Biomimetic Design Strategy Research Articles

Bioinspired Bouligand-Structured Cellulose Nanocrystals/Poly(vinyl alcohol) Composite Hydrogel for Enhanced Impact Resistance.

Impact-protective materials are gaining importance because of the widespread occurrence of impact damage. Hydrogels have emerged as promising candidates owing to their lightweight and flexible nature. However, achieving soft impact-resistant hydrogels with exceptional stiffness, strength, and toughness remains a challenge. Inspired by the Bouligand structure found in the smasher dactyl club of stomatopods, we propose a straightforward multiscale hierarchical structural design strategy. This strategy integrates self-assembly and salting-out techniques to enhance the impact resistance of soft hydrogels. Rigid cellulose nanocrystals (CNCs) self-assemble into Bouligand-like structures within soft poly(vinyl alcohol) (PVA) matrix via supramolecular interactions. This rational structural design combines the CNC Bouligand structure with a cross-linked network of soft PVA crystalline domains, resulting in a composite hydrogel with impressive mechanical properties: high tensile fracture strength (30.2 MPa), elastic modulus (62.7 MPa), and fracture energy (75.6 kJ m-2), surpassing those of other tough hydrogels. Moreover, the multiscale hierarchical structure facilitates various energy dissipation mechanisms, including crack twisting, tortuous crack paths, and PVA chain orientation, resulting in notable force attenuation (80.4%) in the composite hydrogel. This biomimetic design strategy opens new avenues for developing soft and lightweight impact-resistant materials.

Advanced biomimetic design strategies for porous structures promoting bone integration with additive-manufactured Ti6Al4V scaffolds

The natural bone structure exhibits a radial gradient with dense cortical bone externally and porous cancellous bone internally. However, previous studies proposing scaffold designs have predominantly focused on homogeneous porous structures. Moreover, no consensus exists on the optimal structure for gradient porous scaffolds. Our scaffold closely imitated the natural bone structure by incorporating a gradient of pillar diameters. Additionally, we introduced a inverse gradient structure and three uniform diameter pillar structures (400 μm, 600 μm, and 1000 μm) for comparative analysis. Mechanical testing revealed that the compressive strength and elastic modulus of the Ti6Al4V porous scaffolds gradually increased with an increase in pillar diameter. In vitro experiments demonstrated that both the biomimetic gradient and inverse gradient scaffolds promoted osteogenic differentiation, with higher ALP activity (alkaline phosphatase) and osteogenesis-related gene expression compared to the uniform pillar structure scaffolds. The in vivo experiments confirmed these results, highlighting the superior ability of the biomimetic gradient Ti6Al4V porous scaffold to induce new bone formation. Based on our findings, we suggest that the optimal porous structure should have fine-diameter pillars (approximately 400 μm) internally to enhance cell penetration, while coarse-diameter pillars (approximately 800 μm) should be used externally to increase the cell attachment area and enhance mechanical strength. Overall, our study contributes to the field of bone tissue engineering by providing a biomimetic scaffold design that closely imitates the structure of natural bone and promotes osteogenic activity.

Biomimetic Hydrogel Strategies for Cancer Therapy.

Recent developments in biomimetic hydrogel research have expanded the scope of biomedical technologies that can be used to model, diagnose, and treat a wide range of medical conditions. Cancer presents one of the most intractable challenges in this arena due to the surreptitious mechanisms that it employs to evade detection and treatment. In order to address these challenges, biomimetic design principles can be adapted to beat cancer at its own game. Biomimetic design strategies are inspired by natural biological systems and offer promising opportunities for developing life-changing methods to model, detect, diagnose, treat, and cure various types of static and metastatic cancers. In particular, focusing on the cellular and subcellular phenomena that serve as fundamental drivers for the peculiar behavioral traits of cancer can provide rich insights into eradicating cancer in all of its manifestations. This review highlights promising developments in biomimetic nanocomposite hydrogels that contribute to cancer therapies via enhanced drug delivery strategies and modeling cancer mechanobiology phenomena in relation to metastasis and synergistic sensing systems. Creative efforts to amplify biomimetic design research to advance the development of more effective cancer therapies will be discussed in alignment with international collaborative goals to cure cancer.

A dragonfly-wings like self-powered magnetic field sensor with vibration noise restriction function

As the rapid development of the Internet of Things (IoT), the demand for the self-powered sensors and devices has become urgent. In this work, we present a self-powered magnetic field sensor based on a biomimetic dragonfly-wings like magnetoelectric (DWL-ME) laminated cantilever. The two pairs of wings in DWL-ME cantilever operating in anti-phase vibration modal has shown a strong magnetoelectric coupling for converting magnetic field energy into electric energy with an energy harvesting density of as high as 100 µWOe−2cm−3. It also shows a linear response to an alternating magnetic field (HAC) with a high detectability of 2.7 nT at 60 Hz. Compared to traditional cantilever beam ME sensors, its vibration noise is also effectively decreased by more than 30 dB due to the anti-phase vibration modal of two pairs of wings. The proposed biomimetic design strategy has inspirational significance for future sustainable, self-powered intelligent sensor networks.

A Bioinspired Design of Protective Al2O3/Polyurethane Hierarchical Composite Film Through Layer-By-Layer Deposition.

Structural materials such as ceramics, metals, and carbon fiber-reinforced plastics (CFRP) are frequently threatened by large compressive and impact forces. Energy absorption layers, i.e., polyurethane and silicone foams with excellent damping properties, are applied on the surfaces of different substrates to absorb energy. However, the amount of energy dissipation and penetration resistance are limited in commercial polyurethane foams. Herein, a distinctive nacre-like architecture design strategy is proposed by integrating hard porous ceramic frameworks and flexible polyurethane buffers to improve energy absorption and impact resistance. Experimental investigations reveal the bioinspired designs exhibit optimized hardness, strength, and modulus compared to that of polyurethane. Due to the multiscale energy dissipation mechanisms, the resulting normalized absorbed energy (≈8.557MJ m-3) is ≈20 times higher than polyurethane foams under 50% quasi-static compression. The bioinspired composites provide superior protection for structural materials (CFRP, glass, and steel), surpassing polyurethane films under impact loadings. It is shown CFRP coated with the designed materials can withstand more than ten impact loadings (in energy of 10 J) without obvious damage, which otherwise delaminates after a single impact. This biomimetic design strategy holds the potential to offer valuable insights for the development of lightweight, energy-absorbent, and impact-resistant materials.

Biomimetic papilla texture by femtosecond laser for high-strength CFRTP/A6061-T6 FSSW hybrid structures

The lightweight design concept in structural applications has generated interest in hybrid structures of carbon-fiber-reinforced thermoplastics (CFRTP) and metals as attractive structure components. However, these hybrid structures face challenges due to the significant differences in physical and chemical properties between CFRTP and metals, resulting in limited strength and rendering them unsuitable for advanced transportation. To address these limitations, the current research focuses on creating a biomimetic texture on A6061-T6 (6061) surfaces using femtosecond laser to manufacture high-strength hybrid structures, inspired by organismal body surfaces. The CFRTP and 6061 were joined by friction stir spot welding (FSSW). The femtosecond laser treatment produces double-scale roughness on 6061 surfaces and causes carbon to absorb into alumina. These changes in physical and chemical structures enhance the compatibility between 6061 and CFRTP. The biomimetic rough aluminum surface creates effective mechanical interlock at the interface with CFRTP, preventing the initiation and propagation of fracture cracks. The presence of absorbed carbon enhances the Al-O covalency, which influences the bonding behavior at CFRTP/6061 interfaces. The improved compatibility, mechanical interlock, and enhanced bonding behavior synergistically strengthen the joint strength of CFRTP/6061 hybrid structure modified by the biomimetic papilla structure. Current biomimetic design strategy inherits the remarkable natural wisdom and is expected to provide valuable insights for the development and application of CFRTP/metal hybrid structures.

Small-Diameter Blood Vessel Substitutes: Biomimetic Approaches to Improve Patency.

Small-dimeter blood vessels (<6 mm) are required in coronary bypass and peripheral bypass surgery to circumvent blocked arteries. However, they have poor patency rates due to thrombus formation, intimal hyperplasia at the distal anastomosis, and compliance mismatch between the native artery and the graft. This review covers the state-of-the-art technologies for improving graft patency with a focus on reducing compliance mismatch between the prosthesis and the native artery. The focus of this article is on biomimetic design strategies to match the compliance over a wide pressure range.

Nanozymes with biomimetically designed properties for cancer treatment.

Nanozymes, as a type of nanomaterials with enzymatic catalytic activity, have demonstrated tremendous potential in cancer treatment owing to their unique biomedical properties. However, the heterogeneity of tumors and the complex tumor microenvironment pose significant challenges to the in vivo catalytic efficacy of traditional nanozymes. Drawing inspiration from natural enzymes, scientists are now using biomimetic design to build nanozymes from the ground up. This approach aims to replicate the key characteristics of natural enzymes, including active structures, catalytic processes, and the ability to adapt to the tumor environment. This achieves selective optimization of nanozyme catalytic performance and therapeutic effects. This review takes a deep dive into the use of these biomimetically designed nanozymes in cancer treatment. It explores a range of biomimetic design strategies, from structural and process mimicry to advanced functional biomimicry. A significant focus is on tweaking the nanozyme structures to boost their catalytic performance, integrating them into complex enzyme networks similar to those in biological systems, and adjusting functions like altering tumor metabolism, reshaping the tumor environment, and enhancing drug delivery. The review also covers the applications of specially designed nanozymes in pan-cancer treatment, from catalytic therapy to improved traditional methods like chemotherapy, radiotherapy, and sonodynamic therapy, specifically analyzing the anti-tumor mechanisms of different therapeutic combination systems. Through rational design, these biomimetically designed nanozymes not only deepen the understanding of the regulatory mechanisms of nanozyme structure and performance but also adapt profoundly to tumor physiology, optimizing therapeutic effects and paving new pathways for innovative cancer treatment.

Nature-inspired batteries: from biomaterials to biomimetic design strategies

Bio-inspired materials and design serve as a source of inspiration for the design of electrodes, electrolytes, interfaces and devices, inducing flexibility, selective ionic transport, self-healing properties or biodegradability.

Exploración de enfoques sustentables en la Expo de Dubái de 2020: una mezcla de diseños biofílicos y biomímesis

Dubai Expo 2020 provides an international platform for advancing innovation through meticulously curated exhibits with themes such as sustainability and cultural exchange displayed in pavilions dedicated to individual countries. This research study uses biophilic or biomimetic design strategies to assess the sustainability practices employed in a group of pavilions at the Dubai Expo 2020 that employ biophilic and/or biomimetic design strategies. Biophilic philosophy emphasizes nature-based concepts to foster positive relationships between humans and living organisms, whereas biomimicry imitates natural processes/systems for building practices. Incorporating biophilic and/or biomimetic techniques into pavilion design provides visitors with a one-of-a-kind experience while displaying explicit sustainability principles that go beyond the event's existing architectural framework guidelines. The research evaluation process includes architectural structure designs, materials used during production/creation periods, energy efficiency measurements implemented, and sustainable water management plans based on natural ecological systems. It will also evaluate the adherence of each pavilion chosen to genuine sustainability values by analyzing the incorporation of nature-based concepts into its overall design for potential future reference applications. These techniques have significant potential to improve human health, reduce environmental impact, and encourage global resiliency when implemented beyond Dubai Expo 2020. In conclusion, the research aims to inspire sustainable designs well beyond the Dubai Expo 2020 by demonstrating how biophilic or biomimetic practices are crucial facilitators in constructing spaces that maximize human welfare without endangering the environment. It is also a foundational resource for architects and urban planners committed to advancing sustainable architectural practices through future development projects prioritizing human welfare and environmental protection.

3D Printed Voronoi Structures Inspired by Paracentrotus lividus Shells

The present paper investigates the mechanical behavior of a biomimetic Voronoi structure, inspired by the microstructure of the shell of the sea urchin Paracentrotus lividus, with its characteristic topological attributes constituting the technical evaluation stage of a novel biomimetic design strategy. A parametric design algorithm was used as a basis to generate design permutations with gradually increasing rod thickness, node count, and model smoothness, geometric parameters that define a Voronoi structure and increase its relative density as they are enhanced. Physical PLA specimens were manufactured with a fused filament fabrication (FFF) printer and subjected to quasi-static loading. Finite element analysis (FEA) was conducted in order to verify the experimental results. A minor discrepancy between the relative density of the designed and printed models was calculated. The tests revealed that the compressive behavior of the structure consists of an elastic region followed by a smooth plateau region and, finally, by the densification zone. The yield strength, compressive modulus, and plateau stress of the structure are improved as the specific geometric parameters are enhanced. The same trend is observed in the energy absorption capabilities of the structure while a reverse one characterizes the densification strain of the specimens. A second-degree polynomial relation is also identified between the modulus, plateau stress, and energy capacity when plotted against the relative density of the specimens. Distinct Voronoi morphologies can be acquired with similar mechanical characteristics, depending on the design requirements and application. Potential applications include lightweight structural materials and protective gear and accessories.

Limpet radula-inspired triangular groove TBM cutter for hard rock breakage with low specific wear

The development of high-performance cutters that effectively break hard rocks without serious cutter wear is urgently required for tunnel boring machines (TBMs), but remains a key challenge. Herein, inspired by limpet radula, we present a biomimetic design strategy for creating a triangular groove cutter that exhibits strong hard rock-breaking capability and low specific wear. The bio-inspired triangular grooving on the cutting edge triggers a continuous impact action at the cutter-rock interface that enhances the rock-breaking capability of the cutter but aggravates cutter wear. The impact is negatively related to the grooved-edge length of the cutter, and by regulating the grooved-edge length, the cutter performs hard-rock breaking via a cutter-rock interaction combining rolling and impact and prevent itself from catastrophic wear. Discrete element analysis indicates that the bio-inspired triangular groove cutter induces the intersection of long cracks and the formation of large rock debris on the rock surface. Evidently, our biomimetic design strategy demonstrates great promise for high-performance TBM cutters.

Biomimetic Gradient Bouligand Structure Enhances Impact Resistance of Ceramic-Polymer Composites.

Biological materials relied on multiple synergistic structural design elements typically exhibit excellent comprehensive mechanical properties. Hierarchical incorporation of different biostructural elements into a single artificial material is a promising approach to enhance mechanical properties, but remains challenging. Herein, a biomimetic structural design strategy is proposed by coupling gradient structure with twisted plywood Bouligand structure, attempting to improve the impact resistance of ceramic-polymer composites. Via robocasting and sintering, kaolin ceramic filaments reinforced by coaxially aligned alumina nanoplatelets are arranged into Bouligand structure with a gradual transition in filament spacing along the thickness direction. After the following polymer infiltration, biomimetic ceramic-polymer composites with a gradient Bouligand (GB) structure are eventually fabricated. Experimental investigations reveal that the incorporation of gradient structure into Bouligand structure improves both the peak force and total energy absorption of the obtained ceramic-polymer composites. Computational modeling further suggests the substantial improvement in impact resistance by adopting GB structure, and clarifies the underlying deformation behavior of the biomimetic GB structured composites under impact. This biomimetic design strategy may provide valuable insights for developing lightweight and impact-resistant structural materials in the future.

Engineering Heart Valve Interfaces Using Melt Electrowriting: Biomimetic Design Strategies from Multi-Modal Imaging.

Interfaces within biological tissues not only connect different regions but also contribute to the overall functionality of the tissue. This is especially true in the case of the aortic heart valve. Here, melt electrowriting (MEW) is used to engineer complex, user-defined, interfaces for heart valve scaffolds. First, a multi-modal imaging investigation into the interfacial regions of the valve reveals differences in collagen orientation, density, and recruitment in previously unexplored regions including the commissure and inter-leaflet triangle. Overlapping, suturing, and continuous printing methods for interfacing MEW scaffolds are then investigated for their morphological, tensile, and flexural properties, demonstrating the superior performance of continuous interfaces. G-codes for MEW scaffolds with complex interfaces are designed and generated using a novel software and graphical user interface. Finally, a singular MEW scaffold for the interfacial region of the aortic heart valve is presented incorporating continuous interfaces, gradient porosities, variable layer numbers across regions, and tailored fiber orientations inspired by the collagen distribution and orientation from the multi-modal imaging study. The scaffold exhibits similar yield strain, hysteresis, and relaxation behavior to porcine heart valves. This work demonstrates the ability of a bioinspired approach for MEW scaffold design to address the functional complexity of biological tissues.

Bioinspired inverse enamel-like columnar composites reproducing the mechanical properties and tribological performance of human enamel

The development of high-performance dental materials that mimic human enamel is urgently required for clinical applications, but remains a key challenge. Herein, we present a biomimetic design strategy for creating inverse enamel-like columnar composites that replicate the mechanical properties and tribological performance of the natural enamel. Inverse to the enamel consisting of hard rods and surrounding relatively soft inter-rod, the composites are assembled from a cellular-structured ceramic scaffold and resin columns. This architecture helps to avoid dramatic stiffness and hardness decreases due to the presence of flexible substances and provides an elegant combination of mechanical properties that strikingly resemble that of natural enamel. Consequently, the inverse enamel-like columnar composites have encouraging tribological performance characterized by an enamel-matched coefficient of friction and wear rate, as well as low abrasive potential to opposing natural teeth, demonstrating great promise for next-generation dental restorations/replacements and other applications. More importantly, the proposed design strategy can be extended to other biological prototypes, thus facilitating the development of various high-performance functional materials.

Recent progress of bioinspired cartilage hydrogel lubrication materials

AbstractHydrogels have been considered as potential candidates for cartilage replacement due to their high‐water content, extreme network hydration, excellent biocompatibility and tunable mechanical properties. Currently, the development of high‐performance cartilage‐inspired hydrogel lubrication materials has become a hot topic in the field of biomedical materials. This review focusses on the recent development of cartilage‐inspired high‐strength hydrogels from the viewpoints of bionic surface/interface and biotribology. Specifically, the composition structure and extraordinary lubrication mechanism of the natural articular cartilage are overviewed first. Subsequently, some of the novel biomimetic design strategies for preparing high strength cartilage hydrogels with various network structures are summarised in detail, while systematic evaluation of lubrication properties and mechanisms are discussed. Furthermore, new surface modification means for improving the lubrication feature of high strength cartilage hydrogel materials are presented. In addition, in order to demonstrate the application potential of cartilage hydrogels in clinical, several bonding methods to decorate hydrogels onto surfaces of natural bone tissues or artificial joint materials are introduced. Finally, current challenges and future research directions are discussed for cartilage‐inspired hydrogel lubrication materials.

The Synergy of Biomimetic Design Strategies for Tissue Constructs

AbstractThe regeneration and repair of complex structures, interfaces, and mechanical properties present in natural tissues remains a challenge. To move beyond simplified tissue engineered constructs, nature is a source of inspiration for complex, hierarchical scaffold designs. Recent advances in additive manufacturing allow for increasingly complex fabrication of architectures that better mimic the multiscale structure‐function relationship found in natural tissues. In this review, scaffold‐based and scaffold‐free approaches and the synergistic use of fabrication technologies (two things make a third) to produce more biomimetic implants are described. Recent advanced scaffold designs such as auxetic mechanical metamaterials and induced fibrillar alignment are highlighted. Next, the pre‐programmed assembly of spheroids, tissue strands, and other modular building blocks without the need for permanent exogenous scaffold support are discussed. Furthermore, the application of hybridized manufacturing processes to fabricate hierarchical functional constructs is outlined for the osteochondral unit, vascular grafts, and peripheral nerves.

A novel conceptual design of a biomimetic oral implant and its biomechanical effect on the repairment of a large mandibular defect

This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests. The designed implant conceptually mimicked the morphology and elastic modulus of the mandibular bone. Basing on a CT-image-based patient-specific reconstruction of the tumor-excised mandible, the biomechanical effects of the implants with three materials (PEEK/n-HA/CF, PEEK/HA and Ti6Al4V), two surgical conditions (removed and retained muscles), and two postoperative stages (early and late) were fully investigated by a static finite element analysis. Moreover, according to clinical interests (e.g. failure and stability of the implant and rivets), maximum von Mises stresses and strains of the implant and rivets, maximum implant-bone gap in the early postoperative stage, and maximum von Mises stress of the mandible were mainly analyzed. The results showed that the implant composed of Ti6Al4V material was suitable for the current design strategy with respect to the other two PEEK-based materials. Although the implants in the muscle-retained surgical condition had relative greater indices compared to the muscle-removed surgical condition, the index difference between the two conditions was slight. The biomechanical indices indicating the failure and loosening risks of implant and rivets were much reduced in the late postoperative stage with respect to the early postoperative stage due to the osteointegration at the implant-bone interface. Generally, the proposed novel design strategy could be useful to guide the design of the oral implant addressing different implant materials and surgical conditions, and further made proper suggestion to clinicians and patients.

Biomimetic design strategy of complex porous structure based on 3D printing Ti-6Al-4V scaffolds for enhanced osseointegration

Ti6Al4V is extensively utilized as orthopedic implants owing to its outstanding biocompatibility and mechanical qualities. However, because Ti6Al4V has a high strength, it is substantially stiffer than natural bone, resulting in stress shielding. To resolve this issue, an effective way is to construct porous titanium alloy scaffolds with adjustable pore size and porosity, and 3D printing technology may be utilized to build complex bespoke forms that fit our specifications. In this work, 3D-printed porous Ti6Al4V scaffolds with imitation of trabecular structure (ITS) and the corresponding regular structure scaffolds (RS), which have three different average pore size (300/400/500 μm), were prepared by selective laser melting technology. A series of in vitro and in vivo experiments were used to assess the scaffolds' physiochemical characteristics, as well as their osseointegration capabilities. The findings revealed that the ITS scaffolds were conducive to cell proliferation and osteogenic differentiation. And the in vivo performance was examined through rabbit tibia bone defect model, the results demonstrated that the ITS scaffolds with average pore size of 400 μm showed the ideal osseointegration potential. Therefore 3D-printed titanium scaffolds with imitation of trabecular structure provides a viable bio-inspired structural and functional design method of titanium alloy orthopedic implants.

A novel amelogenesis-inspired hydrogel composite for the remineralization of enamel non-cavitated lesions.

Enamel non-cavitated lesions (NCLs) are subsurface enamel porosity from carious demineralization. The developed enamel cannot repair itself once NCLs occurs. The regeneration of mineral crystals in a biomimetic environment is an effective way to repair enamel subsurface defects. Previously, an amelogenin-derived peptide named QP5 was proven to repair demineralized enamel. In this work, inspired by amelogenesis, a novel biomimetic hydrogel composite containing the QP5 peptide and bioactive glass (BG) was designed, in which QP5 could promote enamel remineralization by guiding the calcium and phosphorus ions provided by BG. Also, BG could adjust the mineralization micro-environment to alkalinity, simulating the pH regulation of ameloblasts during enamel maturity. The BQ hydrogel composite showed biosafety and possessed capacity for enamel binding, ion release and pH buffering. Enamel NCLs treated with the BQ hydrogel composite showed a higher reduction in lesion depth and mineral loss both in vitro and in vivo. Moreover, compared to the hydrogels containing only BG or QP5, groups treated with the BQ hydrogel composite attained more surface microhardness recovery and color recovery, exhibiting resistance to erosion and abrasion of the remineralization layer. We envision that the BQ hydrogel composite can provide a biomimetic micro-environment to favor enamel remineralization, thus reducing the lesion depth and increasing the mineral content as a promising biomimetic material for enamel NCLs.