Search Results (4,121)

Regarding the current issues in Xinjiang, China, during the harvesting of cotton stalks, the lack of specialized, efficient, and durable cutting blades for cotton stalks causes uneven cutting, high power consumption, and short blade life. In this study, a biomimetic serrated blade was designed based on the Trictenotomidae mandible for efficient, low-power-consumption cutting. The biomimetic design, FEM-SPH coupled simulation, bench test, combined with response surface methodology, and field test were used. The simulation results showed that under the same working conditions, the maximum shear stress was 34.81% lower than that for the ordinary blade and 22.05% lower than that for the ordinary serrated blade. And the bench test results showed that cutting power consumption was reduced by about 20.12% and 15.69% compared to the ordinary cutting blade and serrated cutting blade, respectively. When cutting velocity was 1.3 m/s, cutting inclination angle was 11°, and ratio of cutting velocity and feeding velocity was 1.1, the biomimetic serrated cutting blade could achieve effective cutting of cotton stalks and obtain better quality of cutting—the cutting power per unit area and the cutting-edge angle after cutting cotton stalks were 52.08 kJ/m² and 6°, respectively. The research results can provide a theoretical basis and support for the utilization of cotton stalks out of the field, as well as the cutting of other similar crop stalks. Full article

Although nanomedicine has enabled significant advances in drug delivery, the clinical translation of conventional synthetic nanocarriers is limited by immune clearance, non-specific biodistribution, and gastrointestinal instability. This poses major challenges for therapy targeting the intestines. Cell membrane-coated nanotechnology (CMCT) and membrane vesicle-based systems have emerged as biomimetic platforms integrating synthetic nanomaterials with naturally derived biological interfaces. These biohybrid systems inherit biological functions originating from cells, including immune evasion, prolonged circulation, lesion homing, and microenvironment-responsive interactions, through the direct transfer of intact membrane components. This review summarizes recent advances in CMCT and membrane vesicle-based strategies for intestinal drug delivery. It covers fabrication methodologies, programmable manufacturing approaches, and functional regulation enabled by diverse membrane sources and hybrid engineering designs. Applications in inflammatory bowel disease, colorectal cancer, and intestinal infections are highlighted, emphasizing key therapeutic mechanisms, such as targeting inflammation, neutralizing toxins, modulating the immune system, and regulating the microbiome. We also discuss the major challenges of translation, such as preserving membrane and coating integrity, ensuring oral stability, achieving batch reproducibility, and ensuring biosafety. Overall, this review establishes a conceptual and engineering framework to guide the transition of membrane-based nanocarriers from passive biomimicry to adaptive, clinically translatable intestinal delivery systems. Full article

Background: Sulfated chitosan (ChS) is a chemically modified polysaccharide derived from chitin that mimics heparan sulfate (HS) structures and has emerged as a promising antimicrobial biomaterial. Piscirickettsia salmonis, the etiological agent of Salmonid Rickettsial Septicemia (SRS), represents the main driver of antibiotic use in Chilean aquaculture. Objective: In this study, the in vitro antibacterial activity of ChS against P. salmonis was evaluated. Methods: Elemental characterization by SEM-EDS and FTIR analysis confirmed successful sulfation of the polymer, with a degree of sulfation ranging from 0.92 to 0.95. Additionally, X-ray diffraction (XRD) analysis revealed a reduction in polymer crystallinity, indicating a transition toward a more amorphous structure associated with increased molecular flexibility and functional group accessibility. Results: Antibacterial assays revealed a minimum inhibitory concentration (MIC) of 1500 µg/mL and a minimum bactericidal concentration (MBC ≥ 1500 µg/mL). LIVE/DEAD™ fluorescence imaging showed the formation of bacterial aggregates with increasing size, frequency, and red fluorescence compared to controls over the exposure to ChS, indicating progressive membrane damage. This was supported by a reduction (p < 0.05) in the Green/Red fluorescence ratio of 37–46% between 5 h and 96 h of exposure, corresponding to alteration of the cell membrane. Scanning electron microscopy revealed pronounced morphological alterations by ChS, including surface disruption and loss of cellular integrity. This was more severe compared to commercial chitosan (ChC). Also, ChS reduced (p < 0.05) biofilm formation (>50% at day 6 and 34.8% at day 8). Conclusions: These results demonstrated that ChS disrupts the cell membrane and reduces biofilm formation in P. salmonis, thereby affecting viability. This is the first report of the antibacterial effect of ChS, an HS analogue, against P. salmonis. Full article

Access to clean water remains a critical global challenge, particularly in arid and fog-rich regions where conventional resources are limited. Fog water harvesting has emerged as a low-energy alternative; however, the performance of traditional collectors (typically 3–10 L m⁻² day⁻¹) remains constrained by inefficient droplet capture and transport. This review provides a systematic and critical analysis of recent advances in membrane-based fog harvesting technologies, focusing on material design, surface engineering, and structural optimization. The analysis shows that nanostructured and electrospun membrane systems can enhance water collection rates to ~20–60 L m⁻² day⁻¹, representing up to a 5–6 times improvement over conventional meshes. Furthermore, biomimetic and Janus wettability designs significantly improve droplet nucleation and directional transport, while hierarchical micro/nanostructures accelerate coalescence and runoff dynamics. At the structural level, optimized collector geometries (vertical harp designs) demonstrate ~3–4 times higher collection efficiency compared to traditional Raschel mesh due to reduced clogging and enhanced drainage. Despite these advances, key challenges remain, including material durability, fouling resistance, lack of standardized testing protocols, and limited large-scale validation. This review identifies critical design–performance relationships and proposes a framework linking surface wettability, morphology, and environmental parameters to harvesting efficiency. Future directions emphasize the development of durable, scalable membrane systems and the integration of fog harvesting with hybrid water supply technologies. Full article

Diabetic wounds are a common and severe complication of diabetes mellitus, characterized by delayed healing due to persistent inflammation, impaired angiogenesis, and cellular dysfunction. Conventional therapeutic approaches remain limited in efficacy. In recent years, exosomes have attracted considerable attention in wound healing and regenerative medicine because of their crucial role in intercellular communication and tissue repair. However, rapid clearance of exosomes in vivo greatly limits their therapeutic efficacy. To address this critical limitation, we engineered a decellularized extracellular matrix (dECM)-based hydrogel system functionalized with exosomes derived from skin-derived precursor cells (SKPs). This biomimetic scaffold was designed to serve as a local exosome-delivery platform at the wound site, with the aim of improving exosome utilization and augmenting their regenerative effects. Comprehensive in vitro characterization demonstrated that the exosome-loaded composite hydrogels exhibited robust pro-angiogenic activity, as evidenced by enhanced endothelial cell proliferation, migration, and tube formation. Moreover, the hydrogels displayed significant antibacterial effects against wound-relevant pathogens and potent reactive oxygen species (ROS)-scavenging capacity, thereby mitigating oxidative damage. Notably, the composite hydrogels also promoted the phenotypic polarization of macrophages toward the pro-regenerative M2 phenotype. In parallel, in vivo studies using a streptozotocin-induced diabetic rat wound model confirmed that treatment with the composite hydrogels significantly accelerated wound closure rates compared to control groups. Histological and immunohistochemical analyses revealed enhanced angiogenesis, as evidenced by increased CD31-positive microvessel density, as well as improved collagen deposition, re-epithelialization, and an attenuated local inflammatory microenvironment characterized by reduced pro-inflammatory cytokine expression and elevated M2 macrophage infiltration. Collectively, the SKPs exosome-loaded dECM based composite hydrogels developed in this study represent a potential therapeutic strategy for the treatment of diabetic wounds. Full article

Subsoiling can break the plough pan and improve the root growth environment. The effect of the traditional subsoiler is poor, as it relies only on the chisel tine, but pneumatic subsoiling can improve the soil structure more efficiently through the negative pressure generated by the jet hole. This research used computational fluid dynamics and the discrete element method to optimize the biomimetic structure of the jet hole, model the pneumatic subsoiling process at a depth of 330 mm, and observe the movement of soil particles as airflow passes through. The effect of the jet hole at different positions and sizes on the plough pan soil was analyzed, and fluid domains and measurement areas were set up to observe the upward movement, diffusion, stabilization, and settling of soil particles under the action of airflow. The results of the soil bin experiment validated the accuracy of the simulation model through draft force and vertical force, and the average error between the simulation and experimental data was 2.8%. The study revealed that the increase in the rate of soil porosity reached a maximum of 3.65% when the jet hole was positioned above the chisel tine with a radius of 4 mm. The biomimetic jet hole pneumatic subsoiler designed in this study, along with the established CFD-DEM coupled simulation model capable of predicting pneumatic subsoiling performance, can provide references for the design and application of a pneumatic subsoiler. Furthermore, it also provides a theoretical basis for understanding the mechanism of airflow on soil during pneumatic subsoiling operations. Full article

Nanogrooves provide instructive cues to cells in culture. Several nanofabrication techniques have been developed to create biomimetic substrates, advancing our understanding of cell adhesion. Their integration into nervous system models highlights the critical role of the extracellular matrix (ECM) in developing functional tissue constructs for in vitro platforms such as Brain-on-Chip (BoC) and Nervous System-on-Chip (NoC). This study presents a nanofabrication approach that integrates photolithography and microtransfer molding (μTM) to pattern nanogrooves using photocurable polymer NOA81 onto microelectrode array (MEA) plates. The resulting nanogrooves exhibited a pattern periodicity of 976 nm and a ridge width of 232 nm, as confirmed by scanning electron microscopy and atomic force microscopy. We assessed the biocompatibility and functional impact of these modified substrates using human induced pluripotent stem cell (hiPSC)-derived neuronal cultures. Neurons cultured on nanogroove-modified MEAs exhibited aligned neural processes due to the anisotropic surface features and expressed vivid spiking behavior and higher burst frequency compared to randomly cultured neuronal networks. In conclusion, the proposed fabrication technique integrates nanogrooves with commercial MEAs using a combination of microtransfer molding and photolithography, resulting in modified culture substrates that enhance spike activity and network organization, aiding in the development of more in vivo-like neural models. Full article

Cannabinol (CBN) is a highly lipophilic phytocannabinoid whose biomedical application is limited by poor water solubility. In this study, colloidal hydroxyapatite nanoparticles (nHAp) were evaluated as a carrier for CBN, and their effect on model lipid membranes was investigated. Interactions between CBN and lipids were examined using Langmuir monolayers and lipid bilayers (black lipid membranes, BLMs). Langmuir monolayer studies revealed strong interactions between CBN and lipids, resulting in changes in isotherms, compressibility, and monolayer stability. BLM measurements indicated that delivery of CBN via nHAp modifies the electrical properties and stability of the lipid bilayer, suggesting alterations in membrane organization and permeability. These results demonstrate that hydroxyapatite nanoparticles can effectively serve as a carrier for cannabinol while modulating its interactions with lipid membranes. Full article

Ovarian tissue cryopreservation is the primary fertility preservation strategy for prepubertal girls and patients requiring urgent gonadotoxic therapy. However, the risk of reintroducing malignant cells has prompted the development of safer alternatives, including follicle isolation followed by three-dimensional scaffold encapsulation for transplantation. Fibrin is a promising biomaterial for bioengineered ovary construction, although its ability to support early human follicle maintenance remains unclear. Follicles isolated from cryopreserved ovarian tissues of six patients were encapsulated within fibrin scaffolds of graded concentrations (high, medium, low). After 7 days of in vitro culture, follicle survival and diameter change were quantified. A total of 282 follicles (45.4 ± 10.1 µm) were embedded into fibrin scaffolds. After culture, 237 viable follicles were detected, yielding an overall survival of 84%. Follicle diameter increased to 58.8 ± 12.0 µm. Follicle survival rates were comparable across groups, while mean follicle diameter was 56.3 ± 12.5 µm (high), 61.9 ± 13.4 µm (medium), and 57.4 ± 9.3 µm (low). Follicles cultured in medium-concentration fibrin demonstrated significantly larger diameters compared with both high and low groups (p < 0.05), with no difference between high and low groups. Fibrin-based bioprosthetic ovary scaffolds support short-term in vitro maintenance of isolated human follicles, preserving spherical morphology and granulosa cell layer integrity. Medium-concentration fibrin was associated with greater follicle diameter expansion compared with higher and lower concentrations, indicating that scaffold composition influences early morphometric changes during in vitro follicle culture. Full article

Industrial surface inspection is fundamental to advanced manufacturing, yet reliable robotic image acquisition in complex geometries remains challenging due to severe occlusions and the inherent trade-off between resolution and coverage. Inspired by human visual inspection behaviors and perception–action coordination mechanisms, this paper proposes a hierarchical trajectory optimization framework for robotic image acquisition based on measured point clouds. Specifically, a multi-constraint preprocessing model is developed to emulate human-like active perception strategies, enabling occlusion-aware viewpoint generation over complex concave and convex surfaces with adaptive camera orientation. Building upon this, a multi-objective trajectory optimization method is introduced to coordinate global coverage and local motion efficiency, jointly optimizing viewpoint sequencing, path length, and motion smoothness hierarchically. To further enhance flexibility in constrained environments, a Pose Reachability Augmented Generative Adversarial Network (PRAGAN) is proposed to learn feasible and adaptable imaging postures under kinematic constraints. Experimental results on an industrial robotic platform equipped with 2D and 3D vision systems demonstrate 100% coverage of key surface areas, a 47.0% reduction in path length, and a 37.5% decrease in solution time compared with the baseline in the physical experiments, while ensuring collision-free operation. Both simulation and real-world experiments validate that the proposed framework effectively captures human-inspired perception and motion coordination, providing a practical and scalable solution for complex industrial surface inspection. Full article

The limited self-starting capability of H-type Darrieus Vertical-Axis Wind Turbines (VAWT) remains one of the main obstacles to their deployment in low-power and urban applications, where wind conditions are typically weak and intermittent. Although several passive geometric modification strategies have been proposed to enhance initial torque generation, most available studies rely predominantly on numerical simulations, with limited systematic experimental validation under low tip-speed ratio (TSR) conditions. In this work, the influence of passive blade modifications on self-starting performance is assessed through a combined numerical–experimental approach. An integrated numerical–experimental framework was used to systematically compare passive blade configurations under equivalent low-wind conditions. Two modified configurations, a biomimetic profile incorporating passive trailing-edge devices and an asymmetric J-type geometry, were optimized using transient CFD simulations of the first rotation cycle and a Design of Experiments (DOE) framework. Additively manufactured full-rotor test blades were then manufactured via additive manufacturing and tested in a controlled wind tunnel at 3.0 m/s and 2.25 m/s. Start-up time, azimuthal robustness, tip-speed-ratio evolution, and static start-up torque (interpreted through its corresponding torque coefficient) were measured and compared against a baseline NACA0018 profile. The biomimetic configuration consistently produced higher start-up torque and shorter acceleration times, achieving self-starting in 66.7% of the evaluated azimuthal positions at 2.25 m/s, compared to 22.2% for the baseline profile. Within the investigated operating range, this configuration emerged as the most robust passive strategy. The agreement between CFD predictions and experimental measurements supports the use of first-cycle maximum torque as a representative indicator of self-starting performance. These findings highlight the comparative value of first-cycle maximum torque as a practical metric for passive self-starting design assessment in low-TSR Darrieus turbines. These findings provide direct experimental evidence to guide the rational design of Darrieus turbines intended for marginal wind conditions. Full article

The aerodynamic characteristics of wingsails on unmanned surface vessels (USVs) play a crucial role in enhancing propulsion performance. Two-dimensional wingsail airfoils of owl wings, merganser wings, seagull wings, and teal wings were obtained through biomimetic design. Then a numerical investigation was conducted on the four biomimetic airfoils using the SST k-ω turbulence model to evaluate their aerodynamic performance. The results demonstrate that the bionic merganser airfoil exhibits the most superior lift performance, achieving a maximum lift coefficient of 3.21 across angles of attack ranging from 0° to 60° among the four biomimetic wingsails, and the bionic seagull airfoil is second, while the bionic teal airfoil shows the weakest lift characteristics. As the angle of attack increases, flow separation emerges at the trailing edge of the biomimetic airfoils, leading to the formation of separation vortices. For example, the backflow zone on the suction surface of the biomimetic merganser wingsail, caused by unsteady flow, persists at an angle of attack of 16 degrees. The vortex structure at the trailing edge of the biomimetic merganser wingsail periodically generates, develops, detaches, and dissipates, which affects the backflow of the suction surface of the wingsail and interferes with its lift coefficient. The study provides an excellent reference for selecting high-performance USV wingsails. Full article

This review summarizes current knowledge on naturally occurring pristimerin-pristimerin triterpenoid dimers, a rare and structurally diverse class of secondary metabolites reported mainly from Celastraceae species. Known dimers are compiled with emphasis on botanical sources and key architectural features, including the variety of interunit linkages, regio- and stereochemical diversity, and distinct isomeric forms (including atropisomerism). Major advances in structure elucidation and structural revisions are discussed, highlighting the role of modern spectroscopic tools—particularly 2D NMR methods and chiroptical techniques—in resolving connectivity and absolute configuration, and in correcting several earlier assignments. Proposed biosynthetic scenarios are outlined, focusing on the reactivity of the quinone-methide motif and its interconversion with 2,3-diketone forms, as well as (hetero) Diels-Alder-type processes; selected biomimetic studies are summarized as supportive evidence for these pathways. A critical overview of available biological data indicates that many pristimerin dimers display limited activity in common antimicrobial and cytotoxicity assays when compared with monomeric congeners, which may point to alternative ecological roles or storage/transport functions in planta. Finally, key knowledge gaps and future directions are identified, including improved isolation coverage, rigorous synthetic/biomimetic work, and broader pharmacological screening beyond standard panels. Full article

Artificial muscles such as braided pneumatic actuators (BPAs) offer many advantages for robotic systems, including high durability and strength-to-weight ratios. However, their use in robotic systems is still extremely limited, in part due to their poor force, length, and pressure characterization. In this work, a test setup is created to compare force produced by Festo fluidic BPAs with leading models. Our analysis of the data has resulted in (1) the development of new equations to calculate force as functions of pressure and contraction for Festo BPAs with uninflated diameters of 10;20, and (2) a novel equation for the maximum force in 10;20 diameter Festo BPAs as a function of their resting length. This will lead to faster design processes and the development of new systems such as biomimetic robots that are able to more accurately reproduce the range of motion and isometric torque profiles that exist in the animals they are mimicking. Full article