Biomimetics

29 pages, 3233 KiB

Open AccessReview

A Comprehensive Review on Bioprinted Graphene-Based Material (GBM)-Enhanced Scaffolds for Nerve Guidance Conduits

by Siheng Su and Jilong Wang

Biomimetics 2025, 10(4), 213; https://doi.org/10.3390/biomimetics10040213 - 31 Mar 2025

Peripheral nerve injuries (PNIs) pose significant challenges to recovery, often resulting in impaired function and quality of life. To address these challenges, nerve guidance conduits (NGCs) are being developed as effective strategies to promote nerve regeneration by providing a supportive framework that guides [...] Read more.

Peripheral nerve injuries (PNIs) pose significant challenges to recovery, often resulting in impaired function and quality of life. To address these challenges, nerve guidance conduits (NGCs) are being developed as effective strategies to promote nerve regeneration by providing a supportive framework that guides axonal growth and facilitates reconnection of severed nerves. Among the materials being explored, graphene-based materials (GBMs) have emerged as promising candidates due to their unique properties. Their unique properties—such as high mechanical strength, excellent electrical conductivity, and favorable biocompatibility—make them ideal for applications in nerve repair. The integration of 3D printing technologies further enhances the development of GBM-based NGCs, enabling the creation of scaffolds with complex architectures and precise topographical cues that closely mimic the natural neural environment. This customization significantly increases the potential for successful nerve repair. This review offers a comprehensive overview of properties of GBMs, the principles of 3D printing, and key design strategies for 3D-printed NGCs. Additionally, it discusses future perspectives and research directions that could advance the application of 3D-printed GBMs in nerve regeneration therapies. Full article

(This article belongs to the Special Issue 3D Bio-Printing for Regenerative Medicine Applications)

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Graphical abstract

32 pages, 25500 KiB

Open AccessArticle

Aerodynamic Characteristics of a Tandem Flapping Wing in Inclined Stroke Plane Hovering with Ground Effect

by Arun Raj Shanmugam, Chang Hyun Sohn and Ki Sun Park

Biomimetics 2025, 10(4), 212; https://doi.org/10.3390/biomimetics10040212 - 30 Mar 2025

Abstract

The present two-dimensional study investigates the ground effect on the aerodynamic characteristics of a tandem flapping wing in inclined stroke plane hovering using ANSYS Fluent. The role of various wing kinematics parameters (flapping frequency f, stroke amplitude A_o/c, and phase difference [...] Read more.

The present two-dimensional study investigates the ground effect on the aerodynamic characteristics of a tandem flapping wing in inclined stroke plane hovering using ANSYS Fluent. The role of various wing kinematics parameters (flapping frequency f, stroke amplitude A_o/c, and phase difference ψ = 0° and 180°), in combination with ground distance (D* = D/c), is studied. The results reveal that a large stroke amplitude A_o/c decreases vertical force generation for both in-phase and counter-stroking patterns. The vertical force notably increases for both in-phase and counter-stroking wings when D* is extremely small (D* = 0.5). A maximum vertical force enhancement of approximately 65% and 35% is observed for in-phase and counter-stroking patterns, respectively, at D* = 0.5. This enhancement is primarily attributed to the strengthening of detached vortices on the lower surface of the wings during the middle of the downstroke when flapping at extremely small ground distances. In addition, the wing–wing interaction and secondary rebound vortex, caused by wing–ground interaction, also play a key role in vertical force generation. The wing–ground interaction positively influences both vertical and thrust force generation for in-phase and counter-stroking wings at small ground distances. In general, the vertical and thrust forces generated by in-phase stroking wings are greater than those produced by counter-stroking wings. Full article

(This article belongs to the Special Issue Bio-Inspired Flapping Wing Aerodynamics for Propulsion and Power Generation: 2nd Edition)

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18 pages, 6347 KiB

Open AccessArticle

Mineral Composition of Skeletal Elements in Dorid Nudibranchia Onchidoris muricata (Gastropoda, Mollusca)

by Dmitry A. Ozerov, Ekaterina D. Nikitenko, Alexey A. Piryazev, Andrey I. Lavrov and Elena V. Vortsepneva

Biomimetics 2025, 10(4), 211; https://doi.org/10.3390/biomimetics10040211 - 29 Mar 2025

Abstract

Energy-dispersive X-ray spectrometry (EDX), a standard technique in mineralogy and criminalistics, has not yet been fully incorporated into the study of various biomineral structures of invertebrates, despite the growing popularity of this topic in the last few decades. This is partly due to [...] Read more.

Energy-dispersive X-ray spectrometry (EDX), a standard technique in mineralogy and criminalistics, has not yet been fully incorporated into the study of various biomineral structures of invertebrates, despite the growing popularity of this topic in the last few decades. This is partly due to EDX’s limitations and data interpretation complexities. This study used EDX to analyze the spicules’ elemental composition of nudibranch gastropod mollusk Onchidoris muricata prepared via two methods (sectioning and fracturing). Hierarchical clustering and compositional data analysis of the resulting elemental data revealed three distinct spicule populations with varying element ratios, suggesting spicule transformation pathways. Two of the three clusters had a uniform layered microstructure, yet they showed reliable differences in element ratios. Raman spectroscopy confirmed the spicules’ calcite or magnesian–calcite composition. EDX analysis of spicule sections, coupled with other analytical techniques, revealed mineral structure transformations and provided insights into the biomineral nature. The sample preparation method with epoxy-embedding, preserving surrounding tissues in their active state, allowed for the analysis of tissue elemental composition and the elucidation of their role in mineralization. Full article

(This article belongs to the Special Issue Principles of Biomimetic Mineralization and Creation of Composite Materials)

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20 pages, 8274 KiB

Open AccessArticle

A Structural Optimization Framework for Biodegradable Magnesium Interference Screws

by Zhenquan Shen, Xiaochen Zhou, Ming Zhao and Yafei Li

Biomimetics 2025, 10(4), 210; https://doi.org/10.3390/biomimetics10040210 - 28 Mar 2025

Abstract

Biodegradable magnesium alloys have garnered increasing attention in recent years, with magnesium alloy–based biomedical devices being clinically used. Unlike biologically inert metallic materials, magnesium-based medical devices degrade during service, resulting in a mechanical structure that evolves over time. However, there are currently few [...] Read more.

Biodegradable magnesium alloys have garnered increasing attention in recent years, with magnesium alloy–based biomedical devices being clinically used. Unlike biologically inert metallic materials, magnesium-based medical devices degrade during service, resulting in a mechanical structure that evolves over time. However, there are currently few computer-aided engineering methods specifically tailored for magnesium-based medical devices. This paper introduces a structural optimization framework for Mg-1Ca interference screws, accounting for degradation using a continuum damage model (CDM). The Optimal Latin Hypercube Sampling (OLHS) technique was employed to sample within the design space. Pull-out strengths were used as the optimization objective, which were calculated through finite element analysis (FEA). Both Response Surface Methodology (RSM) and Kriging models were employed as surrogate models and optimized using the Sequential Quadratic Programming (SQP) algorithm. The results from the Kriging model were validated through FEA, and were found to be acceptable. The relationships between the design parameters, the rationale behind the methodology, and its limitations are discussed. Finally, a final design is proposed along with recommendations for interference screw design. Full article

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14 pages, 4690 KiB

Open AccessArticle

The Effect of Honeycomb-Structured Hydrophilic–Hydrophobic Mixed Surfaces on the Spreading Process of Liquid Droplets

by Chenyue Zhu, Mark Alston and Yuying Yan

Biomimetics 2025, 10(4), 209; https://doi.org/10.3390/biomimetics10040209 - 28 Mar 2025

Abstract

Honeycomb-structured, mixed-wettability surfaces have attracted significant attention due to their potential for tailoring surface properties and controlling fluid dynamics at the nanoscale. However, the underlying mechanisms governing droplet spreading and wettability modulation remain insufficiently understood. This study, using molecular dynamics simulations, reveals that [...] Read more.

Honeycomb-structured, mixed-wettability surfaces have attracted significant attention due to their potential for tailoring surface properties and controlling fluid dynamics at the nanoscale. However, the underlying mechanisms governing droplet spreading and wettability modulation remain insufficiently understood. This study, using molecular dynamics simulations, reveals that periodic hydrophilic–hydrophobic areas within honeycomb structures induce unique oscillatory spreading behaviors and allow the precise modulation of equilibrium contact angles. The findings demonstrate that honeycomb designs can effectively transition surfaces between hydrophilic and hydrophobic states, with practical applications in boiling heat transfer, thermal management, and advanced materials development. Full article

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18 pages, 6674 KiB

Open AccessArticle

Model Predictive Control with Optimal Modelling for Pneumatic Artificial Muscle in Rehabilitation Robotics: Confirmation of Validity Though Preliminary Testing

by Dexter Felix Brown and Sheng Quan Xie

Biomimetics 2025, 10(4), 208; https://doi.org/10.3390/biomimetics10040208 - 28 Mar 2025

Abstract

This paper presents a model predictive controller (MPC) based on dynamic models generated using the Particle Swarm Optimisation method for accurate motion control of a pneumatic artificial muscle (PAM) for application in rehabilitation robotics. The physical compliance and lightweight nature of PAMs make [...] Read more.

This paper presents a model predictive controller (MPC) based on dynamic models generated using the Particle Swarm Optimisation method for accurate motion control of a pneumatic artificial muscle (PAM) for application in rehabilitation robotics. The physical compliance and lightweight nature of PAMs make them desirable for use in the field but also introduce nonlinear dynamic properties which are difficult to accurately model and control. As well as the MPC, three other control systems were examined for a comparative study: a particle-swarm optimised proportional-integral-derivative controller (PSO-PID), an iterative learning controller (ILC), and classical PID control. A series of different waveforms were used as setpoints for each controller, including addition of external loading and simulated disturbance, for a system consisting of a single PAM. Based on the displacement error measured for each experiment, the PID controller performed worst with the largest error values and an issue with oscillating about the setpoint. PSO-PID performed better but still poorly compared with the other intelligent controllers, as well as still exhibiting oscillation, which is undesirable in any human–robot interaction as it can heavily impact the comfort and safety of the system. ILC performed well with rapid convergence to steady-state and low-error values, as well as mitigation of loads and disturbance; however, it performed poorly under changing frequency of input. MPC generally performed the best of the controllers tested here, with the lowest error values and a rapid response to changes in setpoint, as well as no required learning period due to the predictive algorithm. Full article

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

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13 pages, 3259 KiB

Open AccessArticle

FRNet V2: A Lightweight Full-Resolution Convolutional Neural Network for OCTA Vessel Segmentation

by Dongxu Gao, Liang Wang, Youtong Fang, Du Jiang and Yalin Zheng

Biomimetics 2025, 10(4), 207; https://doi.org/10.3390/biomimetics10040207 - 27 Mar 2025

Abstract

Optical coherence tomography angiography (OCTA) is an advanced non-invasive imaging technique that can generate three-dimensional images of retinal and choroidal vessels. It is of great value in the diagnosis and monitoring of a variety of ophthalmic diseases. However, most existing methods for blood [...] Read more.

Optical coherence tomography angiography (OCTA) is an advanced non-invasive imaging technique that can generate three-dimensional images of retinal and choroidal vessels. It is of great value in the diagnosis and monitoring of a variety of ophthalmic diseases. However, most existing methods for blood vessel segmentation in OCTA images rely on an encoder–decoder architecture. This architecture typically involves a large number of parameters and leads to slower inference speeds. To address these challenges and improve segmentation efficiency, this paper proposes a lightweight full-resolution convolutional neural network named FRNet V2 for blood vessel segmentation in OCTA images. FRNet V2 combines the ConvNeXt V2 architecture with deep separable convolution and introduces a recursive mechanism. This mechanism enhances feature representation while reducing the amount of model parameters and computational complexity. In addition, we design a lightweight hybrid adaptive attention mechanism (DWAM) that further improves the segmentation accuracy of the model through the combination of channel self-attention blocks and spatial self-attention blocks. The experimental results show that on two well-known retinal image datasets (OCTA-500 and ROSSA), FRNet V2 can achieve Dice coefficients and accuracy comparable to other methods while reducing the number of parameters by more than 90%. In conclusion, FRNet V2 provides an efficient and lightweight solution for fast and accurate OCTA image blood vessel segmentation in resource-constrained environments, offering strong support for clinical applications. Full article

(This article belongs to the Special Issue Bio-Inspired Artificial Intelligence in Healthcare)

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27 pages, 120429 KiB

Open AccessReview

Mussel-Inspired Hydrogel Applied to Wound Healing: A Review and Future Prospects

by Yanai Chen, Yijia Cao, Pengyu Cui and Shenzhou Lu

Biomimetics 2025, 10(4), 206; https://doi.org/10.3390/biomimetics10040206 - 26 Mar 2025

Abstract

The application background of mussel-inspired materials is based on the unique underwater adhesive ability of marine mussels, which has inspired researchers to develop bionic materials with strong adhesion, self-healing ability, biocompatibility, and environmental friendliness. Specifically, 3, 4-dihydroxyphenylalanine (DOPA) in mussel byssus is able [...] Read more.

The application background of mussel-inspired materials is based on the unique underwater adhesive ability of marine mussels, which has inspired researchers to develop bionic materials with strong adhesion, self-healing ability, biocompatibility, and environmental friendliness. Specifically, 3, 4-dihydroxyphenylalanine (DOPA) in mussel byssus is able to form non-covalent forces on a variety of surfaces, which are critical for the mussel’s underwater adhesion and enable the mussel-inspired material to dissipate energy and repair itself under external forces. Mussel-inspired hydrogels are ideal medical adhesive materials due to their unique physical and chemical properties, such as excellent tissue adhesion, hemostasis and bacteriostasis, biosafety, and plasticity. This paper reviewed chitosan, cellulose, hyaluronic acid, gelatin, alginate, and other biomedical materials and discussed the advanced functions of mussel-inspired hydrogels as wound dressings, including antibacterial, anti-inflammatory, and antioxidant properties, adhesion and hemostasis, material transport, self-healing, stimulating response, and so on. At the same time, the technical challenges and limitations of the biomimetic mussel hydrogel in biomedical applications were further discussed, and its potential solutions and future research developments in the field of biomedicine were highlighted. Full article

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22 pages, 3030 KiB

Open AccessArticle

Effect of Octacalcium Phosphate on Osteogenic Differentiation of Induced Pluripotent Stem Cells in a 3D Hybrid Spheroid Culture

by Yuki Sugai, Ryo Hamai, Yukari Shiwaku, Takahisa Anada, Kaori Tsuchiya, Tai Kimura, Manami Tadano, Kensuke Yamauchi, Tetsu Takahashi, Hiroshi Egusa and Osamu Suzuki

Biomimetics 2025, 10(4), 205; https://doi.org/10.3390/biomimetics10040205 - 26 Mar 2025

Abstract

Octacalcium phosphate (OCP) has been shown to exhibit an osteogenic property and, therefore, has been utilized recently as a bone substitute, clinically. However, the stimulatory capacity for induced pluripotent stem (iPS) cells is not known. This study investigated whether OCP enhances osteoblastic differentiation [...] Read more.

Octacalcium phosphate (OCP) has been shown to exhibit an osteogenic property and, therefore, has been utilized recently as a bone substitute, clinically. However, the stimulatory capacity for induced pluripotent stem (iPS) cells is not known. This study investigated whether OCP enhances osteoblastic differentiation of three-dimensionally cultured spheroids of iPS cells compared to hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). Mouse iPS cells were mixed with smaller (less than 53 μm) or larger (300–500 μm) sizes of calcium phosphate (CaP) granules and cultured in a laboratory-developed oxygen-permeable culture chip under minimizing hypoxia for up to 21 days. Osteoblastic differentiation was estimated by the cellular alkaline phosphatase (ALP) activities. The degree of supersaturation (DS) with respect to CaP phases was determined from the media chemical compositions. Incubated CaP materials were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The culture promoted well the formation of hybrid spheroids of CaP materials and iPS cells regardless of the type of materials and their granule sizes. The ALP activity of OCP was about 1.5 times higher than that of β-TCP and HA in smaller granule sizes. FTIR, XRD, and DS analyses showed that larger OCP granules tended to hydrolyze to HA slightly faster than smaller granules with time while HA and β-TCP materials tended to remain unchanged. In conclusion, the results suggest that OCP enhances the osteogenic differentiation of iPS cells more than HA and β-TCP through a mechanism of hydrolyzing to HA. This inherent material property of OCP is essential for enhancing the osteoblastic differentiation of iPS cells. Full article

(This article belongs to the Special Issue Biomimetic Strategies to Enhance Bone Tissue Healing, Remodeling and Regeneration)

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25 pages, 1822 KiB

Open AccessReview

Biomimetic Approaches in the Development of Optimised 3D Culture Environments for Drug Discovery in Cardiac Disease

by Jenny Shepherd

Biomimetics 2025, 10(4), 204; https://doi.org/10.3390/biomimetics10040204 - 26 Mar 2025

Abstract

Cardiovascular disease remains the leading cause of death worldwide, yet despite massive investment in drug discovery, the progress of cardiovascular drugs from lab to clinic remains slow. It is a complex, costly pathway from drug discovery to the clinic and failure becomes more [...] Read more.

Cardiovascular disease remains the leading cause of death worldwide, yet despite massive investment in drug discovery, the progress of cardiovascular drugs from lab to clinic remains slow. It is a complex, costly pathway from drug discovery to the clinic and failure becomes more expensive as a drug progresses along this pathway. The focus has begun to shift to optimisation of in vitro culture methodologies, not only because these must be undertaken are earlier on in the drug discovery pathway, but also because the principles of the 3Rs have become embedded in national and international legislation and regulation. Numerous studies have shown myocyte cell behaviour to be much more physiologically relevant in 3D culture compared to 2D culture, highlighting the advantages of using 3D-based models, whether microfluidic or otherwise, for preclinical drug screening. This review aims to provide an overview of the challenges in cardiovascular drug discovery, the limitations of traditional routes, and the successes in the field of preclinical models for cardiovascular drug discovery. It focuses on the particular role biomimicry can play, but also the challenges around implementation within commercial drug discovery. Full article

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

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18 pages, 11715 KiB

Open AccessArticle

Interaction of Manganese-Doped Copper Oxide Nano-Platelets with Cells: Biocompatibility and Anticancer Activity Assessment

by Ioan-Ovidiu Pană, Alexandra Ciorîță, Sanda Boca, Simona Guțoiu, Irina Kacso, Maria Olimpia Miclăuș, Oana Grad, Ana Maria Raluca Gherman, Cristian Leostean and Maria Suciu

Biomimetics 2025, 10(4), 203; https://doi.org/10.3390/biomimetics10040203 - 26 Mar 2025

Abstract

Understanding cellular interaction with nanomaterials represents a subject of great interest for the validation of new diagnostic and therapeutic tools. A full characterization of a designed product includes the evaluation of its impact on specific biological systems, including the study of cell behavior [...] Read more.

Understanding cellular interaction with nanomaterials represents a subject of great interest for the validation of new diagnostic and therapeutic tools. A full characterization of a designed product includes the evaluation of its impact on specific biological systems, including the study of cell behavior as a response to that particular interaction. Copper and copper-based nanoparticles (CuO NPs) have emerged as valuable building blocks for various biomedical applications such as antibacterial and disinfecting agents for infectious diseases, and the evaluation of the metabolism of food, including the iron required for proteins and enzymes or as drug delivery systems in cancer therapy. In this study, the biological impact of manganese-doped crystalline copper oxide (CuO:Mn) nano-platelets on human normal BJ fibroblasts and human A375 skin melanoma was assessed. The particles were synthesized at room temperature via the hydrothermal method. A complete physicochemical characterization of the materials was performed by employing various techniques including X-ray diffraction, electron microscopy, X-Ray photoelectron spectroscopy, and dynamic light scattering. Morphological investigations revealed a flat structure with nearly straight edges, with sizes spanning in the nanometer range. XRD analysis confirmed the formation of the CuO phase with good crystallinity, while XPS provided insights into the Mn doping. The findings indicate that nano-platelets interact with cells actively by mediating essential molecular processes. The exogenous manganese triggers increased MnSOD production in mitochondria, compensating ROS produced by external stress factors (Cu²⁺ ions), and mimics the endogenous SODs production, which compensates internal ROS production as it normally results from cell biochemistry. The effect is differentiated in normal cells compared to malignant cells and deserves investigation. Full article

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16 pages, 8312 KiB

Open AccessArticle

3D-Printed Soft Bionic Inchworm Robot Powered by Magnetic Force

by Deli Xia, Luying Zhang, Weihang Nong, Qingshan Duan and Jiang Ding

Biomimetics 2025, 10(4), 202; https://doi.org/10.3390/biomimetics10040202 - 26 Mar 2025

Abstract

Based on soft body structure and unique gait of bending and stretching, Soft Bionic Inchworm Robots (SBIRs) are used in pipeline inspection and terrain exploration. Many existing SBIRs rely on complex production mechanisms and are cable-driven, which hinders rapid production and smooth movement [...] Read more.

Based on soft body structure and unique gait of bending and stretching, Soft Bionic Inchworm Robots (SBIRs) are used in pipeline inspection and terrain exploration. Many existing SBIRs rely on complex production mechanisms and are cable-driven, which hinders rapid production and smooth movement through complex environments, respectively. To address these challenges, this paper introduces a 3D-printed SBIR, featuring a 3D-printed body actuated by magnetic forces. We introduce the design and production process of the 3D-SBIR and analyze its motion gait. Subsequently, the material composition model and bending deformation model of the robot are developed based on the theory of hyper-elastic materials. The accuracy of the model is validated using simulation analysis and experimental testing of the robot. Meanwhile, we carry out a magnetic simulation analysis and discuss the factors influencing the size of the magnetic force. Finally, a series of experiments are conducted to prove the excellent locomotion capability of the robot. The 3D-SBIR demonstrates remarkable flexibility and multimodal movement capabilities. It can navigate through narrow curved passages with ease, passively overcome obstacles, climb steps up to 0.8 times its body height, and perform a seamless transition while moving across a horizontal plane onto a vertical plane. The 3D-SBIR proposed in this paper is characterized by rapid production, cable-free actuation, and multimodal motion capabilities, making it well suited for moving in unstructured environments. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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29 pages, 8461 KiB

Open AccessArticle

Three-Dimensional UAV Path Planning Based on Multi-Strategy Integrated Artificial Protozoa Optimizer

by Qingbin Sun, Xitai Na, Zhihui Feng, Shiji Hai and Jinshuo Shi

Biomimetics 2025, 10(4), 201; https://doi.org/10.3390/biomimetics10040201 - 25 Mar 2025

Abstract

Three-dimensional UAV path planning is crucial in practical applications. However, existing metaheuristic algorithms often suffer from slow convergence and susceptibility to becoming trapped in local optima. To address these limitations, this paper proposes a multi-strategy integrated artificial protozoa optimization (IAPO) algorithm for UAV [...] Read more.

Three-dimensional UAV path planning is crucial in practical applications. However, existing metaheuristic algorithms often suffer from slow convergence and susceptibility to becoming trapped in local optima. To address these limitations, this paper proposes a multi-strategy integrated artificial protozoa optimization (IAPO) algorithm for UAV 3D path planning. First, the tent map and refractive opposition-based learning (ROBL) are employed to enhance the diversity and quality of the initial population. Second, in the algorithm’s autotrophic foraging stage, we design a dynamic optimal leadership mechanism, which accelerates the convergence speed while ensuring robust exploration capability. Additionally, during the reproduction phase of the algorithm, we update positions using a Cauchy mutation strategy. Thanks to the heavy-tailed nature of the Cauchy distribution, the algorithm is less likely to become trapped in local optima during exploration, thereby increasing the probability of finding the global optimum. Finally, we incorporate the simulated annealing algorithm into the heterotrophic foraging and reproduction stages, effectively preventing the algorithm from getting trapped in local optima and reducing the impact of inferior solutions on the convergence efficiency. The proposed algorithm is validated through comparative experiments using 12 benchmark functions from the 2022 IEEE Congress on Evolutionary Computation (CEC), outperforming nine common algorithms in terms of convergence speed and optimization accuracy. The experimental results also demonstrate IAPO’s superior performance in generating collision-free and energy-efficient UAV paths across diverse 3D environments. Full article

(This article belongs to the Special Issue Bio-Inspired Optimization Algorithms and Designs for Engineering Applications: 3rd Edition)

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18 pages, 5498 KiB

Open AccessArticle

Development and Evaluation of a Novel Upper-Limb Rehabilitation Device Integrating Piano Playing for Enhanced Motor Recovery

by Xin Zhao, Ying Zhang, Yi Zhang, Peng Zhang, Jinxu Yu and Shuai Yuan

Biomimetics 2025, 10(4), 200; https://doi.org/10.3390/biomimetics10040200 - 25 Mar 2025

Abstract

This study developed and evaluated a novel upper-limb rehabilitation device that integrates piano playing into task-oriented occupational therapy, addressing the limitations of traditional continuous passive motion (CPM) training in patient engagement and functional recovery. The system features a bi-axial sliding platform for precise [...] Read more.

This study developed and evaluated a novel upper-limb rehabilitation device that integrates piano playing into task-oriented occupational therapy, addressing the limitations of traditional continuous passive motion (CPM) training in patient engagement and functional recovery. The system features a bi-axial sliding platform for precise 61-key positioning and a ten-link, four-loop robotic hand for key striking. A hierarchical control framework incorporates MIDI-based task mapping, finger optimization using an improved Hungarian algorithm, and impedance–admittance hybrid control for adaptive force–position modulation. An 8-week randomized controlled trial demonstrated that the experimental group significantly outperformed the control group, with a 74.7% increase in Fugl–Meyer scores (50.5 ± 2.5), a 14.6-point improvement in the box and block test (BBT), a 20.2-s reduction in nine-hole peg test (NHPT) time, and a 72.6% increase in rehabilitation motivation scale (RMS) scores (55.4 ± 3.8). The results indicate that combining piano playing with robotic rehabilitation enhances neuroplasticity and engagement, significantly improving motor function, daily activity performance, and rehabilitation adherence. This mechanical-control synergy introduces a new paradigm for music-interactive rehabilitation, with potential applications in home-based remote therapy and multimodal treatment integration. Full article

(This article belongs to the Special Issue Recent Advances in Wearable Bioelectronics in Healthcare/Medical Devices)

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16 pages, 7495 KiB

Open AccessArticle

Optimization of Structural Parameters and Mechanical Performance Analysis of a Novel Redundant Actuation Rehabilitation Training Robot

by Junyu Wu, He Wang, Yubin Liu, Zhuoqi Man, Xiaofan Yang, Xuanming Cao, Hegao Cai and Jie Zhao

Biomimetics 2025, 10(4), 199; https://doi.org/10.3390/biomimetics10040199 - 25 Mar 2025

Abstract

The integration of redundant structures into robotic systems enhances the degrees of freedom (DOFs), flexibility, and capability to perform complex tasks. This study evaluates the mechanical performance of a 9-DOF series-parallel hybrid redundant device designed for rehabilitation training of patients with balance disorders. [...] Read more.

The integration of redundant structures into robotic systems enhances the degrees of freedom (DOFs), flexibility, and capability to perform complex tasks. This study evaluates the mechanical performance of a 9-DOF series-parallel hybrid redundant device designed for rehabilitation training of patients with balance disorders. The redundant structural design improves the robot’s movement flexibility, optimizes load distribution, and mitigates stress concentration in local joints or components. To optimize the robot’s overall structural parameters and reduce joint driving forces, a genetic algorithm (GA) was employed. A custom dataset was created by collecting motion-related data, including foot posture and position. The robot’s mechanical characteristics were comprehensively analyzed, followed by simulation experiments. The results demonstrate that incorporating the redundant structure, along with the optimization of structural parameters, significantly enhances the robot’s mechanical performance. This study provides a solid foundation for the functional development and control system design of rehabilitation robots, extending the capabilities of existing systems and offering a novel, reliable, and efficient therapeutic tool for patients with balance disorders. Full article

(This article belongs to the Special Issue Recent Advances in Robotics and Biomimetics)

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16 pages, 6670 KiB

Open AccessArticle

Enhancing Thrust in Underwater Bio-Inspired Propulsion Fin Using Shear-Stiffening Gel

by Shunichi Kobayashi and Yusuke Jonishi

Biomimetics 2025, 10(4), 198; https://doi.org/10.3390/biomimetics10040198 - 25 Mar 2025

Abstract

In this study, we investigated the thrust enhancement in a bio-inspired underwater propulsion fin using a shear-stiffening gel. Shear-stiffening gels exhibit velocity-dependent stiffness, i.e., they become stiffer during high-speed deformation and softer during low-speed motion, providing adaptive mechanical properties without requiring complex mechanisms. [...] Read more.

In this study, we investigated the thrust enhancement in a bio-inspired underwater propulsion fin using a shear-stiffening gel. Shear-stiffening gels exhibit velocity-dependent stiffness, i.e., they become stiffer during high-speed deformation and softer during low-speed motion, providing adaptive mechanical properties without requiring complex mechanisms. A “compound joint” incorporating a dilatant compound, a material of shear-stiffening gel, was developed and experimentally evaluated against a “rigid joint” and a flexible “urethane joint”. A speed-ratio control strategy was employed to assign faster and slower oscillations during positive and negative thrust intervals, respectively. The results demonstrated that the compound joint achieved a balance between high thrust and stable performance. Its adaptive stiffness effectively reduced deformation during high-speed oscillations, enhanced thrust while maintaining flexibility during low-speed intervals, and minimized thrust fluctuations. Compared with the rigid and urethane joints, the compound joint exhibited a superior balance between a high average thrust and low thrust variation. Full article

(This article belongs to the Special Issue Biomimicry and Functional Materials: 4th Edition)

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36 pages, 2866 KiB

Open AccessArticle

Optimizing the Design of TES Tanks for Thermal Energy Storage Applications Through an Integrated Biomimetic-Genetic Algorithm Approach

by Nadiya Mehraj, Carles Mateu, Gabriel Zsembinszki and Luisa F. Cabeza

Biomimetics 2025, 10(4), 197; https://doi.org/10.3390/biomimetics10040197 - 24 Mar 2025

Abstract

Building upon an experimentally validated bio-inspired thermal energy storage (TES) tank design, this study introduced a novel computational framework that integrated genetic algorithms (GA) with biomimetic principles to systematically generate TES tank geometries. Inspired by natural thermal distribution patterns found in vascular networks, [...] Read more.

Building upon an experimentally validated bio-inspired thermal energy storage (TES) tank design, this study introduced a novel computational framework that integrated genetic algorithms (GA) with biomimetic principles to systematically generate TES tank geometries. Inspired by natural thermal distribution patterns found in vascular networks, the AI-driven methodology explored 13 geometric parameters, focusing on branching structures and spatial distribution, and resulted in computationally generated designs with a 29% increase in heat transfer surface area while maintaining manufacturability constraints within a fixed tank diameter of 150 mm and height of 155 mm. Unlike previous biomimetic TES studies that relied on predefined geometric configurations, this approach developed AI-driven bio-inspired structures within experimentally validated dimensional constraints, ensuring geometric relevance while allowing for broader structural exploration. The resulting designs exhibited key characteristics of high-efficiency bio-inspired configurations while providing a systematic, scalable methodology for TES tank architecture. This study represented the first step in integrating AI-driven biomimicry into TES tank design, establishing a structured framework for generating high-performance, manufacturable configurations. While the current work focused on computational design, future research will emphasize experimental validation and real-world implementation to confirm the practical thermal and structural benefits of these AI-generated bio-inspired designs. By bridging the gap between computational intelligence and nature-inspired engineering, this research provided a scalable pathway for developing more efficient, manufacturable, and sustainable TES solutions for energy storage applications. Full article

(This article belongs to the Special Issue Nature-Inspired Metaheuristic Optimization Algorithms 2025)

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25 pages, 15691 KiB

Open AccessReview

The Right Tool for the Job: A Review of Insect Mouthparts as a Tool Kit for Biomimetic Studies

by Matthew S. Lehnert, Kendall O. Myers and Kristen E. Reiter

Biomimetics 2025, 10(4), 196; https://doi.org/10.3390/biomimetics10040196 - 24 Mar 2025

Abstract

Few traits exhibit a more diverse collection of exemplary structure–function relationships than the mouthparts of insects. The global dominance of insects is attributed to their diverse food sources, which are matched by an array of morphological and chemical adaptations: a ‘tool kit’ for [...] Read more.

Few traits exhibit a more diverse collection of exemplary structure–function relationships than the mouthparts of insects. The global dominance of insects is attributed to their diverse food sources, which are matched by an array of morphological and chemical adaptations: a ‘tool kit’ for biomimicry. This review provides an overview of insect mouthparts that have contributed to biomimetics, including information about morphology and functionality in relation to particular feeding mechanisms. Themes in the groups of insects employed for particular biomimetic studies, including their lineages and feeding strategies, are identified along with suggestions for future studies, which together underscore the importance and promise of the development of novel engineered devices inspired by the unique ‘tools’ of insect mouthparts. Full article

(This article belongs to the Special Issue Functional Morphology and Biomimetics: Learning from Insects)

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36 pages, 8872 KiB

Open AccessArticle

The Modified Sparrow Search Algorithm with Brown Motion and Levy Flight Strategy for the Class Integration Test Order Generation Problem

by Chongyang Jiao, Qinglei Zhou, Wenning Zhang and Chunyan Zhang

Biomimetics 2025, 10(4), 195; https://doi.org/10.3390/biomimetics10040195 - 21 Mar 2025

Abstract

Software testing identifies potential errors and defects in software. A crucial component of software testing is integration testing, and the generation of class integration test orders (CITOs) is a critical topic in integration testing. The research shows that search-based algorithms can solve this [...] Read more.

Software testing identifies potential errors and defects in software. A crucial component of software testing is integration testing, and the generation of class integration test orders (CITOs) is a critical topic in integration testing. The research shows that search-based algorithms can solve this problem effectively. As a novel search-based algorithm, the sparrow search algorithm (SSA) is good at finding the optimal to optimization problems, but it has drawbacks like weak population variety later on and the tendency to easily fall into the local optimum. To overcome its shortcomings, a modified sparrow search algorithm (MSSA) is developed and applied to the CITO generation issue. The algorithm is initialized with a good point set strategy, which distributes the sparrows evenly in the solution space. Then, the discoverer learning strategy of Brownian motion is introduced and the Levy flight is utilized to renew the positions of the followers, which balances the global search and local search of the algorithm. Finally, the optimal solution is subjected to random wandering to increase the probability of the algorithm jumping out of the local optimum. Using the overall stubbing complexity as a fitness function to evaluate different class test sequences, experiments are conducted on open-source Java systems, and the experimental results demonstrate that the MSSA generates test orders with lower stubbing cost in a shorter time than other novel intelligent algorithms. The superiority of the proposed algorithm is verified by five evaluation indexes: the overall stubbing complexity, attribute complexity, method complexity, convergence speed, and running time. The MSSA has shown significant advantages over the BSSA in all aspects. Among the nine systems, the total overall stubbing complexity of the MSSA is 13.776% lower than that of the BSSA. Total time is reduced by 23.814 s. Full article

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