3,186 results on '"Soft materials"'
Search Results
2. Deep Indentation Tests of Soft Materials Using Mobile and Stationary Devices.
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Nowak, Joanna and Kaczmarek, Mariusz K.
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ELASTICITY , *MATERIALS testing , *FOOD quality , *URETHANE foam , *FOOD testing - Abstract
Measurements of the properties of soft materials are important from the point of view of medical diagnostics of soft tissues as well as testing the quality of food products and many technical materials. One of the frequently used techniques for testing such materials, attractive due to its non-invasive nature, is the indentation technique, which does not puncture the material. The difficulty of testing soft materials, which affects the objectivity of the results, is related to the problems of stable positioning of the studied material in relation to the indentation apparatus, especially with a device held by the operator. This work concerns the comparison of test results using an indentation apparatus mounted on mobile and stationary handles. The tested materials are cylindrical samples of polyurethane foams with three different stiffnesses and the same samples with a 0.5 or 1 mm thick silicone layer. The study presented uses an apparatus with a flat cylindrical indenter, with a surface area of 1 cm2, pressed to a depth of 10 mm (so-called deep tests). Based on the recorded force changes over time, five descriptors of the indentation test were determined and compared for both types of handles. The tests performed showed that the elastic properties of foam materials alone and with a silicone layer can be effectively characterized by the maximum forces during recessing and retraction and the slopes of the recessing and retraction curves. In the case of two-layer materials, these descriptors reflect both the characteristics of the foams and the silicone layer. The results show that the above property of the deep indentation method distinguishes it from the shallow indentation method. The repeatability of the tests performed in the mobile and stationary holders were determined to be comparable. [ABSTRACT FROM AUTHOR]
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- 2024
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3. The Application of Regenerated Silk Fibroin in Tissue Repair.
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Li, Zhaoyi, Tan, Guohongfang, Xie, Huilin, and Lu, Shenzhou
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WOUND healing , *SILK fibroin , *BIOMEDICAL materials , *TISSUE remodeling , *DRUG carriers , *SKIN regeneration , *TISSUE scaffolds - Abstract
Silk fibroin (SF) extracted from silk is non-toxic and has excellent biocompatibility and biodegradability, making it an excellent biomedical material. SF-based soft materials, including porous scaffolds and hydrogels, play an important role in accurately delivering drugs to wounds, creating microenvironments for the adhesion and proliferation of support cells, and in tissue remodeling, repair, and wound healing. This article focuses on the study of SF protein-based soft materials, summarizing their preparation methods and basic applications, as well as their regenerative effects, such as drug delivery carriers in various aspects of tissue engineering such as bone, blood vessels, nerves, and skin in recent years, as well as their promoting effects on wound healing and repair processes. The authors expect SF soft materials to play an important role in the field of tissue repair. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Acoustic Properties of Stretchable Liquid Metal‐Elastomer Composites for Matching Layers in Wearable Ultrasonic Transducer Arrays.
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Krings, Ethan J., Hage, Benjamin D., Truong, Sequoia L., Reeser, Kiersten A., Fox, Eli L., Snyder, Matthew G., Walker, Quentin, Bashford, Gregory R., and Markvicka, Eric J.
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ACOUSTIC impedance , *DOPPLER ultrasonography , *LIQUID metals , *ULTRASONIC transducers , *ULTRASONIC arrays - Abstract
Ultrasound is a safe, noninvasive diagnostic technique used to measure internal structures such as tissues, organs, and arterial and venous blood flow. Skin‐mounted wearable ultrasound devices can enable long‐term continuous monitoring of patients to provide solutions to critical healthcare needs. However, stretchable ultrasound devices that are composed of ultrasonic transducers embedded in an elastomer matrix are incompatible with existing rigid acoustic matching layers, leading to reduced energy transmission and reduced imaging resolution. Here, a systematic study of soft composites with liquid metal (LM) fillers dispersed in elastomers reveals key strategies to tune the acoustic impedance of soft materials. Experiments supported by theoretical models demonstrate that the increase in acoustic impedance is primarily driven by the increase in density with negligible changes to the speed of sound through the material. By controlling the volume loading and particle size of the LM fillers, a material is created that achieves a high acoustic impedance 4.8 Mrayl, (> 440% increase over the polymer matrix) with low modulus (< 1 MPa) and high stretchability (> 100% strain). When the device is mechanically strained, a small decrease is observed in acoustic impedance (< 15%) with negligible decrease in sound transmittance and impact on attenuation for all droplet sizes. The stretchable acoustic matching layer is then integrated with a wearable ultrasound device and the ability to measure motion is demonstrated using a phantom model as is performed in Doppler ultrasound. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Liquid Metal‐Based Biosensors: Fundamentals and Applications.
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Jamalzadegan, Sina, Kim, Sooyoung, Mohammad, Noor, Koduri, Harshita, Hetzler, Zach, Lee, Giwon, Dickey, Michael D., and Wei, Qingshan
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LIQUID metals , *BIOLOGICAL systems , *PATIENT monitoring , *ELECTRIC conductivity , *THERMAL conductivity - Abstract
Biosensors are analytical tools for monitoring various parameters related to living organisms, such as humans and plants. Liquid metals (LMs) have emerged as a promising new material for biosensing applications in recent years. LMs have attractive physical and chemical properties such as deformability, high thermal and electrical conductivity, low volatility, and low viscosity. LM‐based biosensors represent a new strategy in biosensing particularly for wearable and real‐time sensing. While early demonstrations of LM biosensors focus on monitoring physical parameters such as strain, motion, and temperature, recent examples show LM can be an excellent sensing material for biochemical and biomolecular detection as well. In this review, the recent progress of LM‐based biosensors for personalized healthcare and disease monitoring via both physical and biochemical signaling is survey. It is started with a brief introduction of the fundamentals of biosensors and LMs, followed by a discussion of different mechanisms by which LM can transduce biological or physiological signals. Next, it is reviewed example LM‐based biosensors that have been used in real biological systems, ranging from real‐time on‐skin physiological monitoring to target‐specific biochemical detection. Finally, the challenges and future directions of LM‐integrated biosensor platforms is discussed. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Harnessing Gravity‐Induced Instability of Soft Materials: Mechanics and Application.
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Lü, Chaofeng, Li, Kecheng, Du, Yangkun, Zhang, Haoran, Liu, Congshan, and Zhan, Haifei
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WRINKLE patterns , *ELASTIC modulus , *TISSUES , *ELASTOMERS , *GRAVITY - Abstract
This work offers a comprehensive overview of how gravity affects soft materials, with a particular emphasis on gravity‐induced instability. Soft materials, including biological tissues, elastomers, and gels, are characterized by low elastic moduli and the ability to undergo significant deformations. These large deformations can lead to instabilities and the emergence of distinctive surface patterns when even small perturbations are introduced. An in‐depth understanding of these gravity‐induced instabilities in soft materials is of paramount importance for both fundamental scientific research and practical applications across diverse domains. The underlying mechanisms governing these instabilities are delved in and elucidate the techniques employed to study and manipulate them. Further, the gravity‐induced wrinkling and the Rayleigh‐Taylor (RT) instability in soft materials are zoomed in, highlighting how altered gravity environments impact natural and synthetic systems. Lastly, current and potential applications are underscored where gravity‐induced instabilities are already making an impact or may hold promise in the near future. In sum, the exploration of gravity‐induced instabilities in soft materials paves the way for innovative applications and advancements in a wide range of fields. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Advanced Flexible Sensing Technologies for Soft Robots.
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Qu, Juntian, Cui, Guangming, Li, Zhenkun, Fang, Shutong, Zhang, Xianrui, Liu, Ang, Han, Mingyue, Liu, Houde, Wang, Xueqian, and Wang, Xiaohao
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APPROPRIATE technology , *ROBOTS , *SURGICAL robots , *ROBOTICS , *BIOLOGICAL systems , *SMART materials , *SOFT robotics - Abstract
Soft robots have recently attracted increasing interest due to their advantages in durability, flexibility, and deformability, which enable them to adapt to unstructured environments and perform various complex tasks. Perception is crucial for soft robots. To better mimic biological systems, sensors need to be integrated into soft robotic systems to obtain both proprioceptive and external perception for effective usage. This review summarizes the latest advancements in flexible sensing feedback technologies for soft robotic applications. It begins with an introduction to the development of various flexible sensors for soft robots, followed by an in‐depth exploration of smart materials and advanced manufacturing methods. A detailed description of flexible sensing modalities and methodologies is also included in the review to illustrate the continuous breakthrough of the technology. In addition, the applications of soft robots based on these advanced sensing technologies are concluded as well. The challenges of flexible sensing technologies for soft robots and promising solutions are finally discussed and analyzed to provide a prospect for future development. By examining the recent advances in intelligent flexible sensing technologies, this review is dedicated to highlighting the potential of soft robotics and motivating innovation within the field. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Chemical Botany: Bottlebrush Polymers in Materials Science.
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Lapkriengkri, Intanon, Albanese, Kaitlin R., Rhode, Andrew, Cunniff, Austin, Pitenis, Angela A., Chabinyc, Michael L., and Bates, Christopher M.
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Molecular architectures known as bottlebrush polymers provide unique opportunities to tune the structure and properties of soft materials with applications ranging from rubbers to thin films and composites. This review addresses recent developments and future opportunities in the field with an emphasis on materials science enabled by contemporary bottlebrush chemistry. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Rigidity‐Tunable Materials for Soft Engineering Systems.
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Roh, Yeonwook, Lim, Daseul, Kang, Minji, Cho, Junggwang, Han, Seungyong, and Ko, Seung Hwan
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ENGINEERING systems ,MECHANICAL behavior of materials ,TASK performance ,ENERGY consumption - Abstract
Engineering systems that leverage the flexibility and softness of soft materials have been fostering revolutionary progress and broad interest across various applications. The inherently flexible mechanical properties of these materials lay the groundwork for engineering systems that can adapt comparably to biological organisms, enabling them to adjust to unpredictable environments effectively. However, alongside the positive benefits of softness, these systems face challenges such as low durability, continuous energy demands, and compromised task performance due to the inherently low stiffness of soft materials. These limitations pose significant obstacles to the practical impact of soft engineering systems in the real world beyond innovative concepts. This review presents a strategy that employs materials with variable stiffness to balance adaptability advantages with the challenge of low rigidity. The developments are summarized in materials capable of stiffness modulation alongside their applications in electronics, robotics, and biomedical fields. This focus on stiffness modulation at the material unit level is a critical step toward enabling the practical application of soft engineering systems in real‐world scenarios. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Soft Actuators and Actuation: Design, Synthesis, and Applications.
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Kalulu, Mulenga, Chilikwazi, Bright, Hu, Jun, and Fu, Guodong
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Soft actuators are one of the most promising technological advancements with potential solutions to diverse fields’ day‐to‐day challenges. Soft actuators derived from hydrogel materials possess unique features such as flexibility, responsiveness to stimuli, and intricate deformations, making them ideal for soft robotics, artificial muscles, and biomedical applications. This review provides an overview of material composition and design techniques for hydrogel actuators, exploring 3D printing, photopolymerization, cross‐linking, and microfabrication methods for improved actuation. It examines applications of hydrogel actuators in biomedical, soft robotics, bioinspired systems, microfluidics, lab‐on‐a‐chip devices, and environmental, and energy systems. Finally, it discusses challenges, opportunities, advancements, and regulatory aspects related to hydrogel actuators. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Damage Prediction for Integrated DEAP and MRE Soft Actuators.
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Bernat, Jakub, Kołota, Jakub, Gajewski, Piotr, Marcinkowska, Agnieszka, Komosinski, Maciej, and Szczęsny, Szymon
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ACTUATORS , *HAPTIC devices , *SOFT robotics , *MANUFACTURING processes , *HIGH voltages - Abstract
Soft robotics is a hot scientific topic in areas such as medicine and medical care, implantology, haptic technologies, and the design of various flexible structures. Integrated actuators (DEAP and MRE) are characterized by special functionality and a wider range of operations than when used individually. Such actuators can later be controlled with high voltages ranging from several to a dozen or so kV. Unfortunately, the production process of integrated actuators is multi-stage and therefore more complicated. Thus, at the stage of prototyping, microscopic errors often occur that cannot be detected using simple measurement methods. The result of such errors is actuator damage at the testing stage or in subsequent application. Unfortunately, due to high voltages, actuator damage usually leads to it catching fire, which is potentially dangerous. This work presents an approach that enables the prediction of actuator damage at the testing stage. The results of modeling damaged actuators, a modified safe testing method, and a complete supervising system for testing the actuator with protection are shown. The work is also enriched with a set of data from the analyzed damage to DEAP and MRE actuators, which may prove useful in other research on the actuators of soft robotics. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Elastic instabilities of soft laminates with stiffening behavior.
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Yao, Qi, Arora, Nitesh, Chen, Dean, Xiang, Yuhai, and Rudykh, Stephan
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LAMINATED materials , *MICROSCOPY , *NUMERICAL analysis - Abstract
• The elastic instability phenomenon in hyperelastic layered materials with the phases exhibiting stiffening behavior is studied • A closed-form expression for the critical stretch of macroscopic instability is derived • An analytical prediction based on Bloch-Floquet analysis for the microscopic instability is exhibited • The critical parameters and transition of instability modes are found to be highly tunable with phase stiffening This paper investigates the elastic instability behavior in soft periodic laminates subjected to finite strains, with a focus on both macroscopic and microscopic instabilities. Considering the deformation-induced phase stiffening, the Gent model with a high bulk-to-shear modulus ratio describes the behavior of incompressible phases. This non-Gaussian statistics-based model captures the non-linear constitutive results from the limited extensibility of polymeric molecular chains. This paper derives an analytical prediction for the onset of macroscopic (or longwave) instability and microscopic instability as functions of material parameters. Moreover, a numerical Bloch-Floquet analysis is imposed on identifying the instability behavior under compression. We consider a wide range of phase combinations and find that the relatively rapid stiffening of the matrix compared to the stiff layer increases the stability of laminates by decreasing the critical stretch ratio. Essentially, properly manipulating the stiffening parameters can produce an absolutely stable region without observed instability. This paper also systematically illustrates the changes in instability and the transition between macro and micro instability in fully Gent laminates, which show higher stability than fully neo-Hookean laminates with larger critical stretch ratios. The critical characteristics of instabilities, such as critical stretch ratios and critical wavenumbers, can be controlled by the choice of stiffening parameters and other material properties, enlarging the tuning of soft laminates for desired buckling patterns in practical applications. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Friction in Rolling a Cylinder on or Under a Viscoelastic Substrate with Adhesion.
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Nazari, R., Papangelo, A., and Ciavarella, M.
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In classical experiments, it has been found that a rigid cylinder can roll both on and under an inclined rubber plane with a friction force that depends on a power law of velocity, independent of the sign of the normal force. Further, contact area increases significantly with velocity with a related power law. We try to model qualitatively these experiments with a numerical boundary element solution with a standard linear solid and we find for sufficiently large Maugis–Tabor parameter λ qualitative agreement with experiments. However, friction force increases linearly with velocity at low velocities (like in the case with no adhesive hysteresis) and then decays at large speeds. Quantitative agreement with the Persson–Brener theory of crack propagation is found for the two power law regimes, but when Maugis–Tabor parameter λ is small, the cut-off stress in Persson–Brener theory depends on all the other dimensionless parameters of the problem. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Development and application of a 3D image analysis strategy for focused ion beam – Scanning electron microscopy tomography of porous soft materials.
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Prochukhan, Nadezda, Rafferty, Aran, Canavan, Megan, Daly, Dermot, Selkirk, Andrew, Rameshkumar, Saranya, and Morris, Michael A.
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In recent years, the potential of porous soft materials in various device technologies has increased in importance due to applications in fields, such as wearable electronics, medicine, and transient devices. However, understanding the 3‐dimensional architecture of porous soft materials at the microscale remains a challenge. Herein, we present a method to structurally analyze soft materials using Focused Ion Beam – Scanning Electron Microscopy (FIB‐SEM) tomography. Two materials, polymethyl methacrylate (PMMA) membrane and pine wood veneer were chosen as test‐cases. FIB‐SEM was successfully used to reconstruct the true topography of these materials in 3D. Structural and physical properties were subsequently deduced from the rendered 3D models. The methodology used segmentation, coupled with optimized thresholding, image processing, and reconstruction protocols. The 3D models generated pore size distribution, pore inter‐connectivity, tortuosity, thickness, and curvature data. It was shown that FIB‐SEM tomography provides both an informative and visual depiction of structure. To evaluate and validate the FIB‐SEM reconstructions, porous properties were generated from the physical property analysis techniques, gas adsorption analysis using Brunauer‐Emmett‐Teller (BET) surface area analysis and mercury intrusion porosimetry (MIP) analysis. In general, the data obtained from the FIB‐SEM reconstructions was well‐matched with the physical data. Research Highlights: Porous specimens of both synthetic and biological nature, a poly(methyl methacrylate) membrane and a pine veneer respectively, are reconstructed via FIB‐SEM tomography without resin‐embedding.Different thresholding and reconstruction methods are explored whereby shadowing artifacts are present with the aid of free open‐source software.Reconstruction data is compared to physical data: MIP, gas adsorption isotherms which are analyzed via BET and Barrett‐Joyner‐Halenda (BJH) analysis to yield a full picture of the materials. [ABSTRACT FROM AUTHOR]
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- 2024
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15. 3D-printed self-healing, biodegradable materials and their applications.
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Li, Yu, Ma, Guangmeng, Guo, Fawei, Luo, Chunyi, Wu, Han, Luo, Xin, Zhang, Mingtao, Wang, Chenyun, Jin, Qingxin, and Long, Yu
- Abstract
3D printing is a versatile technology capable of rapidly fabricating intricate geometric structures and enhancing the performance of flexible devices in comparison to conventional fabrication methods. However, 3D-printed devices are susceptible to failure as a result of minuscule structural impairments, thereby impacting their overall durability. The utilization of self-healing, biodegradable materials in 3D printing holds immense potential for increasing the longevity and safety of devices, thereby expanding the application prospects for such devices. Nevertheless, enhancing the self-repairing capability of devices and refining the 3D printing performance of self-healing materials are still considerable challenges that need to be addressed to achieve optimal outcomes. This paper reviews recent developments in the field of advancements in 3D printing using self-healing and biodegradable materials. First, it investigates self-healing and biodegradable materials that are compatible with 3D printing techniques, discussing their printability, material properties, and factors that influence print quality. Then, it explores practical applications of self-healing and biodegradable 3D printing technology in depth. Finally, it critically offers practical perspectives on this topic. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Analytical model of friction at low shear rates for soft materials in 3D printing.
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Njezic, Sasa, Zivic, Fatima, Savic, Slobodan, Petrovic, Nenad, Pesic, Zivana Jovanovic, Stefanovic, Anja, Milenkovic, Strahinja, and Grujovic, Nenad
- Abstract
The biological properties of silicone elastomers such as polydimethylsiloxane (PDMS) have widespread use in biomedicine for soft tissue implants, contact lenses, soft robots, and many other small medical devices, due to its exceptional biocompatibility. Additive manufacturing of soft materials still has significant challenges even with major advancements that have occurred in development of these technologies for customized medical devices and tissue engineering. The aim of this study was to develop a mathematical model of tangential stress in relation to shear stress, shear rate, 3D printing pressure and velocity, for non-Newtonian gels and fluids that are used as materials for 3D printing. This study used FENE (finitely extensible nonlinear elastic model) model, for non-Newtonian gels and fluids to define the dependences between tangential stress, velocity, and pressure, considering viscosity, shear stress and shear rates as governing factors in soft materials friction and adhesion. Experimental samples were fabricated as showcases, by SLA and FDM 3D printing technologies: elastic polymer samples with properties resembling elastic properties of PDMS and thermoplastic polyurethane (TPU) samples. Experimental 3D printing parameters were used in the developed analytical solution to analyse the relationships between governing influential factors (tangential stress, printing pressure, printing speed, shear rate and friction coefficient). Maple software was used for numerical modelling. Analytical model applied on a printed elastic polymer, at low shear rates, exhibited numerical values of tangential stress of 0.208–0.216 N m - 2 at printing velocities of 0.9 to 1.2 mm s - 1, while the coefficient of friction was as low as 0.09–0.16. These values were in accordance with experimental data in literature. Printing pressure did not significantly influence tangential stress, whereas it was slightly influenced by shear rate changes. Friction coefficient linearly increased with tangential stress. Simple analytical model of friction for elastic polymer in SLA 3D printing showed good correspondence with experimental literature data for low shear rates, thus indicating possibility to use it for prediction of printing parameters towards desired dimensional accuracy of printed objects. Further development of this analytical model should enable other shear rate regimes, as well as additional soft materials and printing parameters. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Brittle and ductile yielding in soft materials.
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Kamani, Krutarth M. and Rogers, Simon A.
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YIELD stress , *MATERIAL plasticity , *PHYSICS - Abstract
Many soft materials yield under mechanical loading, but how this transition from solid-like behavior to liquid-like behavior occurs can vary significantly. Understanding the physics of yielding is of great interest for the behavior of biological, environmental, and industrial materials, including those used as inks in additive manufacturing and muds and soils. For some materials, the yielding transition is gradual, while others yield abruptly. We refer to these behaviors as being ductile and brittle. The key rheological signatures of brittle yielding include a stress overshoot in steady-shear-startup tests and a steep increase in the loss modulus during oscillatory amplitude sweeps. In this work, we show how this spectrum of yielding behaviors may be accounted for in a continuum model for yield stress materials by introducing a parameter we call the brittility factor. Physically, an increased brittility decreases the contribution of recoverable deformation to plastic deformation, which impacts the rate at which yielding occurs. The model predictions are successfully compared to results of different rheological protocols from a number of real yield stress fluids with different microstructures, indicating the general applicability of the phenomenon of brittility. Our study shows that the brittility of soft materials plays a critical role in determining the rate of the yielding transition and provides a simple tool for understanding its effects under various loading conditions. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Dielectric Elastomer Actuators with Enhanced Durability by Introducing a Reservoir Layer.
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Jung, Sumin, Kang, Minchae, and Han, Min-Woo
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DIELECTRICS , *DIELECTRIC properties , *ELASTOMERS , *BIOMIMETICS , *ACTUATORS , *BIOMIMETIC materials , *ARTIFICIAL muscles - Abstract
A Dielectric Elastomer Actuator (DEA) consists of electrodes with a dielectric layer between them. By controlling the design of the electrodes, voltage, and frequency, the operating range and speed of the DEA can be adjusted. These DEAs find applications in biomimetic robots, artificial muscles, and similar fields. When voltage is applied to the DEA, the dielectric layer undergoes compression and expansion due to electrostatic forces, which can lead to electrical breakdown. This phenomenon is closely related to the performance and lifespan of the DEA. To enhance stability and improve dielectric properties, a DEA Reservoir layer is introduced. Here, stability refers to the ability of the DEA to perform its functions even as the applied voltage increases. The Reservoir layer delays electrical breakdown and enhances stability due to its enhanced thickness. The proposed DEA in this paper is composed of a Reservoir layer and electrode layer. The Reservoir layer is placed between the electrode layers and is independently configured, not subjected to applied voltage like the electrode layers. The performance of the DEA was evaluated by varying the number of polymer layers in the Reservoir and electrode designs. Introducing the Reservoir layer improved the dielectric properties of the DEA and delayed electrical breakdown. Increasing the dielectric constant through the DEA Reservoir can enhance output characteristics in response to electrical signals. This approach can be utilized in various applications in wearable devices, artificial muscles, and other fields. [ABSTRACT FROM AUTHOR]
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- 2024
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19. A Linear Fit for Atomic Force Microscopy Nanoindentation Experiments on Soft Samples.
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Kontomaris, Stylianos Vasileios, Malamou, Anna, Zachariades, Andreas, and Stylianou, Andreas
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YOUNG'S modulus ,SCANNING probe microscopy ,NANOSTRUCTURED materials ,GAUSSIAN function - Abstract
Atomic Force Microscopy (AFM) nanoindentation is a powerful technique for determining the mechanical properties of soft samples at the nanoscale. The Hertz model is typically used for data processing when employing spherical indenters for small indentation depths (h) compared to the radius of the tip (R). When dealing with larger indentation depths, Sneddon's equations can be used instead. In such cases, the fitting procedure becomes more intricate. Nevertheless, as the h/R ratio increases, the force–indentation curves tend to become linear. In this paper the potential of using the linear segment of the curve (for h > R) to determine Young's modulus is explored. Force–indentation data from mouse and human lung tissues were utilized, and Young's modulus was calculated using both conventional and linear approximation methods. The linear approximation proved to be accurate in all cases. Gaussian functions were applied to the results obtained from both classic Sneddon's equations and the simplified approach, resulting in identical distribution means. Moreover, the simplified approach was notably unaffected by contact point determination. The linear segment of the force–indentation curve in deep spherical indentations can accurately determine the Young's modulus of soft materials at the nanoscale. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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20. Technology Roadmap for Flexible Sensors
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Luo, Yifei, Abidian, Mohammad Reza, Ahn, Jong-Hyun, Akinwande, Deji, Andrews, Anne M, Antonietti, Markus, Bao, Zhenan, Berggren, Magnus, Berkey, Christopher A, Bettinger, Christopher John, Chen, Jun, Chen, Peng, Cheng, Wenlong, Cheng, Xu, Choi, Seon-Jin, Chortos, Alex, Dagdeviren, Canan, Dauskardt, Reinhold H, Di, Chong-an, Dickey, Michael D, Duan, Xiangfeng, Facchetti, Antonio, Fan, Zhiyong, Fang, Yin, Feng, Jianyou, Feng, Xue, Gao, Huajian, Gao, Wei, Gong, Xiwen, Guo, Chuan Fei, Guo, Xiaojun, Hartel, Martin C, He, Zihan, Ho, John S, Hu, Youfan, Huang, Qiyao, Huang, Yu, Huo, Fengwei, Hussain, Muhammad M, Javey, Ali, Jeong, Unyong, Jiang, Chen, Jiang, Xingyu, Kang, Jiheong, Karnaushenko, Daniil, Khademhosseini, Ali, Kim, Dae-Hyeong, Kim, Il-Doo, Kireev, Dmitry, Kong, Lingxuan, Lee, Chengkuo, Lee, Nae-Eung, Lee, Pooi See, Lee, Tae-Woo, Li, Fengyu, Li, Jinxing, Liang, Cuiyuan, Lim, Chwee Teck, Lin, Yuanjing, Lipomi, Darren J, Liu, Jia, Liu, Kai, Liu, Nan, Liu, Ren, Liu, Yuxin, Liu, Yuxuan, Liu, Zhiyuan, Liu, Zhuangjian, Loh, Xian Jun, Lu, Nanshu, Lv, Zhisheng, Magdassi, Shlomo, Malliaras, George G, Matsuhisa, Naoji, Nathan, Arokia, Niu, Simiao, Pan, Jieming, Pang, Changhyun, Pei, Qibing, Peng, Huisheng, Qi, Dianpeng, Ren, Huaying, Rogers, John A, Rowe, Aaron, Schmidt, Oliver G, Sekitani, Tsuyoshi, Seo, Dae-Gyo, Shen, Guozhen, Sheng, Xing, Shi, Qiongfeng, Someya, Takao, Song, Yanlin, Stavrinidou, Eleni, Su, Meng, Sun, Xuemei, Takei, Kuniharu, Tao, Xiao-Ming, Tee, Benjamin CK, Thean, Aaron Voon-Yew, and Trung, Tran Quang
- Subjects
Data Management and Data Science ,Information and Computing Sciences ,Humans ,Wearable Electronic Devices ,Quality of Life ,soft materials ,mechanics engineering ,flexible electronics ,conformable sensors ,bioelectronics ,human-machine interfaces ,body area sensor networks ,technology translation ,sustainable electronics ,Nanoscience & Nanotechnology - Abstract
Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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- 2023
21. 3D characterization of kinematic fields and poroelastic swelling near the tip of a propagating crack in a hydrogel
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Li, Chenzhuo, Zubko, Danila, Delespaul, Damien, and Kolinski, John Martin
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- 2024
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22. Effect of nonhomogeneity on compression of solid circular cylinders made of functionally graded incompressible neo-Hookean materials
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Mendil, Fatsah, Bechir, Hocine, and Methia, Mounir
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- 2024
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23. Reprogrammable Metamaterial Processors for Soft Machines.
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Jiao, Zhongdong, Hu, Zhenhan, Dong, Zeyu, Tang, Wei, Yang, Huayong, and Zou, Jun
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UNIT cell , *BOOLEAN algebra , *METAMATERIALS , *UNIVERSAL design , *UNIVERSAL algebra - Abstract
Soft metamaterials have attracted extensive attention due to their remarkable properties. These materials hold the potential to program and control the morphing behavior of soft machines, however, their combination is limited by the poor reprogrammability of metamaterials and incompatible communication between them. Here, printable and recyclable soft metamaterials possessing reprogrammable embedded intelligence to regulate the morphing of soft machines are introduced. These metamaterials are constructed from interconnected and periodically arranged logic unit cells that are able to perform compound logic operations coupling multiplication and negation. The scalable computation capacity of the unit cell empowers it to simultaneously process multiple fluidic signals with different types and magnitudes, thereby allowing the execution of sophisticated and high‐level control operations. By establishing the laws of physical Boolean algebra and formulating a universal design route, soft metamaterials capable of diverse logic operations can be readily created and reprogrammed. Besides, the metamaterials' potential of directly serving as fluidic processors for soft machines is validated by constructing a soft latched demultiplexer, soft controllers capable of universal and customizable morphing programming, and a reprogrammable processor without reconnection. This work provides a facile way to create reprogrammable soft fluidic control systems to meet on‐demand requirements in dynamic situations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Soft multi‐layer actuators integrated with the functions of electrical energy harvest and storage.
- Author
-
Feng, Haihang, Zhou, Peidi, Peng, Qinglu, and Weng, Mingcen
- Subjects
- *
ENERGY harvesting , *ELECTRICAL energy , *ENERGY storage , *ACTUATORS , *ENERGY function , *ARTIFICIAL muscles - Abstract
Soft multi‐layer actuators are smart, lightweight, and flexible, which can be used in a wide range of fields such as artificial muscles, advanced medical devices, and wearable devices. The research on the actuation property of the soft actuators has made significant progress, paving the way for the controllable motions of the actuators. However, compared with the intelligence and adaptability of life in nature, these actuators still have the problem of insufficient intelligence. The phenomenon is reflected in a lack of continuous supply of energy. Therefore, it has become a development trend to combine functions such as energy harvesting, storage, and conversion with actuators to build intelligent actuators. This concept presents a synopsis of the advancements made in soft actuators that have been coupled with the capabilities of electrical energy harvesting and storage. The design concepts and typical applications of this soft smart actuators are introduced in detail. Finally, the future research directions and applications of smart actuators are prospected from our perspective. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Using a solvent-induced self-assembly approach to fabricate and tune the organogels and hydrogels.
- Author
-
Wang, Ruicong, Hao, Xiaoting, and Yang, Haikuan
- Subjects
- *
ATOMIC force microscopy , *TRANSMISSION electron microscopy , *SOLVENTS , *FOURIER transforms , *TRANSITION temperature , *INFRARED spectroscopy - Abstract
In the present work, stable organogels and hydrogels could be formed by dimeric-dehydrocholic acid derivative (DDAD) in different solvents. Compared with the organogels, the hydrogels formed by DDAD were found to be thermal reversible and had higher gel-to-solution transition temperature. The supramolecular structures in the organogels and hydrogels were further studied by using transmission electron microscopy (TEM) and atomic force microscopy (AFM). TEM and AFM images of the supramolecular gels showed that the solvent effects played a crucial role in morphological structures. Specifically, the organogel had a three-dimensional porous network structure. While, the hydrogel had a supramolecular structure made up of long fibers. Fourier transformation infrared spectroscopy (FT-IR) showed that multiple hydrogen bonds among the gelator molecules were the main driving forces in gel formation. On this base, the solvent effects on the gelation abilities and thermal stability were discussed. Thus, the present study provides a solvent-induced self-assembly approach and contributes substantially to the development of the supramolecular gels as soft materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Recent Advances on Underwater Soft Robots.
- Author
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Qu, Juntian, Xu, Yining, Li, Zhenkun, Yu, Zhenping, Mao, Baijin, Wang, Yunfei, Wang, Ziqiang, Fan, Qigao, Qian, Xiang, Zhang, Min, Xu, Minyi, Liang, Bin, Liu, Houde, Wang, Xueqian, Wang, Xiaohao, and Li, Tiefeng
- Subjects
REMOTE submersibles ,UNDERWATER exploration ,MARINE resources ,SMART materials ,SOFT robotics ,ROBOTICS ,ROBOTS - Abstract
The ocean environment has enormous uncertainty due to the influence of complex waves and undercurrents. The human beings are limited in their abilities to detect and utilize marine resources without powerful tools. Soft robots employ soft materials to simplify the complex mechanical structures in rigid robots and adapt their morphology to the environment, making them suitable for performing some challenging tasks in place of manual labor. Due to superior flexible and deformable bodies, underwater soft robots have played significant roles in numerous applications in recent decades. Meanwhile, various technical challenges still need to be tackled to ensure the reliability and practical performance of underwater soft robots in complicated ocean environment. Nowadays, some researchers have developed underwater soft robotic systems based on biomimetics and other disciplines, aiming at comprehensive exploration of ocean and appropriate utilization of unexploited resources. This review presents the recent advances of underwater soft robots in the aspects of intelligent soft materials, fabrication, actuation, locomotion patterns, power storage, sensing, control, and modeling; additionally, the existing challenges and perspectives are analyzed as well. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Network physics of attractive colloidal gels: Resilience, rigidity, and phase diagram.
- Author
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Nabizadeh, Mohammad, Nasirian, Farzaneh, Xinzhi Li, Saraswat, Yug, Waheibi, Rony, Hsiao, Lilian C., Dapeng Bi, Ravandi, Babak, and Jamali, Safa
- Subjects
- *
COLLOIDAL gels , *PHASE diagrams , *GAUSSIAN mixture models , *PHYSICS - Abstract
Colloidal gels exhibit solid-like behavior at vanishingly small fractions of solids, owing to ramified space-spanning networks that form due to particle-particle interactions. These networks give the gel its rigidity, and with stronger attractions the elasticity grows as well. The emergence of rigidity can be described through a mean field approach; nonetheless, fundamental understanding of how rigidity varies in gels of different attractions is lacking. Moreover, recovering an accurate gelation phase diagram based on the system's variables has been an extremely challenging task. Understanding the nature of colloidal clusters, and how rigidity emerges from their connections is key to controlling and designing gels with desirable properties. Here, we employ network analysis tools to interrogate and characterize the colloidal structures. We construct a particle-level network, having all the spatial coordinates of colloids with different attraction levels, and also identify polydisperse rigid fractal clusters using a Gaussian mixture model, to form a coarse-grained cluster network that distinctly shows main physical features of the colloidal gels. A simple mass-spring model then is used to recover quantitatively the elasticity of colloidal gels from these cluster networks. Interrogating the resilience of these gel networks shows that the elasticity of a gel (a dynamic property) is directly correlated to its cluster network's resilience (a static measure). Finally, we use the resilience investigations to devise [and experimentally validate] a fully resolved phase diagram for colloidal gelation, with a clear solid-liquid phase boundary using a single volume fraction of particles well beyond this phase boundary. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Rigorous Progress in Coarse-Graining.
- Author
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Noid, W.G., Szukalo, Ryan J., Kidder, Katherine M., and Lesniewski, Maria C.
- Abstract
Low-resolution coarse-grained (CG) models provide remarkable computational and conceptual advantages for simulating soft materials. In principle, bottom-up CG models can reproduce all structural and thermodynamic properties of atomically detailed models that can be observed at the resolution of the CG model. This review discusses recent progress in developing theory and computational methods for achieving this promise. We first briefly review variational approaches for parameterizing interaction potentials and their relationship to machine learning methods. We then discuss recent approaches for simultaneously improving both the transferability and thermodynamic properties of bottom-up models by rigorously addressing the density and temperature dependence of these potentials. We also briefly discuss exciting progress in modeling high-resolution observables with low-resolution CG models. More generally, we highlight the essential role of the bottom-up framework not only for fundamentally understanding the limitations of prior CG models but also for developing robust computational methods that resolve these limitations in practice. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Unified and accurate simulation for large elastic strain responses of rubberlike soft materials under multiple modes of loading.
- Author
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Kang, Jia, Tan, Long-Xu, Liu, Quan-Pu, Wang, Si-Yu, Bruhns, Otto T., and Xiao, Heng
- Subjects
- *
PARAMETER identification , *ELASTICITY - Abstract
A new and explicit form of the multi-axial elastic potential for elastic soft materials is constructed by means of two invariants of the Hencky strain. The new elasticity model with this form can bypass coupling complexities and uncertainties usually involved in parameter identification. Namely, exact closed-form solutions of decoupled nature are obtainable for stress responses under multiple benchmark modes. Unlike usual solutions with numerous coupled parameters, such new solutions are independent of one another and, as such, data sets for multiple benchmark modes can be separately matched with mutually independent single-variable functions. A comparative study is presented between a few well-known models and the new model. Results show that predictions from the former agree well with uniaxial and biaxial data, as known in the literature, but would be at variance with data for the constrained stress response in the plane-strain extension. In contrast, predictions from the new model agree accurately with all data sets. Furthermore, exact solutions for the Poynting effect of freely twisted elastic thin-walled tube are obtained from the new model. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Ultrashort Cationic Peptide Fmoc-FFK as Hydrogel Building Block for Potential Biomedical Applications.
- Author
-
Gallo, Enrico, Diaferia, Carlo, Giordano, Sabrina, Rosa, Elisabetta, Carrese, Barbara, Piccialli, Gennaro, Borbone, Nicola, Morelli, Giancarlo, Oliviero, Giorgia, and Accardo, Antonella
- Subjects
HYDROGELS in medicine ,BIOMEDICAL engineering ,SCANNING electron microscopy ,BIOCOMPATIBILITY ,SUPRAMOLECULAR polymers - Abstract
Fmoc-diphenylalanine (Fmoc-FF) is a low-molecular-weight peptide hydrogelator. This simple all-aromatic peptide can generate self-supporting hydrogel materials, which have been proposed as novel materials for diagnostic and pharmaceutical applications. Our knowledge of the molecular determinants of Fmoc-FF aggregation is used as a guide to design new peptide-based gelators, with features for the development of improved tools. Here, we enlarge the plethora of Fmoc-FF-based hydrogelated matrices by studying the properties of the Fmoc-FFK tripeptide, alone or in combination with Fmoc-FF. For multicomponent matrices, the relative weight ratios between Fmoc-FFK and Fmoc-FF (specifically, 1/1, 1/5, 1/10, and 1/20 w/w) are evaluated. All the systems and their multiscale organization are studied using different experimental techniques, including rheology, circular dichroism, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). Preliminary profiles of biocompatibility for the studied systems are also described by testing them in vitro on HaCaT and 3T3-L1 cell lines. Additionally, the lysine (K) residue at the C-terminus of the Fmoc-FF moiety introduces into the supramolecular material chemical functions (amino groups) which may be useful for modification/derivatization with bioactive molecules of interest, including diagnostic probes, chelating agents, active pharmaceutical ingredients, or peptide nucleic acids. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
31. Highly stretchable alginate/methylcellulose hydrogels for 3D bio-printing: photopolymerization approach enhancing structural integrity
- Author
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Sorour Sadeghzade, Jinrui Cao, Rui Yang, Yuanlong Li, Yanping Li, Dingcong Zhang, Jingyi Liu, Ziyue Yu, Liang Fang, and Hongyan Yuan
- Subjects
Hydrogel ,Printability ,Stretchability ,Soft materials ,Hyper viscoelastic materials ,Science (General) ,Q1-390 - Abstract
In recent years, 3D hydrogels based on alginate (Alg) have undergone substantial advancements, holding transformative potential for biomedicine and regenerative medicine. Nevertheless, the viscosity of Alg needs to be further increased, in order to print complex 3D structures. Attempts to adjust printability often employ rheological modifiers like methylcellulose (MC), but these still lack mechanical integrity for broader biomedical applications. Our study sought to chemically modify Alg/MC to create a photopolymerizable hydrogel by incorporating acrylate-based monomers, which would enhance the curing ability of the base hydrogel, leading to better mechanical properties of Alg/MC, such as stretchability and stability with shape recovery. Comprehensive mechanical assessments unveiled remarkable tensile properties, achieving a notable specific strength benchmark of 44.72 kPa/(g.cm-3) before reaching the point of fracture. This represents a substantial 250 % improvement compared to samples lacking the acrylate monomer. Biomedical assessments confirmed the hydrogel's promising potential, especially with the MG-63 cell line, underscoring its suitability for advanced applications like tissue engineering.
- Published
- 2024
- Full Text
- View/download PDF
32. Deep Indentation Tests of Soft Materials Using Mobile and Stationary Devices
- Author
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Joanna Nowak and Mariusz K. Kaczmarek
- Subjects
indentation test ,mechanical parameters ,soft materials ,phantoms ,objectivity of measurements ,mobile and stationary apparatus ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Measurements of the properties of soft materials are important from the point of view of medical diagnostics of soft tissues as well as testing the quality of food products and many technical materials. One of the frequently used techniques for testing such materials, attractive due to its non-invasive nature, is the indentation technique, which does not puncture the material. The difficulty of testing soft materials, which affects the objectivity of the results, is related to the problems of stable positioning of the studied material in relation to the indentation apparatus, especially with a device held by the operator. This work concerns the comparison of test results using an indentation apparatus mounted on mobile and stationary handles. The tested materials are cylindrical samples of polyurethane foams with three different stiffnesses and the same samples with a 0.5 or 1 mm thick silicone layer. The study presented uses an apparatus with a flat cylindrical indenter, with a surface area of 1 cm2, pressed to a depth of 10 mm (so-called deep tests). Based on the recorded force changes over time, five descriptors of the indentation test were determined and compared for both types of handles. The tests performed showed that the elastic properties of foam materials alone and with a silicone layer can be effectively characterized by the maximum forces during recessing and retraction and the slopes of the recessing and retraction curves. In the case of two-layer materials, these descriptors reflect both the characteristics of the foams and the silicone layer. The results show that the above property of the deep indentation method distinguishes it from the shallow indentation method. The repeatability of the tests performed in the mobile and stationary holders were determined to be comparable.
- Published
- 2024
- Full Text
- View/download PDF
33. The Application of Regenerated Silk Fibroin in Tissue Repair
- Author
-
Zhaoyi Li, Guohongfang Tan, Huilin Xie, and Shenzhou Lu
- Subjects
silk fibroin ,soft materials ,wound repair ,tissue regeneration ,hydrogels ,porous scaffolds ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Silk fibroin (SF) extracted from silk is non-toxic and has excellent biocompatibility and biodegradability, making it an excellent biomedical material. SF-based soft materials, including porous scaffolds and hydrogels, play an important role in accurately delivering drugs to wounds, creating microenvironments for the adhesion and proliferation of support cells, and in tissue remodeling, repair, and wound healing. This article focuses on the study of SF protein-based soft materials, summarizing their preparation methods and basic applications, as well as their regenerative effects, such as drug delivery carriers in various aspects of tissue engineering such as bone, blood vessels, nerves, and skin in recent years, as well as their promoting effects on wound healing and repair processes. The authors expect SF soft materials to play an important role in the field of tissue repair.
- Published
- 2024
- Full Text
- View/download PDF
34. Liquid Crystal Emulsions: A Versatile Platform for Photonics, Sensing, and Active Matter.
- Author
-
Concellón, Alberto
- Subjects
- *
EMULSIONS , *PHOTONICS , *NANOSTRUCTURED materials , *TECHNOLOGICAL innovations , *ARTIFICIAL muscles , *OPTICAL reflectors - Abstract
The self‐assembly of liquid crystals (LCs) is a fascinating method for controlling the organization of discrete molecules into nanostructured functional materials. Although LCs are traditionally processed in thin films, their confinement within micrometre‐sized droplets has recently revealed new properties and functions, paving the way for next‐generation soft responsive materials. These recent findings have unlocked a wealth of unprecedented applications in photonics (e.g. reflectors, lasing materials), sensing (e.g. biomolecule and pathogen detection), soft robotics (e.g. micropumps, artificial muscles), and beyond. This Minireview focuses on recent developments in LC emulsion designs and highlights a variety of novel potential applications. Perspectives on the opportunities and new directions for implementing LC emulsions in future innovative technologies are also provided. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Theoretical Puncture Mechanics of Soft Compressible Solids.
- Author
-
Fregonese, Stefano, Zhiyuan Tong, Sibo Wang, and Bacca, Mattia
- Subjects
- *
BULK modulus , *ACTIVATION energy , *NONLINEAR oscillators , *COMPRESSIBILITY , *MECHANICAL behavior of materials - Abstract
Accurate prediction of the force required to puncture a soft material is critical in many fields like medical technology, food processing, and manufacturing. However, such a prediction strongly depends on our understanding of the complex nonlinear behavior of the material subject to deep indentation and complex failure mechanisms. Only recently, we developed theories capable of correlating puncture force with material properties and needle geometry. However, such models are based on simplifications that seldom limit their applicability to real cases. One common assumption is the incompressibility of the cut material, albeit no material is truly incompressible. In this article, we propose a simple model that accounts for linearly elastic compressibility, and its interplay with toughness, stiffness, and elastic strain stiffening. Confirming previous theories and experiments, materials having high toughness and low modulus exhibit the highest dimensionless puncture resistance at a given needle radius. Surprisingly, in these conditions, we observe that incompressible materials exhibit the lowest puncture resistance, where volumetric compressibility can create an additional (strain) energy barrier to puncture. Our model provides a valuable tool to assess the puncture resistance of soft compressible materials and suggests new design strategies for sharp needles and puncture-resistant materials. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. Does the Gel Biter create an illusion of food texture perception due to differences in mastication speed ?
- Author
-
Hirose, Kosuke, Ogawa, Jun, Watanabe, Yosuke, Shiblee, M. D. Nahin Islam, Kawakami, Masaru, and Furukawa, Hidemitsu
- Abstract
One of the new computational frameworks is physical reservoir computing. Focusing on this method, we have previously developed a soft-matter artificial mouth "Gel Biter", which is composed of multiple polymeric materials based on the structure of the human oral cavity. This soft machine can discriminate even subtle differences in food texture with high accuracy. In general, chewing speed differs from person to person. Then, we focus on the result that brittle foods tend to be chewed faster or more finely based on sensory evaluation in some cognitive studies. This study has analyzed the accuracy of the Gel Biter by changing the parameters of its robotic arm and the differences in food texture perceived when the chewing speed is changed. As a result, there is no significant difference in discrimination accuracy for each speed. The cluster analysis shows that the food characteristics are captured and classified. In addition, the estimation results for Fast chewing indicate that the mechanical mouth also generates the illusion that humans perceive different food textures. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Multicomponent Peptide-Based Hydrogels Containing Chemical Functional Groups as Innovative Platforms for Biotechnological Applications.
- Author
-
Giordano, Sabrina, Gallo, Enrico, Diaferia, Carlo, Rosa, Elisabetta, Carrese, Barbara, Borbone, Nicola, Scognamiglio, Pasqualina Liana, Franzese, Monica, Oliviero, Giorgia, and Accardo, Antonella
- Subjects
HYDROGELS ,PEPTIDES ,IONIC strength ,ORGANIC compounds ,TRIPEPTIDES - Abstract
Multicomponent hydrogels (HGs) based on ultrashort aromatic peptides have been exploited as biocompatible matrices for tissue engineering applications, the delivery of therapeutic and diagnostic agents, and the development of biosensors. Due to its capability to gel under physiological conditions of pH and ionic strength, the low molecular-weight Fmoc-FF (N
α -fluorenylmethoxycarbonyl-diphenylalanine) homodimer is one of the most studied hydrogelators. The introduction into the Fmoc-FF hydrogel of additional molecules like protein, organic compounds, or other peptide sequences often allows the generation of novel hydrogels with improved mechanical and functional properties. In this perspective, here we studied a library of novel multicomponent Fmoc-FF based hydrogels doped with different amounts of the tripeptide Fmoc-FFX (in which X= Cys, Ser, or Thr). The insertion of these tripeptides allows to obtain hydrogels functionalized with thiol or alcohol groups that can be used for their chemical post-derivatization with bioactive molecules of interest like diagnostic or biosensing agents. These novel multicomponent hydrogels share a similar peptide organization in their supramolecular matrix. The hydrogels' biocompatibility, and their propensity to support adhesion, proliferation, and even cell differentiation, assessed in vitro on fibroblast cell lines, allows us to conclude that the hybrid hydrogels are not toxic and can potentially act as a scaffold and support for cell culture growth. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
38. A Review of Soft Microrobots: Material, Fabrication, and Actuation.
- Author
-
Ye, Min, Zhou, Yan, Zhao, Hongyu, Wang, Ziya, Nelson, Bradley J., and Wang, Xiaopu
- Subjects
MICROROBOTS ,ENVIRONMENTAL remediation ,TISSUE engineering ,INDIVIDUALIZED medicine - Abstract
Microrobots have shown great potential in many applications, such as non‐invasive surgery, tissue engineering, precision medicine, and environmental remediation. Within the past decade, soft microrobot has become one of the important branches. It is aimed to create soft and deformable microrobots with high bioaffinity, which can perform complex tasks noninvasively in inaccessible small spaces in the body. Herein, the latest research progress of soft microrobots regarding the three cornerstones of this field is reviewed: material, fabrication, and actuation. First, various materials that are used for the fabrication of soft microrobots are summarized, and their characteristics and functions are discussed. Second, various fabrication methods of soft microrobots are introduced, and their applicability to different materials is discussed. Third, the actuation methods of soft microrobots are discussed, as well as their pros, cons, and adaptability. Moreover, the outstanding behaviors of soft microrobots in biomedical and environmental applications are introduced with some typical examples published recently. Finally, current clinical use challenges of soft microrobots are pointed out, and their intelligentization is proposed and discussed for further innovative development. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Dynamically Tunable Structural Colors Enabled by Pixelated Programming of Soft Materials on Thickness.
- Author
-
Huang, Mengting, Wang, Yifei, Liu, Xuan, Zhang, Songyu, Yuan, Cong‐Long, Hu, Hong‐Long, and Zheng, Zhi‐Gang
- Subjects
- *
STRUCTURAL colors , *PHOTORESISTS - Abstract
Structural colors are widespread in nature and have become an important component of the lives. Considerable efforts have been made toward reversible color tuning, which underpins intriguing applications, including color displays, anti‐counterfeiting, and information encryption. However, the limited size, complicated fabrication processes, and low modulation speeds of structural colors are the main obstacles to their further development. Herein, a facile method to realize dynamically tunable structural colors is presented, which are enabled by the pixelated programming of soft materials on thickness. Pixelated photoresist microarrays with different heights are obtained using a digitalized lithography technique, enabling delicate control over the thickness of the liquid crystal (LC) layers. Stimuli‐responsive LCs endow structural colors with dynamic and reversible tunability and exhibit remarkable switching speeds with external stimuli. The proposed strategy sheds new light on dynamically tunable structural colors and promotes the development of optical anti‐counterfeiting, thermal sensors, and advanced information encryption. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. ON THE AFFERRANTE-CARBONE THEORY OF ULTRATOUGH TAPE PEELING.
- Author
-
Ciavarella, Michele, McMeeking, Robert M., and Cricrì, Gabriele
- Subjects
- *
SOLID mechanics , *ADHESIVE tape , *MECHANICS (Physics) , *CRITICAL velocity , *VISCOELASTIC materials - Abstract
In a simple and interesting theory of ultratough peeling of an elastic tape from a viscoelastic substrate, Afferrante and Carbone find that there are conditions for which the load for steady state peeling could be arbitrarily large in steady state peeling, at low angles of peeling - what they call "ultratough" peeling (Afferrante, L., Carbone, G., 2016, The ultratough peeling of elastic tapes from viscoelastic substrates, Journal of the Mechanics and Physics of Solids, 96, pp.223-234). Surprisingly, this seems to lead to toughness enhancement higher than the limit value observed in a very large crack in an infinite viscoelastic body, possibly even considering a limit on the stress transmitted. The Afferrante-Carbone theory seems to be a quite approximate, qualitative theory and many aspects and features of this "ultratough" peeling (e.g. conformity with the Rivlin result at low peel angles) are obtained also through other mechanisms (Begley, M.R., Collino, R.R., Israelachvili, J.N., McMeeking, R.M., 2013, Peeling of a tape with large deformations and frictional sliding, Journal of the Mechanics and Physics of Solids, 61(5), pp. 1265-1279) although not at “critical velocities”. Experimental and/or numerical verification would be most useful. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Reprogrammable Metamaterial Processors for Soft Machines
- Author
-
Zhongdong Jiao, Zhenhan Hu, Zeyu Dong, Wei Tang, Huayong Yang, and Jun Zou
- Subjects
metamaterials ,reprogrammable ,soft machines ,soft materials ,soft robots ,Science - Abstract
Abstract Soft metamaterials have attracted extensive attention due to their remarkable properties. These materials hold the potential to program and control the morphing behavior of soft machines, however, their combination is limited by the poor reprogrammability of metamaterials and incompatible communication between them. Here, printable and recyclable soft metamaterials possessing reprogrammable embedded intelligence to regulate the morphing of soft machines are introduced. These metamaterials are constructed from interconnected and periodically arranged logic unit cells that are able to perform compound logic operations coupling multiplication and negation. The scalable computation capacity of the unit cell empowers it to simultaneously process multiple fluidic signals with different types and magnitudes, thereby allowing the execution of sophisticated and high‐level control operations. By establishing the laws of physical Boolean algebra and formulating a universal design route, soft metamaterials capable of diverse logic operations can be readily created and reprogrammed. Besides, the metamaterials' potential of directly serving as fluidic processors for soft machines is validated by constructing a soft latched demultiplexer, soft controllers capable of universal and customizable morphing programming, and a reprogrammable processor without reconnection. This work provides a facile way to create reprogrammable soft fluidic control systems to meet on‐demand requirements in dynamic situations.
- Published
- 2024
- Full Text
- View/download PDF
42. Stimuli‐responsive fluorescent hydrogels: Strategies and applications
- Author
-
Mengying Lei, Qian Wang, Ruirui Gu, and Da‐Hui Qu
- Subjects
fluorescent hydrogels ,luminescence mechanism ,responsive materials ,soft materials ,supramolecular chemistry ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract Stimuli‐responsive fluorescent hydrogels are three‐dimensional networked polymeric materials with tunable luminescence and dynamic properties, which play an important role as a water‐rich soft material in the fields of information encryption, bionic actuation, bioimaging, environmental monitoring, and luminescent materials. Compared with conventional hydrogels, their unique luminescent properties allow the visualization of microscopic dynamics within the polymer network. By rational inclusion of dynamic motifs, such as photoswitches, AIEgens, lanthanide complexes, and host–guest complexes, these materials are endowed with tunability of emission, shape, and phase in time and space in response to environmental effectors. In this review, we summarize the fabrication strategies that are mainly used by recently reported stimuli‐responsive fluorescent hydrogels and the applications of these materials.
- Published
- 2024
- Full Text
- View/download PDF
43. Recent Advances on Underwater Soft Robots
- Author
-
Juntian Qu, Yining Xu, Zhenkun Li, Zhenping Yu, Baijin Mao, Yunfei Wang, Ziqiang Wang, Qigao Fan, Xiang Qian, Min Zhang, Minyi Xu, Bin Liang, Houde Liu, Xueqian Wang, Xiaohao Wang, and Tiefeng Li
- Subjects
actuation ,control ,fabrication ,sensing ,soft materials ,underwater soft robots ,Computer engineering. Computer hardware ,TK7885-7895 ,Control engineering systems. Automatic machinery (General) ,TJ212-225 - Abstract
The ocean environment has enormous uncertainty due to the influence of complex waves and undercurrents. The human beings are limited in their abilities to detect and utilize marine resources without powerful tools. Soft robots employ soft materials to simplify the complex mechanical structures in rigid robots and adapt their morphology to the environment, making them suitable for performing some challenging tasks in place of manual labor. Due to superior flexible and deformable bodies, underwater soft robots have played significant roles in numerous applications in recent decades. Meanwhile, various technical challenges still need to be tackled to ensure the reliability and practical performance of underwater soft robots in complicated ocean environment. Nowadays, some researchers have developed underwater soft robotic systems based on biomimetics and other disciplines, aiming at comprehensive exploration of ocean and appropriate utilization of unexploited resources. This review presents the recent advances of underwater soft robots in the aspects of intelligent soft materials, fabrication, actuation, locomotion patterns, power storage, sensing, control, and modeling; additionally, the existing challenges and perspectives are analyzed as well.
- Published
- 2024
- Full Text
- View/download PDF
44. A Humanoid Saxophone-Playing Robot Based on Instrument-Centered Design : Sound Improvement with Fingers Using Hybrid Soft Materials
- Author
-
Uchiyama, Jun, Hashimoto, Tomoyuki, Ohta, Hina, Lin, Jia-Yeu, Cosentino, Sarah, Takanishi, Atsuo, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Chen, Jessie Y. C., editor, and Fragomeni, Gino, editor
- Published
- 2023
- Full Text
- View/download PDF
45. Additive Manufacturing Techniques in Fabrication of Soft Robotic Sensors and Actuators: A Review
- Author
-
Kumar, Baibhav, Dalla, Vijay Kumar, Haldar, Aditya, Cavas-Martínez, Francisco, Editorial Board Member, Chaari, Fakher, Series Editor, di Mare, Francesca, Editorial Board Member, Gherardini, Francesco, Series Editor, Haddar, Mohamed, Editorial Board Member, Ivanov, Vitalii, Series Editor, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Deepak, B.B.V.L., editor, Bahubalendruni, M.V.A. Raju, editor, Parhi, D.R.K., editor, and Biswal, Bibhuti Bhusan, editor
- Published
- 2023
- Full Text
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46. Damage Prediction for Integrated DEAP and MRE Soft Actuators
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Jakub Bernat, Jakub Kołota, Piotr Gajewski, Agnieszka Marcinkowska, Maciej Komosinski, and Szymon Szczęsny
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soft robotics ,soft materials ,DEAP and MRE actuators ,testing ,microdamage ,Technology - Abstract
Soft robotics is a hot scientific topic in areas such as medicine and medical care, implantology, haptic technologies, and the design of various flexible structures. Integrated actuators (DEAP and MRE) are characterized by special functionality and a wider range of operations than when used individually. Such actuators can later be controlled with high voltages ranging from several to a dozen or so kV. Unfortunately, the production process of integrated actuators is multi-stage and therefore more complicated. Thus, at the stage of prototyping, microscopic errors often occur that cannot be detected using simple measurement methods. The result of such errors is actuator damage at the testing stage or in subsequent application. Unfortunately, due to high voltages, actuator damage usually leads to it catching fire, which is potentially dangerous. This work presents an approach that enables the prediction of actuator damage at the testing stage. The results of modeling damaged actuators, a modified safe testing method, and a complete supervising system for testing the actuator with protection are shown. The work is also enriched with a set of data from the analyzed damage to DEAP and MRE actuators, which may prove useful in other research on the actuators of soft robotics.
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- 2024
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47. Dielectric Elastomer Actuators with Enhanced Durability by Introducing a Reservoir Layer
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Sumin Jung, Minchae Kang, and Min-Woo Han
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dielectric elastomer ,soft actuator ,soft robotics ,soft materials ,Organic chemistry ,QD241-441 - Abstract
A Dielectric Elastomer Actuator (DEA) consists of electrodes with a dielectric layer between them. By controlling the design of the electrodes, voltage, and frequency, the operating range and speed of the DEA can be adjusted. These DEAs find applications in biomimetic robots, artificial muscles, and similar fields. When voltage is applied to the DEA, the dielectric layer undergoes compression and expansion due to electrostatic forces, which can lead to electrical breakdown. This phenomenon is closely related to the performance and lifespan of the DEA. To enhance stability and improve dielectric properties, a DEA Reservoir layer is introduced. Here, stability refers to the ability of the DEA to perform its functions even as the applied voltage increases. The Reservoir layer delays electrical breakdown and enhances stability due to its enhanced thickness. The proposed DEA in this paper is composed of a Reservoir layer and electrode layer. The Reservoir layer is placed between the electrode layers and is independently configured, not subjected to applied voltage like the electrode layers. The performance of the DEA was evaluated by varying the number of polymer layers in the Reservoir and electrode designs. Introducing the Reservoir layer improved the dielectric properties of the DEA and delayed electrical breakdown. Increasing the dielectric constant through the DEA Reservoir can enhance output characteristics in response to electrical signals. This approach can be utilized in various applications in wearable devices, artificial muscles, and other fields.
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- 2024
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48. 3D printing of soft and biological materials : applications to human cochlear modelling and beyond
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Lei, Iek Man and Huang, Yan Yan Shery Huang
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Soft materials ,Hydrogels ,Extrusion 3D printing - Abstract
3D printing has emerged as a promising tool for on-demand and rapid fabrication of materials. The field of soft material printing typically utilises inks that exhibit viscoelastic properties with elastic moduli in the kPa - MPa range, such as hydrogels and elastomers. Although soft material printing has been frequently used for creating biomimetic mini tissues, its ability to imitate organ functions as a direct result of organ anatomy is yet to be fully realised, and continued innovation in printing method and flexible machinery are needed to drive the field forward. My PhD thesis focuses on advancing the field of soft material printing. Specifically, there are three main scopes in my work. Firstly, I developed an affordable and fully customisable extrusion-based printing platform for soft materials. The platform is equipped with multiple printheads for heterogeneous construct printing, and heating systems and a UV module for tuning the material rheology during and after printing. A detailed assembly instruction and the software design are provided, hence new users can facilely replicate the platform and contribute to the continued development of the platform. In summary, it is anticipated that this entirely hackable platform can facilitate the widespread adoption of the technology, overcoming the cost and flexibility barriers presented in commercial systems. Secondly, to realise the potential of 3D printing for imitating physiological phenomena related to anatomical structures, I created 3D printed cochleae that exhibit similar electro-anatomical features resembling human cochleae. These biomimetic cochlear models were integrated with machine learning to advance clinical predictions of 'current spread' for cochlear implant (CI) patients. The co-modelling framework demonstrated autonomous predictions of patient electric field imaging profile or cochlear geometry, unfolded the electro-anatomical factors causing CI stimulus spread, assisted on-demand printing for CI testing, and inferred patients' in vivo cochlear tissue resistivity by CI telemetry. This framework might facilitate physical modelling and digital twin innovations for neuromodulation implants in healthcare. Lastly, I demonstrate the high flexibility and versatile functionalities of the custom-made 3D extrusion printing platform. Apart from 3D CAD models, the standard geometry input used in 3D printing, the platform accepts unconventional geometry inputs to suit different needs, including coordinates, equations and pictures. Advanced operations, such as liquid dispensing, printing with variable speed and non-planar printing, are permitted with the platform. With the aid of support baths, heating and UV tools, a wide variety of soft materials, including naturally derived hydrogels, pH-responsive hydrogels and elastomers, were successfully printed using the platform. Overall, the perspective provided in this work might guide new users to efficiently design printing processes for soft materials that do not possess suitable rheological and mechanical properties for creating 3D structures with conventional extrusion methods.
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- 2021
49. Functional adhesive hydrogels for biological interfaces
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Changyi Liu, Kexin Peng, Yilun Wu, and Fanfan Fu
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biological interfaces ,biological sensors ,hydrogel electronics ,soft materials ,tissue scaffolds ,Medical technology ,R855-855.5 - Abstract
Abstract Hydrogel adhesives are extensively employed in biological interfaces such as epidermal flexible electronics, tissue engineering, and implanted device. The development of functional hydrogel adhesives is a critical, yet challenging task since combining two or more attributes that seem incompatible into one adhesive hydrogel without sacrificing the hydrogel's pristine capabilities. In this Review, we highlight current developments in the fabrication of functional adhesive hydrogels, which are suitable for a variety of application scenarios, particularly those that occur underwater or on tissue/organ surface conditions. The design strategies for a multifunctional adhesive hydrogel with desirable properties including underwater adhesion, self‐healing, good biocompatibility, electrical conductivity, and anti‐swelling are discussed comprehensively. We then discuss the challenges faced by adhesive hydrogels, as well as their potential applications in biological interfaces. Adhesive hydrogels are the star building blocks of bio‐interface materials for individualized healthcare and other bioengineering areas.
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- 2023
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50. A Review of Soft Microrobots: Material, Fabrication, and Actuation
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Min Ye, Yan Zhou, Hongyu Zhao, Ziya Wang, Bradley J. Nelson, and Xiaopu Wang
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actuation ,fabrication ,soft materials ,soft microrobots ,Computer engineering. Computer hardware ,TK7885-7895 ,Control engineering systems. Automatic machinery (General) ,TJ212-225 - Abstract
Microrobots have shown great potential in many applications, such as non‐invasive surgery, tissue engineering, precision medicine, and environmental remediation. Within the past decade, soft microrobot has become one of the important branches. It is aimed to create soft and deformable microrobots with high bioaffinity, which can perform complex tasks noninvasively in inaccessible small spaces in the body. Herein, the latest research progress of soft microrobots regarding the three cornerstones of this field is reviewed: material, fabrication, and actuation. First, various materials that are used for the fabrication of soft microrobots are summarized, and their characteristics and functions are discussed. Second, various fabrication methods of soft microrobots are introduced, and their applicability to different materials is discussed. Third, the actuation methods of soft microrobots are discussed, as well as their pros, cons, and adaptability. Moreover, the outstanding behaviors of soft microrobots in biomedical and environmental applications are introduced with some typical examples published recently. Finally, current clinical use challenges of soft microrobots are pointed out, and their intelligentization is proposed and discussed for further innovative development.
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- 2023
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