Bio-inspired Design Research Articles

Bioinspired design and validation of a soft robotic end-effector with integrated SMA-driven suction capabilities.

The exploration of adaptive robotic systems capable of performing complex tasks in unstructured environments, such as underwater salvage operations, presents a significant challenge. Traditional rigid grippers often struggle with adaptability, whereas bioinspired soft grippers offer enhanced flexibility and adaptability to varied object shapes. In this study, we present a novel bioinspired soft robotic gripper integrated with a shape memory alloy (SMA) actuated suction cup, inspired by the versatile grasping strategies of octopus arms and suckers. Our design leverages a tendon-driven composite arm, enabling precise bending and adaptive grasping, combined with SMA technology to create a compact, efficient suction mechanism. We develop comprehensive kinematic and static models to predict the interaction between arm bending deflection and suction force, thereby optimizing the gripper's performance. Experimental validation demonstrates the efficacy of our integrated design, highlighting its potential for advanced manipulation tasks in challenging environments. This work provides a new perspective on the integration of bioinspired design principles with smart materials, paving the way for future innovations in adaptive robotic systems.&#xD.

Miniature Robots for Battling Bacterial Infection.

Micro/nanorobots have shown great promise for minimally invasive bacterial infection therapy. However, bacterial infections usually form biofilms inside the body by aggregation and adhesion, preventing antibiotic penetration and increasing the likelihood of recurrence. Moreover, a substantial portion of the infection happens in those hard-to-access regions, making delivery of antibiotics to infected sites or tissues difficult and exacerbating the challenge of addressing bacterial infections. Micro/nanorobots feature exceptional mobility and controllability, are able to deliver drugs to specific sites (targeted delivery), and enhance drug penetration. In particular, the emergence of bioinspired microrobot surface design strategies have provided effective alternatives for treating infections, thereby preventing the possible development of bacterial resistance. In this paper, we review the recent advances in design, mechanism, and actuation modalities of micro/nanorobots with exceptional antimicrobial features, highlighting active therapy strategies for bacterial infections and derived complications at various organs, from the laboratory bench to in vivo applications. The current challenges and future research directions in this field are summarized. Those breakthroughs in micro/nanorobots offer a huge potential for clinical translation for bacterial infection therapy.

Bio-Inspired Secondary Levitation Structure Design for High-Temperature Superconducting Maglev Train

Bio-Inspired Secondary Levitation Structure Design for High-Temperature Superconducting Maglev Train

Bioinspired Design of Vascularized Glassy Metal-Organic Frameworks Electrolyte for Quasi-Solid-State Sodium Batteries

Quasi-solid-state electrolytes (QSSEs) are regarded as the most promising alternative for next-generation battery technology due to the compatibility of assemble process and high safety. However, the rational design of solid hosts to ensure the high-efficiency utilization of tiny liquid electrolytes and the deep understanding of ion transport mechanisms at heterogeneous structures are still challenging. Herein, inspired by the ion transport in biological blood vessels, we propose a nitrogen vacancy modified glassy metal-organic framework (MOF) as Na-ion QSSEs host, which shows multilevel ions transport channels, isotropy property, and no grain boundaries. The vascularized glassy MOF enables the reasonable distribution of a small amount of solvent (14 wt.% (solvent as a percentage of QSSE by mass)) in both macro and microenvironments with specific functions, boosting the fast Na-ion transport (1.18 × 10−4 S cm–1, 30°C) and Na-ion transfer number (0.92), and homogeneous Na-ion nucleation/propagation even at -50°C. Meanwhile, the quasi-solid-state Na||Na3V2(PO4)3/C cell demonstrates excellent rate capability and long cycling stability (0.0288% capacity decay per cycle after 500 cycles). The bioinspired design of glassy MOF will shed light on new avenues for the development of energy storage and conversion.

A Novel Triad of Bio-Inspired Design, Digital Fabrication, and Bio-Derived Materials for Personalised Bone Repair.

The emerging paradigm of personalised bone repair embodies a transformative triad comprising bio-inspired design, digital fabrication, and the exploration of innovative materials. The increasing average age of the population, alongside the rising incidence of fractures associated with age-related conditions such as osteoporosis, necessitates the development of customised, efficient, and minimally invasive treatment modalities as alternatives to conventional methods (e.g., autografts, allografts, Ilizarov distraction, and bone fixators) typically employed to promote bone regeneration. A promising innovative technique involves the use of cellularised scaffolds incorporating mesenchymal stem cells (MSCs). The selection of materials-ranging from metals and ceramics to synthetic or natural bio-derived polymers-combined with a design inspired by natural sources (including bone, corals, algae, shells, silk, and plants) facilitates the replication of geometries, architectures, porosities, biodegradation capabilities, and mechanical properties conducive to physiological bone regeneration. To mimic internal structures and geometries for construct customisation, scaffolds can be designed using Computer-aided Design (CAD) and fabricated via 3D-printing techniques. This approach not only enables precise control over external shapes and internal architectures but also accommodates the use of diverse materials that improve biological performance and provide economic advantages. Finally, advanced numerical models are employed to simulate, analyse, and optimise the complex processes involved in personalised bone regeneration, with computational predictions validated against experimental data and in vivo studies to ascertain the model's ability to predict the recovery of bone shape and function.

Design of a Bionic Spider Robot with a Two-Degrees-of-Freedom Leg Structure and Body Frame

Spiders have unique biological characteristics and excellent maneuverability, making them an ideal model for bionic robot design. However, traditional bionic spider robot designs usually have multiple degrees of freedom and confront many challenges. These challenges include complex control requirements, higher energy consumption, larger size and weight, higher risk of failure, and higher cost. This study proposes a leg design with two degrees of freedom to reduce its control and manufacturing costs. It can better control leg movement and improve leg force through a multi-link mechanism and a dual-motor system. In addition, the triangular gait and hexagonal body structure align the weight of the body with the support point, thereby enhancing stability. This study offers a comprehensive and organized approach to bio-inspired robot design, providing a valuable reference for future bionic robot development.

Advances in Spiky Antibacterial Materials: From Bioinspired Design to Application

Bacterial infections, particularly those caused by drug‐resistant bacteria, pose a significant threat to human life and health safety. Despite the preparation and application of numerous antibacterial and disinfection materials, addressing their low efficiency and the emergence of drug resistance remains an urgent concern. Inspired by natural spike antibacterial structures such as those found on cicada wings, extensive research has been conducted on biomimetic antibacterial materials with spiky structures. This review provides an overview of the natural spike antibacterial structure and mechanism, introduces surface coatings and micro/nanoparticle materials featuring spike structures inspired by nature, explores microneedle arrays based on spike antibacterial properties, and showcases applications of these innovative antibacterial materials. Finally, potential avenues for optimization and future development directions for antibacterial materials with spike structures are discussed.

Bio-inspired optimisation design strategy of graded hemp core for hybrid carbon/hemp sandwich laminates

Bio-inspired optimisation design strategy of graded hemp core for hybrid carbon/hemp sandwich laminates

One-shot manufacturable soft-robotic pump inspired by embryonic tubular heart.

Soft peristaltic pumps, which use soft ring actuators instead of mechanical pistons or rollers, offer advantages in transporting liquids with non-uniform solids, such as slurry, food, and sewage. Recent advances in 3D printing with flexible thermoplastic polyurethane (TPU) present the potential for single-step fabrication of these pumps, distinguished from handcrafted, multistep traditional silicone casting methods. However, because of the relatively high hardness of TPU, TPU-based soft peristaltic pumps contract insufficiently and thus cannot perform as well as silicone-based ones. Improving the performance is crucial for fully automated, one-step manufactured soft pumps to lead to industrial use. This study aims to enhance TPU-based soft pumps through bioinspired design. Specifically, it proposed a design inspired by embryonic tubular hearts, in contrast to previous studies that mimicked digestive tracts. The new design facilitated long-axis stretching of an elliptical lumen during non-concentric contractile motion, akin to embryonic tubular hearts. The design was optimized for ring actuators and pumps 3D-printed with shore hardness 85 A TPU filament. The ring actuator achieved over 99% lumen closure with the best designs. The soft pumps transported water at flow rates of up to 218 ml min-1and generated a maximum discharge pressure of 355 mm Hg, comparable to the performance of blood pumps used in continuous renal replacement therapy.

The Role of Bio-Inspired Soft Robotic Gloves in Stroke Rehabilitation: A Comprehensive Analytical Review

Stroke is a leading cause of long-term disability, with many survivors experiencing impaired motor function. Traditional rehabilitation methods often face limitations in achieving full functional recovery. In recent years, bio-inspired soft robotic gloves have emerged as a promising solution for enhancing stroke rehabilitation, mimicking the natural movement and adaptability of biological systems. This paper provides a comprehensive analytical review of bio-inspired soft robotic gloves designed for stroke rehabilitation, focusing on their development, fabrication methods and therapeutic applications. The primary objective of this review is to evaluate the role of bio-inspired designs in the creation of soft robotic gloves and assess their effectiveness in facilitating motor recovery post-stroke. A systematic analysis of existing literature is conducted, exploring various fabrication techniques, including soft material integration, actuators and sensors, as well as the application of these gloves in clinical and therapeutic settings. Findings from this review reveal that bio-inspired soft robotic gloves show significant potential in improving patient outcomes by enhancing finger and hand movement through assisted motor control. These devices offer advantages in terms of comfort, flexibility and adaptability, allowing for prolonged and intensive rehabilitation sessions. However, limitations remain, such as the high cost of fabrication, challenges in achieving precise motor control and the lack of large-scale clinical trials to validate long-term efficacy. The research has several implications: (1) Theoretical: advancing the understanding of bio-inspired design principles in soft robotics; (2) Methodological: highlighting fabrication techniques that enhance glove performance and user adaptability. This review offers original value by consolidating and analysing recent developments in bio-inspired soft robotic gloves, contributing to both the academic literature and practical applications in stroke rehabilitation. It emphasizes the necessity of future research to address current limitations, especially in optimizing performance and reducing production costs, while enhancing patient outcomes.

Novel Bio-inspired Design for the Carcass Layer of Flexible Risers with Increased Strength Under External Pressure

Novel Bio-inspired Design for the Carcass Layer of Flexible Risers with Increased Strength Under External Pressure

Eliminating Charge Transfer at Cathode-Electrolyte Interface for Ultrafast Kinetics in Na-Ion Batteries.

Sodium-ion batteries suffer from kinetic problems stemming from sluggish ion transport across the electrode-electrolyte interface, causing rapid energy decay during fast-charging or low-temperature operation. One exciting prospect to enhance kinetics is constructing neuron-like electrodes that emulate fast signal transmission in a nervous system. It has been considered that these bioinspired designs enhance electron/ion transport of the electrodes through carbon networks. However, whether they can avoid sluggish charge transfer at the electrode-electrolyte interface remains unknown. By connecting the openings of carbon nanotubes with the surface of carbon-coated Na3V2O2(PO4)2F cathode nanoparticles, here we use carbon nanotubes to trap Na+ ions released from the nanoparticles during charge. Therefore, Na+ movement is confined only inside the neuron-like cathode, eliminating ion transport between the electrolyte and cathode, which has been scarcely achieved in conventional batteries. As a result, a 14-fold reduction in interfacial charge transfer resistance is achieved when compared to unmodified cathodes, leading to superior fast-charging performance and excellent cyclability up to 200C, and surprisingly, reversible operation at low temperatures down to -60 °C without electrolyte modification, surpassing other Na3V2O2(PO4)2F-based batteries reported to date. As battery operation has relied on charge transfer at the electrode-electrolyte interface for over 200 years, our approach departs from this traditional ion transport paradigm, paving the way for building better batteries that work under harsh conditions.

Biomimetic design of elastomers with improved mechanical properties by integrating hydrogen bonds with covalent crosslinking bonds

It is an important issue for rubber to realize reinforcement and expand application gallery in material science and engineering. In the present work, we initiated a bioinspired design to introduce sacrificial hydrogen bonds by post-modifying sulfur crosslinked carboxyl nitrile rubber with pendent urazole through triazolinedione “click” chemistry. The post-modification of the crosslinked rubber can not only avoid adverse effect of the grafted urazoles on rubber vulcanization, but also enable to evaluate the effect of sacrificial hydrogen bonds on the rubber based on a consistent covalent network. Under external stress, the hydrogen bonds between the urazoles can function as sacrificial bonds that would rupture prior to covalent bonds, during which enormous energy is dissipated and meanwhile facilitates the rubber chain orientation. In light of the unique energy dissipating mechanism, the modulus, ultimate stress, and toughness of the hydrogen bonds and sulfur bonds dual-crosslinked rubber material are improved simultaneously without sacrificing the stretchability, and these properties can be easily manipulated by varying the grafting ratio of urazoles.

Biomimetic Multi-Interface Design of Raspberry-like Absorbent: Gd-doped FeNi3@Covalent Organic Framework Derivatives for Efficient Electromagnetic Attenuation.

Structural design and interface regulation are useful strategies for achieving strong electromagnetic wave absorption (EMWA) and broad effective absorption bandwidth (EAB). Herein, a monomer-mediated strategy is employed to control the growth of covalent organic framework (COF) wrapping flower-shaped Gd-doped FeNi3 (GFN), and a novel raspberry-like absorbent based on biomimetic design is fabricated by thermal catalysis. Further, a unique dielectric-magnetic synergistic system is constructed by utilizing the COF-derived nitrogen-doped porous carbon (NPC) as the shell and anisotropic GFN as the core. The electromagnetic parameters of the GFN@NPC composites can be tuned by adjusting the proportions of GFN and NPC. Off-axis electron holography results further clarify the interface polarization and microscale magnetic interactions affecting the EMW loss mechanism. As a result, the GFN@NPC samples exhibit broad EMWA performance. The EAB values of all GFN@NPC composites reach up to 6.0 GHz, with the GFN@NPC-2 sample showing a minimum reflection loss (RLmin) of -69.6 dB at 1.68 mm. In addition, GFN@NPC-2 achieves a maximum radar cross-section (RCS) reduction of 29.75 dB·m2. A multi-layer gradient structure is also constructed using metamaterial simulation to achieve an ultra-wide EAB of 12.24 GHz. Overall, this work provides a novel bio-inspired design strategy to develop high-performance EMWA materials.

Incorporating Single-Copper Sites and Host Defense Peptides into a Nanoreactor for Antibacterial Therapy by Bioinspired Design

A sustainable solution to the dramatic spread of antibiotic resistance threatening public health security is the development of antibiotic-free antimicrobial substances. Inspired by natural host defense mechanisms involving amino-terminal copper−nickel binding motif (ATCUN) antimicrobial peptides (AMPs), we have designed and prepared an artificial complex (Cu@G-AMPs) incorporating single-atom Cu catalysts for antibacterial therapy. The substrate of the complex, formed from guanine doped with abundant heteroatoms, anchored single Cu atoms with a coordination number of 2 and an average bond length of 1.91Å. Interestingly, Cu@G-AMPs, exhibiting Fenton-like catalytic activity, caused the inactivation of methicillin-resistant Staphylococcus aureus (MRSA) by generating and delivering reactive oxygen species (ROS) cargo. Mechanistically, the intrinsic stress response system of MRSA underwent an irreversible collapse when Cu@G-AMPs initiated its offensive program associated with non-specific targets. Furthermore, Cu@G-AMPs, which inherited the immunomodulatory properties of AMPs, sequentially carried out the functions of pulling edge closure, stabilizing granulation tissue, promoting collagen fiber proliferation, alleviating inflammation, and promoting neovascularization in wound areas infected by MRSA. Our results show that Cu@G-AMPs will provide a new perspective on untangling the complex regulatory networks that resistant bacteria have cultivated to deactivate commercial antibiotics.

Sawtooth-shaped microsaws for enhanced transdermal drug delivery: Improved drug loading and piercing efficiency

This study presents a novel approach to transdermal drug delivery with the introduction of sawtooth-shaped MicroSaws (MSs), a bioinspired microneedle design that significantly enhances drug loading and piercing efficiency. Unlike traditional microneedles (MNs), MSs, with dimensions of 0.2 mm width, 0.4 mm length, and 0.65 mm height, are engineered using epoxy acrylate (EA) via digital light processing (DLP) 3D printing and coated with polyethylene glycol diacrylate (PEGDA) to ensure biocompatibility. Experimental results demonstrate that MSs outperform conventional MNs in both mechanical piercing tests and drug release studies, showcasing a 30 % increase in drug loading capacity and a 25 % improvement in pierceability. The unique sawtooth design not only facilitates deeper penetration but also creates microchannels that enhance drug diffusion across the stratum corneum. This innovation in microneedle technology holds significant promise for improving patient compliance and therapeutic outcomes in transdermal drug delivery systems.

A Spring Model for Pullout Behavior of Curved, Flexible Structures Embedded in Soil

ABSTRACTThe shape and flexibility of embedded structures, such as tree roots, piles, and anchors, have important impacts on the pullout behavior. However, the rate and manner of mobilization of soil resistances along such structures has not been rigorously explored across a wide range of shapes and structural properties. A spring model for computing compatible displacements of the structure and soil for curved, flexible structures is defined, validated against commonly used methods for computing pile pullout behavior, and then parametrically explored to demonstrate how resistances are mobilized along the length of such structures. The present model allows description of combined axial and transverse loading of these nonlinear structures. The simulation results for the case of normally consolidated clay show that the curvature of a structure causes the distribution of bearing resistance to extend further along the structure than for linear cases. The requirement of equilibrium of the structure produces a coupling between the mobilized bearing and tensile resistance in terms of rate of development and magnitude. Thus, the choices of structure shape impact the magnitude and distribution of mobilized resistance of embedded flexible structures. Implications for anchorage of tree root structures and principles of bioinspired design of anchorage systems are discussed.

A Biodegradable, Porous Flier Inspired by a Parachute-Like Tragopogon Fruit for Environmental Preservation.

New devices inspired by flying seeds, or more technically by fruits with dispersal units, could have a significant impact for environmental monitoring and aerial seeding. Among the various types of dispersal units (e.g., winged, gliding), parachuted or plumed units offer the lowest vertical descent speed (i.e., 0.3-0.7 ms-1), making them an appealing solution for wind-driven distribution over large areas. Here, a biodegradable and porous parachute flier based on cellulose acetate, inspired by a Tragopogon pratensis fruit is presented. A micrometric-thick pappus is 3D printed and integrated with a porous colorimetric indicator or a porous beak, with micrometric pores, fabricated through injection molding and leaching techniques. Thanks to the bioinspired design and the lightweight porous structure, the artificial Tragopogon mimics the aerodynamics and descent speed of the natural species. Its feasibility is demonstrated in aerial seeding by integrating the beak with a mustard seed (as a model), and in environmental monitoring by coupling it with colorimetric indicators for rain pH and nitrate levels in soils. The proposed flier represents a significant advancement as it is the first parachute-like biodegradable solution, seamlessly integrated into natural ecosystems, thus contributing to moving a step forward in artificial solutions with zero impact.

90-degree peeling of elastic thin films from elastic soft substrates: Theoretical solutions and experimental verification

Peeling of thin films has been widely used in adhesion measurement, film transfer and bio-inspired design. Most previous studies focused on the peeling of thin films from rigid substrates, but soft substrates are common in practical applications. Herein, we propose a two-dimensional model based on the bilinear cohesive law to characterize the 90-degree peeling of elastic thin films from elastic soft substrates, and obtain theoretical solutions expressed in terms of the Chebyshev series. The theoretical solutions match well with the finite element method results, including the load-displacement curves and the bulging deformation of soft substrates. We find that with decreasing substrate modulus, the maximum peeling force (Pmax) decreases but the steady-state peeling force remains unchanged. With the present solutions, the interfacial strength and fracture energy can be extracted simultaneously from the 90-degree peeling experiments of thin film/soft substrate systems, and then the experimentally measured Pmax for different film thicknesses can be well predicted. Furthermore, we obtain a new power scaling law of Pmax, where the scaling exponent depends on substrate elasticity. These results can help us measure the interfacial properties of thin film/soft substrate systems via peel tests, and regulate their peeling behaviors by interface design.

Natural Selection on Hydroxyapatite Fiber Orientations for Resisting Damage of Enamel

Teeth have excellent mechanical properties, with high wear resistance and excellent fracture resistance. This is due to their well-organized multilevel hierarchical structure. While a number of studies in the last decades have revealed the relationship between tooth structure and mechanical properties, there is still no general agreement on how different orientations of hydroxyapatite (HAp) fibers affect the mechanical properties of enamel. With a scanning electron microscope and nanoindenter, the orientations of HAp fibers and their properties were investigated. HAp fibers have two different orientations: parallel and perpendicular to the surface. Fibers oriented parallel to the surface exhibited higher hardness, elastic modulus and wear resistance. Under applied force, fibers oriented perpendicular to the surface suffered deeper shearing in the protein along the long axis, resulting in lower mechanical properties. Teeth resist damaging fractures by combining hard and soft structures. This study may lead to new insights into how nature selects for tooth structure and provide a theoretical basis for the bioinspired design.