During biological evolution, numerous organisms have developed hair-like attachment structures to achieve stable adhesion on diverse surfaces. This has inspired researchers to explore biomimetic adhesive microstructures, wherein mushroom-shaped structures have received extensive attention, while spatula-shaped ones better suited for adhesion on rough surfaces have received comparatively less. Here, we present two bio-inspired adhesive prototypes, both featuring an inclined seta and spatulate tip. One prototype incorporates a variable cross-section cylinder with a leaflike thin plate, while the other comprises a uniform cross-section square column and a wedge thick plate, exhibiting geometric transition at the seta-tip joint. Finite element analysis is utilized to investigate the adhesive contact behaviours of these prototypes under vertical displacement on surfaces with varying roughness, specifically asperity radii of 30 nm, 1 μm and infinity (flat surface). The results reveal that compared to the surface with a 30 nm radius asperity, the spatula could adapt relatively well to the single asperity with a 1 μm radius due to such asymmetric structures, which also lead to a leverage phenomenon that will compete with adhesive forces and encourage the contact surfaces to separate. Although the thicker spatula tip exhibits poor flexibility, resulting in reduced effective contact area and adhesion, it may allow the regulation of attachment under unidirectional loading. This study contributes novel insights into the contact behaviour of spatula-shaped adhesive structures and provides valuable inspiration for the future development of artificial adhesives.

Introduction: The three-period minimal surface (TPMS) structure has great potential in the fields of lightweight and energy absorption due to its high strength, high porosity, and self-supporting characteristics. However, previous studies have predominantly focused on aspects such as wall thickness, unit cell size, periodicity, and level set values. The impact of amplitude factors on the topological shape and mechanical properties of TPMS structures has not been fully elucidated.

Methods: Inspired by the amplitude characteristics of cuttlefish bone structure, this paper proposes a design method of TPMS structures with variable amplitude. Firstly, taking the classical Primitive, Gyroid, and Diamond structures as the research objects, the influence of amplitude on the topological morphology and relative density of TPMS structures was analyzed using the parametric method. Subsequently, the quasi-static compressive mechanical properties and energy absorption capacity of the Gyroid structure were studied through experiments and numerical simulations.

Results: The change in the amplitude led to a significant change in the topological morphology of the structure, but the maximum relative density of the structure only changed by 1.5 %. The deformation modes of Gyroid structures of different amplitudes were identical, but as amplitude increased, mechanical properties and energy absorption capacity such as elastic modulus, yield strength and specific energy absorption increased.

Conclusions：The results indicated that the amplitude change has little effect on the relative density and deformation mode of the TPMS structure, but it can significantly regulate the mechanical properties of the structure on a large scale. With an increase in the amplitude factor, the densification strain of the structure slightly decreased, while the energy absorption capacity increased significantly. The research content can guide the design for the development of tissue scaffolds or energy-absorbing devices.

Over the past few years, interest in wearable exoskeleton gloves has grown. These tools can be used to help those who are healthy or to support those who have neurological and musculoskeletal conditions like stroke, spinal cord injury, etc. The hand, which is the human body's most flexible limb, encounters more difficult problems and recovers considerably more slowly than the lower and upper limbs. In light of these difficulties, a novel therapy called exoskeleton-based rehabilitation has gained increased significance. In this work, we concentrate on creating a wearable exoskeleton glove that is inexpensive to improve the user's grasping abilities. The tool significantly raises the user's gripping capacity, which raises their quality of life. The exoskeleton glove is designed to assist human hands with limited mobility during the motion rehabilitation process and to improve the grasping and dexterous manipulation capabilities of the hands of both impaired and able-bodied individuals. The proposed model consists of two types of systems, mainly the tendon driven system and the pneumatic system. The tendon-driven system is the system that helps in the flexion and extension movements of the hand. The efficiency of the exoskeleton glove is evaluated by performing the basic movements of hand like abduction, adduction, flexion, and extension. The developed hybrid exoskeleton glove can efficiently enhance the grasping capabilities of its users, offering, affordable, lightweight and easy-to-operate solutions that can assist in the execution of activities of daily living (ADL).

Introduction

One major challenge for electronic skin (e-skin) is the need for soft and stretchable electronic materials, as conventional materials present limited functionality, low surface adhesion, and relatively high power consumption. The development of skin-like hydrogel devices introduces additional challenges, such as low ambient stability, because of their sensitivity to environmental conditions. Research and development are making progress in addressing these challenges, and there have been notable advancements in the field of biomimetic hydrogel-based e-skin. Innovations in this area have the potential to pay off. Organizations that invest in and develop innovative e-skin technologies based on biomimetic hydrogels can secure intellectual property rights through patents. In this regard, this work is dedicated to reviewing the state-of-the-art by presenting what has been patented in regards to biomimetic hydrogel-based e-skin.

Methods

Different patent databases were employed, utilizing diverse sets of keywords and associated terms. Searches were carried out based on patent titles, abstracts, and claims to ensure the comprehensive coverage and retrieval of relevant information. The search was then filtered regarding publication year, jurisdiction, and patent classifications.

Results

The inception of biomimetic hydrogel-based e-skin patenting can be precisely traced back to the earliest priority date, pinpointing 1988 as the commencement year. Notably, the zenith of patent document activity occurred in 2013 and 2021. Analysis reveals that the United States and China stand out as the most prolific nations in patenting biomimetic hydrogel-based e-skin. The majority of inventions pertaining to biomimetic hydrogel-based e-skin, specifically designed for hydrogels or hydrocolloids for use in prostheses or as coating chemical sensors, are distinguished by their functional attributes and physical properties.

Conclusions

This work, which offers a competitive analysis spanning trends in biomimetic hydrogel-based e-skin, provides several recommendations aimed at guiding the formulation of innovative research strategies.

Insects optimize friction in their joints by combining microstructures with a—so far unknown—lubricant. To develop environmentally friendly lubricants, we research the sophisticated tribological system found in the joints of beetles. We characterize the lubricant as well as the microstructure of the joints to gain inspiration for the development of a degradable and—hopefully—superior alternative to mineral-oil-based lubricants. However, restrained by the tiny quantities of beetle lubricant and the compactness of their joints, this tribological analysis is challenging. Therefore, we apply atomic force microscopy (AFM) to record the joints' microstructures and the lubricant's frictional properties. Furthermore, we research the inner structure of the bearing surface in beetle joints by focused ion beam (FIB) tomography. With this approach, we discover a network of channels supplying the lubricant to pores which represent the inlets of the hinged joint system. As a subsequent step, we analyze different types of presently available plant mucilage using AFM friction measurements to compare the suitability of plant mucilage as an alternative lubricant to the tiny quantities of beetle lubricant. Finally, we develop an artificial surface mimicking the microstructure of beetle joints. We determine its frictional properties utilizing colloidal AFM probes in the dry state as well as the lubricated state with plant mucilage as the lubricant.

Introduction: To develop an active drug into a suitable dosage form, pharmaceutical scientists combine various excipients (additives) obtained from different sources. Considering the trends of advancements in the field of biomimetics, we hypothesize that biomaterials contained in different plant parts have inherent biological properties that can mimic what is desired of a drug excipient. In this project, the researchers seek to explore a range of plant-derived constituents and analyze them towards optimizing their use as pharmaceutical excipients in dosage form development.

Method: A range of desired pharmaceutical product qualities was selected to be the focus of the study. Following this, a comprehensive literature survey is being carried out to identify plant and herb parts with documented records of possessing these desired traits in their composition and biological activity. The availability of these plant parts in Africa was also considered. The identified plant parts will be collected, after which the constituents of interest will be extracted from them. These constituents will be characterized and optimized for the prospects of enhancing pharmaceutical formulations, leveraging their natural pathways of activity.

Results: The following dosage form properties have been identified as the primary considerations in this study: bioadhesion/mucoadhesion, disintegration, solubilization, binding, thickening, and taste enhancement. A literature survey is ongoing to determine what plants elicit these properties in their natural life cycles. The outcome of this literature exploration will guide the plant procurement and extraction phases.

Conclusion: Driven by the possibility of having plant constituents replicate their biological characteristics upon incorporation in pharmaceutical dosage forms, this study expects to generate usable biomimetic-derived drug excipients in a bid to make final pharmaceutical products more affordable and therapeutically effective.

Utilizing green nanomaterials in a biomimetic setting to treat wastewater emulates the sustainability and efficiency of natural systems. In this study, wood apple (WA) outer shell extract was used as a reducing and stabilizing agent in a simple, inexpensive, and environmentally friendly green approach to synthesize Ag nanoparticles (NPs), ZnO NPs, and Ag@ZnO nanocomposites (NCs) as potential photocatalysts for the degradation of an industrial dye known as Brilliant Blue (BB). Synthesis parameters of Ag NPs, ZnO NPs, and Ag@ZnO NCs were evaluated in this research utilizing various analytical methods. Surface plasmon resonance peaks for Ag NPs, ZnO NPs, and Ag@ZnO NCs were observed at 400–470 nm, 320–370 nm, and 400–500 nm, respectively. The appearance of a Fourier transform infrared band in the 500–700 cm^-1 region is attributed to the Zn-O bond stretching mode, indicating the formation of ZnO NPs and Ag@ZnO NCs. The SEM images of WA-mediated Ag NPs, ZnO NPs, and Ag@ZnO NCs illustrate spherical, flake, and flower-shapes, respectively, while the average sizes of these three types of particles are determined to be 15.04 ± 5.40 nm, 82.40 ± 3.24 nm, and 12.08 ± 2.91 nm, respectively, as per transmission electron microscopic investigation. Moreover, X-ray diffraction patterns confirm the synthesis of pure crystalline structures, with a face-centered cubic structure for Ag and a hexagonal wurtzite structure for ZnO NPs during the synthesis of Ag@ZnO NCs. The biogenic WA-mediated ZnO NPs show a remarkable photodegradation efficiency of 65.8% under the optimum conditions of catalytic load, pH, and dye concentration, whereas WA-mediated Ag NPs and Ag@ZnO NC show 13.9% and 63.7% photodegradation efficiency, respectively, at 240 min. The study reveals that WA-mediated ZnO NPs and Ag@ZnO NCs exhibit nearly identical photo-catalytic activity against the BB dye, presenting new opportunities for sustainable use in textile and wastewater treatment.

The horizontal axis wind turbine is prone to flow separation during operation, which can affect the flow characteristics of the wind turbine and lead to performance degradation. As one of the methods of passive control, the leading-edge protuberances of the humpback whale have been proven to suppress flow separation and enhance performance. This study employs biomimetic principles to investigate the flow control mechanism by adding bionic leading-edge protuberances to wind turbine blades. The three parameters (amplitude, attenuation and number) that control the protuberances are nonlinear and non-uniform. The influence of leading-edge protuberances on the aerodynamic performance of a wind turbine is analyzed via the computational fluid dynamics method. The results indicate that the addition of protuberances can improve airfoil performance, increase the low-pressure area, and delay flow separation. For the single leading-edge protuberance, the pressure coefficient of the peak section decreases, and the pressure coefficient of the trough section on both sides increases. In this research, the bionic protuberance parametric structure applied to the blade leading-edge of the horizontal axis wind turbine proposed is a supplement to the existing bionic design method, which provides new research data for improving the design of wind turbine blades by using biomimetic principles. In addition, it holds practical value for guiding practical applications.

Introduction. The development of new strategies to repair large segmental bone defects is currently an ongoing challenge all around the world, and biomaterials suitable for dealing with this are in high demand. An important aim in this field is to achieve simultaneously both the mechanical and biological requirements of the implant site.

Methodology. In this study, we propose obtaining a bioinspired bone tissue substitute using the stiff and modulable mycelium of Ganoderma sessile. The mycelium was cultured on a substrate composed of alginate crosslinked by hydroxyapatite nanoparticles (ALG-HAn), with in vitro osteogenic properties previously verified by the authors. Then, the mycelium was inactivated and sterilized by autoclaving to obtain the final biomaterial.

Results. Using scanning electron microscopy (SEM), it was possible to confirm that the mycelium acts as a directing agent of the biomaterial microstructure. The mycelium colonized the ALG-HAn substrate, leading to the formation of a trabecular bone-like network with a hierarchical structure. Moreover, static water contact angle assays demonstrated that the presence of ALG in the membranes significantly reduced the hydrophobicity of the biomaterials. Finally, to test the interaction between blood cells and biomaterial, we verify the lack of hemolysis in human plasma samples.

Conclusion. The promising results of this work will provide a new perspective for the future development of mycelium-based biomaterials applied for bone tissue regeneration.

Introduction

Wetting affects chemical and physical properties. In aluminum, superhydrophobic surfaces keep fog, ice, and corrosion at bay. Biomimicry replicates natural processes. The high surface energy of aluminum limits its intrinsic dewetting properties. Existing surface modification methods have disadvantages, such as hazardous chemicals, high costs, and harsh processing conditions. This work is environmentally friendly and overcomes traditional limitations.

Methods

Aluminum alloy plates (AA5083) of commercial grade (ASTM-B-209M) were used in the study. Stationary friction stir processing (sFSP) was carried out on a universal milling machine focused solely on surface characteristics using transition metal powders (99% purity). The prepared samples were polished with abrasive papers to 1000 grit after processing. In the microwave hot water treatment (mHWT), processed and unprocessed samples were processed for 10 min at 800 W. A silanization agent was vapor-deposited on the samples following mHWT at 55°C for 60 minutes.

Results

The low-strain-rate sFSP of aluminum alloys results in substantial grain refinement, reaching ~1 µm for processed samples and ~ 30 µm for unprocessed samples. Refined grains have a dense and networked nanostructure after mHWT. After silanization, the samples exhibit excellent contact angles (>155°), low tilt angles (<10°), and low contact angle hysteresis (<5°). The processed samples, featuring highly refined grains, demonstrate low water adhesion (~16 µN) compared to unprocessed samples (~50 μN), attributed to the high interfacial energy of the Cassie state, effectively entrapping air. These processed samples exhibit remarkable de-wetting properties and mechanical resilience, owing to the strong negative capillary pressure (>1100 kPa) generated by highly dense networked nanostructures.

Conclusions

In conclusion, the research helps to develop sustainable and durable superhydrophobic aluminum surfaces. The environmentally friendly and cost-effective strategies explored have far-reaching implications for industrial applications, emphasizing opportunities for advancements and practical utilization across various industries.