress concentration among hard phases while leveraging the high ionic charge mobility in soft and intermediate phases. Impressively, the elastomer achieves an extraordinary piezoionic coefficient of about 6.0 mV kPa-1, a more than threefold improvement over current hydrogels and ionogels. The resulting power density of 1.3 µW cm-3 sets a new benchmark, exceeding that of state-of-the-art piezoionic gels. Notably, this elastomer combines outstanding stretchability, remarkable toughness, and rapid self-healing capability, underscoring its potential for real-world applications. This work may represent a stride toward mechanically robust energy harvesting systems and provide insights into ionotronic systems for human-machine interaction.

Amphibious Polymer Materials with High Strength and Superb Toughness in Various Aquatic and Atmospheric Environments.

Herein, the fabrication of amphibious polymer materials with outstanding mechanical performances, both underwater and in the air is reported. A polyvinyl alcohol/poly(2-methoxyethylacrylate) (PVA/PMEA) composite with multiscale nanostructures is prepared by combining solvent exchange and thermal annealing strategies, which contributes to nanophase separation with rigid PVA-rich and soft PMEA-rich phases and high-density crystalline domains of PVA chains, respectively. Benefiting from the multiscale nanostructure, the PVA/PMEA hydrogel demonstrates excellent stability in harsh (such as acidic, alkaline, and saline) aqueous solutions, as well as superior mechanical behavior with a breaking strength of up to 34.8 MPa and toughness of up to 214.2 MJ m-3 . Dehydrating the PVA/PMEA hydrogel results in an extremely robust plastic with a breaking strength of 65.4 MPa and toughness of 430.9 MJ m-3 . This study provides a promising phase-structure engineering route for constructing high-performance polymer materials for complex load-bearing environments.

Peeling-Stiffening Self-Adhesive Ionogel with Superhigh Interfacial Toughness.

Self-adhesive materials that can directly adhere to diverse solid surfaces are indispensable in modern life and technologies. However, it remains a challenge to develop self-adhesive materials with strong adhesion while maintaining its intrinsic softness for efficient tackiness. Here, a peeling-stiffening self-adhesive ionogel that reconciles the seemingly contradictory properties of softness and strong adhesion is reported. The ionogel contains two ionophilic repeating units with distinct associating affinities, which allows to adaptively wet rough surface in the soft dissipating state for adhering, and to dramatically stiffen to the glassy state upon peeling. The corresponding modulus increases by 117 times driven by strain-rate-induced phase separation, which greatly suppresses crack propagation and results in a super high interfacial toughness of 8046 J m-2 . The self-adhesive ionogel is also transparent, self-healable, recyclable, and can be easily removed by simple moisture treatment. This strategy provides a new way to design high-performance self-adhesive materials for intelligent soft devices.

Guiding Zn Uniform Deposition with Polymer Additives for Long-lasting and Highly Utilized Zn Metal Anodes.

The parasitic side reaction on Zn anode is the key issue which hinders the development of aqueous Zn-based energy storage systems on power-grid applications. Here, a polymer additive (PMCNA) engineered by copolymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-acryloyl glycinamide (NAGA) was employed to regulate the Zn deposition environment for satisfying side reaction inhibition performance during long-term cycling with high Zn utilization. The PMCNA can preferentially adsorb on Zn metal surface to form a uniform protective layer for effective water molecule repelling and side reaction resistance. In addition, the PMCNA can guide Zn nucleation and deposition along 002 plane for further side reaction and dendrite suppression. Consequently, the PMCNA additive can enable the Zn//Zn battery with an ultrahigh depth of discharge (DOD) of 90.0 % for over 420 h, the Zn//active carbon (AC) capacitor with long cycling lifespan, and the Zn//PANI battery with Zn utilization of 51.3 % at low N/P ratio of 2.6.

Marginal effects of public health measures and COVID-19 disease burden in China: A large-scale modelling study.

China had conducted some of the most stringent public health measures to control the spread of successive SARS-CoV-2 variants. However, the effectiveness of these measures and their impacts on the associated disease burden have rarely been quantitatively assessed at the national level. To address this gap, we developed a stochastic age-stratified metapopulation model that incorporates testing, contact tracing and isolation, based on 419 million travel movements among 366 Chinese cities. The study period for this model began from September 2022. The COVID-19 disease burden was evaluated, considering 8 types of underlying health conditions in the Chinese population. We identified the marginal effects between the testing speed and reduction in the epidemic duration. The findings suggest that assuming a vaccine coverage of 89%, the Omicron-like wave could be suppressed by 3-day interval population-level testing (PLT), while it would become endemic with 4-day interval PLT, and without testing, it would result in an epidemic. PLT conducted every 3 days would not only eliminate infections but also keep hospital bed occupancy at less than 29.46% (95% CI, 22.73-38.68%) of capacity for respiratory illness and ICU bed occupancy at less than 58.94% (95% CI, 45.70-76.90%) during an outbreak. Furthermore, the underlying health conditions would lead to an extra 2.35 (95% CI, 1.89-2.92) million hospital admissions and 0.16 (95% CI, 0.13-0.2) million ICU admissions. Our study provides insights into health preparedness to balance the disease burden and sustainability for a country with a population of billions.

Association of vaccination, international travel, public health and social measures with lineage dynamics of SARS-CoV-2.

Continually emerging SARS-CoV-2 variants of concern that can evade immune defenses are driving recurrent epidemic waves of COVID-19 globally. However, the impact of measures to contain the virus and their effect on lineage diversity dynamics are poorly understood. Here, we jointly analyzed international travel, public health and social measures (PHSM), COVID-19 vaccine rollout, SARS-CoV-2 lineage diversity, and the case growth rate (GR) from March 2020 to September 2022 across 63 countries. We showed that despite worldwide vaccine rollout, PHSM are effective in mitigating epidemic waves and lineage diversity. An increase of 10,000 monthly travelers in a single country-to-country route between endemic countries corresponds to a 5.5% (95% CI: 2.9 to 8.2%) rise in local lineage diversity. After accounting for PHSM, natural immunity from previous infections, and waning immunity, we discovered a negative association between the GR of cases and adjusted vaccine coverage (AVC). We also observed a complex relationship between lineage diversity and vaccine rollout. Specifically, we found a significant negative association between lineage diversity and AVC at both low and high levels but not significant at the medium level. Our study deepens the understanding of population immunity and lineage dynamics for future pandemic preparedness and responsiveness.

Alleviating Side Reactions on Zn Anodes for Aqueous Batteries by a Cell Membrane Derived Phosphorylcholine Zwitterionic Protective Layer.

Aqueous zinc (Zn) ion batteries are attractive for next generation batteries with high safety, yet their applications are still hindered by the uncontrollable dendrite formation and side reactions on Zn anode. Here, a polyzwitterion protective layer (PZIL) was engineered by polymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) in carboxymethyl chitosan (CMCS), which renders the following merits: the choline groups of MPC can preferentially adsorb onto Zn metal to avoid side reactions; the charged phosphate groups chelate with Zn2+ to regulate the solvation structure, further improving side reaction inhibition; the Hofmeister effect between ZnSO4 and CMCS can enhance the interfacial contact during electrochemical characterization. Consequently, the symmetrical Zn battery with PZIL can keep stable for more than 1000 hours under the ultra-high current density of 40 mA cm-2 . The PZIL confers the Zn/MnO2 full battery and Zn/active carbon (AC) capacitor with stable cycling performance under high current density.

3D Printing of Ionogels with Complementary Functionalities Enabled by Self-Regulating Ink.

Shaping soft and conductive materials into sophisticated architectures through 3D printing is driving innovation in myriad applications, such as robotic counterparts that emulate the synergic functions of biological systems. Although recently developed multi-material 3D printing has enabled on-demand creation of intricate artificial counterparts from a wide range of functional viscoelastic materials. However, directly achieving complementary functionalities in one ink design remains largely unexplored, given the issues of printability and synergy among ink components. In this study, an easily accessible and self-regulating tricomponent ionogel-based ink design to address these challenges is reported. The resultant 3D printed objects, based on the same component but with varying ratios of ink formulations, exhibit distinct yet complementary properties. For example, their Young's modulus can differ by three orders of magnitude, and some structures are rigid while others are ductile and viscous. A theoretical model is also employed for predicting and controlling the printing resolution. By integrating complementary functionalities, one further demonstrates a representative bioinspired prototype of spiderweb, which mimics the sophisticated structure and multiple functions of a natural spiderweb, even working and camouflaging underwater. This ink design strategy greatly extends the material choice and can provide valuable guidance in constructing diverse artificial systems by 3D printing.

Mechanically Adaptative and Environmentally Stable Ionogels for Energy Harvest.

Converting building and environment heat into electricity is a promising strategy for energy harvest to tackle global energy and environmental problems. The processing challenges, mechanical brittleness, and low environmental tolerance of typical thermoelectric materials, however, prevent them from realizing their full potential when employed in outdoor building systems. Herein, a general concept based on synergistic ionic associations to significantly improve the mechanical properties and harsh environment stability for high-performance ionic-type thermoelectric (i-TE) gels is explored. They demonstrate extraordinarily high stretchability (1300-2100%), fast self-healing (120 s), temperature insensitivity, and great water-proof performance, and could be painted on a variety of surfaces. The n-type ionic Seebeck coefficient is up to -8.8 mV K-1 and the ionic conductivity is more than 0.14 mS cm-1 . Both exhibit remarkable thermal and humidity stability (293-333 K, 20-100 RH%), which are rarely achieved in previous studies. Even on a cloudy day, the open-circuit thermovoltage for a painted i-TE array with an area of about 8.5 × 10-3 m2 is above 2 V. This research offers a promising approach for gathering significant waste heat and even solar energy on outside building surfaces in an effective and sustainable manner.