Biomimetics

30 pages, 3427 KiB

Open AccessArticle

An Enhanced Team-Oriented Swarm Optimization Algorithm (ETOSO) for Robust and Efficient High-Dimensional Search

by Adel BenAbdennour

Biomimetics 2025, 10(4), 222; https://doi.org/10.3390/biomimetics10040222 - 3 Apr 2025

This paper introduces the Enhanced Team-Oriented Swarm Optimization (ETOSO) algorithm, a novel refinement of the Team-Oriented Swarm Optimization (TOSO) algorithm aimed at addressing the stagnation problem commonly encountered in nature-inspired optimization approaches. ETOSO enhances TOSO by integrating innovative strategies for exploration and exploitation, [...] Read more.

This paper introduces the Enhanced Team-Oriented Swarm Optimization (ETOSO) algorithm, a novel refinement of the Team-Oriented Swarm Optimization (TOSO) algorithm aimed at addressing the stagnation problem commonly encountered in nature-inspired optimization approaches. ETOSO enhances TOSO by integrating innovative strategies for exploration and exploitation, resulting in a simplified algorithm that demonstrates superior performance across a broad spectrum of benchmark functions, particularly in high-dimensional search spaces. A comprehensive comparative evaluation and statistical tests against 26 established nature-inspired optimization algorithms (NIOAs) across 15 benchmark functions and dimensions (D = 2, 5, 10, 30, 50, 100, 200) confirm ETOSO’s superiority relative to solution accuracy, convergence speed, computational complexity, and consistency. Full article

(This article belongs to the Special Issue Advances in Swarm Intelligence Optimization Algorithms and Applications)

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22 pages, 9907 KiB

Open AccessArticle

Advanced Modular Honeycombs with Biomimetic Density Gradients for Superior Energy Dissipation

by Yong Dong, Jie He, Dongtao Wang, Dazhi Luo, Yanghui Zeng, Haixia Feng, Xizhen You and Lumin Shen

Biomimetics 2025, 10(4), 221; https://doi.org/10.3390/biomimetics10040221 - 3 Apr 2025

Abstract

The honeycomb configuration has been widely adopted in numerous sectors owing to its superior strength-to-weight ratio, rigidity, and outstanding energy absorption properties, attracting substantial academic attention and research interest. This study introduces a biomimetic modular honeycomb configuration inspired by the variable-density biological enhancement [...] Read more.

The honeycomb configuration has been widely adopted in numerous sectors owing to its superior strength-to-weight ratio, rigidity, and outstanding energy absorption properties, attracting substantial academic attention and research interest. This study introduces a biomimetic modular honeycomb configuration inspired by the variable-density biological enhancement characteristics of tree stem tissues. This study examined the out-of-plane compressive behavior and mechanical characteristics of modular honeycomb structures. A numerical model of the modular honeycomb was constructed utilizing finite element technology, enabling simulation studies at varying impact velocities. The improved weight-bearing and impact-absorbing properties of modular honeycomb structures are investigated using theoretical analysis and computer simulations. It also scrutinizes the effects of boundary and matching conditions on the honeycomb’s performance. The results indicate that adjusting the thickness of the walls in both the matrix honeycomb and sub-honeycomb structures can substantially improve their resistance to low-velocity out-of-plane compression impacts. Furthermore, the energy absorption capacity of modular honeycombs during high-velocity impacts is significantly influenced by multiple factors: the impact velocity, the density of the honeycomb structure, and the distribution of wall thickness within the sub-honeycomb and the primary honeycomb matrix. Notably, the modular honeycomb with an optimally designed structure demonstrates superior high-speed impact resistance compared to conventional honeycombs of equivalent density. These insights underscore the potential for advanced honeycomb designs to further advance material performance in structural applications. Full article

(This article belongs to the Special Issue Biomimetic Energy-Absorbing Materials or Structures)

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Graphical abstract

4 pages, 1266 KiB

Open AccessEditorial

Biological Attachment Systems and Biomimetics—In Memory of William Jon P. Barnes

by Thies H. Büscher and Stanislav N. Gorb

Biomimetics 2025, 10(4), 220; https://doi.org/10.3390/biomimetics10040220 - 2 Apr 2025

Abstract

Any system preventing the separation of two surfaces may be defined as an attachment system [...] Full article

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

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23 pages, 2370 KiB

Open AccessArticle

Designing Effective Drug Therapies Using a Multiobjective Spider-Wasp Optimizer

by Trong-The Nguyen, Thi-Kien Dao, Van-Thien Nguyen and Duc-Tinh Pham

Biomimetics 2025, 10(4), 219; https://doi.org/10.3390/biomimetics10040219 - 2 Apr 2025

Abstract

Designing effective drug therapies requires balancing competing objectives, such as therapeutic efficacy, safety, and cost efficiency—a task that poses significant challenges for conventional optimization methods. To address this, we propose the multi-objective spider–wasp optimizer (MOSWO), a novel approach uniquely emulating the cooperative predation [...] Read more.

Designing effective drug therapies requires balancing competing objectives, such as therapeutic efficacy, safety, and cost efficiency—a task that poses significant challenges for conventional optimization methods. To address this, we propose the multi-objective spider–wasp optimizer (MOSWO), a novel approach uniquely emulating the cooperative predation dynamics between spiders and wasps observed in nature. MOSWO integrates adaptive mechanisms for exploration and exploitation to resolve complex trade-offs in multiobjective drug design. Unlike existing approaches, the algorithm employs a dynamic population-partitioning strategy inspired by predator–prey interactions, enabling efficient Pareto frontier discovery. We validate MOSWO’s performance through extensive experiments on synthetic benchmarks and real-world case studies spanning antiviral and antibiotic therapies. Results demonstrate that MOSWO surpasses state-of-the-art methods (NSGA-II, MOEA/D, MOGWO, and MOPSO), achieving 11% higher hypervolume scores, 8% lower inverted generational distance scores, 9% higher spread scores, a 30% faster convergence, and superior robustness against noisy biological datasets. The framework’s adaptability to diverse therapeutic scenarios underscores its potential as a transformative tool for computational pharmacology. Full article

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43 pages, 37541 KiB

Open AccessArticle

Hybrid Adaptive Crayfish Optimization with Differential Evolution for Color Multi-Threshold Image Segmentation

by Honghua Rao, Heming Jia, Xinyao Zhang and Laith Abualigah

Biomimetics 2025, 10(4), 218; https://doi.org/10.3390/biomimetics10040218 - 2 Apr 2025

Abstract

To better address the issue of multi-threshold image segmentation, this paper proposes a hybrid adaptive crayfish optimization algorithm with differential evolution for color multi-threshold image segmentation (ACOADE). Due to the insufficient convergence ability of the crayfish optimization algorithm in later stages, it is [...] Read more.

To better address the issue of multi-threshold image segmentation, this paper proposes a hybrid adaptive crayfish optimization algorithm with differential evolution for color multi-threshold image segmentation (ACOADE). Due to the insufficient convergence ability of the crayfish optimization algorithm in later stages, it is challenging to find a more optimal solution for optimization. ACOADE optimizes the maximum foraging quantity parameter p and introduces an adaptive foraging quantity adjustment strategy to enhance the randomness of the algorithm. Furthermore, the core formula of the differential evolution (DE) algorithm is incorporated to balance ACOADE’s exploration and exploitation capabilities better. To validate the optimization performance of ACOADE, the IEEE CEC2020 test function was selected for experimentation, and eight other algorithms were chosen for comparison. To verify the effectiveness of ACOADE for threshold image segmentation, the Kapur entropy method and Otsu method were used as objective functions for image segmentation and compared with eight other algorithms. Subsequently, the peak signal-to-noise ratio (PSNR), feature similarity index measure (FSIM), structural similarity index measure (SSIM), and Wilcoxon test were employed to evaluate the quality of the segmented images. The results indicated that ACOADE exhibited significant advantages in terms of objective function value, image quality metrics, convergence, and robustness. Full article

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Graphical abstract

17 pages, 3808 KiB

Open AccessReview

Smart Nanocarriers in Cosmeceuticals Through Advanced Delivery Systems

by Jinku Kim

Biomimetics 2025, 10(4), 217; https://doi.org/10.3390/biomimetics10040217 - 2 Apr 2025

Abstract

Nanomaterials have revolutionized various biological applications, including cosmeceuticals, enabling the development of smart nanocarriers for enhanced skin delivery. This review focuses on the role of nanotechnologies in skincare and treatments, providing a concise overview of smart nanocarriers, including thermo-, pH-, and multi-stimuli-sensitive systems, [...] Read more.

Nanomaterials have revolutionized various biological applications, including cosmeceuticals, enabling the development of smart nanocarriers for enhanced skin delivery. This review focuses on the role of nanotechnologies in skincare and treatments, providing a concise overview of smart nanocarriers, including thermo-, pH-, and multi-stimuli-sensitive systems, focusing on their design, fabrication, and applications in cosmeceuticals. These nanocarriers offer controlled release of active ingredients, addressing challenges like poor skin penetration and ingredient instability. This work discusses the unique properties and advantages of various nanocarrier types, highlighting their potential in addressing diverse skin concerns. Furthermore, we address the critical aspect of biocompatibility, examining potential health risks associated with nanomaterials. Finally, this review highlights current challenges, including the precise control of drug release, scalability, and the transition from in vitro to in vivo applications. We also discuss future perspectives such as the integration of digital technologies and artificial intelligence for personalized skincare to further advance the technology of smart nanocarriers in cosmeceuticals. Full article

(This article belongs to the Special Issue Advances in Biogenic and Biomimetic Materials: From Bionanomedicine to Environmental Applications and Beyond)

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19 pages, 2297 KiB

Open AccessArticle

A Biomimetic Approach to Diode Laser Use in Endodontic Treatment of Immature Teeth: Thermal, Structural, and Biological Analysis

by Dijana D. Mitic, Maja S. Milosevic Markovic, Igor D. Jovanovic, Dragan D. Mancic, Kaan Orhan, Vukoman R. Jokanovic and Dejan Lj. Markovic

Biomimetics 2025, 10(4), 216; https://doi.org/10.3390/biomimetics10040216 - 2 Apr 2025

Abstract

The root walls of immature permanent teeth are often weak, thin, and short, making regenerative endodontic treatment (RET) necessary. The goal of RET is to create a favorable environment for further root development. A biomimetic approach is essential for thorough disinfection, followed by [...] Read more.

The root walls of immature permanent teeth are often weak, thin, and short, making regenerative endodontic treatment (RET) necessary. The goal of RET is to create a favorable environment for further root development. A biomimetic approach is essential for thorough disinfection, followed by the preservation and potential stimulation of stem cells from surrounding tissue to enable root regeneration and continued development. The objective of this study was to assess temperature changes on the external root surface, structural alterations in the internal root walls following irradiation with a 940 nm diode laser, and the biocompatibility of stem cells from the apical papilla (SCAPs). Irradiation was performed with varying output powers (0.5 W, 1 W, 1.5 W, and 2 W) in continuous mode for 5 s over four consecutive cycles. Thermographic measurements during irradiation, the micro-CT analysis of root samples, and mitochondrial activity of SCAPs were evaluated. The heating effect correlated directly with a higher output power and thinner root walls. A 1 W output power was found to be safe for immature teeth, particularly in the apical third of the root, while 1.5 W could be safely used for mature mandibular incisors. Diode laser irradiation at 1 W and 1.5 W significantly stimulated SCAPs’ mitochondrial activity within 24 h post-irradiation, indicating a potential photobiostimulatory effect. However, no significant changes were observed at lower (0.5 W) and higher (2 W) output powers. The area of open tubular space inside the root canal was significantly reduced after irradiation, regardless of the applied power. Additionally, irradiation contributed to the demineralization of the dentin on the inner root walls. Future studies should explore the impact of irrigants used between irradiation cycles, the potential benefits of conical laser tips for more even energy distribution, and a thorough analysis of how disinfection protocols affect both the dentin structure and stem cell viability. Full article

(This article belongs to the Special Issue Functional Biomimetic Materials and Devices for Biomedical Applications: 4th Edition)

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Graphical abstract

18 pages, 4141 KiB

Open AccessArticle

FROM: A Fish Recognition-Inspired Optimization Method for Multi-Agent Decision-Making Problems with a Fluid Environment

by Yuchen Wang and Lei Sun

Biomimetics 2025, 10(4), 215; https://doi.org/10.3390/biomimetics10040215 - 2 Apr 2025

Abstract

Underwater multi-agent systems face critical hydrodynamic constraints that significantly degrade the performance of conventional constraint optimization algorithms in dynamic fluid environments. To meet the needs of underwater multi-agent applications, a fish recognition-inspired optimization method (FROM) is proposed in this paper. The proposed method [...] Read more.

Underwater multi-agent systems face critical hydrodynamic constraints that significantly degrade the performance of conventional constraint optimization algorithms in dynamic fluid environments. To meet the needs of underwater multi-agent applications, a fish recognition-inspired optimization method (FROM) is proposed in this paper. The proposed method introduces the characteristics of fish recognition. There are two major improvements in the proposed method: the neighbor topology improvement based on vision recognition and the learning strategies improvement based on hydrodynamic recognition. The computational complexity of the proposed algorithm was analyzed, and it was found to be acceptable. The statistical analysis of the experimental results shows that the FROM algorithm performs better than other algorithms in terms of minimum, maximum, standard deviation, mean, and median values calculated from objective functions. With solid experiment results, we conclude that the proposed FROM algorithm is a better solution to solve multi-agent decision-making problems with fluid environment constraints. Full article

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24 pages, 1540 KiB

Open AccessReview

Myoelectric Control in Rehabilitative and Assistive Soft Exoskeletons: A Comprehensive Review of Trends, Challenges, and Integration with Soft Robotic Devices

by Alejandro Toro-Ossaba, Juan C. Tejada and Daniel Sanin-Villa

Biomimetics 2025, 10(4), 214; https://doi.org/10.3390/biomimetics10040214 - 1 Apr 2025

Abstract

Soft robotic exoskeletons have emerged as a transformative solution for rehabilitation and assistance, offering greater adaptability and comfort than rigid designs. Myoelectric control, based on electromyography (EMG) signals, plays a key role in enabling intuitive and adaptive interaction between the user and the [...] Read more.

Soft robotic exoskeletons have emerged as a transformative solution for rehabilitation and assistance, offering greater adaptability and comfort than rigid designs. Myoelectric control, based on electromyography (EMG) signals, plays a key role in enabling intuitive and adaptive interaction between the user and the exoskeleton. This review analyzes recent advancements in myoelectric control strategies, emphasizing their integration into soft robotic exoskeletons. Unlike previous studies, this work highlights the unique challenges posed by the deformability and compliance of soft structures, requiring novel approaches to motion intention estimation and control. Key contributions include critically evaluating machine learning-based motion prediction, model-free adaptive control methods, and real-time validation strategies to enhance rehabilitation outcomes. Additionally, we identify persistent challenges such as EMG signal variability, computational complexity, and the real-time adaptability of control algorithms, which limit clinical implementation. By interpreting recent trends, this review highlights the need for improved EMG acquisition techniques, robust adaptive control frameworks, and enhanced real-time learning to optimize human-exoskeleton interaction. Beyond summarizing the state of the art, this work provides an in-depth discussion of how myoelectric control can advance rehabilitation by ensuring more responsive and personalized exoskeleton assistance. Future research should focus on refining control schemes tailored to soft robotic architectures, ensuring seamless integration into rehabilitation protocols. This review is a foundation for developing intelligent soft exoskeletons that effectively support motor recovery and assistive applications. Full article

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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

Abstract

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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Biomimetics

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