Hierarchically structured bioinspired nanocomposites

Cholesteric Contact Lenses for Diabetics-Related Noninvasive Glucose Monitoring and Eye Healthcare

Blood sugar monitoring has crucial significance for diabetes mellitus diagnosis, and noninvasive continuous detection methods are the future development trend. Among various noninvasive detection methods, glucose detection in tears has the advantages of a high level of subject compliance, minimal pollution, and accuracy. However, sensors used for detecting glucose concentration in tears usually embed noble microelectrical components into contact lenses, making the process complicated and costly, and easily cause environmental pollution and resource wastage. Here, we propose a construction strategy for contact lenses based on the cellulose nanocrystal (CNC) cholesteric structure, preparing products that change color according to the concentration of glucose. In addition, the surface of the contact lenses can be loaded with drugs for adjuvant treatment of diabetic eye complications. Contact lenses offer advantages such as a fast response speed (<240 s), high sensitivity with distinct colors at specific glucose concentrations (green at 0 mM, yellow at 5 mM, and red at 10 mM), and a reversible response process. Furthermore, they exhibit good biocompatibility (90% cell viability by CCK-8 assay) and biodegradability (complete biodegradation in soil within 120 days). CNC cholesteric contact lenses realize noninvasive, wearable continuous glucose detection, providing a new strategy for health monitoring of diabetics.

Hierarchical Building Blocks with Alternating Hard Cores and Flexible Chains for Ultrahigh Strength Aerogel

Low strength is a critical issue hindering the development and application of SiO2 aerogels. Although some progress has been made in optimizing mechanical flexibility, there is still a gap from practical application standards. Regarding this, we implemented a molecular-level design featuring an alternating hard-core and soft-chain structure to sacrificially enhance compressive strength and significantly improve deformability, and engineered hierarchical building blocks to bolster structural stability at the nanoscale. The resulting SiO2-based aerogel demonstrated a strong combination of singular performance advantages and multifunctionality, including ultrahigh compressive strength, exceptional deformability and structural stability, thermal superinsulation capabilities, superhydrophobicity, and notable hydrophobic stability. Particularly, the compressive strength not only surpassed previously reported aerogel materials (65.6 MPa at 0.245 g/cm3), but its lightweight high-strength characteristics also outperformed various ultralight 1D nanofiber aerogels (ln(E) ≈ ln(ρ)1.65256). This combination offers an attractive material system for robust thermal superinsulation in mechanically complex and highly humid environments.

Bioinspired Multifunctional and Dynamic Color-Tuning Photonic Devices

Tremendous progress has been achieved in comprehending the scientific principles governing nature and translating them into practical applications. Among the areas of interest within photonic systems, bioinspired color-tuning devices originating from physical structure modulation hold significant importance. This Review provides an overview of cutting-edge advancements in bioinspired structural color-tuning photonic devices across various applications. First, we delve into the origins, design principles, and fundamental physics underlying bioinspired structural color systems by showcasing diverse living species found in nature. Subsequently, we explore various photonic nano/microscale building blocks, including one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures, along with their fabrication techniques. Additionally, we present various biomimetic material systems and strategies for fabricating dynamic structural color devices. Furthermore, we discuss recent breakthroughs in biomimetic photonic systems across key application areas including sensing, interactive soft robotics, digital information encryption/decryption, dynamic displays, and energy. In summary, this Review provides a comprehensive analysis of bioinspired color-tuning photonic devices, shedding light on their intricate structure-function relationships, and aims to inspire the adoption and development of advanced color-tuning strategies. Finally, we address current challenges and offer insights into potential groundbreaking developments in the field of bioinspired optical materials.

An in-situ assembled cobweb-like adhesive with high processability

Low temperature tolerant adhesive with high flexibility and adhesion strength is highly desired yet challenging owing to the presence of obvious volume shrinkage, increased brittleness, and reduced transmission of mechanical stress at low temperature. Inspired by the cobweb, we hereby develop a kind of flexible adhesive that can be used at low temperature by in-situ polymerization of disulfide bond-based polymer with polyoxometalate. This low-temperature tolerant adhesive presents high flexibility and adhesion strength, good processability and reversible adhesion ability, a wide tolerable temperature range (i.e., -196 to 50 °C), and a long-lasting adhesion effect (>80 days, -196 °C) that is significantly better than commercial solvent-free adhesives. The adhesive can be processed into high-strength cobwebs, injected into tiny tube models, and adhered onto complicated interfaces. Notably, it enables to be kilogram-scale produced through a solvent-free method, holding promise for potential utilization in fields like repairing artifacts or precision instruments with micro-fractures at low temperature.

DeepSyn: Operable Chemical Retrosynthetic Design with the DeepSeek R1 Model

Chemical synthesis is inherently a complex, time-sensitive endeavor that involves not just selecting a starting substrate but also precisely configuring reaction conditions, equipment, and procedural steps. To address these challenges, we introduce DeepSyn, an advanced chemical notation transformation system that integrates the DeepSeek R1 model with reactive generation (RAG) techniques. DeepSyn is meticulously engineered to process critical experimental details and dynamically leverage a comprehensive knowledge database. This system is designed to formulate executable experimental protocols, meticulously outlining each step, pathway, and condition tailored to specific hardware requirements and enhancing reproducibility and precision. Our evaluations demonstrate that DeepSyn consistently delivers precise experimental design recommendations across a variety of conditions, which is substantiated by its integration with lab automation tools. This validation underscores DeepSyn's significant potential in advancing new material discovery, presenting a robust platform for methodical, machine-oriented experimental design.

Hierarchical Engineering of Amphiphilic Peptides Nanofibrous Crosslinkers toward Mechanically Robust, Functionally Customable, and Sustainable Supramolecular Hydrogels

Hierarchical architectures spanning multiple length scales are ubiquitous in biological tissues, conferring them with both mechanical robustness and dynamic functionalities via structural reorganization under loads. The design of hierarchical architectures within synthetic hydrogels to concurrently achieve mechanical reinforcement and functional integration remains challenging. Here, a biomimetic hierarchical engineering approach is reported to develop mechanically robust and function-customizable supramolecular hydrogels by utilizing strong yet dynamic fibrous nanoarchitectures of amphiphilic peptides as crosslinkers. This design, on one hand, resolves the strength-toughness trade-off in hydrogel design through energy-dissipative mechanisms involving dynamic detachment and reinsertion of peptides within their assembled nanostructures upon loading. On the other hand, the amphiphilicity and sequence programmability of peptides allow spatially orthogonal integration of multiple dynamic functionalities across distinct structural domains, including lipophilic fluorophore encapsulation, photopatterning capability, and anisotropic contraction. Capitalizing on its ultralow hysteresis and rapid recovery properties, the hydrogel's effectiveness is demonstrated as high-sensitivity strain sensors. Moreover, the fully noncovalent crosslinking strategy permits closed-loop recycling and reprocessing via reversible crosslinker disassembly-reassembly processes. Through systematic extension of this principle across diverse peptide systems, a generalized platform is demonstrated for creating advanced soft materials that synergistically integrate traditionally incompatible attributes of mechanical robustness, customable dynamic functionality, and environmental sustainability.

Hierarchical design of silkworm silk for functional composites

Silk-reinforced composites (SRCs) manifest the unique properties of silkworm silk fibers, offering enhanced mechanical strength, biocompatibility, and biodegradability. These composites present an eco-friendly alternative to conventional synthetic materials, with applications expanding beyond biomedical engineering, flexible electronics, and environmental filtration. This review explores the diverse forms of silkworm silk fibers including fabrics, long fibers, and nanofibrils, for functional composites. It highlights advancements in composite design and processing techniques that allow precise engineering of mechanical and functional performance. Despite substantial progress, challenges remain in making optimally functionalized SRCs with multi-faceted performance and understanding the mechanics for reverse-design of SRCs. Future research should focus on the unique sustainable, biodegradable and biocompatible advantages and embrace advanced processing technology, as well as artificial intelligence-assisted material design to exploit the full potential of SRCs. This review on SRCs will offer a foundation for future advancements in multifunctional and high-performance silk-based composites.

Tough and strong bioinspired high-entropy all-ceramics with a contiguous network structure

Developing bioinspired all-ceramics with plastic phases is considered one of the most effective ways to simultaneously achieve enhanced strength and toughness in ceramic materials for high-temperature applications. Here we explore tough and strong bioinspired high-entropy all-ceramics with a contiguous network structure that are able to serve up to 1300 °C. Specifically, we develop the high-entropy all-ceramics, featuring a unique contiguous network distribution of the Cr7C3 plastic phase within the predominant high-entropy carbide (HEC) hard phase, through a high-entropy composition-engineering strategy. The resulting materials exhibit impressive fracture initiation toughness of 12.5 ± 1.5 MPa·m1/2 and flexural strength of 613 ± 52 MPa at room temperature, as well as ~97% strength retention up to 1300 °C due to their good high-temperature stability, surpassing the performance of most other reported bioinspired ceramics. Further experimental and theoretical investigations demonstrate that the Cr7C3 phase can undergo plastic deformation by forming nanoscale shear bands with significant crystal defects, resulting in multiple toughening mechanisms involving crack-bridging of unfractured Cr7C3 ligaments and crack deflection in the HEC/Cr7C3 all-ceramics. This work successfully develops tough and strong bioinspired high-entropy all-ceramics capable of serving up to 1300 °C, offering an innovative strategy that facilitates further design of bioinspired ceramics applicable at higher temperatures.

Mussel-Inspired Molecular Strategies for Fabricating Functional Materials With Underwater Adhesion and Self-Healing Properties

The exceptional underwater adhesion and self-healing capabilities of mussels have fascinated researchers for over two decades. Extensive studies have shown that these remarkable properties arise from a series of reversible and dynamic molecular interactions involving mussel foot proteins. Inspired by these molecular interaction strategies, numerous functional materials exhibiting strong underwater adhesion and self-healing performance have been successfully developed. This review systematically explores the nanomechanical mechanisms of mussel-inspired molecular interactions, mainly revealed by direct force measurement techniques such as surface forces apparatus and atomic force microscopy. The development of functional materials, including coacervates, coatings, and hydrogels, with underwater adhesion and self-healing properties, is then summarized. Furthermore, the macroscopic material performances are correlated with the underlying molecular mechanisms, providing valuable insights for the rational design of next-generation mussel-inspired functional materials with enhanced underwater adhesion and self-healing properties.

Possibilities and Limits of DNA-Enabled Programmable 2D Self-Assembly

Programmable self-assembly provides a promising avenue to improve upon traditional synthesis and create multicomponent materials with emergent properties and arbitrary nanoscale complexity. However, its most successful realizations utilizing DNA often use complicated arduous procedures that result in low yields. Here, we employ coarse-grained molecular dynamics to uncover the ranges of temperatures and misbinding strengths needed for successful one-pot self-assembly of generic, two-dimensional (2D), and distinguishable tiles. Analysis of the energies associated with a single-stranded DNA interacting with all other sequences within a mixture revealed that the success of DNA-based assembly is primarily determined by the strongest misbinding a given sequence can encounter with a sequence highly similar to its reverse complement. This enabled us to design optimized sequence ensembles with acceptably weak and consequently rare misbinding. An estimate is provided for the maximum size of, and complexity of sequences needed to synthesize self-assembled structures with high accuracy and yield, with potential relevance for DNA-functionalized low-dimensional materials for electronics and energy storage.

Bamboo-inspired anisotropic hydrogels with enhanced mechanical properties via cellulose nanocrystal-reinforced heterostructures

Mimicking anisotropic materials is challenging due to their complex structural and mechanical properties. In this study, we developed biomimetic hydrogels that replicate the anisotropic characteristics of bamboo by incorporating cellulose nanocrystals (CNCs) into polyethylene glycol diacrylate (PEGDA) hydrogels. The inclusion of CNCs significantly enhanced the mechanical strength, with a 0.5% CNCs concentration increasing the modulus by 1.9 times, from 110 kPa to 208 kPa. By utilizing CNCs-doped regions to mimic the vascular bundles of bamboo and the undoped regions to represent the parenchyma tissue, we created biomimetic anisotropic hydrogels. These hydrogels displayed pronounced anisotropy, with the axial modulus exceeding the radial modulus, successfully demonstrating the creation of anisotropic materials. This method was also successfully applied to polyacrylic acid (PAA) hydrogels, further highlighting its versatility. These anisotropic biomimetic hydrogels exhibit distinct mechanical sensing properties in different directions, with the axial direction being 1.36 times more sensitive than the radial direction. This generalizable approach offers valuable insights for developing other anisotropic materials.

Stepwise Self-Assembly of Multisegment Mesoporous Silica Nanobamboos for Enhanced Thermal Insulation

Imitating the multinodal structures of plants and arthropods, precisely engineered multisegment nanostructures demonstrate enhanced synergistic properties and exceptional functionalities that surpass those of individual components. Utilizing micelle assemblies for constructing segments allows for precise structural control but requires management of interactions and assembly from molecular to mesoscopic levels, posing a significant challenge. In this paper, we present a stepwise self-assembly strategy to fabricate multisegment mesoporous silica (mSiO2) nanobamboos. The nanobamboos are characterized by 16-25 shuttle-shaped mesoporous segments connected end-to-end in line, forming the main chains with an overall length of approximately 0.7-1.0 μm. Each individual segment is composed of 10-13 parallel layers, with an average layer thickness of ∼2.5 nm. The formation of this multisegment mesoporous nanobamboos, as proven by in situ testing, is initiated by the formation of shuttle-shaped segments from small bilayer micelle units, which then further assemble to form the nanobamboo. This stepwise self-assembly can be regulated from a kinetic perspective, thereby obtaining multisegment mesoporous nanostructures with varying lengths and branched morphologies. Due to multiple segments along with multilayer mesostructures, the nanobamboos can significantly restrict gas flow, resulting in a very low thermal conductivity (∼41.67 mW·m-1·K-1). By blending the multisegment mSiO2 nanobamboos with cellulose nanofibers, mechanically stable, lightweight, and porous aerogels with an ultralow thermal conductivity (∼19.85 mW·m-1·K-1) can be obtained, verifying their potential in thermal insulation devices. The fabrication of this multisegment mesoporous nanobamboos enhances our understanding of micro-to-nanoscale assembling, establishing a foundation for precise control of complex structures.

Self-healing behavior of superhard covalent bond materials

In recent years, superhard covalently bonded materials have drawn a great deal of attention due to their excellent mechanical properties and potential applications in various fields. This review focuses on the self-healing behavior of these materials, outlining state-of-the-art research results. In detail, we discuss current self-healing mechanisms of self-healing materials including extrinsic healing mechanisms (such as microencapsulation, oxidative healing, shape memory, etc.) and intrinsic healing (dynamic covalent bonding, supramolecular interactions, diffusion, defect-driven processes, etc.). We also provide an overview of the progress in the self-healing behavior of superhard covalently bonded materials and the mechanisms of permanent covalent bonding healing. Additionally, we analyze the factors that influence the healing properties of these materials. Finally, the main findings and an outlook on the future directions and challenges of this emerging field are summarized in the Conclusion section.

Research Progress in Ceramic-Metal Composites: Designing Interface Structures for High Mechanical Performance

Ceramic-metal composites possess exceptional hardness and wear resistance, as well as high strength and ductility, rendering them highly promising for a wide range of applications. However, the performance of these composites can be significantly restricted by weak interfacial bonding, leading to crack formation at the interfaces; and ultimately, material failure. Therefore, poor interfacial bonding between ceramics and metals is a critical factor limiting the performance. Interfacial bonding strength can be enhanced by regulating the interface structure, which in turn, improves mechanical property. This review focuses on how to design strong interfacial structures in ceramic-metal composites, with particular emphasis on alumina ceramic-metal composites. It seeks to analyze the categorization of interfacial structures, design principles, and strategies for their formation, and examines the impact of interfacial bonding strength on the mechanical properties. Finally, it discusses the regulation of interfacial reactions, optimization of interface structures, integration of various interface designs, improvements in manufacturing technology, and the use of theoretical calculations to enhance interfacial bonding strength.

Nacre-inspired graphene oxide/chitosan supported Pd species composite paper-like membrane with superior catalytic performance

Recent studies have shown that graphene oxide (GO) nanosheets can form a nacre-like bioinspired layered structure with polysaccharide of chitosan (CS), leading to composites with excellent mechanical properties. In this study, we go further steps by immobilization of Pd species (both Pd2+ and Pd0) within nacre-like bioinspired layered GO-CS composite paper-like membranes by vacuum-assisted self-assembly process to fabricate novel GO-CS-Pd composite membrane catalysts for the first time. Synergistic interactions from hydrogen bonding (between the GO nanosheets and CS chains) and ionic bonding (between the GO nanosheets and Pd2+ ions) have been efficiently achieved, resulting in significantly improvement of the mechanical properties. Meanwhile, the in-situ grown Pd0 nanoparticles were homogeneously incorporated in the interstices of the nacre-like GO-CS composite membranes. The mechanical properties, specific area performances, and Pd0 nanoparticles size of the resultant GO-CS-Pd composite membrane are mainly tuned by the loading amount of CS. The membranes are high active for Suzuki reactions of aromatic halides and phenylboronic acid with catalyst loading as low as 0.05 mol%, and can be recycled for 8 runs without significant loss of activities. Positron annihilation lifetime spectroscopy and other structural characterization methods are implemented to characterize the unique compartmentalization structure in the nacre-like composite membranes.

Bioinspired Strong and Tough Layered Bulk Composites via Mycelial Interface Anchoring Strategy

Lightweight structural composite materials are widely used in automobiles, aerospace, and other fields. However, achieving the integration of structural and functional properties, such as the ability to monitor external forces, remains a significant challenge. Nacre and turtle shells in nature are strong and tough due to their unique ordered structure of alternating soft and hard phases. Inspired by this, an interface anchoring strategy is proposed which leverages hyphae (filamentous structure forming the vegetative part of fungi) to fix the hard-phase graphene nanosheets (GNs) and the soft-phase intertwined polymer matrix to form theree-dimentional (3D) layered bulk composites (LBCs). The growth pattern of fungi is utilized to place GNs and assemble polyethylene glycol-polyvinyl alcohol (PEG-PVA) to fabricate the LBCs, which is different from most existing preparation methods of bulk biomimetic composites. The LBCs exhibit self-regenerative capabilities and are amenable to scalable manufacturing. These composites demonstrate impressive mechanical properties, including a specific strength of 92.8 MPa g cm-3, fracture toughness of 6.5 MPa m-1/2, and impact resistance of ∼3.1 kJ m-2, outperforming both natural nacre and other biomimetic layered composites. Furthermore, the LBCs display effective protective warning functions under external force stimulations, making them a promising material for anti-collision applications in industries such as sports and aerospace.

Regulating Growth of Strontium Carbonate in Self-Assembled Chiral Chitin Matrices with Robust Mechanical Properties

The exoskeleton of arthropods exhibits a Bouligand structure, composed of a chitin matrix and calcium carbonate crystals, which confer exceptional mechanical properties. While many studies focus on the relationship between structure and performance, few investigate the mineral growth process within the Bouligand matrix. Here, chiral chitin films are prepared through evaporation-induced self-assembly of chitin nanowhiskers, and subsequently incubated in SrCO3 mineralizing solution. Initially, precursors deposit on the film surface and transform into mineralized points, which then radially expand outward along the surface and propagate inward until coalescing into a continuous mineral layer. The growth rate of these mineralized points is significantly enhanced by increasing the reaction temperature; at 60 °C, the growth rate is 13 times faster (650.4 μm2/min) compared to that at 25 °C (49.7 μm2/min). Finally, SrCO3/chitin composite bulks are fabricated by stacking and hot-pressing multiple mineralized chitin films, adhered using sodium alginate (SA) solution through spin coating. The resulting SrCO3/chitin@SA composites exhibit a bending strength of 64.2 MPa, representing a 27% increase over pure chitin bulk and a 105% increase over pure SrCO3 bulk. Our work provides a strategy for low-temperature fabrication of high-performance artificial composites.

Emergent Locomotion in Self-Sustained, Mechanically Connected Soft Matter Ringsf

In nature, the interplay between individual organisms often leads to the emergence of complex belabours, of which sophistication has been refined through millions of years of evolution. Synthetic materials research has focused on mimicking the natural complexity, e.g., by harnessing non-equilibrium states to drive self-assembly processes. However, it is highly challenging to understand the interaction dynamics between non-equilibrium entities and to obtain collective behavior that can arise autonomously through interaction. In this study, thermally fueled, twisted rings exhibiting self-sustained movements are used as fundamental units and their interactive behaviors and emergent functions are investigated. The rings are fabricated from connected thermoresponsive liquid crystal elastomers (LCEs) strips that undergo zero-elastic-energy-mode, autonomous motions upon a heat gradient. Single-ring structures with various twisting numbers and nontrivial links, and connected knots where several LCE rings (N = 2,3,4,5) are studied and linked. The observations uncover that controlled locomotion of the structures can emerge when N ≥ 3. The locomotion can be programmed by controlling the handedness at the connection points between the individual rings. These findings illustrate how group activity emerges from individual responsive material components through mechanical coupling, offering a model for programming autonomous locomotion in soft matter constructs.

Manipulating the Assembly and Architecture of Fibrillar Silk

Silk is a unique and exceptionally strong biological material. However, no synthetic method has yet come close to replicating the properties of natural silk. This shortfall is attributed to an insufficient understanding of both silk nanofibril structure and the mechanism of formation. Here in situ atomic force microscopy (AFM) and photo-induced force microscopy (PiFM) is utilized to investigate the formation process and define the basic structural paradigm of individual silk nanofibrils. By visualizing the multistage process of silk nanofibril formation, the importance of conformational transformations along the assembly pathway is revealed. Unfolded silk structures initially accumulate into amorphous clusters, which then evolve into crystal nuclei via conformational transformation into β-crystallites. Nanofibril elongation then occurs through the attachment of silk molecules at a single end of the nanofibril tip; this is facilitated through the formation of a new amorphous cluster that then repeats the aforementioned conformational transformation. However, enzymatic digestion of the amorphous regions leads to direct, rapid elongation of β-crystalline fibers. These findings imply that the energy landscape is characterized by shallow minima associated with intermediate states, which can be eliminated by introducing β-crystallites, and motivate research into the directed modification of the silk assembly pathway to select for features beneficial to specific applications.

Biomimetic Intrafibrillar Mineralization of Hierarchically Structured Amyloid-Like Fibrils

Intrafibrillar mineralization is essential not only as a fundamental process in forming biological hard tissues but also as a foundation for developing advanced composite fibril-based materials for innovative applications. Traditionally, only natural collagen fibrils have been shown to enable intrafibrillar mineralization, presenting a challenge in designing ordered hierarchical fibrils from common protein aggregation that exhibit similar high intrafibrillar mineralization activity. In this study, a mechanically directed two-step transformation method is developed that converts phase-transitioned protein nanofilms into crystalline, hierarchical amyloid-like fibrils with multilayer structures, which effectively control the growth and lateral organization of hydroxyapatite within adaptive gaps. The resulting mineralized HSAF achieves a hardness of 0.616 ± 0.007 GPa and a modulus of 19.06 ± 3.54 GPa-properties closely resembling native hard tissues-and exhibits exceptionally high bioactivity in promoting both native bone tissue growth and further intrafibrillar mineralization, achieving 76.9% repair in a mice cranial defect model after 8 weeks and outperforming other regenerative materials. This remarkable performance, stemming from the unique structure and composition of the fibers, positions HSAF as a promising candidate for biomedical and engineering applications. These findings advance the understanding of biomineralization mechanisms and establish a foundation for developing high-bioactivity materials for hard tissue regeneration.

Nucleus-Spike 3D Hierarchical Superstructures via a Lecithin-Mediated Biomineralization Approach

3D hierarchical superstructures (3DHSs) are key products of nature's evolution and have raised wide interest. However, the preparation of 3DHSs composed of building blocks with different structures is rarely reported, and regulating their structural parameters is challenging. Herein, a simple lecithin-mediated biomineralization approach is reported for the first time to prepare gold 3DHSs composed of 0D nucleus and 1D protruding dendritic spikes. It is demonstrated that a hydrophobic complex by coordination of disulfiram (DSF) with a share of chloroauric acid is the key to forming the 3DHSs. Under the lecithin mediation, chloroauric acid is first reduced to form the 0D nucleus, followed by the spike growth through the reduction of the hydrophobic complex. The prepared 3DHSs possess well-defined morphology with a spike length of ≈95 nm. Notably, the hierarchical spike density is systematically manipulated from 38.9% to 74.3% by controlling DSF concentrations. Moreover, the spike diameter is regulated from 9.2 to 12.9 nm by selecting different lecithin concentrations to tune the biomineralization process. Finite-difference time-domain (FDTD) simulations reveal that the spikes form "hot spots". The dense spike structure endows the 3DHSs with sound performance in surface-enhanced Raman scattering (SERS) applications.

Metal-based nanoplatforms for enhancing the biomedical applications of berberine: current progress and future directions

The isoquinoline alkaloid berberine, a bioactive compound derived from various plants, has demonstrated extensive therapeutic potential. However, its clinical application is hindered by poor water solubility, low bioavailability, rapid metabolism, and insufficient targeting. Metal-based nanoplatforms offer promising solutions, enhancing drug stability, controlled release, and targeted delivery. This review comprehensively explores the synthesis, physicochemical properties, and biomedical applications of metal-based nanocarriers, including gold, silver, iron oxide, zinc oxide, selenium, and magnetic nanoparticles, for berberine delivery to improve berberine's therapeutic efficacy. Recent advancements in metal-based nanocarrier systems have significantly improved berberine delivery by enhancing cellular uptake, extending circulation time, and enabling site-specific targeting. However, metal-based nanoplatforms encounter several limitations of potential toxicity, limited large-scale productions, and regulatory constraints. Addressing these limitations necessitates extensive studies on biocompatibility, long-term safety, and clinical translation. By summarizing the latest innovations and clinical perspectives, this review aims to guide future research toward optimizing berberine-based nanomedicine for improved therapeutic efficacy.

Hierarchical Deformation Mechanisms and Energy Absorption in Bioinspired Thin-Walled Structures

Lightweight, hierarchical thin-walled tubes are essential in aerospace and transportation for their exceptional impact resistance and energy absorption capabilities. This study applies bionic design principles to revolutionize traditional thin-walled tube structures, enhancing their energy absorption performance. Inspired by natural models-spider webs, beetle elytra, cuttlebone, and spiral wood fibers-integrated bionic hierarchical thin-walled tubes (IBHTTs) with diverse bionic structural and material combinations are developed using additive manufacturing. Mechanical tests and simulations demonstrated distinct deformation behaviors and significant performance enhancements. An IBHTT incorporating spider web, beetle elytra, and cuttlebone-inspired designs achieved a 129.7% increase in absorbed energy (EA) and a 21.8% improvement in specific energy absorption(SEA) compared to conventional tubes. Introducing spiral wood fiber-inspired features further improved toughness under compression and impact, with helical formations enabling mutual squeezing and self-twisting, resulting in a 397.5% increase in absorbed energy and a 67.0% boost in specific energy absorption. Furthermore, IBHTTs with adjustable helical angles exhibited distinct mechanical and energy absorption characteristics, enabling tailored compressive responses through custom spiral configurations. These findings lay the groundwork for designing advanced thin-walled tubes to meet diverse application demands, pushing the boundaries of bionic engineering.

Full-Multiscale Spontaneous Organization for Optically Anisotropic Titania Films

Titania films with a completely controlled hierarchical structure, at microscopic, mesoscopic, and macroscopic scales, are successfully prepared by carefully combining "top-down" and "bottom-up" nanoprocesses. The titania films are composed of regularly arranged anatase nanocrystals, which form a 2D hexagonal mesostructure with cylindrical mesopores. Furthermore, the cylindrical mesopores are aligned in one direction in the plane of the film over the whole area. Thus, hierarchical structural regularities over multiple length scales, i.e., atomic (10-10 m), mesoscopic (10-8 m), and macroscopic (10-2 m) scales, are achieved. The mesoporous titania films with a controlled alignment are prepared via sol-gel chemistry using the self-assembly process of amphiphilic molecules combined with a lithographically prepared anisotropic substrate with a fine wavy cross-section. The carefully designed sol-gel process using Pluronic P123 as a structure-directing agent allows the retention of the aligned mesoporous structure as well as the formation of crack-free films even after the crystallization of titania. The anisotropic mesoporous structure with pore walls composed of high-refractive-index crystalline titania exhibits remarkable optical anisotropy, birefringence. This full-multiscale structural control of an inorganic material, from atomic to centimeter scales, affords distinguished functionalities to artificially prepared nanomaterials, paving the way for creating new values.

Construction of a Biomimetic Tubular Scaffold Inspired by Sea Sponge Structure: Sponge-Like Framework and Cell Guidance

Engineering hollow fibers with precise surface microstructures is challenging; yet, essential for guiding cells alignment and ensuring proper vascular tissue function. Inspired by Euplectella sponges, a novel strategy to engineer biomimetic hollow fibers with spiral surface microstructures is developed. Using oxidized bacterial cellulose, bacterial cellulose, and polydopamine, a "brick-and-mortar" scaffold is created through precise shear control during microfluidic coaxial spinning. The scaffold mimics natural extracellular matrices, providing mechanical stability and supporting cell growth. In vitro studies show successful co-culture of endothelial cells (ECs) and smooth muscle cells (SMCs), with SMCs aligning along spiral surface microstructures and ECs forming a confluent inner layer. In vivo implantation confirms biocompatibility, biodegradability, and low immunogenicity. This Euplectella-inspired scaffold presents a promising approach for vascular tissue engineering and regenerative medicine.

Quasi-Solid Gel Electrolytes for Alkali Metal Battery Applications

Alkali metal batteries (AMBs) have undergone substantial development in portable devices due to their high energy density and durable cycle performance. However, with the rising demand for smart wearable electronic devices, a growing focus on safety and durability becomes increasingly apparent. An effective strategy to address these increased requirements involves employing the quasi-solid gel electrolytes (QSGEs). This review focuses on the application of QSGEs in AMBs, emphasizing four types of gel electrolytes and their influence on battery performance and stability. First, self-healing gels are discussed to prolong battery life and enhance safety through self-repair mechanisms. Then, flexible gels are explored for their mechanical flexibility, making them suitable for wearable devices and flexible electronics. In addition, biomimetic gels inspired by natural designs are introduced for high-performance AMBs. Furthermore, biomass materials gels are presented, derived from natural biomaterials, offering environmental friendliness and biocompatibility. Finally, the perspectives and challenges for future developments are discussed in terms of enhancing the ionic conductivity, mechanical strength, and environmental stability of novel gel materials. The review underscores the significant contributions of these QSGEs in enhancing AMBs performance, including increased lifespan, safety, and adaptability, providing new insights and directions for future research and applications in the field.

Modulating the Structural Complexity of AuNCs Aggregates for Generation of Bright Luminescence

Self-assembly of coinage metal nanoclusters constitutes an important branch for the construction of bright luminescent materials. They also serve as a class of promising building blocks for the study of hierarchically organized assemblies due to their potential of generating high structural complexity. However, the strong intercluster interactions exert great difficulty and uncertainty on the modulation of the outcome aggregation structures. To explore a feasible methodology for constructing complex structures that combine order and disorder, accompanied by emerging desirable optical performances, herein we manipulate the supramolecular interactions of a gold nanocluster, namely, DPT-AuNCs through the incorporation of an amphiphilic cation, i.e., 1-dodecyl-3-methylimidazolium (DMI+). Diverse aggregation structures are obtained through coassembly, and a sea urchin-like aggregate with a complexity index of CI = 16.5 is formed by elevating the concentration of DMI+. Moreover, a positive correlation between structural complexity and emission intensity was observed, and strongly luminescent NCs-based aggregates were obtained. The mechanism for the emergence of structural complexity is demonstrated via kinetic studies, 1H NMR titration, theoretical computation, etc. The cation-π interaction is found to be vital for the association between DMI+ and DPT-AuNCs, which modulates the supramolecular interactions for assembly and in turn facilitates the growth of aggregates in multiple dimensions. The sea urchin-like aggregate is formed through a dynamic assembly process, mediated by the pre-equilibrium of DMI+ micelles at high concentrations. Finally, the luminescent NC aggregates can also be obtained by incorporating different types of amphiphilic cations, thus generalizing the method for constructing complex assembly structures.

Stress-induced self-assembly of hierarchically twisted stripe arrays

Hierarchical organization is prevalent in nature, yet the artificial construction of hierarchical materials featuring asymmetric structures remains a big challenge. Herein, we report a stress-induced self-assembly strategy for the synthesis of hierarchically twisted stripe arrays (HTSAs) with mesoporous structures. A soft and thin mesostructured film assembled by micelles and TiO2 oligomers is the prerequisite. Then, the external stress coming from the exfoliation process triggers the deformation of this mesostructured film into hierarchically twisted structures. The stripe width and twist degree can be well manipulated by adjusting the cross-linking degree and thickness of the mesostructured films. Furthermore, this strategy is facile and versatile to synthesize HTSAs with diverse components, including carbon, Al2O3 and ZrO2. We find that mesoporous TiO2 HTSAs can serve as an ideal integrator for adsorption-enrichment-detection process, exhibiting a rapid and high adsorption capacity towards molecules at low concentrations and enabling the subsequent surface-enhanced Raman scattering (SERS) detection. Such twisted stripe arrays achieve 2.3-fold and 5.6-fold enhancements in SERS compared with flat surfaces and solution conditions, respectively, due to the increased Raman scattering among the hierarchical, twisted, and mesoporous structures.

Prediction of carbon nanostructure mechanical properties and the role of defects using machine learning

Graphene-based nanostructures hold immense potential as strong and lightweight materials, however, their mechanical properties such as modulus and strength are difficult to fully exploit due to challenges in atomic-scale engineering. This study presents a database of over 2,000 pristine and defective nanoscale CNT bundles and other graphitic assemblies, inspired by microscopy, with associated stress-strain curves from reactive molecular dynamics (MD) simulations using the reactive INTERFACE force field (IFF-R). These 3D structures, containing up to 80,000 atoms, enable detailed analyses of structure-stiffness-failure relationships. By leveraging the database and physics- and chemistry-informed machine learning (ML), accurate predictions of elastic moduli and tensile strength are demonstrated at speeds 1,000 to 10,000 times faster than efficient MD simulations. Hierarchical Graph Neural Networks with Spatial Information (HS-GNNs) are introduced, which integrate chemistry knowledge. HS-GNNs as well as extreme gradient boosted trees (XGBoost) achieve forecasts of mechanical properties of arbitrary carbon nanostructures with only 3 to 6% mean relative error. The reliability equals experimental accuracy and is up to 20 times higher than other ML methods. Predictions maintain 8 to 18% accuracy for large CNT bundles, CNT junctions, and carbon fiber cross-sections outside the training distribution. The physics- and chemistry-informed HS-GNN works remarkably well for data outside the training range while XGBoost works well with limited training data inside the training range. The carbon nanostructure database is designed for integration with multimodal experimental and simulation data, scalable beyond 100 nm size, and extendable to chemically similar compounds and broader property ranges. The ML approaches have potential for applications in structural materials, nanoelectronics, and carbon-based catalysts.

Hierarchically Structured Catalysts Toward Sustainable Hydrogen Economy: Electro- and Thermo-Chemical Pathways

Hydrogen, as an important clean energy source, plays a more and more crucial role in decarbonizing the planet and meeting the global climate challenge due to its high energy density and zero-emission. The demand for sustainable hydrogen is increasing drastically worldwide as driven by the global shift towards low-carbon energy solutions. Thermochemical catalysis process dominates hydrogen production at scale given its relatively mature technology and commercialization status, as well as the established manufacturing infrastructure. While due to its environmentally friendly nature and growing abundant sources of renewable electricity, the electrochemical path for hydrogen production is rising as a major alternative to the thermochemical means. Nevertheless, hierarchically structured catalysts and devices have gradually taken the center stage toward replacing the traditional counterparts, especially with the rapid advancement of the design and manufacture of such ordered nanostructure assemblies toward high activity, efficient mass transport, and superb stability. In this review, the latest progress of the hierarchically structured catalysts for hydrogen production have been surveyed on electro- and thermo- chemical pathways comparatively. It covers the structure designs of atomic dispersion, nanoscale surfaces and interfaces for achieving highly active and durable catalysts, components, and devices. Both electrochemical and thermochemical approaches are reviewed in terms of the vast design details, engineered benefits, and understandings of various Pt-group metal (PGM) and non-PGM based transition metal catalysts for hydrogen production. As the growing trend, brief discussions are also presented toward the high-level assembly and manufacture of complexly structured components and devices at scale in the electrochemical and thermochemical energy systems.

Regio-Selective Mechanical Enhancement of Polymer-Grafted Nanoparticle Composites via Light-Mediated Crosslinking

Polymer-brush-grafted nanoparticles (PGNPs) that can be covalently crosslinked post-processing enable the fabrication of mechanically robust and chemically stable polymer nanocomposites with high inorganic filler content. Modifying PGNP brushes to append UV-activated crosslinkers along the polymer chains would permit a modular crosslinking strategy applicable to a diverse range of nanocomposite compositions. Further, light-activated crosslinking reactions enable spatial control of crosslink density to program intentionally inhomogeneous mechanical responses. Here, a method of synthesizing composites using UV-crosslinkable brush-coated nanoparticles (referred to as UV-XNPs) is introduced that can be applied to various monomer compositions by incorporating photoinitiators into the polymer brushes. UV crosslinking of processed UV-XNP structures can increase their tensile modulus up to 15-fold without any noticeable alteration to their appearance or shape. By using photomasks to alter UV intensity across a sample, intentionally designed inhomogeneities in crosslink density result in predetermined anisotropic shape changes under strain. This unique capability of UV-XNP materials is applied to stiffness-patterned flexible electronic substrates that prevent the delamination of rigid components under deformation. The potential of UV-XNPs as functional, soft device components is further demonstrated by wearable devices that can be modified post-fabrication to customize their performance, permitting the ability to add functionality to existing device architectures.

Ligand Inter-Relation Analysis Via Graph Theory Predicts Macrophage Response

Graph theory has been widely used to quantitatively analyze complex networks of molecules, materials, and cells. Analyzing the dynamic complex structure of extracellular matrix can predict cell-material interactions but has not yet been demonstrated. In this study, graph theory-based mathematical modeling of RGD ligand graph inter-relation is demonstrated by differentially cutting off RGD-to-RGD interlinkages with flexibly conjugated magnetic nanobars (MNBs) with tunable aspect ratio. The RGD-to-RGD interlinkages are less effectively cut off by MNBs with a lower aspect ratio, which decreases the shortest path while increasing the number of instances thereof, thereby augmenting RGD nano inter-relation. This facilitates integrin recruitment of macrophages and thus actin fiber assembly and vinculin expression, which mediates pro-regenerative polarization, involving myosin II, actin polymerization, and rho-associated protein kinase. Unidirectional pre-aligning or reversibly lifting highly elongated MNBs both increase RGD nano inter-relation, which promotes host macrophage adhesion and switches their polarization from pro-inflammatory to pro-regenerative phenotype. The latter approach produces nano-spaces through which macrophages can penetrate and establish RGD links thereunder. Using graph theory, this study presents the example of mathematically modeling the functionality of extracellular-matrix-mimetic materials, which can help elucidate complex dynamics of the interactions occurring between host cells and materials via versatile geometrical nano-engineering.

Mesoscale orchestration of collagen-based hierarchical mineralization

Mesoscale building blocks are instrumental in bridging multilevel hierarchical mineralization, endowing macroscale entities with remarkable functionality and mechanical properties. However, the mechanism orchestrating the homogeneous morphology of mesoscale mineralized motifs in collagen-based hard tissues remains unknown. Here, utilizing avian tendons as a mineralization model, we reveal a robust correlation between the mesoscale mineralized spherules and the presence of phosvitin. By designing a phosvitin-stabilized biomineral cluster medium, we replicate the well-defined mesoscale spherical structure within collagen matrix in vitro and ex vivo. In-depth studies reveal that phosvitin undergoes a conformational transition in the presence of biominerals at physiological concentrations, and self-assembles into mineral-dense amyloid-like aggregates. The spatial binding of these mineral-dense aggregates to collagen serves as a template for guiding the formation of mineralized spherules on the mesoscale. On the nanoscale, this binding facilitates mineral precursor release and diffusion into the fibrils for intrafibrillar mineralization. This discovery underscores the pivotal role of phosvitin-biomineral aggregates in templating hierarchical mineralization from the mesoscale to the nanoscale. This study not only elucidates the intricate mechanism underlying the collagen-based mineralization hierarchy but also promotes a cutting-edge advance in highly biomimetic material design and regenerative medicine.

Emergence of Voronoi-Patterned Cellular Membranes via Confinement Transformation of Self-Assembled Metal-Organic Frameworks

The self-assembly of nanoparticles allows the fabrication of complex, nature-inspired architectures. Among these, Voronoi tessellations─intricate patterns found in many natural systems such as insect wings and plant tissues─have broad implications across materials science, biology, and geography. However, replicating these irregular yet organized features at the nanoscale through nanoparticle self-assembly remains challenging. Here, we introduce a confinement transformation method to generate two-dimensional (2D) Voronoi patterns by converting metal-organic frameworks, specifically zeolitic imidazolate framework-8 (ZIF-8), into layered hydroxides. The process begins with the self-assembly of ZIF-8 particles into densely packed monolayers at the liquid-air interface, driven by the Marangoni effect. Subsequent Ni2+-induced etching converts the floating ZIF-8 monolayer into a freestanding membrane composed of interconnected polygonal cells, closely resembling the geometric characteristics of Voronoi tessellations. We systematically investigate the parameters affecting the transformation of ZIF-8 particles, shedding light on the mechanism governing Voronoi pattern formation. Mechanical testing and simulations demonstrate that the resulting cellular membranes exhibit enhanced stress distribution and crack resistance, attributed to their Voronoi-patterned architecture. These robust, monolithic membranes composed of Ni-based hydroxides, when serving as catalyst support materials, can synergistically enhance the intrinsic activity of Pt catalysts for alkaline hydrogen evolution reaction by facilitating water dissociation. This work presents a promising approach for creating nature-inspired materials with optimal stress management, superior mechanical properties, and potential catalytic applications.

Bridging Biological Multiscale Structure and Biomimetic Ceramic Construction

The brittleness of traditional ceramics severely limits their application progress in engineering. The multiscale structural design of organisms can solve this problem, but it still lacks sufficient research and attention. The underlined main feature is the multiscale hierarchical structures composed of basic nano-microstructure units arranged in order, which is currently impossible to achieve through artificial synthesis driven by high temperatures. This perspective aims to bridge the gap between biostructural materials and biomimetic ceramics, highlighting the relationship between bioinspired structures and interfacial interaction of structure densification in biomimetic ceramics. Therefore, we could accomplish densification and ceramic development at room temperature, consequently correlating the structure, properties, and functions of materials and accelerating the development of the next generation of advanced functional ceramics.

Dry Bondable Porous Silk Fibroin Films for Embedding Micropatterned Electronics in Hierarchical Silk Nacre

Future structural materials is not only be lightweight, strong, and tough, but also capable of integrating functions like sensing, adaptation, self-healing, deformation, and recovery as needed. Although bio-inspired materials are well developed, directly integrating microelectronic patterns into nacre-mimetic structures remains challenging, limiting the widespread application of electronic biomimetic materials. Here, an in situ freeze-drying method is reported for the successful preparation of porous silk fibroin materials that can achieve dry bonding. The in situ freeze-drying method preserves the structural integrity of the lyophilized membrane while reducing procedural steps, achieving control over pore gradient not feasible with traditional freeze-drying techniques. By leveraging their smooth surfaces and capacity to support heat transfer patterns, layer-by-layer assembly at a macroscopic scale is achieved. The material's excellent mechanical properties, controllable graded structure, and adjustable degradation behavior enable the construction of electronically functionalized hierarchical structures. Additionally, the dry-state, layer-by-layer bonding method for porous polymer films provides advantages in precision control, mechanical stability, functional versatility, hierarchical structuring, and scalability. It represents an innovative approach, offering multi-functional and customizable bulk materials, especially suited for biomedical applications. This work offers an effective pathway for developing high-performance and multifunctional biomimetic devices with controllable hierarchical structures.

MXene-Vitrimer Nanocomposites: Photo-Thermal Repair, Reinforcement, and Conductivity at Low Volume Fractions Through a Percolative Voronoi-Inspired Microstructure

An innovative process to multifunctional vitrimer nanocomposites with a percolative MXene minor phase is reported, marking a significant advancement in creating stimuli-repairable, reinforced, sustainable, and conductive nanocomposites at diminished loadings. This achievement arises from a Voronoi-inspired biphasic morphological design via a straight-forward three-step process involving ambient-condition precipitation polymerization of micron-sized prepolymer powders, aqueous powder-coating with 2D MXene (Ti3C2Tz), and melt-pressing of MXene-coated powders into crosslinked films. Due to the formation of MXene-rich boundaries between thiourethane vitrimer domains in a pervasive low-volume fraction conductive network, a low percolation threshold (≈0.19 vol.%) and conductive polymeric nanocomposites (≈350 S m-1) are achieved. The embedded MXene skeleton mechanically bolsters the vitrimer at intermediate loadings, enhancing the modulus and toughness by 300% and 50%, respectively, without mechanical detriment compared to the neat vitrimer. The vitrimer's dynamic-covalent bonds and MXene's photo-thermal conversion properties enable repair in minutes through short-term thermal treatments for full macroscopic mechanical restoration or in seconds under 785 nm light for rapid localized surface repair. This versatile fabrication method to nanocoated pre-vitrimer powders and morphologically complex nanocomposites is compatible with classic composite manufacturing, and when coupled with the material's exceptional properties, holds immense potential for revolutionizing advanced composites and inspiring next-generation smart materials.

Bio-Informed Porous Mineral-Based Composites

Certain biominerals, such as sea sponges and echinoderm skeletons, display a fascinating combination of mechanical properties and adaptability due to the well-defined structures spanning various length scales. These materials often possess high density normalized mechanical properties because they contain well-defined pores. The density-normalized mechanical properties of synthetic minerals are often inferior because the pores are stochastically distributed, resulting in an inhomogeneous stress distribution. The mechanical properties of synthetic materials are limited by the degree of structural and compositional control currently available fabrication methods offer. In the first part of this review, examples of structural elements nature uses to impart exceptional density normalized Young's moduli to its porous biominerals are showcased. The second part highlights recent advancements in the fabrication of bio-informed mineral-based composites possessing pores with diameters that span a wide range of length scales. The influence of the processing of mineral-based composites on their structures and mechanical properties is summarized. Thereby, it is aimed at encouraging further research directed to the sustainable, energy-efficient fabrication of synthetic lightweight yet stiff mineral-based composites.

Dynamic Peptide Nanoframework-Guided Protein Coassembly: Advancing Adhesion Performance with Hierarchical Structures

Hierarchical structures are essential in natural adhesion systems. Replicating these in synthetic adhesives is challenging due to intricate molecular mechanisms and multiscale processes. Here, we report three phosphorylated peptides featuring a hydrophobic self-assembly motif linked to a hydrophilic phosphorylated sequence (pSGSS), forming peptide fibril nanoframeworks. These nanoframeworks effectively coassemble with elastin-derived positively charged proteins (PCP), resulting in complex coacervate-based adhesives with hierarchical structures. Our method enables the controlled regulation of both cohesion and adhesion properties in the adhesives. Notably, the complex adhesives formed by the dityrosine-containing peptide and PCP demonstrate an exceptional interfacial adhesion strength of up to 30 MPa, outperforming most known supramolecular adhesives and rivaling cross-linked chemical adhesives. Additionally, these adhesives show promising biocompatibility and bioactivity, making them suitable for applications such as visceral hemostasis and tissue repair. Our findings highlight the utility of bioinspired hierarchical assembly combined with bioengineering techniques in advancing biomedical adhesives.

Opal-Inspired SiO2-Mediated Carbon Dot Doping Enables the Synthesis of Monodisperse Multifunctional Afterglow Nanocomposites for Advanced Information Encryption

Despite recent advancements in inorganic and organic phosphors, creating monodisperse afterglow nanocomposites (NCs) remains challenging due to the complexities of wet chemistry synthesis. Inspired by nanoinclusions in opal, we introduce a novel SiO2-mediated carbon dot (CD) doping method for fabricating monodisperse, multifunctional afterglow NCs. This method involves growing a SiO2 shell matrix on monodisperse nanoparticles (NPs) and doping CDs into the SiO2 shell under hydrothermal conditions. Our approach preserves the monodispersity of the parent NP@SiO2 NCs while activating a green afterglow in the doped CDs with an impressive lifetime of 1.26 s. Additionally, this method is highly versatile, allowing for various core and dopant combinations to finely tune the afterglow through core-to-CD or CD-to-dye energy transfer. Our findings significantly enhance the potential of SiO2 coatings, transforming them from merely enhancing the biocompatibility of NCs to serving as a versatile matrix for emitters, facilitating afterglow generation and paving the way for new applications.

Preparation of nanocellulose-silk fibroin stiff hydrogel and high absorbing-low expansion xerogel via polysaccharide-protein interactions

Inspired by the unique environmental sensitivities of polysaccharides and proteins, nanocellulose (NC) and silk fibroin (SF) nanocomposite hydrogels with tailored network structures and mechanical properties were developed by varying induction methods and assembly sequences. In the optimal process, SF was first assembled along the NC template to create a unique nanobead-like structure under thermal induction, followed by crosslinking in an acetic acid coagulation bath to form a polysaccharide-protein nanocomposite hydrogel with high mechanical strength, with elastic modulus as of 62,330 G' in Pa at only 0.25 wt% NC and 1.5 wt% SF. The introduction of carboxyl groups to NC via TEMPO-mediated oxidation and the formation of nanobead-like structures improved structure stability and significantly enhanced water retention. The NC-SF nanocomposite hydrogels exhibited excellent mechanical properties, while the derived xerogels offered outstanding liquid absorption (up to 2300 %) and retention with minimal volume expansion upon liquid binding (dissolution ratio below 5 %). These properties make them promising candidates for biodegradable, biocompatible materials in applications such as sanitary products, diapers, and hemostatic matrices.

Biomimetic Structural Hydrogels Reinforced by Gradient Twisted Plywood Architectures

Naturally structural hydrogels such as crustacean exoskeletons possess a remarkable combination of seemingly contradictory properties: high strength, modulus, and toughness coupled with exceptional fatigue resistance, owing to their hierarchical structures across multiple length scales. However, replicating these unique mechanical properties in synthetic hydrogels remains a significant challenge. This work presents a synergistic approach for constructing hierarchical structural hydrogels by employing cholesteric liquid crystal self-assembly followed by nanocrystalline engineering. The resulting hydrogels exhibit a long-range ordered gradient twisted plywood structure with high crystallinity to mimic the design of crustacean exoskeletons. Consequently, the structural hydrogels achieve an unprecedented combination of ultrahigh strength (46 ± 3 MPa), modulus (496 ± 25 MPa), and toughness (170 ± 14 MJ m-3), together with recorded high fatigue threshold (32.5 kJ m-2) and superior impact resistance (48 ± 2 kJ m-1). Additionally, through controlling geometry and compositional gradients of the hierarchical structures, a programmable shape morphing process allows for the fabrication of complex 3D hydrogels. This study not only offers valuable insights into advanced design strategies applicable to a broad range of promising hierarchical materials, but also pave the ways for load-bearing applications in tissue engineering, wearable devices, and soft robotics.

Mechanically Stable and Damage Resistant Freestanding Ultrathin Silver Nanowire Films with Closely Packed Crossed-Lamellar Structure

One-dimensional (1D) functional nanowires are widely used as nanoscale building blocks for assembling advanced nanodevices due to their unique functionalities. However, previous research has mainly focused on nanowire functionality, while neglecting the structural stability and damage resistance of nanowire assemblies, which are critical for the long-term operation of nanodevices. Biomaterials achieve excellent mechanical stability and damage resistance through sophisticated structural design. Here, we successfully prepared a mechanically stabilized monolamella silver nanowire (Ag NW) film, based on a facile bubble-mediated assembly and nondestructive transfer strategy with the assistance of a porous mixed cellulose ester substrate, inspired by the hierarchical structure of biomaterial. Owing to the closely packed arrangement of Ag NWs combined with their weak interfaces, the monolamellar Ag NW film can be transferred to arbitrary substrates without damage. Furthermore, freestanding multilamellar Ag NW films with impressive damage resistance can be obtained from the monolamellar Ag NW film, through the introduction of bioinspired closely packed crossed-lamellar (CPCL) structure. This CPCL structure maximizes intra- and interlamellar interactions among Ag NWs ensuring efficient stress transfer and uniform electron transport, resulting in excellent mechanical durability and stable electrical properties of the multilamellar Ag NW films.

Emerging Sustainable Structural Materials by Assembling Cellulose Nanofibers

Under the guidance of the carbon peaking and carbon neutrality goals, the urgency for green ecological construction and the depletion of nonrenewable resources highlight the importance of the research and development of sustainable new materials. Cellulose nanofiber (CNF) is the most abundant natural nanoscale building block widely existing on Earth. CNF has unique intrinsic physical properties, such as low density, low coefficient of thermal expansion, high strength, and high modulus, which is an ideal candidate with outstanding potential for constructing sustainable materials. In recent years, CNF-based structural material has emerged as a sustainable lightweight material with properties very different from traditional structural materials. Here, to comprehensively introduce the assembly of structural materials based on CNF, it starts with an overview of different forms of CNF-based materials, including fibers, films, hydrogels, aerogels, and structural materials. Next, the challenges that need to be overcome in preparing CNF-based structural materials are discussed, their assembly methods are introduced, and an in-depth analysis of the advantages of the CNF-based hydrogel assembly strategy to fabricate structural materials is conducted. Finally, the unique properties of emerging CNF-based structural materials are summarized and concluded with an outlook on their design and functionalization, potentially paving the way toward new opportunities.

Boosting the Strength and Toughness of Polymer Blends via Ligand-Modulated MOFs

Mechanically robust and tough polymeric materials are in high demand for applications ranging from flexible electronics to aerospace. However, achieving both high toughness and strength in polymers remains a significant challenge due to their inherently contradictory nature. Here, a universal strategy for enhancing the toughness and strength of polymer blends using ligand-modulated metal-organic framework (MOF) nanoparticles is presented, which are engineered to have adjustable hydrophilicity and lipophilicity by varying the types and ratios of ligands. Molecular dynamics (MD) simulations demonstrate that these nanoparticles can effectively regulate the interfaces between chemically distinct polymers based on their amphiphilicity. Remarkably, a mere 0.1 wt.% of MOF nanoparticles with optimized amphiphilicity (ML-MOF(5:5)) delivered ≈1.1- and ≈34.1-fold increase in strength and toughness of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) blend, respectively. Moreover, these amphiphilicity-tailorable MOF nanoparticles universally enhance the mechanical properties of various polymer blends, such as polypropylene (PP)/polyethylene (PE), PP/polystyrene (PS), PLA/poly (butylene adipate-co-terephthalate) (PBAT), and PLA/polycaprolactone (PCL)/PBS. This simple universal method offers significant potential for strengthening and toughening various polymer blends.

Butterfly wing-inspired superhydrophobic photonic cellulose nanocrystal films for vapor sensors and asymmetric actuators

Cellulose nanocrystals (CNCs)-based stimuli responsive photonic materials demonstrate great application potential in mechanical and chemical sensors. However, due to the hydrophilic property of cellulose molecular, a significant challenge is to build a water-resistant photonic CNCs material. Here, inspired by butterfly wings with vivid structural color and superhydrophobic property, we have designed a CNCs based superhydrophobic iridescent film with hierarchical structures. The iridescent colored layer is ascribed to the chiral nematic alignment of CNCs, the superhydrophobic layer is ascribed to the micro-nano structures of polymer microspheres. Specially, superhydrophobic iridescent CNCs film could be used as an efficient colorimetric humidity sensor due to the existence of 'stomates' on superhydrophobic layer, which allowed the humid gas to enter into and out from the humidity responsive chiral nematic layers. Meanwhile, superhydrophobic iridescent films show out-standing self-cleaning and anti-fouling performance. Moreover, when the one side of the CNCs film was covered with superhydrophobic layer, the Janus film displays asymmetric expansion and bending behaviors as well as responsive structural colors in hydrous ethanol. This CNCs based hierarchical photonic materials have promising applications including photonic sensors suitable for extreme environment and smart photonic actuators.

Quantifying Interface-Performance Relationships in Electrochemical CO2 Reduction through Mixed-Dimensional Assembly of Nanocrystal-on-Nanowire Superstructures

Fine-tuning the interfacial sites within heterogeneous catalysts is pivotal for unravelling the intricate structure-property relationship and optimizing their catalytic performance. Herein, a simple and versatile mixed-dimensional assembly approach is proposed to create nanocrystal-on-nanowire superstructures with precisely adjustable numbers of biphasic interfaces. This method leverages an efficient self-assembly process in which colloidal nanocrystals spontaneously organize onto Ag nanowires, driven by the solvophobic effect. Importantly, varying the ratio of the two components during assembly allows for accurate control over both the quantity and contact perimeter of biphasic interfaces. As a proof-of-concept demonstration, a series of Au-on-Ag superstructures with varying numbers of Au/Ag interfaces are constructed and employed as electrocatalysts for electrochemical CO2-to-CO conversion. Experimental results reveal a logarithmic linear relationship between catalytic activity and the number of Au/Ag interfaces per unit mass of Au-on-Ag superstructures. This work presents a straightforward approach for precise interface engineering, paving the way for systematic exploration of interface-dependent catalytic behaviors in heterogeneous catalysts.

Nacre-Inspired Nanocomposites from Natural Polypeptide ε-Poly-l-Lysine and Natural Clay Montmorillonite: Remarkable Reinforcing Effect at Low Polymer Content and Its Mechanism

Nanocomposites composed of the cationic polypeptide ε-poly-l-lysine (ε-PL) and natural sodium montmorillonite (MMT) were prepared and evaluated. These MMT/ε-PL composites formed highly ordered nanostructures resembling natural nacreous layers by a simple process. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses confirmed that a small amount of ε-PL remarkably enhanced the MMT orientation in the composites. This MMT orientation-enhancing effect of ε-PL was more pronounced than that of poly(vinyl alcohol) (PVA), which is one of the most popular ingredients of MMT-based composites. The orientation enhancement provided by ε-PL was primarily driven by ionic interactions and responsible for high mechanical properties at low polymer content. This remarkable reinforcing effect of ε-PL on MMT at a low polymer content will help to develop high-performance and sustainable nacreous composites. In addition, it improves our understanding of the reinforcing mechanism of natural nacre, which exhibits excellent mechanical properties even with relatively small amounts of organic component.

Biphasic interface templated synthesis of wrinkled MOFs for the construction of cascade sensing platform based on the encapsulated gold nanoclusters and enzymes

The design and construction of MOFs with flower-like structure could afford sufficient space for the immobilization of guests with large size and interconnected transport channels for their mass diffusion although it remains a challenge. Herein, wrinkled Ce-based hierarchically porous UiO-66 (Ce-WUiO-66) with good crystallinity was successfully synthesized for the first time using bicontinuous emulsion composed of 1-heptanol, water and F127 (PEO106PPO70PEO106) surfactant as a template. F127 played a key role in the formation of emulsions as a stabilizer, and meanwhile its PEO segments interacted with MOF precursors to guide the evolvement of crystallized pore walls. Through controlling the ratios of heptanol to water and the salinity, the distances of the pleat openings and the morphology of the resultant Ce-WUiO-66 were facilely regulated. In virtue of its highly open radial structure, Ce-WUiO-66 could serve as an ideal platform for loading multiple substances to build a cascade sensing system. As a proof of concept, we designed an amino acid (AA) cascade probe by co-immobilizing gold nanoclusters (AuNCs) and LAA oxidase into Ce-WUiO-66. The aggregation-induced-emission enhancement resulted from the encapsulation of AuNCs into Ce-WUiO-66 significantly improved the detection sensitivity and the detection limit of corresponding substrates reached as low as 10-8 M. The proposed biphasic interface assembly strategy is hopefully to provide a new route for the rational design of MOFs with various open pore structure and broaden their potential applications with multiple large-size substances involved besides the currently exemplified cascade sensing platform.