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Biomimetics, Volume 7, Issue 4 (December 2022) – 112 articles

Cover Story (view full-size image): Plants and animals are often inspiration for biomimetic engineering. However, the actual strength of using biological systems as source for information often falls short: the isolation of core principles from similar functional systems solving the same problem. We compared the adhesive systems of the eggs of a leaf insect and the seeds of the ivy gourd. They evolved convergently in two different kingdoms and are built from different structures. Both systems employ a water-soluble glue, reinforced by fibrous surface structures that adapt to substrate asperities. The differences in the morphology of the fibers are responsible for fulfilling the respective tasks. Similarities of these systems, as well as differences resulting from their different purposes, can be informative for biomimetics. View this paper
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11 pages, 548 KiB  
Review
Overview on Adjunct Ingredients Used in Hydroxyapatite-Based Oral Care Products
by Joachim Enax, Bennett T. Amaechi, Erik Schulze zur Wiesche and Frederic Meyer
Biomimetics 2022, 7(4), 250; https://doi.org/10.3390/biomimetics7040250 - 19 Dec 2022
Cited by 5 | Viewed by 2245
Abstract
Hydroxyapatite, Ca5(PO4)3(OH), is a biomimetic active ingredient, which is used in commercial oral care products such as toothpastes and mouthwashes worldwide. Clinical studies (in vivo) as well as in situ and in vitro studies have shown the [...] Read more.
Hydroxyapatite, Ca5(PO4)3(OH), is a biomimetic active ingredient, which is used in commercial oral care products such as toothpastes and mouthwashes worldwide. Clinical studies (in vivo) as well as in situ and in vitro studies have shown the preventive effects of hydroxyapatite in various field of oral care. In some products, hydroxyapatite is combined with other active ingredients, to achieve an additional antibacterial effect or to promote gum health. This review analyzes the efficacy of six selected natural and nature-inspired ingredients that are commonly used together with hydroxyapatite. These additional actives are either antibacterial (lactoferrin, xylitol, and zinc) or promote gum health (allantoin, bisabolol, and hyaluronic acid). A systematic literature search was performed, and all studies found on each ingredient were analyzed. In summary, all analyzed ingredients mentioned in this review are well described in scientific studies on their beneficial effect for oral health and can be used to expand the preventive effect of hydroxyapatite in oral care products. Full article
(This article belongs to the Special Issue Biomimetic Approach to Dental Implants)
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17 pages, 4505 KiB  
Article
Effect of Segment Types on Characterization of Soft Sensing Textile Actuators for Soft Wearable Robots
by Ayse Feyza Yilmaz, Fidan Khalilbayli, Kadir Ozlem, Hend M. Elmoughni, Fatma Kalaoglu, Asli Tuncay Atalay, Gökhan Ince and Ozgur Atalay
Biomimetics 2022, 7(4), 249; https://doi.org/10.3390/biomimetics7040249 - 19 Dec 2022
Cited by 4 | Viewed by 2447
Abstract
The use of textiles in soft robotics is gaining popularity because of the advantages textiles offer over other materials in terms of weight, conformability, and ease of manufacture. The purpose of this research is to examine the stitching process used to construct fabric-based [...] Read more.
The use of textiles in soft robotics is gaining popularity because of the advantages textiles offer over other materials in terms of weight, conformability, and ease of manufacture. The purpose of this research is to examine the stitching process used to construct fabric-based pneumatic bending actuators as well as the effect of segment types on the actuators’ properties when used in soft robotic glove applications. To impart bending motion to actuators, two techniques have been used: asymmetry between weave and weft knit fabric layers and mechanical anisotropy between these two textiles. The impacts of various segment types on the actuators’ grip force and bending angle were investigated further. According to experiments, segmenting the actuator with a sewing technique increases the bending angle. It was discovered that actuators with high anisotropy differences in their fabric combinations have high gripping forces. Textile-based capacitive strain sensors are also added to selected segmented actuator types, which possess desirable properties such as increased grip force, increased bending angle, and reduced radial expansion. The sensors were used to demonstrate the controllability of a soft robotic glove using a closed-loop system. Finally, we demonstrated that actuators integrated into a soft wearable glove are capable of grasping a variety of items and performing various grasp types. Full article
(This article belongs to the Special Issue Biologically Inspired Robotics)
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16 pages, 19505 KiB  
Article
Integration of Antifouling and Underwater Sound Absorption Properties into PDMS/MWCNT/SiO2 Coatings
by Pan Cao, Huming Wang, Mingyi Zhu, Yifeng Fu and Chengqing Yuan
Biomimetics 2022, 7(4), 248; https://doi.org/10.3390/biomimetics7040248 - 18 Dec 2022
Cited by 3 | Viewed by 2145
Abstract
Any surface immersed in sea water will suffer from marine fouling, including underwater sound absorption coatings. Traditional underwater sound absorption coatings rely heavily on the use of toxic, biocide-containing paints to combat biofouling. In this paper, an environmentally-friendly nanocomposite with integrated antifouling and [...] Read more.
Any surface immersed in sea water will suffer from marine fouling, including underwater sound absorption coatings. Traditional underwater sound absorption coatings rely heavily on the use of toxic, biocide-containing paints to combat biofouling. In this paper, an environmentally-friendly nanocomposite with integrated antifouling and underwater sound absorption properties was fabricated by adopting MWCNTs-COOH and SiO2 into PDMS at different ratios. SEM, FTIR and XPS results demonstrated MWCNTs were mixed into PDMS, and the changes in elements were also analyzed. SiO2 nanoparticles in PDMS decreased the tensile properties of the coating, while erosion resistance was enhanced. Antibacterial properties of the coatings containing MWCNTs-COOH and SiO2 at a ratio of 1:1, 1:3, and 1:5 reached 62.02%, 72.36%, and 74.69%, respectively. In the frequency range of 1500–5000 Hz, the average sound absorption coefficient of PDMS increased from 0.5 to greater than 0.8 after adding MWCNTs-COOH and SiO2, which illustrated that the addition of nanoparticles enhanced the underwater sound absorption performance of the coating. Incorporating MWCNTs-COOH and SiO2 nanoparticles into the PDMS matrix to improve its sound absorption and surface antifouling properties provides a promising idea for marine applications. Full article
(This article belongs to the Section Biomimetic Surfaces and Interfaces)
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19 pages, 5958 KiB  
Article
Anticancer Activity of Thiophene Carboxamide Derivatives as CA-4 Biomimetics: Synthesis, Biological Potency, 3D Spheroid Model, and Molecular Dynamics Simulation
by Mohammed Hawash, Mohammed T. Qaoud, Nidal Jaradat, Samer Abdallah, Shahd Issa, Nawal Adnan, Marah Hoshya, Shorooq Sobuh and Zafer Hawash
Biomimetics 2022, 7(4), 247; https://doi.org/10.3390/biomimetics7040247 - 17 Dec 2022
Cited by 14 | Viewed by 2390
Abstract
The present study aimed to synthesize thiophene carboxamide derivatives, which are considered biomimetics of the anticancer medication Combretastatin A-4 (CA-4), and compare the similarity in the polar surface area (PSA) between the novel series and CA-4. Our results showed that the PSA of [...] Read more.
The present study aimed to synthesize thiophene carboxamide derivatives, which are considered biomimetics of the anticancer medication Combretastatin A-4 (CA-4), and compare the similarity in the polar surface area (PSA) between the novel series and CA-4. Our results showed that the PSA of the most synthesized structures was biomimetic to CA-4, and similar chemical and biological properties were observed against Hep3B cancer cell line. Among the synthesized series 2b and 2e compounds were the most active molecules on Hep3B (IC50 = 5.46 and 12.58 µM, respectively). The 3D results revealed that both 2b and 2e structures confuse the surface of Hep3B cancer cell lines’ spheroid formation and force these cells to aggregate into a globular-shaped spheroid. The 2b and 2e showed a comparable interaction pattern to that observed for CA-4 and colchicine within the tubulin-colchicine-binding pocket. The thiophene ring, due to holding a high aromaticity character, participated critically in that observed interaction profile and showed additional advanced interactions over CA-4. The 2b and 2e tubulin complexes showed optimal dynamics trajectories within a time scale of 100 ns at 300 K temperature, which asserts their high stability and compactness. Together, these findings revealed the biomimetic role of 2b and 2e compounds in CA-4 in preventing cancer progression. Full article
(This article belongs to the Section Biomimetics of Materials and Structures)
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23 pages, 5226 KiB  
Article
A Conductance-Based Silicon Synapse Circuit
by Ashish Gautam and Takashi Kohno
Biomimetics 2022, 7(4), 246; https://doi.org/10.3390/biomimetics7040246 - 16 Dec 2022
Cited by 1 | Viewed by 2318
Abstract
Neuron, synapse, and learning circuits inspired by the brain comprise the key components of a neuromorphic chip. In this study, we present a conductance-based analog silicon synapse circuit suitable for the implementation of reduced or multi-compartment neuron models. Compartmental models are more bio-realistic. [...] Read more.
Neuron, synapse, and learning circuits inspired by the brain comprise the key components of a neuromorphic chip. In this study, we present a conductance-based analog silicon synapse circuit suitable for the implementation of reduced or multi-compartment neuron models. Compartmental models are more bio-realistic. They are implemented in neuromorphic chips aiming to mimic the electrical activities of the neuronal networks in the brain and incorporate biomimetic soma and synapse circuits. Most contemporary low-power analog synapse circuits implement bioinspired “current-based” synaptic models suited for the implementation of single-compartment point neuron models. They emulate the exponential decay profile of the synaptic current, but ignore the effect of the postsynaptic membrane potential on the synaptic current. This dependence is necessary to emulate shunting inhibition, which is thought to play important roles in information processing in the brain. The proposed circuit uses an oscillator-based resistor-type element at its output stage to incorporate this effect. This circuit is used to demonstrate the shunting inhibition phenomenon. Next, to demonstrate that the oscillatory nature of the induced synaptic current has no unforeseen effects, the synapse circuit is employed in a spatiotemporal spike pattern detection task. The task employs the adaptive spike-timing-dependent plasticity (STDP) learning rule, a bio-inspired learning rule introduced in a previous study. The mixed-signal chip is designed in a Taiwan Manufacturing Semiconductor Company 250 nm complementary metal oxide semiconductor technology node. It comprises a biomimetic soma circuit and 256 synapse circuits, along with their learning circuitries. Full article
(This article belongs to the Special Issue Neuromorphic Engineering: Biomimicry from the Brain)
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12 pages, 4715 KiB  
Article
Magnetically Tunable Adhesion of Magnetoactive Elastomers’ Surface Covered with Two-Level Newt-Inspired Microstructures
by Shiwei Chen, Ziyuan Qian, Xiaojiao Fu and Xuan Wu
Biomimetics 2022, 7(4), 245; https://doi.org/10.3390/biomimetics7040245 - 16 Dec 2022
Cited by 1 | Viewed by 1669
Abstract
As one of the new intelligent materials, controllable bionic adhesive materials have great application prospects in many fields, such as wearable electronic devices, wall climbing robot systems, and biomedical engineering. Inspired by the microstructure of the newt pad’s surface, this paper reports a [...] Read more.
As one of the new intelligent materials, controllable bionic adhesive materials have great application prospects in many fields, such as wearable electronic devices, wall climbing robot systems, and biomedical engineering. Inspired by the microstructure of the newt pad’s surface, this paper reports a bionic adhesive surface material with controllable adhesion on dry, wet acrylic, and iron sheet surfaces. The material is prepared by mixing the PDMS matrix with micron carbonyl iron powders (CIPs) and then pouring the mixture into a female mold prepared by Photo-curing 3D Printing for curing. As the mold interior is designed with a two-level microstructure array, the material’s surface not only coated a regular hexagonal column array with a side length of 250 μm and a height of 100 μm but also covered seven dome structures with a diameter of 70 μm on each column. In what follows, the adhesion force of the proposed materials contacted three different surfaces are tested with/without magnetic fields. The experimental results show that the MAEs covered with two-level bionic structures(2L-MAE) reported in this paper exhibit a stronger initial adhesion in the three types of surfaces compared to the normal one. Besides, we also found that the magnetic field will noticeably affect their adhesion performance. Generally, the 2L-MAE’s adhesion will increase with the external magnetic field. When the contact surface is an iron sheet, the material adhesion will be reduced by the magnetic field. Full article
(This article belongs to the Special Issue Biological Adhesives: From Biology to Biomimetics)
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22 pages, 5421 KiB  
Article
Balanced Standing on One Foot of Biped Robot Based on Three-Particle Model Predictive Control
by Yong Yang, Jiyuan Shi, Songrui Huang, Yuhong Ge, Wenhan Cai, Qingkai Li, Xueying Chen, Xiu Li and Mingguo Zhao
Biomimetics 2022, 7(4), 244; https://doi.org/10.3390/biomimetics7040244 - 16 Dec 2022
Cited by 4 | Viewed by 1926
Abstract
Balancing is a fundamental task in the motion control of bipedal robots. Compared to two-foot balancing, one-foot balancing introduces new challenges, such as a smaller supporting polygon and control difficulty coming from the kinematic coupling between the center of mass (CoM) and the [...] Read more.
Balancing is a fundamental task in the motion control of bipedal robots. Compared to two-foot balancing, one-foot balancing introduces new challenges, such as a smaller supporting polygon and control difficulty coming from the kinematic coupling between the center of mass (CoM) and the swinging leg. Although nonlinear model predictive control (NMPC) may solve this problem, it is not feasible to implement it on the actual robot because of its large amount of calculation. This paper proposes the three-particle model predictive control (TP-MPC) approach. It combines with the hierarchical whole-body control (WBC) to solve the one-leg balancing problem in real time. The bipedal robot’s torso and two legs are modeled as three separate particles without inertia. The TP-MPC generates feasible swing leg trajectories, followed by the WBC to adjust the robot’s center of mass. Since the three-particle model is linear, the TP-MPC requires less computational cost, which implies real-time execution on an actual robot. The proposed method is verified in simulation. Simulation results show that our method can resist much larger external disturbance than the WBC-only control scheme. Full article
(This article belongs to the Special Issue Bio-Inspired Design and Control of Legged Robot)
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15 pages, 8261 KiB  
Article
Cell Type-Specific Effects of Implant Provisional Restoration Materials on the Growth and Function of Human Fibroblasts and Osteoblasts
by Takanori Matsuura, Keiji Komatsu, Denny Chao, Yu-Chun Lin, Nimish Oberoi, Kalie McCulloch, James Cheng, Daniela Orellana and Takahiro Ogawa
Biomimetics 2022, 7(4), 243; https://doi.org/10.3390/biomimetics7040243 - 16 Dec 2022
Cited by 5 | Viewed by 1934
Abstract
Implant provisional restorations should ideally be nontoxic to the contacting and adjacent tissues, create anatomical and biophysiological stability, and establish a soft tissue seal through interactions between prosthesis, soft tissue, and alveolar bone. However, there is a lack of robust, systematic, and fundamental [...] Read more.
Implant provisional restorations should ideally be nontoxic to the contacting and adjacent tissues, create anatomical and biophysiological stability, and establish a soft tissue seal through interactions between prosthesis, soft tissue, and alveolar bone. However, there is a lack of robust, systematic, and fundamental data to inform clinical decision making. Here we systematically explored the biocompatibility of fibroblasts and osteoblasts in direct contact with, or close proximity to, provisional restoration materials. Human gingival fibroblasts and osteoblasts were cultured on the “contact” effect and around the “proximity” effect with various provisional materials: bis-acrylic, composite, self-curing acrylic, and milled acrylic, with titanium alloy as a bioinert control. The number of fibroblasts and osteoblasts surviving and attaching to and around the materials varied considerably depending on the material, with milled acrylic the most biocompatible and similar to titanium alloy, followed by self-curing acrylic and little to no attachment on or around bis-acrylic and composite materials. Milled and self-curing acrylics similarly favored subsequent cellular proliferation and physiological functions such as collagen production in fibroblasts and alkaline phosphatase activity in osteoblasts. Neither fibroblasts nor osteoblasts showed a functional phenotype when cultured with bis-acrylic or composite. By calculating a biocompatibility index for each material, we established that fibroblasts were more resistant to the cytotoxicity induced by most materials in direct contact, however, the osteoblasts were more resistant when the materials were in close proximity. In conclusion, there was a wide variation in the cytotoxicity of implant provisional restoration materials ranging from lethal and tolerant to near inert, and this cytotoxicity may be received differently between the different cell types and depending on their physical interrelationships. Full article
(This article belongs to the Special Issue Biomimetic Approach to Dental Implants)
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17 pages, 4610 KiB  
Article
Facile Fabrication of Methyl Gallate Encapsulated Folate ZIF-L Nanoframeworks as a pH Responsive Drug Delivery System for Anti-Biofilm and Anticancer Therapy
by Saeed M. Marji, Mohammad F. Bayan and Abdolelah Jaradat
Biomimetics 2022, 7(4), 242; https://doi.org/10.3390/biomimetics7040242 - 16 Dec 2022
Cited by 10 | Viewed by 2173
Abstract
Zeolitic imidazole frameworks are emerging materials and have been considered an efficient platform for biomedical applications. The present study highlights the simple fabrication of methyl gallate encapsulated folate-ZIF-L nanoframeworks (MG@Folate ZIF-L) by a simple synthesis. The nanoframeworks were characterized by different sophisticated instruments. [...] Read more.
Zeolitic imidazole frameworks are emerging materials and have been considered an efficient platform for biomedical applications. The present study highlights the simple fabrication of methyl gallate encapsulated folate-ZIF-L nanoframeworks (MG@Folate ZIF-L) by a simple synthesis. The nanoframeworks were characterized by different sophisticated instruments. In addition, the drug-releasing mechanism was evidenced by in vitro releasing kinetics at various pH conditions. The anti-biofilm potential confirmed by the biofilm architectural deformations against human infectious pathogens MRSA and N7 clinical strains. Furthermore, anticancer efficacy assessed against A549 lung cancer cells. The result reveals that the MG@Folate ZIF-L exposed a superior cytotoxic effect due to the pH-responsive and receptor-based drug-releasing mechanism. Based on the unique physicochemical and biological characteristics of nanoframeworks, it has overcome the problems of undesired side effects and uncontrolled drug release of existing drug delivery systems. Finally, the in vitro toxicity effect of MG@Folate ZIF-L was tested against the Artemia salina (A. salina) model organism, and the results show enhanced biocompatibility. Overall, the study suggested that the novel MG@Folate ZIF-L nanoframeworks is a suitable material for biomedical applications. It will be very helpful to the future design for targeted drug delivery systems. Full article
(This article belongs to the Special Issue Biomimetic Drug Delivery Systems)
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32 pages, 10712 KiB  
Article
An Improved Chimp-Inspired Optimization Algorithm for Large-Scale Spherical Vehicle Routing Problem with Time Windows
by Yifei Xiang, Yongquan Zhou, Huajuan Huang and Qifang Luo
Biomimetics 2022, 7(4), 241; https://doi.org/10.3390/biomimetics7040241 - 15 Dec 2022
Cited by 6 | Viewed by 1669
Abstract
The vehicle routing problem with time windows (VRPTW) is a classical optimization problem. There have been many related studies in recent years. At present, many studies have generally analyzed this problem on the two-dimensional plane, and few studies have explored it on spherical [...] Read more.
The vehicle routing problem with time windows (VRPTW) is a classical optimization problem. There have been many related studies in recent years. At present, many studies have generally analyzed this problem on the two-dimensional plane, and few studies have explored it on spherical surfaces. In order to carry out research related to the distribution of goods by unmanned vehicles and unmanned aerial vehicles, this study carries out research based on the situation of a three-dimensional sphere and proposes a three-dimensional spherical VRPTW model. All of the customer nodes in this problem were mapped to the three-dimensional sphere. The chimp optimization algorithm is an excellent intelligent optimization algorithm proposed recently, which has been successfully applied to solve various practical problems and has achieved good results. The chimp optimization algorithm (ChOA) is characterized by its excellent ability to balance exploration and exploitation in the optimization process so that the algorithm can search the solution space adaptively, which is closely related to its outstanding adaptive factors. However, the performance of the chimp optimization algorithm in solving discrete optimization problems still needs to be improved. Firstly, the convergence speed of the algorithm is fast at first, but it becomes slower and slower as the number of iterations increases. Therefore, this paper introduces the multiple-population strategy, genetic operators, and local search methods into the algorithm to improve its overall exploration ability and convergence speed so that the algorithm can quickly find solutions with higher accuracy. Secondly, the algorithm is not suitable for discrete problems. In conclusion, this paper proposes an improved chimp optimization algorithm (MG-ChOA) and applies it to solve the spherical VRPTW model. Finally, this paper analyzes the performance of this algorithm in a multi-dimensional way by comparing it with many excellent algorithms available at present. The experimental result shows that the proposed algorithm is effective and superior in solving the discrete problem of spherical VRPTW, and its performance is superior to that of other algorithms. Full article
(This article belongs to the Special Issue Bio-Inspired Design and Optimisation of Engineering Systems)
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15 pages, 2171 KiB  
Article
Deuterohemin-Ala-His-Thr-Val-Glu-Lys (DhHP-6) Mimicking Enzyme as Synergistic Antioxidant and Anti-Inflammatory Material for Periodontitis Therapy
by Jiaqing Yan, Min Liu, Yan Zhang, Ying Zhu, Qiuyan Chen, Yimeng Yang, Min Hu and Huimei Yu
Biomimetics 2022, 7(4), 240; https://doi.org/10.3390/biomimetics7040240 - 14 Dec 2022
Viewed by 2224
Abstract
Periodontitis is an inflammatory disease induced by plaque microorganisms. In the clinic, antibiotic assistant periodontal mechanical therapy is the most effective therapy for the treatment of periodontitis. However, the drug resistance of the antibiotics and the repeated coming and diminishing of the disorder [...] Read more.
Periodontitis is an inflammatory disease induced by plaque microorganisms. In the clinic, antibiotic assistant periodontal mechanical therapy is the most effective therapy for the treatment of periodontitis. However, the drug resistance of the antibiotics and the repeated coming and diminishing of the disorder of oxidation–reduction balance in the inflammatory tissue could not meet the high requirements for periodontic health control in long periods. Deuterohemin-ala-his-thr-val-glu-lys (DhHP-6) is a biomimetic oxidase-mimicking enzyme that simulates the reactive oxygen radical scavenger function of heme by synthesizing the new molecular material following the key structure and amino acid sequence of heme. In this article, we report the antioxidant and anti-inflammatory properties of DhHP-6 by building a inflammatory model for human gingival fibroblasts (HGFs) stimulated by lipolysaccharide (LPS) and its effects on periodontitis in Wistar rats. DhHP-6 reduced the oxidative stress of HGFs by increasing the amount of the reductase species of glutathione (GSH) and catalase (CAT) while decreasing the amount of oxidase species of malonaldehyde (MDA) and reactive oxygen species (ROS). DhHP-6 had a dose-dependent protective effect on alveolar bone absorption in rats with periodontitis, enhanced antioxidant capacity, and reduced inflammation. As determined by Micro-CT scanning, DhHP-6 reduced alveolar bone loss and improved the bone structure of the left maxillary first molar of rats. There were no obvious morphological and histological differences in the rat organs with or without DhHP-6 treatment. These results suggest that DhHP-6 can be used to treat periodontitis by increasing the expression levels of antioxidant enzymes and antioxidants in systemic and local tissues, thereby reducing levels of oxidation products and cyto-inflammatory factors. The synergistic antioxidant and anti-inflammatory effects of DhHP-6 suggest that there are promising applications of this biomimetic enzyme molecular material for the next generation of agents for periodontitis therapy. Full article
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20 pages, 8566 KiB  
Article
Comparative Analysis of the Self-Propelled Locomotion of a Pitching Airfoil near the Flat and Wavy Ground
by Zhiqiang Xin, Zhiming Cai, Yiming Ren and Huachen Liu
Biomimetics 2022, 7(4), 239; https://doi.org/10.3390/biomimetics7040239 - 12 Dec 2022
Cited by 2 | Viewed by 1816
Abstract
In this paper, a pitching airfoil near flat and wavy ground is studied by numerical simulations. The kinematic features of the airfoil and the flow field around it are analyzed to reveal unsteady vorticity dynamics of the self-propelled airfoil in ground effect. The [...] Read more.
In this paper, a pitching airfoil near flat and wavy ground is studied by numerical simulations. The kinematic features of the airfoil and the flow field around it are analyzed to reveal unsteady vorticity dynamics of the self-propelled airfoil in ground effect. The optimal pitching periods at different initial heights above flat ground are obtained, which make the pitching airfoil achieve the maximum lift-to-drag ratio. Compared with flat ground, at the same initial height, the optimal pitching periods vary with the shape of ground. The structure and the strength of the wake vortices shedding from the airfoil are adjusted by the wavelength of ground. This leads to the changes of amplitude and occurrence times of the peak and valley of lift and drag force. The results obtained in this study can provide some inspiration for the design of underwater vehicles in the ground effect. Full article
(This article belongs to the Special Issue Biological and Bio-Inspired Fluid Dynamics)
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23 pages, 10123 KiB  
Article
Research on Six-Wheel Distributed Unmanned Vehicle Path Tracking Strategy Based on Hierarchical Control
by Teng’an Zou, Yulong You, Hao Meng and Yukang Chang
Biomimetics 2022, 7(4), 238; https://doi.org/10.3390/biomimetics7040238 - 12 Dec 2022
Viewed by 1387
Abstract
For the multi-objective control problem of tracking effect and vehicle stability in the path tracking process of six-wheel distributed unmanned vehicles, a control strategy based on hierarchical control (HC) theory is proposed. A hierarchical kinematic model is designed considering the structural advantages of [...] Read more.
For the multi-objective control problem of tracking effect and vehicle stability in the path tracking process of six-wheel distributed unmanned vehicles, a control strategy based on hierarchical control (HC) theory is proposed. A hierarchical kinematic model is designed considering the structural advantages of independent steering and independent driving of the unmanned vehicle, and this model is applied to the path tracking strategy. The strategy is divided into two levels of control. The upper level of control is to use the upper-level kinematic model as the prediction model of model predictive control (MPC), and to convert the solution problem of future control increments into the optimal solution problem of quadratic programming by setting the optimal objective function and constraints. The lower level of control is to map the optimal control quantities obtained from the upper level control to the six-wheel speeds and the four-wheel turning angles through the lower-level kinematics, and to design the six-wheel torque distribution rules based on deterministic torque and stability-based slip rate control for executing the control requirements of the upper level controller to prevent the unmanned vehicle from generating sideslip and precisely generating transverse moment to ensure the stable driving of the unmanned vehicle. Experiments were conducted on the Trucksim/Simulink simulation platform for a variety of road conditions, and the results showed that hierarchical control improved the accuracy of tracking the desired path and the driving stability on complex road surfaces more than MPC. Full article
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12 pages, 3001 KiB  
Article
In-Situ Surface Modification of ITO Substrate via Bio-Inspired Mussel Chemistry for Organic Memory Devices
by Minglei Gong, Wei Li, Fei Fan, Yu Chen and Bin Zhang
Biomimetics 2022, 7(4), 237; https://doi.org/10.3390/biomimetics7040237 - 12 Dec 2022
Cited by 2 | Viewed by 1255
Abstract
The development of organic memory devices, regarding factors such as structure construction, principle exploration, and material design, has become a powerful supplement to traditional silicon-based information storage. The in-situ growth of materials on substrate surfaces can achieve closer bonding between materials and electrodes. [...] Read more.
The development of organic memory devices, regarding factors such as structure construction, principle exploration, and material design, has become a powerful supplement to traditional silicon-based information storage. The in-situ growth of materials on substrate surfaces can achieve closer bonding between materials and electrodes. Bio-inspired by mussel chemistry, polydopamine (PDA) was self-assembled on a flexible substrate as a connecting layer, and 2-bromoiso-butyryl bromide (BiBB) was utilized as an initiator for the polymerization of an iridium complex via surface-initiated atom-transfer radical polymerization (SI-ATRP). A device with the structure of Al/PDA-PPy3Ir/ITO was constructed after the deposition of aluminum. The device exhibited a nonvolatile rewritable memory characteristic with a turn-on voltage of −1.0 V and an ON/OFF current ratio of 6.3 × 103. In addition, the memory performance of the Al/PDA-PPy3Ir/ITO device remained stable at bending states due to the intrinsic flexibility of the active layer, which can be expanded into the establishment of flexible memory devices. Spectroscopy and electrochemical characterization suggested that the resistive memory properties of the device stemmed from charge transfer between PDA and iridium polymer in the active layer (PDA-PPy3Ir) under an applied voltage. Full article
(This article belongs to the Section Biomimetic Design, Constructions and Devices)
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11 pages, 4842 KiB  
Article
Design and Test of Tread-Pattern Structure of Biomimetic Goat-Sole Tires
by Fu Zhang, Yubo Qiu, Shuai Teng, Xiahua Cui, Xinyue Wang, Haoxun Sun, Shaukat Ali, Zhijun Guo, Jiajia Wang and Sanling Fu
Biomimetics 2022, 7(4), 236; https://doi.org/10.3390/biomimetics7040236 - 12 Dec 2022
Cited by 2 | Viewed by 2054
Abstract
To solve the technical problem that wheeled vehicles are prone to skidding on complex ground, due to poor adhesion performance, a tire-tread-structure design method based on the bionic principle is proposed in this paper. The 3D model of a goat’s foot was obtained [...] Read more.
To solve the technical problem that wheeled vehicles are prone to skidding on complex ground, due to poor adhesion performance, a tire-tread-structure design method based on the bionic principle is proposed in this paper. The 3D model of a goat’s foot was obtained using reverse engineering technology, and the curve equation was fitted by extracting the contour data of its outer-hoof flap edge, which was applied to the tire-tread-structure design. The bionic and herringbone-pattern rubber samples were manufactured, and a soil-tank test was carried out using an electronic universal tensile-testing machine, in order to verify the simulation results. The results showed that the overall adhesion of the bionic tread-pattern was greater than that of the normal tread-pattern with the same load applied and the same height and angle of the tread-pattern structure, and the maximum adhesion was increased by 14.23%. This research will provide a reference for optimizing the pattern structure and thus improving the passing performance of wheeled vehicles. Full article
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14 pages, 2639 KiB  
Article
Design of a Felid-like Humanoid Foot for Stability Enhancement
by Zhaoyang Cai, Xuechao Chen, Qingqing Li, Huaxin Liu and Zhangguo Yu
Biomimetics 2022, 7(4), 235; https://doi.org/10.3390/biomimetics7040235 - 12 Dec 2022
Cited by 1 | Viewed by 1932
Abstract
The foot is an important part of humanoid robot locomotion that can help with shock absorption while making contact with the ground. The mechanism of the foot directly affects walking stability. A novel foot mechanism inspired by the toes of felids is proposed. [...] Read more.
The foot is an important part of humanoid robot locomotion that can help with shock absorption while making contact with the ground. The mechanism of the foot directly affects walking stability. A novel foot mechanism inspired by the toes of felids is proposed. The foot has four bionic modules with soft pads and sharp claws installed at the four corners of a flat foot. This foot can reduce the impact experienced during foot landing and increase the time that the foot is in contact with the ground, which can improve the adaptability of the robot to different ground surface conditions with different levels of stiffness. The main structure of the bionic module is a four-bar linkage consisting of a slide way and a spring. Furthermore, the length of the four-bar linkage and the posture of the claw during insertion into soft ground are optimized to improve the stability and buffering performance. The validity of the proposed foot mechanism has been proved in simulations. Full article
(This article belongs to the Special Issue Bio-Inspired Design and Control of Legged Robot)
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14 pages, 2207 KiB  
Article
The Design and Testing of a PEA Powered Ankle Prosthesis Driven by EHA
by Qitao Huang, Bowen Li and Hongguang Xu
Biomimetics 2022, 7(4), 234; https://doi.org/10.3390/biomimetics7040234 - 12 Dec 2022
Cited by 2 | Viewed by 1777
Abstract
Several studies have shown that actuation concepts such as Serial elastic actuator (SEA) can reduce peak power and energy consumption in ankle prostheses. Proper selection and design of the actuation concepts is important to unlock the power source potential. In this work, the [...] Read more.
Several studies have shown that actuation concepts such as Serial elastic actuator (SEA) can reduce peak power and energy consumption in ankle prostheses. Proper selection and design of the actuation concepts is important to unlock the power source potential. In this work, the optimization design, mechanical design, control scheme, and bench experiments of a new powered ankle–foot prosthesis is proposed. The actuation concept of this prosthesis is parallel elastic actuator (PEA) composed of electro-hydrostatic actuator (EHA) as the power kernel and a unidirectional parallel spring as the auxiliary energy storage element. After the appropriate motor and transmission ratio was selected, a dynamic model of the PEA prosthesis was built to obtain the appropriate spring parameters driven by biological data. The design of the hydraulic and mechanical system and the controller were provided for the implementation of the designed system. Bench experiments were performed to verify the performance. The results showed that the designed prosthesis meets the biomechanical dynamics requirements. This result emphasizes the feasibility of the EHA as a power source and actuator and provides new ideas for the design of ankle–foot prostheses. Full article
(This article belongs to the Special Issue Bioinspired Functional Structures)
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19 pages, 2790 KiB  
Article
Effect of the Thumb Orientation and Actuation on the Functionality and Performance of Affordable Prosthetic Hands: Obtaining Design Criteria
by Javier Andrés-Esperanza, Jose L. Iserte-Vilar, Immaculada Llop-Harillo and Antonio Pérez-González
Biomimetics 2022, 7(4), 233; https://doi.org/10.3390/biomimetics7040233 - 11 Dec 2022
Viewed by 1955
Abstract
The advent of 3D printing technologies has enabled the development of low-cost prosthetic underactuated hands, with cables working as tendons for flexion. Despite the particular relevance to human grasp, its conception in prosthetics is based on vague intuitions of the designers due to [...] Read more.
The advent of 3D printing technologies has enabled the development of low-cost prosthetic underactuated hands, with cables working as tendons for flexion. Despite the particular relevance to human grasp, its conception in prosthetics is based on vague intuitions of the designers due to the lack of studies on its relevance to the functionality and performance of the device. In this work, some criteria for designers are provided regarding the carpometacarpal joint of the thumb in these devices. To this end, we studied four prosthetic hands of similar characteristics with the motion of abduction/adduction of the thumb resolved in three different ways: fixed at a certain abduction, coupled with the motion of flexion/extension, and actuated independently of the flexion/extension. The functionality and performance of the hands were assessed for the basic grasps using the Anthropomorphic Hand Assessment Protocol (AHAP) and a reduced version of the Southampton Hand Assessment Procedure (SHAP). As a general rule, it seems desirable that thumb adduction/abduction is performed independently of flexion/extension, although this adds one degree of control. If having this additional degree of control is beyond debate, coupled flexion/extension and adduction/abduction should be avoided in favour of the thumb having a fixed slight palmar abduction. Full article
(This article belongs to the Special Issue Biorobotics)
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21 pages, 5109 KiB  
Article
Standing Balance Control of a Bipedal Robot Based on Behavior Cloning
by Jae Hwan Bong, Suhun Jung, Junhwi Kim and Shinsuk Park
Biomimetics 2022, 7(4), 232; https://doi.org/10.3390/biomimetics7040232 - 9 Dec 2022
Cited by 3 | Viewed by 2894
Abstract
Bipedal robots have gained increasing attention for their human-like mobility which allows them to work in various human-scale environments. However, their inherent instability makes it difficult to control their balance while they are physically interacting with the environment. This study proposes a novel [...] Read more.
Bipedal robots have gained increasing attention for their human-like mobility which allows them to work in various human-scale environments. However, their inherent instability makes it difficult to control their balance while they are physically interacting with the environment. This study proposes a novel balance controller for bipedal robots based on a behavior cloning model as one of the machine learning techniques. The behavior cloning model employs two deep neural networks (DNNs) trained on human-operated balancing data, so that the trained model can predict the desired wrench required to maintain the balance of the bipedal robot. Based on the prediction of the desired wrench, the joint torques for both legs are calculated using robot dynamics. The performance of the developed balance controller was validated with a bipedal lower-body robotic system through simulation and experimental tests by providing random perturbations in the frontal plane. The developed balance controller demonstrated superior performance with respect to resistance to balance loss compared to the conventional balance control method, while generating a smoother balancing movement for the robot. Full article
(This article belongs to the Special Issue Biologically Inspired Robotics)
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12 pages, 1969 KiB  
Article
EEG-Based Mapping of Resting-State Functional Brain Networks in Patients with Parkinson’s Disease
by Sarah Leviashvili, Yael Ezra, Amgad Droby, Hao Ding, Sergiu Groppa, Anat Mirelman, Muthuraman Muthuraman and Inbal Maidan
Biomimetics 2022, 7(4), 231; https://doi.org/10.3390/biomimetics7040231 - 8 Dec 2022
Cited by 4 | Viewed by 2347
Abstract
(1) Background: Directed functional connectivity (DFC) alterations within brain networks are described using fMRI. EEG has been scarcely used. We aimed to explore changes in DFC in the sensory-motor network (SMN), ventral-attention network (VAN), dorsal-attention network (DAN), and central-executive network (CEN) using an [...] Read more.
(1) Background: Directed functional connectivity (DFC) alterations within brain networks are described using fMRI. EEG has been scarcely used. We aimed to explore changes in DFC in the sensory-motor network (SMN), ventral-attention network (VAN), dorsal-attention network (DAN), and central-executive network (CEN) using an EEG-based mapping between PD patients and healthy controls (HCs). (2) Methods: Four-minutes resting EEG was recorded from 29 PD patients and 28 HCs. Network’s hubs were defined using fMRI-based binary masks and their electrical activity was calculated using the LORETA. DFC between each network’s hub-pairs was calculated for theta, alpha and beta bands using temporal partial directed coherence (tPDC). (3) Results: tPDCs percent was lower in the CEN and DAN in PD patients compared to HCs, while no differences were observed in the SMN and VAN (group*network: F = 5.943, p < 0.001) in all bands (group*band: F = 0.914, p = 0.401). However, in the VAN, PD patients showed greater tPDCs strength compared to HCs (p < 0.001). (4) Conclusions: Our results demonstrated reduced connectivity in the CEN and DAN, and increased connectivity in the VAN in PD patients. These results indicate a complex pattern of DFC alteration within major brain networks, reflecting the co-occurrence of impairment and compensatory mechanisms processes taking place in PD. Full article
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9 pages, 822 KiB  
Study Protocol
Myocardial Perfusion and Coronary Physiology Assessment of Microvascular Dysfunction in Patients Undergoing Transcatheter Aortic Valve Implantation—Rationale and Design
by M. M. Dobrolinska, P. Gąsior, A. Błach, R. Gocoł, D. Hudziak and W. Wojakowski
Biomimetics 2022, 7(4), 230; https://doi.org/10.3390/biomimetics7040230 - 8 Dec 2022
Viewed by 1240
Abstract
The prevalence of coronary artery disease (CAD) in patients with severe aortic stenosis (AS) is 30–68%. Nevertheless, there is still not enough evidence to use invasive assessment of lesion severity, because the hemodynamic milieu of AS may impact the fractional flow reserve (FFR) [...] Read more.
The prevalence of coronary artery disease (CAD) in patients with severe aortic stenosis (AS) is 30–68%. Nevertheless, there is still not enough evidence to use invasive assessment of lesion severity, because the hemodynamic milieu of AS may impact the fractional flow reserve (FFR) and non-hyperemic indices. Therefore, the aim of the study is two-fold. First, to measure acute and long-term changes of FFR, index of microvascular resistance (IMR), and coronary flow reserve (CFR) in patients undergoing TAVI procedure. Second, to compare the diagnostic accuracy of intracoronary indices with myocardial perfusion measured by cadmium-zinc-telluride single-photon emission tomography (CZT-SPECT) and find cut-off values defining significant stenosis. We plan to enroll 40 patients eligible for TAVI with intermediate stenosis (30–70%) in the left anterior descending (LAD) coronary artery. In each patient FFR, CFR, and IMR will be measured in addition to myocardial blood flow calculated by CZT-SPECT before and either immediately after TAVI (acute cohort) or in 6 months (late cohort) after the procedure. FFR, CFR, and IMR will be matched with the results of myocardial perfusion measured by CZT-SPECT in the area of LAD. As a result, cut-off values of FFR, CFR, and IMR defining the decreased blood flow will be found. Full article
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32 pages, 1728 KiB  
Review
Biomimetic Approaches in Clinical Endodontics
by Naresh Kumar, Nazrah Maher, Faiza Amin, Hani Ghabbani, Muhammad Sohail Zafar, Francisco Javier Rodríguez-Lozano and Ricardo E. Oñate-Sánchez
Biomimetics 2022, 7(4), 229; https://doi.org/10.3390/biomimetics7040229 - 6 Dec 2022
Cited by 11 | Viewed by 5245
Abstract
In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, [...] Read more.
In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area. Full article
(This article belongs to the Special Issue Biomimetic Platform for Tissue Regeneration)
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15 pages, 3235 KiB  
Article
Kinematic Analysis of Bionic Elephant Trunk Robot Based on Flexible Series-Parallel Structure
by Qitao Huang, Peng Wang, Yuhao Wang, Xiaohua Xia and Songjing Li
Biomimetics 2022, 7(4), 228; https://doi.org/10.3390/biomimetics7040228 - 5 Dec 2022
Cited by 4 | Viewed by 2440
Abstract
Researchers borrow ideas from biological characteristics and behavior in design to make bionic robots that can meet unstructured and complex operating environments. The elephant trunk has been widely imitated by bionic robots because of its strong dexterity and stiffness adjustability. Due to the [...] Read more.
Researchers borrow ideas from biological characteristics and behavior in design to make bionic robots that can meet unstructured and complex operating environments. The elephant trunk has been widely imitated by bionic robots because of its strong dexterity and stiffness adjustability. Due to the complex structure of the current elephant trunk robot, a series-parallel elephant trunk robot based on flexible rod actuation and a 6-degree-of-freedom (6-dof) parallel module is proposed in this paper. The bionic robot has a simple structure and redundant kinematics, which can realize the control of stiffness. This work focuses on the modeling of the flexible driving rod, the kinematics of a single parallel module, and the whole biomimetic robot. The kinematics are verified by simulation, which lays a foundation for future research on stiffness regulation. Full article
(This article belongs to the Special Issue Bioinspired Functional Structures)
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21 pages, 4245 KiB  
Article
The Biomimetics of Mg2+-Concentration-Resolved Microenvironment for Bone and Cartilage Repairing Materials Design
by Zhengqiang Li, Xiaoxue Zheng, Yixing Wang, Tianyi Tao, Zilin Wang, Long Yuan and Bing Han
Biomimetics 2022, 7(4), 227; https://doi.org/10.3390/biomimetics7040227 - 5 Dec 2022
Cited by 1 | Viewed by 2221
Abstract
With the increase in population aging, the tendency of osteochondral injury will be accelerated, and repairing materials are increasingly needed for the optimization of the regenerative processes in bone and cartilage recovery. The local environment of the injury sites and the deficiency of [...] Read more.
With the increase in population aging, the tendency of osteochondral injury will be accelerated, and repairing materials are increasingly needed for the optimization of the regenerative processes in bone and cartilage recovery. The local environment of the injury sites and the deficiency of Mg2+ retards the repairing period via inhibiting the progenitor osteogenesis and chondrogenesis cells’ recruitment, proliferation, and differentiation, which results in the sluggish progress in the osteochondral repairing materials design. In this article, we elucidate the Mg2+-concentration specified effect on the cell proliferation, osteochondral gene expression, and differentiation of modeling chondrocytes (extracted from New Zealand white rabbit) and osteoblasts (MC3T3-E1). The concentration of Mg2+ in the culture medium affects the proliferation, chondrogenesis, and osteogenesis: (i) Appropriate concentrations of Mg2+ promote the proliferation of chondrocytes (1.25–10.0 mM) and MC3T3-E1 cells (2.5–30.0 mM); (ii) the optimal concentration of Mg2+ that promotes the gene expression of noncalcified cartilage is 15 mM, calcified cartilage 10 mM, and subchondral bone 5 mM, respectively; (iii) overdosed Mg2+ leads to the inhibition of cell activity for either chondrocytes (>20 mM) or osteoblasts (>30 mM). The biomimetic elucidation for orchestrating the allocation of gradient concentration of Mg2+ in accordance of the physiological condition is crucial for designing the accurate microenvironment in osteochondral injury defects for optimization of bone and cartilage repairing materials in the future. Full article
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17 pages, 3661 KiB  
Article
Biomechanical and Sensory Feedback Regularize the Behavior of Different Locomotor Central Pattern Generators
by Kaiyu Deng, Alexander J. Hunt, Nicholas S. Szczecinski, Matthew C. Tresch, Hillel J. Chiel, C. J. Heckman and Roger D. Quinn
Biomimetics 2022, 7(4), 226; https://doi.org/10.3390/biomimetics7040226 - 4 Dec 2022
Cited by 3 | Viewed by 1632
Abstract
This work presents an in-depth numerical investigation into a hypothesized two-layer central pattern generator (CPG) that controls mammalian walking and how different parameter choices might affect the stepping of a simulated neuromechanical model. Particular attention is paid to the functional role of features [...] Read more.
This work presents an in-depth numerical investigation into a hypothesized two-layer central pattern generator (CPG) that controls mammalian walking and how different parameter choices might affect the stepping of a simulated neuromechanical model. Particular attention is paid to the functional role of features that have not received a great deal of attention in previous work: the weak cross-excitatory connectivity within the rhythm generator and the synapse strength between the two layers. Sensitivity evaluations of deafferented CPG models and the combined neuromechanical model are performed. Locomotion frequency is increased in two different ways for both models to investigate whether the model’s stability can be predicted by trends in the CPG’s phase response curves (PRCs). Our results show that the weak cross-excitatory connection can make the CPG more sensitive to perturbations and that increasing the synaptic strength between the two layers results in a trade-off between forced phase locking and the amount of phase delay that can exist between the two layers. Additionally, although the models exhibit these differences in behavior when disconnected from the biomechanical model, these differences seem to disappear with the full neuromechanical model and result in similar behavior despite a variety of parameter combinations. This indicates that the neural variables do not have to be fixed precisely for stable walking; the biomechanical entrainment and sensory feedback may cancel out the strengths of excitatory connectivity in the neural circuit and play a critical role in shaping locomotor behavior. Our results support the importance of including biomechanical models in the development of computational neuroscience models that control mammalian locomotion. Full article
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12 pages, 2496 KiB  
Article
Path Planning with Time Windows for Multiple UAVs Based on Gray Wolf Algorithm
by Changchun Zhang, Yifan Liu and Chunhe Hu
Biomimetics 2022, 7(4), 225; https://doi.org/10.3390/biomimetics7040225 - 3 Dec 2022
Cited by 10 | Viewed by 1846
Abstract
The Gray Wolf (GWO) algorithm aims to address the path planning problem of multiple UAVs, and the scene setting is mainly to avoid threats, meet the constraints of UAVs themselves and avoid obstacles between UAVs. The scene setting is relatively simple. To address [...] Read more.
The Gray Wolf (GWO) algorithm aims to address the path planning problem of multiple UAVs, and the scene setting is mainly to avoid threats, meet the constraints of UAVs themselves and avoid obstacles between UAVs. The scene setting is relatively simple. To address such problems, the problem of time windows is considered in this paper, so that the UAV can arrive at the same time, and the Gray Wolf algorithm is used to optimize the problem. Finally, the experimental results verify that the proposed method can plan a safe flight path in the process of multi-UAV flight and reach the goal point at the same time. The mean error of flight time between UAVs of the GWO is 0.213, which is superior to PSO (0.382), AFO (0.315) and GA (0.825). Full article
(This article belongs to the Special Issue Bio-Inspired Flight Systems and Bionic Aerodynamics)
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16 pages, 3159 KiB  
Article
Wnt/β-Catenin Signaling Inhibits Osteogenic Differentiation in Human Periodontal Ligament Fibroblasts
by Ryoya Iizumi and Michiyo Honda
Biomimetics 2022, 7(4), 224; https://doi.org/10.3390/biomimetics7040224 - 3 Dec 2022
Cited by 3 | Viewed by 2055
Abstract
The periodontal ligament is a collagenous tissue that is important for maintaining the homeostasis of cementum and alveolar bone. In tendon cells, Wnt/β-catenin signaling has been reported to regulate the expression level of Scleraxis (Scx) and Mohawk Homeobox (Mkx) [...] Read more.
The periodontal ligament is a collagenous tissue that is important for maintaining the homeostasis of cementum and alveolar bone. In tendon cells, Wnt/β-catenin signaling has been reported to regulate the expression level of Scleraxis (Scx) and Mohawk Homeobox (Mkx) gene and maintain the tissue homeostasis, while its role in the periodontal ligament is unclear. The aim of this study was to investigate the effects of Wnt/β-catenin signaling induced by Wnt-3a stimulation on the inhibition of osteogenic differentiation of human periodontal ligament fibroblasts (HPLFs). During osteogenic differentiation of HPLFs, they formed bone nodules independently of alkaline phosphatase (ALP) activity. After stimulation of Wnt-3a, the expression of β-catenin increased, and nuclear translocation of β-catenin was observed. These data indicate that Wnt-3a activated Wnt/β-catenin signaling. Furthermore, the stimulation of Wnt-3a inhibited the bone nodule formation and suppressed the expression of osteogenic differentiation-related genes such as Runx2, Osteopontin and Osteocalcin, and upregulated the gene expression of Type-I collagen and Periostin (Postn). Scx may be involved in the suppression of osteogenic differentiation in HPLFs. In conclusion, Wnt/β-catenin signaling may be an important signaling pathway that inhibits the osteogenic differentiation in HPLFs by the upregulation of Scx gene expression and downregulation of osteogenic differentiation-related genes. Full article
(This article belongs to the Special Issue Biomimetic Approach to Dental Implants)
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20 pages, 10728 KiB  
Article
A Biomimetic Method to Replicate the Natural Fluid Movements of Swimming Snakes to Design Aquatic Robots
by Elie Gautreau, Xavier Bonnet, Juan Sandoval, Guillaume Fosseries, Anthony Herrel, Marc Arsicault, Saïd Zeghloul and Med Amine Laribi
Biomimetics 2022, 7(4), 223; https://doi.org/10.3390/biomimetics7040223 - 3 Dec 2022
Cited by 10 | Viewed by 2097
Abstract
Replicating animal movements with robots provides powerful research tools because key parameters can be manipulated at will. Facing the lack of standard methods and the high complexity of biological systems, an incremental bioinspired approach is required. We followed this method to design a [...] Read more.
Replicating animal movements with robots provides powerful research tools because key parameters can be manipulated at will. Facing the lack of standard methods and the high complexity of biological systems, an incremental bioinspired approach is required. We followed this method to design a snake robot capable of reproducing the natural swimming gait of snakes, i.e., the lateral undulations of the whole body. Our goal was to shift away from the classical broken line design of poly-articulated snake robots to mimic the far more complex fluid movements of snakes. First, we examined the musculoskeletal systems of different snake species to extract key information, such as the flexibility or stiffness of the body. Second, we gathered the swimming kinematics of living snakes. Third, we developed a toolbox to implement the data that are relevant to technical solutions. We eventually built a prototype of an artificial body (not yet fitted with motors) that successfully reproduced the natural fluid lateral undulations of snakes when they swim. This basis is an essential step for designing realistic autonomous snake robots. Full article
(This article belongs to the Special Issue Biorobotics)
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32 pages, 26620 KiB  
Review
Bio-Inspired Nanomembranes as Building Blocks for Nanophotonics, Plasmonics and Metamaterials
by Zoran Jakšić, Marko Obradov and Olga Jakšić
Biomimetics 2022, 7(4), 222; https://doi.org/10.3390/biomimetics7040222 - 1 Dec 2022
Cited by 3 | Viewed by 2569
Abstract
Nanomembranes are the most widespread building block of life, as they encompass cell and organelle walls. Their synthetic counterparts can be described as freestanding or free-floating structures thinner than 100 nm, down to monatomic/monomolecular thickness and with giant lateral aspect ratios. The structural [...] Read more.
Nanomembranes are the most widespread building block of life, as they encompass cell and organelle walls. Their synthetic counterparts can be described as freestanding or free-floating structures thinner than 100 nm, down to monatomic/monomolecular thickness and with giant lateral aspect ratios. The structural confinement to quasi-2D sheets causes a multitude of unexpected and often counterintuitive properties. This has resulted in synthetic nanomembranes transiting from a mere scientific curiosity to a position where novel applications are emerging at an ever-accelerating pace. Among wide fields where their use has proven itself most fruitful are nano-optics and nanophotonics. However, the authors are unaware of a review covering the nanomembrane use in these important fields. Here, we present an attempt to survey the state of the art of nanomembranes in nanophotonics, including photonic crystals, plasmonics, metasurfaces, and nanoantennas, with an accent on some advancements that appeared within the last few years. Unlimited by the Nature toolbox, we can utilize a practically infinite number of available materials and methods and reach numerous properties not met in biological membranes. Thus, nanomembranes in nano-optics can be described as real metastructures, exceeding the known materials and opening pathways to a wide variety of novel functionalities. Full article
(This article belongs to the Section Biomimetics of Materials and Structures)
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15 pages, 3383 KiB  
Article
States of Aggregation and Phase Transformation Behavior of Metallosurfactant Complexes by Hexacyanoferrate(II): Thermodynamic and Kinetic Investigation of ETR in Ionic Liquids and Liposome Vesicles
by Karuppiah Nagaraj, Subramanian Sakthinathan, Te-Wei Chiu, Subramaniam Kamalesu, Snehal Lokhandwala, Nikhil M. Parekh and Chelladurai Karuppiah
Biomimetics 2022, 7(4), 221; https://doi.org/10.3390/biomimetics7040221 - 30 Nov 2022
Cited by 1 | Viewed by 1578
Abstract
Electronic absorption spectroscopy was used to study the ETR of surfactant–cobalt(III) complexes containing imidazo[4,5-f][1,10]phenanthroline, dipyrido[3,2-d:2′-3′-f]quinoxaline and dipyrido[3,2-a:2′,4′-c](6,7,8,9-tetrahydro)phenazine ligands by using ferrocyanide ions in unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC) and 1-butyl-3-methylimidazolium bromide ((BMIM)Br), at different temperatures under pseudo-first-order conditions using an excess of the [...] Read more.
Electronic absorption spectroscopy was used to study the ETR of surfactant–cobalt(III) complexes containing imidazo[4,5-f][1,10]phenanthroline, dipyrido[3,2-d:2′-3′-f]quinoxaline and dipyrido[3,2-a:2′,4′-c](6,7,8,9-tetrahydro)phenazine ligands by using ferrocyanide ions in unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC) and 1-butyl-3-methylimidazolium bromide ((BMIM)Br), at different temperatures under pseudo-first-order conditions using an excess of the reductant. The reactions were found to be second-order and the electron transfer is postulated as occurring in the outer sphere. The rate constant for the electron transfer reactions was found to increase with increasing concentrations of ionic liquids. Besides these, the effects of surfactant complex ions on liposome vesicles in these same reactions have also been studied on the basis of hydrophobicity. We observed that, below the phase transition temperature, there is an increasing amount of surfactant–cobalt(III) complexes expelled from the interior of the vesicle membrane through hydrophobic effects, while above the phase transition temperature, the surfactant–cobalt(III) complexes are expelled from the interior to the exterior surface of the vesicle. Kinetic data and activation parameters are interpreted in respect of an outer-sphere electron transfer mechanism. By assuming the existence of an outer-sphere mechanism, the results have been clarified based on the presence of hydrophobicity, and the size of the ligand increases from an ip to dpqc ligand and the reactants become oppositely charged. In all these media, the ΔS# values are recognized as negative in their direction in all the concentrations of complexes employed, indicative of a more ordered structure of the transition state. This is compatible with a model in which these complexes and [Fe(CN)6]4− ions bind to the DPPC in the transition state. Thus, the results have been interpreted based on the self-aggregation, hydrophobicity, charge densities of the co-ligand and the reactants with opposite charges. Full article
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