Journal of the Mechanical Behavior of Biomedical Materials最新文献

{"title":"Simulation of a Free Boundary Cell Migration Model through Physics Informed Neural Networks","authors":"Sanchita Malla ,&nbsp;Dietmar Oelz ,&nbsp;Sitikantha Roy","doi":"10.1016/j.jmbbm.2025.106961","DOIUrl":"10.1016/j.jmbbm.2025.106961","url":null,"abstract":"<div><div>Understanding the complexities of single-cell migration is facilitated by computational modeling, which provides important insights into the physiological processes that underlie migration mechanisms. This study developed a computational model for one-dimensional actomyosin flow in a migrating cell with moving boundaries. The model incorporates the complex interplay of actin polymerization, substrate adhesion, and actomyosin dynamics through a system of coupled nonlinear partial differential equations. A physics-informed neural network is designed to understand the dynamic behavior of actin flow and actin concentration within the cell along with the unknown moving boundaries, taking into account the computational cost of solving a dynamic model with a deformable domain. The model’s capacity to depict the complex interaction between biological and physical processes within the cell is demonstrated by the numerical results, which qualitatively agree with experimental and computational data available in the literature. This study demonstrates the application of a deep learning method to simulate a challenging biophysical problem with moving boundaries. The model does not require synthetic data for training and accurately reflects the intricate biophysics of cell migration.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106961"},"PeriodicalIF":3.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143579165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A measure of intrinsic strength, not nominal strength, reflects effects of ex-vivo cortical bone matrix modulation by raloxifene","authors":"Mary Arnhart ,&nbsp;Rachel K. Surowiec ,&nbsp;Matthew R. Allen ,&nbsp;Joseph M. Wallace ,&nbsp;Laura J. Pyrak-Nolte ,&nbsp;John Howarter ,&nbsp;Thomas Siegmund","doi":"10.1016/j.jmbbm.2025.106956","DOIUrl":"10.1016/j.jmbbm.2025.106956","url":null,"abstract":"<div><div>Understanding bone strength is important when assessing bone diseases and their treatment. Bending experiments are often used to determine strength. Then, flexural stresses are calculated from elastic bending theory. With a brittle failure criterion, the maximum flexural tensile stress is equated to (nominal) strength. However, bone is not a perfectly brittle material. A quasi-brittle failure criterion is more appropriate. Such an approach allows for material failure to occur before full fracture. The extent of the subcritical damage domain then introduces a length scale. The intrinsic strength of the bone is calculated from the critical load at fracture and the failure process zone dimensions relative to the specimen size. We apply this approach to human cortical bone specimens extracted from a femur. We determine strength measures in the untreated reference state and after treatment with the selective estrogen receptor modulator raloxifene. We find that the common nominal strength measure does not distinguish between treatments. However, the dimensions of the failure process zone differ between treatments. Intrinsic strength measures then are demonstrated as descriptors of bone strength sensitive to treatment. An extrapolation of laboratory data to whole bone is demonstrated.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106956"},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A shellfish-inspired bionic microstructure design for biological implants: Enhancing protection of antibacterial silver-loaded coatings and promoting osseointegration","authors":"Jionghong Liang ,&nbsp;Aiyi Chen ,&nbsp;Ming Wu ,&nbsp;Xiaolong Tang ,&nbsp;Haixing Feng ,&nbsp;Jiangwen Liu ,&nbsp;Guie Xie","doi":"10.1016/j.jmbbm.2025.106963","DOIUrl":"10.1016/j.jmbbm.2025.106963","url":null,"abstract":"<div><div>Implants incorporating multi-level micro-nano structures and antibacterial coatings offer a promising approach to overcoming the shortcomings of titanium and its alloys in stimulating bone growth and preventing bacterial infections. Silver ions have been identified as promising antibacterial agents. However, silver-loaded surface coatings are susceptible to damage from direct friction, and excessive release of silver ions can lead to cytotoxicity, thereby limiting their practical application. Inspired by the wear-resistant surface structure of natural shellfish, this study developed a biomimetic micro/nano multi-level structure on the titanium alloy (TC4) surfaces. The structure incorporated a biomimetic microgroove structure (BMS) with alkaline heat treatment (AH) of sodium titanate and chitosan/silver (CS/Ag) micro-nanostructured coatings (BMS/AH/CS/Ag). The microstructural armor effectively reduced external mechanical friction, safeguarding the coatings from damage. Compared to the unstructured sample, the biomimetic micro-groove armor group with a large micro-groove angle (θ) exhibited significantly reduced wear volume and only a marginal decrease of 1.86% in inhibition against <em>Staphylococcus aureus</em> (<em>S. aureus</em>) post-wear, highlighting the protective effect of this microstructure on the coating. The outstanding improvement was primarily attributed to the increased micro-groove angle, which enhanced the stability of the microstructure and effectively mitigated the friction. Additionally, the biomimetic micro-nano multi-level structure and coating have shown a significant ability to improve the bioactivity for the implant, promoting the adhesion, proliferation, collagen secretion, and extracellular matrix mineralization of human mesenchymal stem cells (hMSCs), which suggests the potential for enhanced osteogenic differentiation and indicates that this method can effectively improve the clinical performance of the implant.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106963"},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of artificial intelligence in data-centric additive manufacturing processes for biomedical applications","authors":"Saman Mohammadnabi ,&nbsp;Nima Moslemy ,&nbsp;Hadi Taghvaei ,&nbsp;Abdul Wasy Zia ,&nbsp;Sina Askarinejad ,&nbsp;Faezeh Shalchy","doi":"10.1016/j.jmbbm.2025.106949","DOIUrl":"10.1016/j.jmbbm.2025.106949","url":null,"abstract":"<div><div>The role of additive manufacturing (AM) for healthcare applications is growing, particularly in the aspiration to meet subject-specific requirements. This article reviews the application of artificial intelligence (AI) to enhance pre-, during-, and post-AM processes to meet a wider range of subject-specific requirements of healthcare interventions. This article introduces common AM processes and AI tools, such as supervised learning, unsupervised learning, deep learning, and reinforcement learning. The role of AI in pre-processing is described in the core dimensions like structural design and image reconstruction, material design and formulations, and processing parameters. The role of AI in a printing process is described based on hardware specifications, printing configurations, and core operational parameters such as temperature. Likewise, the post-processing describes the role of AI for surface finishing, dimensional accuracy, curing processes, and a relationship between AM processes and bioactivity. The later sections provide detailed scientometric studies, thematic evaluation of the subject topic, and also reflect on AI ethics in AM for biomedical applications. This review article perceives AI as a robust and powerful tool for AM of biomedical products. From tissue engineering (TE) to prosthesis, lab-on-chip to organs-on-a-chip, and additive biofabrication for range of products; AI holds a high potential to screen desired process-property-performance relationships for resource-efficient pre- to post-AM cycle to develop high-quality healthcare products with enhanced subject-specific compliance specification.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106949"},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the aspect ratio and wall heterogeneities on the mechanical behaviour of the aneurysm wall: Experimental investigation on phantom arteries","authors":"Guillaume Plet ,&nbsp;Jolan Raviol ,&nbsp;Alix Lopez ,&nbsp;Edwin-Joffrey Courtial ,&nbsp;Christophe Marquette ,&nbsp;Hélène Magoariec ,&nbsp;Cyril Pailler-Mattei","doi":"10.1016/j.jmbbm.2025.106958","DOIUrl":"10.1016/j.jmbbm.2025.106958","url":null,"abstract":"<div><div>The management of unruptured intracranial aneurysms (UIA) involves assessing the risk of rupture, which requires a thorough understanding of risk factors such as the geometric characteristics of the neck (neck size) or local structural heterogeneities. This study explores the impact of neck size on the rupture risk of the aneurysmal sac and examines how local heterogeneities, such as calcifications or variations in tissue composition, influence the mechanical response of the wall of a saccular aneurysm during the insertion of an innovative arterial wall deformation device (DDP). The results reveal that high aspect ratios (AR) are associated with increased hemodynamic stress, thereby raising the risk of rupture. Additionally, this study provides valuable insights into the complex relationship between tissue heterogeneity, especially calcifications, and the mechanical response of aneurysm walls to mechanical stimuli. It appears that local heterogeneities weaken the integrity of the arterial wall, thus increasing the potential for rupture. Finally, although the DDP is not intended to treat intracranial aneurysms (IA), it could prove to be a relevant tool for deepening the understanding of their rupture mechanisms.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106958"},"PeriodicalIF":3.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of mouse artery tissue properties using experimental testing combined with finite element modelling","authors":"Luli Li ,&nbsp;Ling Gao ,&nbsp;Kian Kun Yap ,&nbsp;Alkystis Phinikaridou ,&nbsp;Marc Masen","doi":"10.1016/j.jmbbm.2025.106953","DOIUrl":"10.1016/j.jmbbm.2025.106953","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Indentation tests have been widely used to determine the material properties of arterial tissue. However, it remains a challenge to extract the relevant material parameters from the force-indentation curves that result from indentation tests. This paper presents a detailed procedure for determining the first-order Ogden parameters, &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, for mouse arterial tissue using a method that combines indentation tests with numerical simulations. The method builds on a previous study (Li and Masen, 2024) and has been expanded to account for the surface roughness of the indented specimen. It is assumed that hyperelastic material behaviour can be linearized for small strain increments, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ɛ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 1%, allowing the model developed by Hayes (Hayes et al., 1972) to be applied to accommodate the contact behaviour in each increment. However, mouse arterial specimens have an irregular or rough surface which complicates the use of Hayes’ model, as the thickness of the specimen is an input parameter into the model. To solve this, we introduce an ‘equivalent thickness’ that can be applied in Hayes’ model by identifying the thickness that yields the smallest variance &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; of the shear moduli among a range of possible specimen thickness values. The shear moduli obtained for the equivalent thickness, denoted as the equivalent shear moduli &lt;span&gt;&lt;math&gt;&lt;msubsup&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;i&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∗&lt;/mo&gt;&lt;/mrow&gt;&lt;/msubsup&gt;&lt;/math&gt;&lt;/span&gt;, along with the corresponding principal strains &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ɛ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; obtained from simulations, were used to calculate the principal stresses &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; using Hooke’s law. By combining the principal stresses &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; across all increments, a nonlinear stress &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;σ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; versus strain &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ɛ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;j&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; curve was generated, from which the first-order Ogden parameters &lt;span&gt;&lt;math&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; were obtained. The proposed method is demonstrated by applying it to simulated force-indentation curves, successfully recovering the input parameters for both thickness and Ogden parameters. The method was subsequently applied to 26 experimentally obtained curves, yielding an average shear modulus &lt;span&gt;&lt;math&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; of 1.22 kPa for the indented mouse arterial tissue specimens, with values ranging from 0.27 to 5.02 kPa. Numerical simulations of the in","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106953"},"PeriodicalIF":3.3,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increasing A-type CO32− substitution decreases the modulus of apatite nanocrystals","authors":"Stephanie Wong ,&nbsp;Abigail Eaton ,&nbsp;Christina Krywka ,&nbsp;Arun Nair ,&nbsp;Christophe Drouet ,&nbsp;Alix Deymier","doi":"10.1016/j.jmbbm.2025.106962","DOIUrl":"10.1016/j.jmbbm.2025.106962","url":null,"abstract":"<div><div>Biological apatite mineral is highly substituted with carbonate (CO₃²⁻). CO₃²⁻ can exchange for either phosphate, known as B-type, or hydroxyl groups, known as A-type. Although the former has been extensively studied, A-type CO₃²⁻ substituted apatites are poorly understood. Therefore, A-type CO₃²⁻ apatites with biologically relevant levels of CO₃²⁻ (1.7–5.8 wt%) were prepared and characterized. The addition of A-type CO₃²⁻ into the apatite structure caused the predicted expansion of the a-axis and contraction of the c-axis in the unit cell. This was accompanied by a significant modification in the atomic order, especially along the a-axis plane, and crystallite size. A combination of in situ loading with synchrotron X-ray Diffraction and Density Functional Theory showed that increasing A-type CO₃²⁻ substitutions also reduced the bulk and elastic moduli of the crystals. These results show that although A-type CO₃²⁻ may inhibit lattice changes caused by B-type CO₃²⁻, A-type CO₃²⁻ enhances the reduction in crystal order and mineral stiffness. These results help us to identify the possible contributions of A-type CO₃²⁻ substitutions in biological apatites that contain both A- and B-type CO₃²⁻. In addition, this implies that the stiffness of bioapatite may change with increasing A-type CO₃²⁻ substitutions, potentially altering the fracture mechanics of calcified tissues and biomaterials.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106962"},"PeriodicalIF":3.3,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of strain rate on the mechanical properties of human ribs: Insights from complete rib bending tests","authors":"S. García-Vilana ,&nbsp;D. Sánchez-Molina ,&nbsp;J. Llumà","doi":"10.1016/j.jmbbm.2025.106954","DOIUrl":"10.1016/j.jmbbm.2025.106954","url":null,"abstract":"<div><div>This study reassesses the mechanical properties of cortical bone by conducting complete rib bending tests to evaluate the effect of strain rate (<span><math><mrow><mn>0</mn><mo>.</mo><mn>0005</mn><mo>&lt;</mo><mover><mrow><mi>ɛ</mi></mrow><mrow><mo>̇</mo></mrow></mover><mo>&lt;</mo><mn>0</mn><mo>.</mo><mn>50</mn></mrow></math></span>) on key mechanical parameters. The research involved <span><math><mrow><mi>n</mi><mo>=</mo><mn>12</mn></mrow></math></span> specimens, divided into balanced groups based on age and strain rate. Unlike the traditional approach, which relies on tensile testing of machined cortical bone fragments, this methodology uses intact ribs subjected to bending, eliminating the need for extensive preparation through machining, and determine the mechanical properties in this test in an accurate computational manner.</div><div>Complete rib bending tests pose unique challenges compared to uniaxial tensile tests. The ribs’ curved shape and variable cross-sections necessitate the application of finite strain theory to accurately measure deformation, accounting for large displacements. This study aims to (1) validate the feasibility of deriving precise mechanical properties directly from intact bones, and (2) confirm that these results align with those from tensile testing, which, although simpler to execute, require greater preparation efforts.</div><div>The findings from the rib bending tests confirm the following: (1) the Young’s modulus of cortical bone decreases with age but remains largely unaffected by strain rate within the range examined; and (2) both maximum strain and maximum stress decline with age but increase with higher strain rates. While these trends were previously observed in tensile tests, this study provides new evidence using the more complex methodology of complete rib bending, and describes the progressive loss of stiffness with damage models.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106954"},"PeriodicalIF":3.3,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Softening of elastic and viscoelastic properties is independent of overstretch rate in cerebral arteries","authors":"Noah Pearson ,&nbsp;Gregory M. Boiczyk ,&nbsp;William J. Anderl ,&nbsp;Michele Marino ,&nbsp;S. Michael Yu ,&nbsp;Kenneth L. Monson","doi":"10.1016/j.jmbbm.2025.106957","DOIUrl":"10.1016/j.jmbbm.2025.106957","url":null,"abstract":"<div><div>Collagenous soft tissues are frequently injured by supraphysiologic mechanical deformation, leading to measurable changes in both extra-cellular matrix (ECM) structure and mechanical properties. While each of these alterations has been well studied following quasi-static deformation, little is known about the influence of high strain rate. Previous investigations of high-rate ECM alterations found tropocollagen denaturation and fibrillar kinking to be rate dependent. Given these observations of rate dependence in microstructure alterations, the present work evaluated if the rate and magnitude of overstretch affect the baseline viscoelastic properties of porcine middle cerebral arteries (MCAs). Changes in tissue response were assessed using a series of harmonic oscillations before and after sub-failure overstretches across a large range of rates and magnitudes. We used collagen-hybridizing peptide (CHP) to evaluate the role of tropocollagen denaturation in mechanical softening. Experiments show that softening is dependent on overstretch magnitude but is independent of overstretch rate. We also note that softening progresses at the same rate for both equilibrium (quasi-static) and non-equilibrium (high-rate) properties. Finally, results suggest that tropocollagen denaturation is not the source of the observed sub-yield softening behavior. This study expands fundamental knowledge on the form-function relationship of constituents in collagen fibrils and clarifies material behavior following sub-failure overstretch across a range of strain rates.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106957"},"PeriodicalIF":3.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of joint deformation on the auxetic behaviour of 3D printed polypropylene structures","authors":"Juliet A. Shepherd,&nbsp;Serena M. Best,&nbsp;Ruth E. Cameron","doi":"10.1016/j.jmbbm.2025.106960","DOIUrl":"10.1016/j.jmbbm.2025.106960","url":null,"abstract":"<div><div>Auxetic structures studied in the literature are often based on relatively stiff, metallic materials and theories regarding their response to mechanical loading cannot be translated directly to polymeric materials. As “soft” auxetics increase in popularity for applications in tissue engineering further investigation into the joint behaviour and effect on their Poisson's ratio is required. 3D printed polypropylene auxetic mesh structures were produced to compare to the requirements for biological cell-stretching devices while investigating the deformation mechanics. The behaviour of the meshes was characterised with tensile force-strain curves and high-definition imaging and the effect of joint behaviour on the Poisson's ratio was evaluated. Isolated unit cell samples of the re-entrant mesh were produced to characterise the in- and out-of-plane behaviour for geometries comprising re-entrant strut angles of 30, 45, and 60° to the tensile straining direction. Force-strain curves with three distinct phases were observed, with linear, plateau, and terminal regions characteristic of re-entrant honeycomb structures. A constant negative Poisson's ratio was measured up to a critical transition strain, at which point it is theorised that the onset of buckling triggers bending-dominated deformation to occur, out-of-plane. The production of full-scale mesh samples with the same 30, 45, and 60° geometry resulted in consistent values for critical transition strain and Poisson's ratios. An auxetic region of strain was defined, where the force is linear and a homogeneous negative Poisson's ratio can be maintained. This region represents the limit within which a biological cell-stretching device could operate successfully for the current mesh design.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106960"},"PeriodicalIF":3.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}