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Solar-driven interfacial evaporation is an efficient method for purifying contaminated or saline water. Nonetheless, the suboptimal design of the structure and composition still necessitates a compromise between evaporation rate and service life. Therefore, achieving efficient production of clean water remains a key challenge. Here, a biomimetic dictyophora hydrogel based on loofah/carbonized sucrose@ZIF-8/polyvinyl alcohol is demonstrated, which can serve as an independent solar evaporator for clean water recovery. This special structural design achieves effective thermal positioning and minimal heat loss, while reducing the actual enthalpy of water evaporation. The evaporator achieves a pure water evaporation rate of 3.88 kg m-2 h-1 and a solar-vapor conversion efficiency of 97.16% under 1 sun irradiation. In comparison, the wastewater evaporation rate of the evaporator with ZIF-8 remains at 3.85 kg m-2 h-1 for 30 days, which is 16.3% higher than the light irradiation without ZIF-8. Equally important, the evaporator also showcases the capability to cleanse water from diverse sources of contaminants, including those with small molecules, oil, heavy metal ions, and bacteria, greatly improving the lifespan of the evaporator.

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Inspired by natural wrinkled surfaces, artificial surfaces with biomimetic wrinkled structures have been widely used to improve optical properties, wettability, and antibacterial properties. However, the preparation of wrinkled structures has the disadvantages of long-time consumption and complex processes. Herein, we prepared a self-wrinkling polyurethane-acrylate (PUA) wood coating via biomimetic self-wrinkling patterns by using a light-emitting diode (LED)/excimer/mercury lamp curing system, which was capable of self-matting, anti-fingerprint and skin-tactile performance. By adjusting the irradiation intensity in the curing system, the wavelength (λ) and amplitude (A) of wrinkles on the coating surface were controlled to enhance the coating performance. After curing by the LED, excimer, and mercury lamps at energy intensities of 500, 30, and 300 mW/cm2 respectively, the self-wrinkling coating showed excellent surface performance. The self-wrinkling coating represented low gloss of 4.1 GU at 85°, high hardness of 4H. Interestingly, the coating surface had a high hydrophobicity (104.5°) and low surface energy (29-30 mN/m) and low coefficient (COF) of friction (0.1-0.2), which were consistent with those of the human skin surface. Besides, the wrinkled structure also improved the thermal stability of the coating samples. This study provided a promising technique for the mass production of self-wrinkling coatings that could be used in wood-based panels, furniture, and leather.

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Under water, on land, or in the air, creatures use a variety of grasping methods to hunt, avoid predators, or carry food. Numerous studies have been conducted to construct a bionic surface for grasping tasks. This paper reviews the typical biomimetic structures and surfaces (wedge-shaped surface, suction cup surface and thorn claw surface) for grasping scenarios. Initially, progress in gecko-inspired wedge-shaped adhesive surfaces is reviewed, encompassing the underlying mechanisms that involve tuning the contact area and peeling behavior. The applications of grippers utilizing this adhesive technology are also discussed. Subsequently, the suction force mechanisms and applications of surfaces inspired by octopus and remora suction cups are outlined. Moreover, this paper introduces the applications of robots incorporating the principles of beetle-inspired and bird-inspired thorn claw structures. Lastly, inspired by remoras' adhesive discs, a composite biomimetic adhesive surface is proposed. It integrates features from wedge-shaped, suction cup, and claw thorn surfaces, potentially surpassing the adaptability of basic bioinspired surfaces. This surface construction method offers a potential avenue to enhance adhesion capabilities with superior adaptability to surface roughness and curvature.

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BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with different antigenic variants, has posed a significant threat to public health. It is urgent to develop inhalable vaccines, instead of injectable vaccines, to elicit mucosal immunity against respiratory viral infections. METHODS: We reported an inhalable hybrid nanovaccine (NVRBD-MLipo) to boost protective immunity against SARS-CoV-2 infection. Nanovesicles derived from genetically engineered 293T cells expressing RBD (NVRBD) were fused with pulmonary surfactant (PS)-biomimetic liposomes containing MPLA (MLipo) to yield NVRBD-MLipo, which possessed virus-biomimetic structure, inherited RBD expression and versatile properties. RESULTS: In contrast to subcutaneous vaccination, NVRBD-MLipo, via inhalable vaccination, could efficiently enter the alveolar macrophages (AMs) to elicit AMs activation through MPLA-activated TLR4/NF-κB signaling pathway. Moreover, NVRBD-MLipo induced T and B cells activation, and high level of RBD-specific IgG and secretory IgA (sIgA), thus elevating protective mucosal and systemic immune responses, while reducing side effects. NVRBD-MLipo also demonstrated broad-spectrum neutralization activity against SARS-CoV-2 (WT, Delta, Omicron) pseudovirus, and protected immunized mice against WT pseudovirus infection. CONCLUSIONS: This inhalable NVRBD-MLipo, as an effective and safe nanovaccine, holds huge potential to provoke robust mucosal immunity, and might be a promising vaccine candidate to combat respiratory infectious diseases, including COVID-19 and influenza.

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Electronic skin (e-skin) capable of acquiring environmental and physiological information has attracted interest for healthcare, robotics, and human-machine interaction. However, traditional 2D e-skin only allows for in-plane force sensing, which limits access to comprehensive stimulus feedback due to the lack of out-of-plane signal detection caused by its 3D structure. Here, a dimension-switchable bioinspired receptor is reported to achieve multimodal perception by exploiting film kirigami. It offers the detection of in-plane (pressure and bending) and out-of-plane (force and airflow) signals by dynamically inducing the opening and reclosing of sensing unit. The receptor's hygroscopic and thermoelectric properties enable the sensing of humidity and temperature. Meanwhile, the thermoelectric receptor can differentiate mechanical stimuli from temperature by the voltage. The development enables a wide range of sensory capabilities of traditional e-skin and expands the applications in real life.

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The microneedle (MN) delivery system presents an attractive administration route for patients with Alzheimer's disease (AD). However, the passive drug delivery mode and low drug loading of MNs often result in unsatisfactory therapeutic efficiency. To address these dilemmas, we developed dual engine-drive bionic MNs for robust AD treatment. Specifically, free rivastigmine (RVT) and RVT particles were co-loaded within the MNs to construct the valve and chambers of the guava, respectively, which can serve as an active engine to promote drug permeation by generating capillary force. K2CO3 and citric acid were introduced as a pneumatic engine into the MNs to promote the permeation of free RVT into deeper skin layers for early intervention in AD. Further, the RVT particles served as a drug depot to provide continuous drug release for prolonged AD treatment. Compared with free RVT-loaded MNs, the dual engine-driven bionic MNs showed an increase in drug loading, cumulative transdermal permeability, and normalized bioavailability of approximately 40%, 22%, and 49%, respectively. Pharmacodynamic studies further confirmed that the dual engine-driven bionic MNs were most effective in restoring memory and recognition functions in mice with short-term memory dysfunction. Therefore, the dual engine-driven bionic MNs hold great promise for highly efficient AD treatment.

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BACKGROUND:Trauma,inflammation,tumors,and other factors commonly result in tissue defects,including damage to bones,joints,skeletal muscles,and associated blood vessels and nerves.Clinically,it is often challenging to repair all the functional injuries involving these tissues,posing great challenges for clinical treatment. OBJECTIVE:To elucidate the application of 3D-printed hydrogel biomimetic structures in motor system tissue injuries. METHODS:Relevant literature published from 2003 to 2023 was retrieved from the CNKI,Wanfang Data,and PubMed databases.The Chinese and English search terms were"3D printing,hydrogel,bone,cartilage,muscle,nerve,vasculature,tissue engineering,biomimetics".After screening,induction and summary,63 relevant articles were finally included for review. RESULTS AND CONCLUSION:(1)3D-printed hydrogels can be achieved in several different ways,such as direct 3D printing,hybrid mode 3D printing,or manufacturing 3D bio-inspired structures in hydrogels by printing intermediate molds.Among these manufacturing processes,extrusion-based printing is currently the most widely used for 3D printing hydrogels with bio-inspired structures.(2)Bioprinting hydrogels enables the production of biovascular structures with complex perfusion patterns,and it can induce the formation of biologically relevant,highly organized,and intact blood vessels.(3)By utilizing bioprinting technology,it is possible to mimic the hierarchical structure and function of natural bone,combining hydrogels with different types of cells and growth factors to create tissue engineering scaffolds that closely resemble the composition and structure of natural bone,thereby facilitating better bone regeneration.(4)Neural fiber structure can be bio-inspired by incorporating different fiber materials into the 3D-printed hydrogel conduit structure.(5)Utilizing specific hydrogel formulations,it is possible to simulate muscle bundle structures or engineer muscle tissues integrating blood vessels and nerves,which can enhance the repair of volumetric muscle injuries in vivo.(6)Based on current related research,methacrylated gelatin,which closely resembles the characteristics of the extracellular matrix,is often considered as a raw material for 3D printing various tissue bio-inspired structures.Researchers also incorporate different growth factors or cells into the hydrogels for bioprinting to achieve the desired tissue repair outcomes.(7)Although there is a lack of clinical trial reports on 3D-printed hydrogel bio-inspired structures,this indicates that the clinical translation of such materials still requires a long-term process.Further improvements are needed in terms of clinical applications,as well as comprehensive in vivo safety assessments.

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Petroleum-derived formaldehyde resin adhesives are serious hazards to human health and depend on limited resources. Abundant, cheap and renewable biomass materials are expected to replace them. However, the contradictory mechanisms of high mechanical strength and fracture toughness affect the use of bioadhesives. Herein, a biomimetic soybean meal (SM) adhesive inspired by the structure of insect cuticles and shell pearl layer was proposed. Specifically, chitosan (CS@DA) modified 3,4-dihydroxybenzoic acid (DA, rich in catechol moiety) was anchored on molybdenum disulfide nanosheets (MoS2) to construct a biomimetic structure with copper hydroxide and SM substrate (SM-MoS2/CS@DA-Cu). Schiff base, ionic, and hydrogen bonding strengthened the cohesion of the adhesive. The ordered alternating stacking "brick-mortar" structure stimulated the lamellar sliding and crack deflection of MoS2, synergistically reinforcing the toughness. Compared to SM adhesive (0.57 MPa and 0.148 J), the wet shear strength and adhesion work of the SM-MoS2/CS@DA-Cu were 1.68 MPa and 0.867 J, with 194.7 % and 485.8 % increases, respectively. The multiple antimicrobial effects of CS@DA, Schiff base, and Cu2+ increased the applicability period of the adhesive to 40 days. The adhesive also displayed favorable water resistance and flame retardancy. Therefore, this peculiar and efficient biomimetic structural design inspired the development of multi-functional composites.

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It is challenging to recapitulate the natural extracellular matrix's hierarchical nano/microfibrous three-dimensional (3D) structure with multilevel pores, good mechanical and hydrophilic properties, and excellent bioactivity for designing and developing advanced biomimetic materials. This work reports a new facile strategy for the scalable manufacturing of such a 3D architecture. Natural polymers in an aqueous solution are interpenetrated into a 3D microfibrous matrix with arbitrary shapes and property characteristics to self-assemble in situ into a nanofibrous network. The collagen fiber-like hierarchical structure and interconnected multilevel pores are achieved by self-assembly of the formed nanofibers within the 3D matrix, triggered by a simple cross-linking treatment. The as-prepared alginate/polypropylene biomimetic matrices are bioactive and have a tunable mechanical property (compressive modulus from ∼17 to ∼24 kPa) and a tunable hydrophilicity (water contact angle from ∼94° to 63°). This facile and versatile strategy allows eco-friendly and scalable manufacturing of diverse biomimetic matrices or modification of any existing porous matrices using different polymers.

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At present, the packing method of "plastic bag-buffer packing-packing paper box" is adopted for bearing packaging. However, the common packing method has a poor packing effect and poor versatility. In this study, a new biomimetic cobweb cushion is proposed to solve the problem of insufficient cushioning capacity of high-precision bearing cushion packaging pads. First, according to the nature of cobweb form, the cobweb cushion structure configuration is determined. Next, based on the structure of the cushion and the relationship between the parameters of radial thread and spiral thread, a mechanical and target optimization model is established. The stress nephogram of bearing and the cobweb cushion are analyzed under three drop heights of 381, 610, and 700 mm, in the finite element simulation software to ensure that the maximum bearings stress is not beyond the material yield strength. Via the 3D printing technology, a cobweb cushion shell cast is made. Drop tests of the bearing were performed, and the results were verified with the finite element simulation analysis. This research can provide technical support for the protection of high-precision bearings from accidental drops during transportation.

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In the field of one-step efficient preparation of dewetting droplet arrays, the process is hampered by the requirement for low chemical wettability of solid surfaces, which restricts the complete transition of wetting state and its broad prospects in biological applications. Inspired by the physical structure of the lotus leaf, enabling it to promote the change of the infiltration state of an aqueous solution on the surface, we developed a method of one-step fabrication of droplet arrays on the biomimetic structural chip designed in the present work. This greatly reduces the need for chemical modification techniques to achieve low wettability and reduces the reliance on complex and sophisticated surface preparation techniques, thus improving the fabrication efficiency of droplet arrays fully generated on a chip by one-step operation without the need for extra liquid phase or the control of harsh barometric pressure. We also studied the influence of dimensions of the biomimetic structure and the preparation process parameters such as number of smears and speed of smearing on the preparation rate and uniformity of the droplet arrays. The amplification of templating DNA molecules in the droplet arrays prepared in a one-step fabrication way is also performed to verify its application potential for DNA molecular diagnosis.

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A structurally stable and antibacterial biomaterial used for temporary cranioplasty with guided bone regeneration (GBR) effects is an urgent clinical requirement. Herein, we reported the design of a biomimetic Ag/bacterial cellulose/hydroxyapatite (Ag/BC@HAp) hydrogel mesh with a double-sided functionalized structure, in which one layer was dense and covered with Ag nanoparticles and the other layer was porous and anchored with hydroxyapatite (HAp) via mineralization for different durations. Such a double-sided functionalized design endowed the hydrogel with distinguished antibacterial activities for inhibiting potential infections and GBR effects that could prevent endothelial cells and fibroblasts from migrating to a defected area and meanwhile show biocompatibility to MC3T3-E1 preosteoblasts. Furthermore, it was found from in vivo experimental results that the Ag/BC@HAp hydrogel with 7-day mineralization achieved optimal GBR effects by improving barrier functions toward these undesired cells. Moreover, this BC-based hydrogel mesh showed an extremely low swelling ratio and strong mechanical strength, which facilitated the protection of soft brain tissues without gaining the risk of intracranial pressure increase. In a word, this study offers a new approach to double-sided functionalized hydrogels and provides effective and safe biomaterials used for temporary cranioplasty with antibacterial abilities and GBR effects.

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Wearable sweat sensors have been developed rapidly in recent years due to the great potential in health monitoring. Developing a convenient manufacturing process and a novel structure to realize timeliness and continuous monitoring of sweat is crucial for the practical application of sweat sensors. Herein, inspired by the striped grooves and granular structures of bamboo leaves, we realized an epidermal patch with biomimetic multilevel structural microfluidic channels for timeliness monitoring of sweat via 3D printing and femtosecond laser processing. The striped grooves and ridges are alternately arranged at the bottom of the microfluidic channels, and the surface of the ridges has rough granular structures. The striped grooves improve the capillary effect in the microchannels by dividing the microchannels, and the granular structures enhance the slip effect of sweat by increasing surface hydrophobicity. The experimental results show that compared with the conventional microfluidic channels, the water collecting rate of the biomimetic microchannels increased by about 60%, which is consistent with the theoretical analysis. The superior sweat-collecting efficiency in the epidermal patch with the biomimetic multistructure enables sensitive, continuous, and stable monitoring of sweat physiological signals. Besides, this work provides new design and manufacturing approaches for other microfluidic applications.

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Rapid and portable water purification (RPWP) technologies, helping travelers survive in the wild, have attracted increasing interest due to increasing activities, such as exploration, field hiking, and excursion. Field water is usually pathogenic because of various soluble and insoluble contaminants. In this study, fish-gill-like biomimetic core-shell-structured nanofiber membranes are designed and synthesized by an in situ oxidation polymerization coating process. A polyimide nanofiber membrane and a polypyrrole (PPy) coating layer are employed as a core and shell, respectively. The biomimetic membranes exhibit dual-functional capacities: a rapid removal of insoluble contaminants owing to the highly porous network and broad-spectrum adsorption of soluble contaminants enabled by the PPy shell. Model studies confirm the excellent ability of the membranes to purify Cr(VI)-contaminated water to drinkable water with a safe capacity of ∼1415 L m-2. Actual application tests show that the membrane can efficiently remove coliform and suspended solids in a muddy water sample taken from a river in Suzhou, China. This study provides a promising route for the design of a single-layer membrane with dual functions for highly efficient RPWP.

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Injuries to the urethra can be caused by malformations, trauma, inflammation, or carcinoma, and reconstruction of the injured urethra is still a significant challenge in clinical urology. Implanting grafts for urethroplasty and end-to-end anastomosis are typical clinical interventions for urethral injury. However, complications and high recurrence rates remain unsatisfactory. To address this, urethral tissue engineering provides a promising modality for urethral repair. Additionally, developing tailor-made biomimetic natural and synthetic grafts is of great significance for urethral reconstruction. In this work, tailor-made biomimetic natural and synthetic grafts are divided into scaffold-free and scaffolded grafts according to their structures, and the influence of different graft structures on urethral reconstruction is discussed. In addition, future development and potential clinical application strategies of future urethral reconstruction grafts are predicted.

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The gular sac tissue of brown pelican featured by the curvy pattern of fibers has an excellent combination of strain-stiffening behavior and fracture resistance. We develop an embroidery-reinforcement and solvent-welding strategy to fabricate a biomimetic elastomer with similar structure to that of the gular sac tissue. The embroidery reinforcement enables a well-designed biomimetic pattern of aramid fibers, and the solvent welding induces strong interfacial interaction between the aramid fibers and polyurethane matrix. This strategy endows the composite with excellent strain-stiffening behavior, fracture resistance, mechanical strength, and toughness, which are even better than the living prototype. Finite elements analysis reveals that the curvy pattern and strong interfacial interaction are crucial for both the J-shape behavior and the mechanical properties. The facile and robust strategy can be extended to other fibers reinforced polymers and should be promising for development of strong and tough soft materials with "J-shape" behavior.

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A post-nanotechnology concept has been assigned to an emerging concept, nanoarchitectonics. Nanoarchitectonics aims to establish a discipline in which functional materials are fabricated from nano-scale components such as atoms, molecules, and nanomaterials using various techniques. Nanoarchitectonics opens ways to form a more unified paradigm by integrating nanotechnology with organic chemistry, supramolecular chemistry, material chemistry, microfabrication technology, and biotechnology. On the other hand, biological systems consist of rational organization of constituent molecules. Their structures have highly asymmetric and hierarchical features that allow for chained functional coordination, signal amplification, and vector-like energy and signal flow. The process of nanoarchitectonics is based on the premise of combining several different processes, which makes it easier to obtain a hierarchical structure. Therefore, nanoarchitectonics is a more suitable methodology for creating highly functional systems based on structural asymmetry and hierarchy like biosystems. The creation of functional materials by nanoarchitectonics is somewhat similar to the creation of functional systems in biological systems. It can be said that the goal of nanoarchitectonics is to create highly functional systems similar to those found in biological systems. This review article summarizes the synthesis of biomimetic and biological molecules and their functional structure formation from various viewpoints, from the molecular level to the cellular level. Several recent examples are arranged and categorized to illustrate such a trend with sections of (i) synthetic nanoarchitectonics for bio-related units, (ii) self-assembly nanoarchitectonics with bio-related units, (iii) nanoarchitectonics with nucleic acids, (iv) nanoarchitectonics with peptides, (v) nanoarchitectonics with proteins, and (vi) bio-related nanoarchitectonics in conjugation with materials.

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Aerogels have great potential in oil absorption applications; however, many reported aerogels have the drawbacks of a low oil-recovery rate and poor mechanical properties, which limit their application. In this study, highly reusable graphene oxide (GO)/TEMPO-oxidized cellulose nanofiber (TOCN)/polyvinyl alcohol (PVA) aerogels with excellent mechanical properties and with an architecture similar to that of Thalia dealbata stems were fabricated through a three-step process of bidirectional-freezing, freeze-drying, and chemical vapor deposition (CVD) modification. After CVD modification, the modified GTPA (MGTPA) accorded hydrophobicity. The synergistic effects of the three components and the unique biomimetic structure conferred biomimetic-MGTPA (b-MGTPA) with excellent compressible properties. As an adsorbent, b-MGTPA showed a high adsorption capacity (75-151 g/g) for various types of organic solvents. In addition, its high compressibility enables b-MGTPA to have fast and highly efficient recovery of absorbed oil through simple mechanical squeezing and it possesses excellent reusable stability (the oil recovery rate and oil retention rate reached 80% and 91.5%, respectively, after 10 repeated absorption-compression cycles).

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In tracheal tissue engineering, the construction of tracheal scaffolds with adequate biodegradable mechanical capacity and biological functions that mimic the structure of a natural trachea is challenging. To explore the feasibility of preparing biomimetic degradable scaffolds with C-type cartilage rings and an inner tracheal wall of polycaprolactone and silk fibroin. A mold was made according to the diameter of a rabbit trachea, and a silk fibroin tube and polycaprolactone ring attached to the tube were obtained by solution casting. The ring was fixed to the tube at a specific spacing using electrostatic spinning technology to construct a biomimetic tracheal scaffold; its porous structure was observed by scanning electron microscopy, its degradation properties were determined by in vitro enzymatic hydrolysis and its mechanical properties were obtained by pressure testing. The composite scaffold was transplanted subcutaneously into a rabbit model, and the scaffold was taken at 1, 2, and 4 weeks after surgery for sectioning to observe pre-vascularization. The Medical Ethics Committee of Guangdong Provincial People's Hospital approved the study. The general view of the biomimetic scaffold: the polycaprolactone ring was fixed firmly on the outer wall of the silk fibroin tube; the two corresponded in size, and they fitted closely. The surface of the polycaprolactone ring was smooth and dense, while the surface of the silk fibroin tube could be seen as a uniform porous structure. Scanning electron microscopy showed that the surface and profile of the fibroin tube had a uniform pore size and distribution. The pores were connected to form a network. In vitro, enzymatic hydrolysis experiments confirmed that the fibroin was degraded easily, with most being degraded at the end of week 1. The degradation slowed at 2, 3, and 4 weeks, while the degradation of polycaprolactone was extremely slow. A compression test showed that the compressive resistance of the silk fibroin-polycaprolactone biomimetic scaffolds was much better than that of the rabbit trachea at close thickness. In the tissue staining experiments, as the material degraded, fibrous tissues and blood vessels grew to replace the material, allowing the scaffold to obtain a blood supply and better mechanical properties. A quantitative analysis of CD31 showed that the results for the vascularization of the scaffold were better at 4 weeks than at 2 weeks following subcutaneous grafting (P < .05). The results confirmed that it is feasible to prepare porous, degradable silk fibroin-polycaprolactone biomimetic scaffolds with good mechanical properties and epithelial biological functions by mold casting.

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Heat exchangers are general equipment for energy exchange in the industrial field. Enhancing the heat transfer of a heat exchanger with low pump energy consumption is beneficial to the maximum utilization of energy. The optimization design for enhanced heat transfer structure is an effective method to improve the heat transfer coefficient. Present research shows that the biomimetic structures applied in different equipment could enhance heat transfer and reduce flow resistance significantly. Firstly, six biomimetic structures including the fractal-tree-like structure, conical column structure, hybrid wetting structure, scale structure, concave-convex structure and superhydrophobic micro-nano structure were summarized in this paper. The biomimetic structure characteristics and heat transfer enhancement and drag reduction mechanisms were analyzed. Secondly, four processing methods including photolithography, nanoimprinting, femtosecond laser processing and 3D printing were introduced as the reference of biomimetic structure machining. Finally, according to the systemic summary of the research review, the prospect of biomimetic heat transfer structure optimization was proposed.