Biomimetics

17 pages, 7638 KiB

Open AccessReview

Supramolecular Adhesives Inspired by Nature: Concept and Applications

by Abhishek Baral and Kingshuk Basu

Biomimetics 2025, 10(2), 87; https://doi.org/10.3390/biomimetics10020087 (registering DOI) - 1 Feb 2025

Supramolecular chemistry, a relatively newly grown field, has emerged as a useful tool to fabricate novel smart materials with multiple uses. Adhesives find numerous uses, from heavy engineering to biomedical science. Adhesives are available in nature; inspired by them and their mechanism of [...] Read more.

Supramolecular chemistry, a relatively newly grown field, has emerged as a useful tool to fabricate novel smart materials with multiple uses. Adhesives find numerous uses, from heavy engineering to biomedical science. Adhesives are available in nature; inspired by them and their mechanism of adhesion, several supramolecular adhesives have been developed. In this review, supramolecular chemistry for the design and fabrication of novel adhesives is discussed. The discussion is divided into two segments. The first one deals with key supramolecular forces, and their implication is designing novel adhesives. In the second part, key applications of supramolecular adhesives have been discussed with suitable examples. This type of review casts light on the current advancements in the field along with the prospects of development. Full article

(This article belongs to the Special Issue Adhesives Inspired by Nature: When Bionics Boost Adhesive Innovation)

21 pages, 4386 KiB

Open AccessArticle

Challenging the Biomimetic Promise—Do Laypersons Perceive Biomimetic Buildings as More Sustainable and More Acceptable?

by Michael Gorki, Olga Speck, Martin Möller, Julius Fenn, Louisa Estadieu, Achim Menges, Mareike Schiller, Thomas Speck and Andrea Kiesel

Biomimetics 2025, 10(2), 86; https://doi.org/10.3390/biomimetics10020086 (registering DOI) - 1 Feb 2025

Abstract

This study investigates whether or not laypersons perceive biomimetic buildings as more sustainable and acceptable, a notion termed the “biomimetic promise”. Employing an experimental design (N = 238), we examined assessments of three real-world biomimetic buildings at the University of Freiburg, namely [...] Read more.

This study investigates whether or not laypersons perceive biomimetic buildings as more sustainable and acceptable, a notion termed the “biomimetic promise”. Employing an experimental design (N = 238), we examined assessments of three real-world biomimetic buildings at the University of Freiburg, namely the Fiber Pavilion in the Botanic Garden, the ceiling of the former zoology auditorium, and the Biomimetic Shell at the technical faculty. Participants were divided into two groups: one group was informed about the biomimetic nature of the buildings and the other group was not. Results showed no significant difference in perceived sustainability or acceptability between the two groups, favoring the hypothesis that there exists no “biomimetic bias”. Notably, with the exception of perceived sustainability comparing the pavilion and the auditorium, significant differences in assessments regarding sustainability and acceptability were observed between the buildings, emphasizing the importance of domain-specific factors in public judgments. These findings suggest that merely framing a technology as biomimetic does not inherently enhance its perceived sustainability or acceptability by laypersons. Instead, the study highlights the need for transparency and clear communication regarding sustainability benefits to gain societal acceptance of biomimetic technologies. Full article

(This article belongs to the Special Issue Biomimetics—A Chance for Sustainable Developments: 2nd Edition)

25 pages, 4974 KiB

Open AccessArticle

Extraction and Purification of the FrHb1 Fraction from Commercial Natural Latex of Hevea brasiliensis for Biomedical Applications

by Ana Karoline Almeida da Silva, Gustavo Adolfo Marcelino de Almeida Nunes, Rafael Mendes Faria, Ana Luiza Coutinho Favilla, Jéssica Dornelas, Marcos Augusto Mountinho Fonseca, Angie Daniela Ibarra Benavides, Lindemberg Barreto Mota da Costa, Mário Fabrício Fleury Rosa, Adson Ferreira da Rocha and Suelia de Siqueira Rodrigues Fleury Rosa

Biomimetics 2025, 10(2), 85; https://doi.org/10.3390/biomimetics10020085 (registering DOI) - 30 Jan 2025

Abstract

Biomaterials interact with biological systems, influencing their responses. Different types of polymers—both natural and synthetic—are widely used in biomedical engineering, among a plethora of healthcare applications, to promote tissue regeneration. The natural rubber latex extracted from Hevea brasiliensis is a biopolymer that whose [...] Read more.

Biomaterials interact with biological systems, influencing their responses. Different types of polymers—both natural and synthetic—are widely used in biomedical engineering, among a plethora of healthcare applications, to promote tissue regeneration. The natural rubber latex extracted from Hevea brasiliensis is a biopolymer that whose biocompatibility makes it a valuable study object. Its great regenerative properties are largely associated with the fraction FrHB1, which has demonstrated angiogenic and wound-healing potential by inducing blood vessel formation, collagen synthesis, and fibroblast migration—crucial factors for tissue repair. This study aimed to develop scalable methods for extracting and purifying the F1 protein fraction from industrialized natural latex for biomedical applications. We tested two types of industrial latex, bi-centrifuged and pre-vulcanized latex as well as 60% centrifuged natural latex to determine the most effective composition used in subsequent extractions and fractionation steps. Then, we isolated FrHB1 from the pre-vulcanized latex using selective precipitation, ultrafiltration, and affinity chromatography. The yield of the first batch of this serum was 40.62% with protein concentration of 1.52 ± 0.06 mg/mL. The second batch had a yield of 49.74%; however, due to results lying outside the analytical curve, its protein concentration could not be calculated. The yield of the third batch was 57.19%, and its protein concentration was 1.8477 ± 0.033 mg/mL. This approach facilitates large-scale therapeutic applications utilizing a commercially viable and accessible resource. Moreover, these findings highlight industrialized natural latex as a sustainable source of bioactive molecules, contributing to advancements in regenerative medicine and tissue engineering. Full article

(This article belongs to the Special Issue Functional Biomimetic Materials and Devices for Biomedical Applications: 3rd Edition)

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Graphical abstract

19 pages, 2217 KiB

Open AccessArticle

Research on the Range of Stiffness Variation in a 2D Biomimetic Spinal Structure Based on Tensegrity Structures

by Xiaobo Zhang, Zhongcai Pei and Zhiyong Tang

Biomimetics 2025, 10(2), 84; https://doi.org/10.3390/biomimetics10020084 - 29 Jan 2025

Abstract

Abstract: This paper presents a novel variable stiffness mechanism, namely the SBTDTS (Spinal Biomimetic Two-Dimensional Tensegrity Structure), which is constructed by integrating bioinspiration derived from biological spinal structures with the T-Bar mechanical design within tensegrity structures. A method for determining the torsional [...] Read more.

Abstract: This paper presents a novel variable stiffness mechanism, namely the SBTDTS (Spinal Biomimetic Two-Dimensional Tensegrity Structure), which is constructed by integrating bioinspiration derived from biological spinal structures with the T-Bar mechanical design within tensegrity structures. A method for determining the torsional stiffness of the SBTDTS around a virtual rotational center is established based on parallel mechanism theory. The relationship between various structural parameters is analyzed through multiple sets of typical parameter combinations. Ultimately, the PSO (Particle Swarm Optimization) algorithm is employed to identify the optimal combination of structural parameters for maximizing the stiffness ratio, , of SBTDTS under different constraint conditions. This optimal configuration is then compared with the RAPRPM (a type of rotational parallel mechanism) under different values of , with an analysis of the distinct advantages of both variable stiffness structures. Full article

15 pages, 10569 KiB

Open AccessArticle

Prediction and Measurement of Hovering Flapping Frequency Under Simulated Low-Air-Density and Low-Gravity Conditions

by Hyeonjun Lim, Giheon Ha and Hoon Cheol Park

Biomimetics 2025, 10(2), 83; https://doi.org/10.3390/biomimetics10020083 - 29 Jan 2025

Abstract

The ability to predict lift is crucial for enabling flapping flights on planets with varying air densities and gravities. After determining the lift required for a flapping flight on Earth, it can be predicted under different conditions using a scaling equation as a [...] Read more.

The ability to predict lift is crucial for enabling flapping flights on planets with varying air densities and gravities. After determining the lift required for a flapping flight on Earth, it can be predicted under different conditions using a scaling equation as a function of air density and gravity, assuming the cycle-average lift coefficient remains constant. However, in flapping wings, passive deformation due to aerodynamic and inertial forces may alter the flapping-wing kinematics, complicating predictions. In this study, we investigated changes in the lift coefficient of flapping wings under various air density and gravity conditions simulated using a low-pressure chamber and tilting stand, respectively. The current study found that the cycle-averaged lift coefficients remained nearly constant, varying by less than 7% across the air density and gravity conditions. The difference between the measured and predicted hovering frequencies increased under a lower air density due to the higher vibration-induced friction. The power consumption analysis demonstrated higher energy demands in thinner atmospheres and predicted a required power of 5.14 W for a hovering flight on Mars, which is a 66% increase compared to that on Earth. Future experiments will test Martian air density and gravity conditions to enable flapping flights on Mars. Full article

(This article belongs to the Special Issue Bioinspired Flapping Wing Aerodynamics: Progress and Challenges)

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30 pages, 5817 KiB

Open AccessArticle

Design and Development of Natural-Product-Derived Nanoassemblies and Their Interactions with Alpha Synuclein

by Ipsita A. Banerjee, Amrita Das, Mary A. Biggs, Chau Anh N. Phan, Liana R. Cutter and Alexandra R. Ren

Biomimetics 2025, 10(2), 82; https://doi.org/10.3390/biomimetics10020082 - 28 Jan 2025

Abstract

Biomimetic nanoassemblies derived from natural products are considered promising nanomaterials due to their self-assembling ability and their favorable interactions with biological molecules leading to their numerous applications as therapeutic agents or as molecular probes. In this work, we have created peptide nanoconjugates of [...] Read more.

Biomimetic nanoassemblies derived from natural products are considered promising nanomaterials due to their self-assembling ability and their favorable interactions with biological molecules leading to their numerous applications as therapeutic agents or as molecular probes. In this work, we have created peptide nanoconjugates of two natural products, β-Boswellic acid (BA) and β-glycyrrhetinic acid (GH). Both BA and GH are known for their medicinal value, including their role as strong antioxidants, anti-inflammatory, neuroprotective and as anti-tumor agents. To enhance the bioavailability of these molecules, they were functionalized with three short peptides (YYIVS, MPDAHL and GSGGL) to create six conjugates with amphiphilic structures capable of facile self-assembly. The peptides were also derived from natural sources and have been known to display antioxidant activity. Depending upon the conjugate, nanofibers, nanovesicles or a mixture of both were formed upon self-assembly. The binding interactions of the nanoconjugates with α-Synuclein, a protein implicated in Parkinson’s disease (PD) was examined through in silico studies and FTIR, circular dichroism and imaging studies. Our results indicated that the nanoassemblies interacted with alpha-synuclein fibrils efficaciously. Furthermore, the nanoassemblies were found to demonstrate high viability in the presence of microglial cells, and were found to enhance the uptake and interactions of α-Synuclein with microglial cells. The nanoconjugates designed in this work may be potentially utilized as vectors for peptide-based drug delivery or for other therapeutic applications. Full article

(This article belongs to the Special Issue Biomimetic Nanotechnology Vol. 4: Advances in Biomimetic Nanotechnology)

18 pages, 3593 KiB

Open AccessArticle

Lateral Spacing of TiO₂ Nanotube Coatings Modulates In Vivo Early New Bone Formation

by Andreea Mariana Negrescu, Iuliana Ionascu, Madalina Georgiana Necula, Niculae Tudor, Maksim Kamaleev, Otilia Zarnescu, Anca Mazare, Patrik Schmuki and Anisoara Cimpean

Biomimetics 2025, 10(2), 81; https://doi.org/10.3390/biomimetics10020081 - 28 Jan 2025

Abstract

Due to the bio-inert nature of titanium (Ti) and subsequent accompanying chronic inflammatory response, an implant’s stability and function can be significantly affected, which is why various surface modifications have been employed, including the deposition of titanium oxide (TiO₂) nanotubes (TNTs) [...] Read more.

Due to the bio-inert nature of titanium (Ti) and subsequent accompanying chronic inflammatory response, an implant’s stability and function can be significantly affected, which is why various surface modifications have been employed, including the deposition of titanium oxide (TiO₂) nanotubes (TNTs) onto the native surface through the anodic oxidation method. While the influence of nanotube diameter on cell behaviour and osteogenesis is very well documented, information regarding the effects of nanotube lateral spacing on the in vivo new bone formation process is insufficient and hard to find. Considering this, the present study’s aim was to evaluate the mechanical properties and the osteogenic ability of two types of TNTs-based pins with different lateral spacing, e.g., 25 nm (TNTs) and 92 nm (spTNTs). The mechanical properties of the TNT-coated implants were characterised from a morphological point of view (tube diameter, spacing, and tube length) using scanning electron microscopy (SEM). In addition, the chemical composition of the implants was evaluated using X-ray photoelectron spectroscopy, while surface roughness and topography were characterised using atomic force microscopy (AFM). Finally, the implants’ hardness and elastic modulus were investigated using nanoindentation measurements. The in vivo new bone formation was histologically evaluated (haematoxylin and eosin—HE staining) at 6 and 30 days post-implantation in a rat model. Mechanical characterisation revealed that the two morphologies presented a similar chemical composition and mechanical strength, but, in terms of surface roughness, the spTNTs exhibited a higher average roughness. The microscopic examination at 1 month post-implantation revealed that spTNTs pins (57.21 ± 34.93) were capable of promoting early new bone tissue formation to a greater extent than the TNTs-coated implants (24.37 ± 6.5), with a difference in the average thickness of the newly formed bone tissue of ~32.84 µm, thus highlighting the importance of this parameter when designing future dental/orthopaedic implants. Full article

(This article belongs to the Special Issue Biomimetic Coating Technologies and Biomaterials for Medical Applications)

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12 pages, 5835 KiB

Open AccessArticle

Biomechanical Optimization of the Human Bite Using Numerical Analysis Based on the Finite Element Method

by Maribel González-Martín, Paula Hermida-Cabrera, Aida Gutiérrez-Corrales, Eusebio Torres-Carranza, Gonzalo Ruiz-de-León, Berta García-Mira, Álvaro-José Martínez-González, Daniel Torres-Lagares, María-Ángeles Serrera-Figallo, José-Luis Gutiérrez-Pérez and María Baus-Domínguez

Biomimetics 2025, 10(2), 80; https://doi.org/10.3390/biomimetics10020080 - 28 Jan 2025

Abstract

Biomechanical bite analysis is essential for understanding occlusal forces and their distribution, especially in the design and validation of dental prostheses. Although the finite element method (FEM) has been widely used to evaluate these forces, the existing models often lack accuracy due to [...] Read more.

Biomechanical bite analysis is essential for understanding occlusal forces and their distribution, especially in the design and validation of dental prostheses. Although the finite element method (FEM) has been widely used to evaluate these forces, the existing models often lack accuracy due to simplified geometries and limited material properties. Methods: A detailed finite element model was developed using Abaqus Standard 2023 software (Dassault Systemes, Vélizy-Villacoublay, France), incorporating scanned 3D geometries of mandibular and maxillary bones. The model included cortical and cancellous bones (Young’s modulus: 5.5 GPa and 13.7 GPa, respectively) and was adjusted to simulate bite forces of 220.7 N based on experimental data. Occlusal forces were evaluated using flexible connectors that replicate molar-to-molar interactions, and the stress state was analyzed in the maxillary and mandibular bones. Results: The FEM model consisted of 1.68 million elements, with mesh sizes of 1–1.5 mm in critical areas. Bite forces on the molars were consistent with clinical trials: first molar (59.3 N), second molar (34.4 N), and third molar (16.7 N). The results showed that the maximum principal stresses in the maxillary bones did not exceed ±5 MPa, validating the robustness of the model for biomechanical predictions. Conclusion: The developed model provides an accurate and validated framework for analyzing the distribution of occlusal forces in intact dentures. This approach allows the evaluation of complex prosthetic configurations and their biomechanical impact, optimizing future designs to reduce clinical complications and improve long-term outcomes. The integration of high-resolution FEM models with clinical data establishes a solid foundation for the development of predictive tools in restorative dentistry. Full article

(This article belongs to the Special Issue Biomaterials in Bone Regeneration: Challenges to Guarantee Appropriate Biological Features: 2nd Edition)

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19 pages, 1249 KiB

Open AccessArticle

Plantar Pressure-Based Gait Recognition with and Without Carried Object by Convolutional Neural Network-Autoencoder Architecture

by Chin-Cheng Wu, Cheng-Wei Tsai, Fei-En Wu, Chi-Hsuan Chiang and Jin-Chern Chiou

Biomimetics 2025, 10(2), 79; https://doi.org/10.3390/biomimetics10020079 - 26 Jan 2025

Abstract

Convolutional neural networks (CNNs) have been widely and successfully demonstrated for closed set recognition in gait identification, but they still lack robustness in open set recognition for unknown classes. To improve the disadvantage, we proposed a convolutional neural network autoencoder (CNN-AE) architecture for [...] Read more.

Convolutional neural networks (CNNs) have been widely and successfully demonstrated for closed set recognition in gait identification, but they still lack robustness in open set recognition for unknown classes. To improve the disadvantage, we proposed a convolutional neural network autoencoder (CNN-AE) architecture for user classification based on plantar pressure gait recognition. The model extracted gait features using pressure-sensitive mats, focusing on foot pressure distribution and foot size during walking. Preprocessing techniques, including region of interest (ROI) selection, feature image extraction, and data horizontal flipping, were utilized to establish a CNN model that assessed gait recognition accuracy under two conditions: without carried items and carrying a 500 g object. To extend the application of the CNN to open set recognition for unauthorized personnel, the proposed convolutional neural network-autoencoder (CNN-AE) architecture compressed the average foot pressure map into a 64-dimensional feature vector and facilitated identity determination based on the distances between these vectors. Among 60 participants, 48 were classified as authorized individuals and 12 as unauthorized. Under the condition of not carrying an object, an accuracy of 91.218%, precision of 93.676%, recall of 90.369%, and an F1-Score of 91.993% were achieved, indicating that the model successfully identified most actual positives. However, when carrying a 500 g object, the accuracy was 85.648%, precision was 94.459%, recall was 84.423%, and the F1-Score was 89.603%. Full article

(This article belongs to the Special Issue Advances in Brain–Computer Interfaces)

18 pages, 4915 KiB

Open AccessArticle

Development of 4D-Printed Arterial Stents Utilizing Bioinspired Architected Auxetic Materials

by Nikolaos Kladovasilakis, Ioannis Filippos Kyriakidis, Emmanouil K. Tzimtzimis, Eleftheria Maria Pechlivani, Konstantinos Tsongas and Dimitrios Tzetzis

Biomimetics 2025, 10(2), 78; https://doi.org/10.3390/biomimetics10020078 - 26 Jan 2025

Abstract

The convergence of 3D printing and auxetic materials is paving the way for a new era of adaptive structures. Auxetic materials, known for their unique mechanical properties, such as a negative Poisson’s ratio, can be integrated into 3D-printed objects to enable them to [...] Read more.

The convergence of 3D printing and auxetic materials is paving the way for a new era of adaptive structures. Auxetic materials, known for their unique mechanical properties, such as a negative Poisson’s ratio, can be integrated into 3D-printed objects to enable them to morph or deform in a controlled manner, leading to the creation of 4D-printed structures. Since the first introduction of 4D printing, scientific interest has spiked in exploring its potential implementation in a wide range of applications, from deployable structures for space exploration to shape-adaptive biomechanical implants. In this context, the current paper aimed to develop 4D-printed arterial stents utilizing bioinspired architected auxetic materials made from biocompatible and biodegradable polymeric material. Specifically, three different auxetic materials were experimentally examined at different relative densities, under tensile and compression testing, to determine their mechanical behavior. Based on the extracted experimental data, non-linear hyperelastic finite element material models were developed in order to simulate the insertion of the stent into a catheter and its deployment in the aorta. The results demonstrated that among the three examined structures, the ‘square mode 3’ structure revealed the best performance in terms of strength, at the same time offering the necessary compressibility (diameter reduction) to allow insertion into a typical catheter for stent procedures. Full article

(This article belongs to the Section Biomimetics of Materials and Structures)

9 pages, 1320 KiB

Open AccessPerspective

Bioinspired Design and Applications of Liquid Gating Gas Valve Membranes

by Yiyao Li, Yang Liu, Rui Xu, Jing Liu and Xu Hou

Biomimetics 2025, 10(2), 77; https://doi.org/10.3390/biomimetics10020077 - 26 Jan 2025

Abstract

In nature, dynamic liquid interfaces play a vital role in regulating gas transport, as exemplified by the adaptive mechanisms of plant stomata and the liquid-lined alveoli, which enable efficient gas exchange through reversible opening and closing. These biological processes provide profound insights into [...] Read more.

In nature, dynamic liquid interfaces play a vital role in regulating gas transport, as exemplified by the adaptive mechanisms of plant stomata and the liquid-lined alveoli, which enable efficient gas exchange through reversible opening and closing. These biological processes provide profound insights into the design of advanced gas control technologies. Inspired by these natural systems, liquid gating membranes have been developed utilizing capillary-stabilized liquids to achieve precise fluid regulation. These membranes offer unique advantages of rapid responses, stain resistance, and high energy efficiency. Particularly, they break through the limitations of traditional solid, porous membranes in gas transport. This perspective introduces bioinspired liquid gating gas valve membranes (LGVMs), emphasizing their opening/closing mechanism. It highlights how external stimuli can be exploited to enable advanced, multi-level gas control through active or passive regulation strategies. Diverse applications in gas flow regulation and selective gas transport are discussed. While challenges related to precise controllability, long-term stability, and scalable production persist, these advancements unlock significant opportunities for groundbreaking innovations across diverse fields, including gas purification, microfluidics, medical diagnostics, and energy harvesting technologies. Full article

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14 pages, 2760 KiB

Open AccessArticle

Clarity Amidst Ambiguity: Towards Precise Definitions in Biological-Informed Disciplines for Enhanced Communication

by Tim Huber and Jörg Müssig

Biomimetics 2025, 10(2), 76; https://doi.org/10.3390/biomimetics10020076 - 25 Jan 2025

Abstract

This study conducts a meta-analysis of over 1000 abstracts to examine the use and consistency of the terminology in biomimetics, bioinspiration, biomimicry, and bionics, focusing on how these terms impact biological study design. Despite the increasing research in these areas, the ambiguous definitions [...] Read more.

This study conducts a meta-analysis of over 1000 abstracts to examine the use and consistency of the terminology in biomimetics, bioinspiration, biomimicry, and bionics, focusing on how these terms impact biological study design. Despite the increasing research in these areas, the ambiguous definitions of key terms complicate study design and interdisciplinary collaboration. The primary aim of this work is to analyse how biological studies in these fields are conceptualised and evaluated, particularly concerning the inconsistent use of terminology. By identifying discrepancies in term usage, we offer refined definitions and practical examples to improve the clarity of study design and research methodologies. Our findings underscore the importance of standardised terminology for ensuring that biological research is accurately designed and executed, leading to more rigorous experimental frameworks and better alignment across disciplines. This meta-analysis reveals how clearer, more consistent terminology can enhance study design in biologically inspired research fields. Full article

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Graphical abstract

28 pages, 8269 KiB

Open AccessArticle

Mechanics of Bio-Inspired Protective Scales

by Antonio Pantano and Vincenzo Baiamonte

Biomimetics 2025, 10(2), 75; https://doi.org/10.3390/biomimetics10020075 - 25 Jan 2025

Abstract

Natural armors found in animals like fish and armadillos offer inspiration for designing protective systems that balance puncture resistance and flexibility. Although segmented armors have been used historically, modern applications are hindered by a limited understanding of their mechanics. This study addresses these [...] Read more.

Natural armors found in animals like fish and armadillos offer inspiration for designing protective systems that balance puncture resistance and flexibility. Although segmented armors have been used historically, modern applications are hindered by a limited understanding of their mechanics. This study addresses these challenges by presenting two novel bio-inspired scale structures with overlapping and staggered configurations, modeled after the elasmoid designs found in fish. Their shapes differ significantly from other artificial scales commonly described in the literature, which are typically flat. Instead, these scales feature a support that extends vertically from the substrate, transitioning into an inclined surface that serves as the protective component. Finite element method tests evaluated their performance in puncture resistance and flexibility. The results showed that one type of scale provided better puncture resistance, while the other type offered greater flexibility. These findings highlight how small geometric variations can significantly influence the balance between protection and flexibility. The results offer new insights into the mechanisms of natural armor and propose innovative designs for personal protective equipment, such as bulletproof vests, protective gloves, and fireproof systems. The finite element simulations employed to test the protective systems can also serve as valuable tools for the scientific community to assess and refine designs. Full article

(This article belongs to the Special Issue Advances in Biomimetics: Patents from Nature)

30 pages, 1709 KiB

Open AccessReview

Performance Portrait Method: Robust Design of Predictive Integral Controller

by Mikulas Huba, Pavol Bistak, Jarmila Skrinarova and Damir Vrancic

Biomimetics 2025, 10(2), 74; https://doi.org/10.3390/biomimetics10020074 - 25 Jan 2025

Abstract

The performance portrait method (PPM) can be characterized as a systematized digitalized version of the trial and error method—probably the most popular and very often used method of engineering work. Its digitization required the expansion of performance measures used to evaluate the step [...] Read more.

The performance portrait method (PPM) can be characterized as a systematized digitalized version of the trial and error method—probably the most popular and very often used method of engineering work. Its digitization required the expansion of performance measures used to evaluate the step responses of dynamic systems. Based on process modeling, PPM also contributed to the classification of models describing linear and non-linear dynamic processes so that they approximate their dynamics using the smallest possible number of numerical parameters. From most bio-inspired procedures of artificial intelligence and optimization used for the design of automatic controllers, PPM is distinguished by the possibility of repeated application of once generated performance portraits (PPs). These represent information about the process obtained by evaluating the performance of setpoint and disturbance step responses for all relevant values of the determining loop parameters organized into a grid. It can be supported by the implementation of parallel calculations with optimized decomposition in the high-performance computing (HPC) cloud. The wide applicability of PPM ranges from verification of analytically calculated optimal settings achieved by various approaches to controller design, to the analysis as well as optimal and robust setting of controllers for processes where other known control design methods fail. One such situation is illustrated by an example of predictive integrating (PrI) controller design for processes with a dominant time-delayed sensor dynamics, representing a counterpart of proportional-integrating (PI) controllers, the most frequently used solutions in practice. PrI controllers can be considered as a generalization of the disturbance–response feedback—the oldest known method for the design of dead-time compensators by Reswick. In applications with dominant dead-time and loop time constants located in the feedback (sensors), as those, e.g., met in magnetoencephalography (MEG), it makes it possible to significantly improve the control performance. PPM shows that, despite the absence of effective analytical control design methods for such situations, it is possible to obtain high-quality optimal solutions for processes that require working with uncertain models specified by interval parameters, while achieving invariance to changes in uncertain parameters. Full article

(This article belongs to the Section Bioinspired Sensorics, Information Processing and Control)

24 pages, 645 KiB

Open AccessReview

Harnessing Gut Microbiota for Biomimetic Innovations in Health and Biotechnology

by Ana Isabel Beltrán-Velasco and Vicente Javier Clemente-Suárez

Biomimetics 2025, 10(2), 73; https://doi.org/10.3390/biomimetics10020073 - 24 Jan 2025

Abstract

The gut microbiota is a complex and dynamic ecosystem that plays a fundamental role in human health by regulating immunity, metabolism, and the gut–brain axis. Beyond its critical physiological functions, it has emerged as a rich source of inspiration for biomimetic innovations in [...] Read more.

The gut microbiota is a complex and dynamic ecosystem that plays a fundamental role in human health by regulating immunity, metabolism, and the gut–brain axis. Beyond its critical physiological functions, it has emerged as a rich source of inspiration for biomimetic innovations in healthcare and biotechnology. This review explores the transformative potential of microbiota-based biomimetics, focusing on key biological mechanisms such as resilience, self-regulation, and quorum sensing. These mechanisms have inspired the development of innovative applications, including personalized probiotics, synbiotics, artificial microbiomes, bioinspired biosensors, and bioremediation systems. Such technologies aim to emulate and optimize the intricate functions of microbial ecosystems, addressing challenges in healthcare and environmental sustainability. The integration of advanced technologies, such as artificial intelligence, bioengineering, and multi-omics approaches, has further accelerated the potential of microbiota biomimetics. These tools enable the development of precision therapies tailored to individual microbiota profiles, enhance the efficacy of diagnostic systems, and facilitate the design of environmentally sustainable solutions, such as waste-to-energy systems and bioremediation platforms. Emerging areas of innovation, including gut-on-chip models and synthetic biology, offer unprecedented opportunities for studying and applying microbiota principles in controlled environments. Despite these advancements, challenges remain. The replication of microbial complexity in artificial environments, ethical concerns regarding genetically engineered microorganisms, and equitable access to advanced therapies are critical hurdles that must be addressed. This review underscores the importance of interdisciplinary collaboration and public awareness in overcoming these barriers and ensuring the responsible development of microbiota-based solutions. By leveraging the principles of microbial ecosystems, microbiota biomimetics represents a promising frontier in healthcare and sustainability. This approach has the potential to revolutionize therapeutic strategies, redefine diagnostic tools, and address global challenges, paving the way for a more personalized, efficient, and sustainable future in medicine and biotechnology. Full article

(This article belongs to the Special Issue Biomimetic Approaches in Healthcare—Innovations Inspired by Nature: 2nd Edition)

15 pages, 7406 KiB

Open AccessArticle

A Finite Element Study of Simulated Fusion in an L4-L5 Model: Influence of the Combination of Materials in the Screw-and-Rod Fixation System on Reproducing Natural Bone Behavior

by Mario Ceddia, Luciano Lamberti and Bartolomeo Trentadue

Biomimetics 2025, 10(2), 72; https://doi.org/10.3390/biomimetics10020072 - 24 Jan 2025

Abstract

The mechanical properties of materials for spinal fixation can significantly affect spinal surgical outcomes. Traditional materials such as titanium exhibit high stiffness, which can lead to stress shielding and adjacent segment degeneration. This study investigates the biomechanical performance of titanium and PEEK (polyetheretherketone) [...] Read more.

The mechanical properties of materials for spinal fixation can significantly affect spinal surgical outcomes. Traditional materials such as titanium exhibit high stiffness, which can lead to stress shielding and adjacent segment degeneration. This study investigates the biomechanical performance of titanium and PEEK (polyetheretherketone) in spinal fixation using finite element analysis, through the evaluation of the Shielding Strength Factor (SSF). Methods: A three-dimensional finite element analysis (FEA) model of an L4/L5 functional spinal unit was developed to simulate the mechanical behavior of three fixation systems: titanium screws and rods (model A), titanium screws with PEEK rods (model B), and PEEK screws and rods (model C). The analysis evaluated stress distribution and load transfer under physiological conditions, in comparison with the intact spine (baseline model). Results: The analysis showed that titanium fixation systems resulted in higher stress shielding effects, with a significant difference in stress distribution compared to PEEK. The maximum stress recorded in the neutral position was 24.145 MPa for PEEK, indicating better biomechanical compatibility. Conclusions: The results suggest that PEEK may be an attractive alternative to titanium for spinal fixation, promoting more healthy load transfer and minimizing the risk of stress shielding complications. Full article

(This article belongs to the Special Issue Mechanical Properties and Functions of Bionic Materials/Structures)

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19 pages, 2788 KiB

Open AccessReview

Exploring Modeling Techniques for Soft Arms: A Survey on Numerical, Analytical, and Data-Driven Approaches

by Shengkai Liu, Hongfei Yu, Ning Ding, Xuchun He, Hengli Liu and Jun Zhang

Biomimetics 2025, 10(2), 71; https://doi.org/10.3390/biomimetics10020071 - 24 Jan 2025

Abstract

Soft arms, characterized by their compliance and adaptability, have gained significant attention in applications ranging from industrial automation to biomedical fields. Modeling these systems presents unique challenges due to their high degrees of freedom, nonlinear behavior, and complex material properties. This review provides [...] Read more.

Soft arms, characterized by their compliance and adaptability, have gained significant attention in applications ranging from industrial automation to biomedical fields. Modeling these systems presents unique challenges due to their high degrees of freedom, nonlinear behavior, and complex material properties. This review provides a comprehensive overview of three primary modeling approaches: numerical methods, analytical techniques, and data-driven models. Numerical methods, including finite element analysis and multi-body dynamics, offer precise but computationally expensive solutions for simulating soft arm behaviors. Analytical models, rooted in continuum mechanics and simplified assumptions, provide insights into the fundamental principles while balancing computational efficiency. Data-driven approaches, leveraging machine learning and artificial intelligence, open new avenues for adaptive and real-time modeling by bypassing explicit physical formulations. The strengths, limitations, and application scenarios of each approach are systematically analyzed, and future directions for integrating these methodologies are discussed. This review aims to guide researchers in selecting and developing effective modeling strategies for advancing the field of soft robotic arm design and control. Full article

(This article belongs to the Special Issue Bioinspired Engineering and the Design of Biomimetic Structures: 2nd Edition)

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21 pages, 1358 KiB

Open AccessArticle

A 3D Face Recognition Algorithm Directly Applied to Point Clouds

by Xingyi You and Xiaohu Zhao

Biomimetics 2025, 10(2), 70; https://doi.org/10.3390/biomimetics10020070 - 23 Jan 2025

Abstract

Face recognition technology, despite its widespread use in various applications, still faces challenges related to occlusions, pose variations, and expression changes. Three-dimensional face recognition with depth information, particularly using point cloud-based networks, has shown effectiveness in overcoming these challenges. However, due to the [...] Read more.

Face recognition technology, despite its widespread use in various applications, still faces challenges related to occlusions, pose variations, and expression changes. Three-dimensional face recognition with depth information, particularly using point cloud-based networks, has shown effectiveness in overcoming these challenges. However, due to the limited extent of extensive 3D facial data and the non-rigid nature of facial structures, extracting distinct facial representations directly from point clouds remains challenging. To address this, our research proposes two key approaches. Firstly, we introduce a learning framework guided by a small amount of real face data based on morphable models with Gaussian processes. This system uses a novel method for generating large-scale virtual face scans, addressing the scarcity of 3D data. Secondly, we present a dual-branch network that directly extracts non-rigid facial features from point clouds, using kernel point convolution (KPConv) as its foundation. A local neighborhood adaptive feature learning module is introduced and employs context sampling technology, hierarchically downsampling feature-sensitive points critical for deep transfer and aggregation of discriminative facial features, to enhance the extraction of discriminative facial features. Notably, our training strategy combines large-scale face scanning data with 967 real face data from the FRGC v2.0 subset, demonstrating the effectiveness of guiding with a small amount of real face data. Experiments on the FRGC v2.0 dataset and the Bosphorus dataset demonstrate the effectiveness and potential of our method. Full article

(This article belongs to the Special Issue Exploration of Bioinspired Computer Vision and Pattern Recognition)

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15 pages, 8962 KiB

Open AccessArticle

Mantises Jump from Smooth Surfaces by Pushing with “Heel” Pads of Their Hind Legs

by Hanns Hagen Goetzke, Malcolm Burrows and Walter Federle

Biomimetics 2025, 10(2), 69; https://doi.org/10.3390/biomimetics10020069 - 22 Jan 2025

Abstract

Juvenile mantises can jump towards targets by rapidly extending their middle and hind legs. Here, we investigate how mantises can perform jumps from smooth surfaces such as those found on many plants. Stagmomantis theophila mantises possess two distinct types of attachment pads on [...] Read more.

Juvenile mantises can jump towards targets by rapidly extending their middle and hind legs. Here, we investigate how mantises can perform jumps from smooth surfaces such as those found on many plants. Stagmomantis theophila mantises possess two distinct types of attachment pads on each foot: three small proximal euplantulae (“heel pads”) with microscopic cuticular ridges and one smooth large distal pair of euplantulae (“toe pad”). Microscopy showed that the surface contact of heel pads is strongly load-dependent; at low normal forces, they make only partial surface contact due to the ridges, but at higher loads they switch to larger areas in full contact. By analysing the kinematics of 64 jumps of 23 third-instar nymphs from glass surfaces and the foot contact areas of their accelerating legs, we show that heel and toe pads fulfil distinct roles. During the acceleration phase of jumps, the contact area of the hind legs’ heel pads tripled, while that of the toe pad decreased strongly, and the toe pad sometimes detached completely before take-off. Although the middle legs also contribute to the jump, they showed a less consistent pattern; the contact areas of their heel and toe pads remained largely unchanged during acceleration. Our findings show that jumping mantises accelerate mainly by pushing with their hind legs and produce grip on smooth surfaces primarily with the heel pads on their proximal tarsus. Full article

(This article belongs to the Special Issue Biological Attachment Systems and Biomimetics)

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