Journal of the Mechanical Behavior of Biomedical Materials最新文献

{"title":"Optimising dental restorative composites: Numerical and statistical analysis of polymerization shrinkage and elastic modulus effects","authors":"Jerrin Thadathil Varghese ,&nbsp;Faisal Islam ,&nbsp;Paul Farrar ,&nbsp;B. Gangadhara Prusty","doi":"10.1016/j.jmbbm.2025.106981","DOIUrl":"10.1016/j.jmbbm.2025.106981","url":null,"abstract":"<div><div>Light-cured resin-based dental restorative composites face challenges from polymerization shrinkage, which induces stress, potentially leading to microleakage, debonding, and recurrent caries. The elastic modulus (<em>E</em>) of these composites also influences stress distribution, with high-stress concentrations potentially leading to fractures in restored teeth. While finite element analysis (FEA) has been used to understand stress distribution, there is a lack of comprehensive studies exploring the combined effects of volumetric polymerization shrinkage (<em>PS%</em>) and <em>E</em> on restored molars. No research has addressed the influence of these factors on stress intensity at crack tips during mastication after shrinkage. This study investigates how variations in <em>E</em> and <em>PS%</em> affect the stress distribution at the restoration-enamel junctions (REJ) and restoration under mastication stimuli and shrinkage. Additionally, the study examines the impact of <em>E</em> and <em>PS%</em> on the stress intensity factor at the crack tip of a restored molar tooth. A 3D model of an upper molar was created from scanned images, converted into a mesh using 10-node tetrahedral elements, and analysed with finite element methods. The values of <em>E</em> ranged from 5 GPa to 25 GPa, and <em>PS%</em> ranged from 1 % to 5 %. Results showed that maximum principal stress varied with different <em>E</em> and <em>PS%</em> values, with the lowest stress occurring at <em>E</em> = 5 GPa and <em>PS%</em> = 1 % and the highest at <em>E</em> = 25 GPa and <em>PS%</em> = 5 %. Changes in these parameters also affected the locations of peak principal stress. Additionally, stress intensity factors decreased with increasing <em>E</em> but rose with higher <em>PS%.</em> Changes in <em>E</em> and <em>PS%</em> influence where and how much the principal stresses occur at the REJ and during restoration in response to shrinkage and mastication stimuli. This highlights the crucial role of material properties in the performance and durability of restorations, providing evidence-based insights that could guide material selection for MOD-restored molar teeth, ultimately enhancing restoration longevity and clinical outcomes.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106981"},"PeriodicalIF":3.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725749","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}

{"title":"Confined and unconfined articular cartilage mechanics: Effect of creep duration on estimations of mechanical properties","authors":"Bo E. Seiferheld ,&nbsp;Hanna Isaksson ,&nbsp;Viktor Jönsson ,&nbsp;Petri Tanska ,&nbsp;Michael S. Andersen","doi":"10.1016/j.jmbbm.2025.106982","DOIUrl":"10.1016/j.jmbbm.2025.106982","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Recent findings suggest that cartilage mechanical function may be a biomarker for early osteoarthritis (OA) pathology. Thus, the development of methodologies for &lt;em&gt;in-vivo&lt;/em&gt; applications has expanded. However, when creep tests are performed, inconsistency in applied stress and testing duration impede meaningful comparisons. Therefore, this study investigates the impact of creep duration on cartilage mechanics through &lt;em&gt;ex-vivo&lt;/em&gt; confined and unconfined compression experiments on healthy bovine cartilage samples (n = 20), subjected to 1 MPa stress for 5 h. A Zener model was fitted to unconfined data and a nonlinear biphasic model was fitted to confined data using durations ranging from 15 min to 5 h. Mechanical properties were compared against the full 5-h dataset to determine relative errors (RE) associated with insufficient creep duration. Based on our findings, we aim to establish a common ground for both &lt;em&gt;in vivo&lt;/em&gt; and &lt;em&gt;ex vivo&lt;/em&gt; environments. Both unconfined (R&lt;sup&gt;2&lt;/sup&gt; = 0.96 ± 0.02) and confined (R&lt;sup&gt;2&lt;/sup&gt; = 0.997 ± 0.003) models fitted the data well over 5 h. For confined creep tests, the aggregate modulus (&lt;em&gt;H&lt;/em&gt;&lt;sub&gt;A&lt;/sub&gt;) was 0.34 ± 0.12 MPa after 5 h and 0.27 ± 0.12 MPa after 1 h (RE ∼ 20 %), while initial permeability (&lt;em&gt;k&lt;/em&gt;&lt;sub&gt;0&lt;/sub&gt;) increased from 0.17 × 10&lt;sup&gt;−15&lt;/sup&gt; m&lt;sup&gt;4&lt;/sup&gt;N&lt;sup&gt;−1&lt;/sup&gt;s&lt;sup&gt;−1&lt;/sup&gt; to 0.56 × 10&lt;sup&gt;−15&lt;/sup&gt; m&lt;sup&gt;4&lt;/sup&gt;N&lt;sup&gt;−1&lt;/sup&gt;s&lt;sup&gt;−1&lt;/sup&gt; (RE ∼ 49 %). The Zener model estimated the initial (&lt;em&gt;E&lt;/em&gt;&lt;sub&gt;1&lt;/sub&gt;) and steady-state (&lt;em&gt;E&lt;/em&gt;&lt;sub&gt;2&lt;/sub&gt;) modulus to be 3.6 ± 0.7 MPa and 3.2 ± 0.3 MPa after 5 h, respectively. After 1 h, these values were 4.7 ± 1.0 MPa (RE ∼ 29 %) and 3.2 ± 0.3 MPa (RE ∼ 2 %). A larger RE (∼57 %) was observed for the relaxation time constant (&lt;em&gt;τ&lt;/em&gt;) determined after 5 h (1688 ± 556 s) and 1 h (781 ± 170 s) with the Zener model. The benefit of extended creep duration diminished after 1–1.5 h for confined compression and 2 h for unconfined compression for non-rate dependent stiffness parameters (i.e., &lt;em&gt;H&lt;/em&gt;&lt;sub&gt;A&lt;/sub&gt;, &lt;em&gt;E&lt;/em&gt;&lt;sub&gt;1&lt;/sub&gt;, &lt;em&gt;E&lt;/em&gt;&lt;sub&gt;2&lt;/sub&gt;). This aligned well with the predefined equilibrium criteria of less than 0.6 μm/min, with equilibrium reached at 71 ± 23 min for confined experiments and 94 ± 25 min for unconfined experiments. In contrast, for parameters controlling the nonlinear material response (i.e., &lt;em&gt;τ&lt;/em&gt;, &lt;em&gt;k&lt;/em&gt;&lt;sub&gt;0,&lt;/sub&gt; &lt;em&gt;M&lt;/em&gt;), 4 h were required for unconfined compression and 1.5 h for confined compression to achieve RE ∼ 10 %. Thus, insufficient creeping duration resulted in large RE, especially for strain-dependent parameters. Therefore, it is recommended to use a clear equilibrium definition when conducting &lt;em&gt;ex vivo&lt;/em&gt; experiments. In the context of clinically viable testing duration (i.e., 45–60 min) RE was ∼20 % for the predicted aggregate modulus and ∼10 % for the nonlinear permeability coefficient. While these errors appear substantia","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106982"},"PeriodicalIF":3.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143714998","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":"Wear and friction resistance of UHMWPE with anisotropic microstructure shaped by mechanical compression","authors":"Lucas Gimenis de Moura (Moura, L. G.) ,&nbsp;Carlos Henrique da Silva (Silva, C. H) ,&nbsp;Rafael Mello Trommer (Trommer, R. M.) ,&nbsp;Clara Muniz Almeida (Almeida, C. M) ,&nbsp;Marcia Marie Maru (Maru, M. M.) ,&nbsp;Carlos Rodrigo de Mello Roesler (Roesler, C. R. M.)","doi":"10.1016/j.jmbbm.2025.106980","DOIUrl":"10.1016/j.jmbbm.2025.106980","url":null,"abstract":"<div><div>This study investigates the tribological behavior of UHMWPE with an anisotropic microstructure induced by uniaxial compression. Reciprocating sliding tests were conducted under loads exceeding the material's elastic limit to reveal differences in friction and wear when sliding parallel (LD) and perpendicular (FD) to the compression axis. The experiments were conducted under a severe wear regime, exceeding the typical contact stresses in orthopedical prostheses. The results highlight the influence of mechanical deformation on wear resistance and friction, providing insights for optimizing UHMWPE performance in biomedical and industrial applications. The molecular structure of the original and compressed UHMWPE specimens was assessed using AFM images, and the microstructural phases were quantified through Raman spectroscopy. The originally directionless lamellar structure appeared aligned along the FD direction in the compressed specimen. Besides that, the amount of crystalline phase, near 50 % in the original specimen, increased to 57 % when the laser beam is polarized along the FD direction and decreased to 29 % polarized along LD direction in the deformed specimen, indicating permanent anisotropy in the polymeric material due to mechanical compression. The average amount of polymer's microstructural phases clearly changed after sliding process, quite considerably in the compressed specimens. Testing along FD path further increased the crystalline phase in this direction, from 57 % to 66 % after the test. In LD direction the same phase increased from 29 % to 76 % after the test, even reversing the microstructural anisotropy in this case. A larger volume of debris was produced in the plastically deformed polymer specimen in comparison to the original material, independently of the tested direction, and despite the increase in the crystalline phase in the deformed material. The pre-strained material demonstrated more susceptibility of to wear, with no correlation with the crystallinity extent of the material. In conclusion, the results contribute to a better understanding of material deformation mechanics, providing insights into optimizing wear resistance in high-stress environments.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106980"},"PeriodicalIF":3.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680833","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":"How robust is the virtual fields method with respect to experimental inhomogeneities for bulge inflation testing of hyperelastic materials?","authors":"Paulien Vandemaele ,&nbsp;Lauranne Maes ,&nbsp;Heleen Fehervary ,&nbsp;Stéphane Avril ,&nbsp;Nele Famaey","doi":"10.1016/j.jmbbm.2025.106965","DOIUrl":"10.1016/j.jmbbm.2025.106965","url":null,"abstract":"<div><div>Mechanical characterization of biological soft tissue can be a challenging process due to its inherent inhomogeneities. Constitutive model calibration based on the virtual fields method enables the use of full-field deformation and thickness data in order to obtain region-specific material parameters. However, for practical reasons, assumptions are often made in model calibration frameworks, e.g., by using the average sample thickness and deriving homogenized material parameters.</div><div>This study investigates the effect of these assumptions on the material parameters predicted by the virtual fields method. To this end, synthetic datasets of bulge inflation experiments were created using a finite element model and parameter identification was performed.</div><div>The ground truth parameters could be retrieved for a homogeneous sample with a high accuracy of 0.15%, even when only part of the full-field deformation data was known. For samples with a nonuniform thickness, the parameters could still be obtained with an error of 4% when taking into account the average sample thickness. However by including the region-specific thickness, parameters and stress responses closer to the ground truth were found, within 1% error. When samples showed inhomogeneous material properties spread throughout the sample, the obtained parameters resulted in a more homogenized stress response, eliminating the minimal and maximal stresses of the ground truth response. The ground truth stress response could not be obtained when the sample consisted of regions of different material properties. Further, only an incremental error of <span><math><mrow><mn>0</mn><mo>.</mo><mn>6</mn><mtext>%</mtext><mi>p</mi><mi>t</mi><mo>.</mo></mrow></math></span> was seen when decreasing the resolution in the parameter fitting framework by a factor 2.5 for both homogeneous samples and samples with a nonuniform thickness.</div><div>These results highlight the robustness of the virtual fields method and can be translated to other test types.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106965"},"PeriodicalIF":3.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706229","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":"Performance parity in cartilage repair: SPMK-g-PEEK versus cartilage–cartilage interfaces","authors":"Robert J. Elkington ,&nbsp;Gregory M. Pryce ,&nbsp;David Keeling ,&nbsp;Richard M. Hall ,&nbsp;Andrew R. Beadling ,&nbsp;Hemant Pandit ,&nbsp;Michael G. Bryant","doi":"10.1016/j.jmbbm.2025.106964","DOIUrl":"10.1016/j.jmbbm.2025.106964","url":null,"abstract":"<div><div>Effective fluid exudation and rehydration are essential for the low-friction function of healthy articular cartilage, facilitating interstitial fluid pressurisation, solute transport, and aqueous lubrication. However, current metallic biomaterials used in focal cartilage repair or hemiarthroplasty compromise this fluid-pressure dependent load support, leading to the erosion of the interfacing cartilage. This study investigates bioinspired hydrophilic 3-sulfopropyl methacrylate potassium salt (SPMK) polymer grafted onto a PEEK substrate (SPMK-g-PEEK) as a potential solution. SPMK-g-PEEK aims to mimic the natural tribology of cartilage by providing an aqueous low friction interface and polyelectrolyte-enhanced tribological rehydration (PETR), supporting fluid recovery and interstitial fluid pressurisation during cartilage sliding. We compare the tribological characteristics of physiological cartilage–cartilage interfaces, which rely on osmotic swelling and hydrodynamic tribological rehydration, with PETR enabled by SPMK-g-PEEK interfaces.</div><div>This study introduces a bespoke Fuzzy-PI controlled biotribometer. Employing a dual-phase testing method, static compression followed by sliding, allows simultaneous measurement of friction and cartilage strain recovery, indicative of interstitial fluid recovery following compressive exudation. Cartilage condyle, unfunctionalised PEEK, and SPMK-g-PEEK surfaces were investigated against flat cartilage plugs, which provide no hydrodynamic entrainment zone for tribological rehydration, and convex cartilage plugs, which create a convergent hydrodynamic zone for tribological rehydration. Matched cartilage–cartilage contacts exhibited low friction coefficients of <span><math><mo>∼</mo></math></span> 0.04 and strain recovery of up to <span><math><mo>∼</mo></math></span> 14% during the sliding phase. SPMK-g-PEEK surfaces sliding against convex cartilage plugs demonstrated similar strain recovery of <span><math><mo>∼</mo></math></span> 13% and reduced friction coefficients of <span><math><mo>∼</mo></math></span> 0.01, due to the combined effects of PETR and hydrodynamic tribological rehydration. In contrast, unfunctionalised PEEK surfaces, similar to current hard biomaterials employed in cartilage resurfacing, showed significantly higher friction and inhibited rehydration. SPMK-g-PEEK effectively mimics the physiological rehydration of connatural articular cartilage surfaces, highlighting its potential as a biomimetic material for cartilage resurfacing.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106964"},"PeriodicalIF":3.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706345","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}

{"title":"Cytocompatibility, fibroblast adhesion and proliferation on surface modified 3D-printed PEEK scaffolds","authors":"Pedro Rendas ,&nbsp;Joana Amorim ,&nbsp;Pedro Viana Baptista ,&nbsp;Catarina Vidal ,&nbsp;Lígia Figueiredo ,&nbsp;Alexandra R. Fernandes ,&nbsp;Bruno Soares","doi":"10.1016/j.jmbbm.2025.106979","DOIUrl":"10.1016/j.jmbbm.2025.106979","url":null,"abstract":"<div><div>Polyetheretherketone (PEEK) is a high-performance thermoplastic that, when combined with Additive Manufacturing (AM), presents considerable advantages to produce customizable implantable medical devices. Despite this potential, PEEK's use as an implant material still presents challenges imposed by its bioinert nature. This study investigates the biofunctionalization of 3D-printed PEEK implants to enhance fibroblasts' cellular response due to their important role in the healing of connective tissue post-implantation. Different combinations of biofunctional features were investigated by surface modifying solid, porous, and surface-rough 3D-printed PEEK samples with the sulfonation treatment and incorporation of hydroxyapatite (HA) particles. The porous scaffold construct was designed based on a gyroid surface and then analysed using micro-CT and compression tests. Fibroblast culture assays were conducted to assess the effects of different surface morphologies on cellular adhesion and proliferation. Preliminary data of fibroblast metabolic activity on differently modified PEEK samples was also collected. Results from the experiments suggest that solid PEEK samples with rough surfaces and subjected to both sulfonation and HA incorporation procedures exhibit the most favourable environment for maintaining fibroblasts morphology and viability. Conversely, the lower adhesion and proliferation on smooth as-printed surfaces highlight the necessity for surface functionalization of 3D-printed PEEK. Additionally, results for metabolic activity paired with cell morphologies observed under SEM indicate that large-scale porous scaffolds may present less favourable environment for fibroblasts viability compared to solid surfaces. These findings offer valuable insights to 3D-printed PEEK biofunctionalization towards the improvement of fibroblast response, particularly considering their active role on extracellular matrix formation which is critical for connective tissue support and cohesion during the healing process after surgical implantation.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106979"},"PeriodicalIF":3.3,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644181","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}

{"title":"Bone mechanical behavior around dental implants: Densification and deformation follow-up by in-situ computed tomography","authors":"Laura Preiss ,&nbsp;Rémy Gauthier ,&nbsp;Hervé Richard ,&nbsp;Loïc Courtois ,&nbsp;Anne-Lise Chopard-Lallier ,&nbsp;Damien Fabrègue ,&nbsp;Jérôme Chevalier ,&nbsp;Nicolas Courtois","doi":"10.1016/j.jmbbm.2025.106966","DOIUrl":"10.1016/j.jmbbm.2025.106966","url":null,"abstract":"<div><div>The state of bone tissue around dental implants is a crucial factor influencing their early clinical outcomes. Currently, this state is mainly defined by its primary stability, both in terms of biomechanical analysis and clinically. The clinical methods used for quantifying this stability—such as the Implant Stability Quotient (ISQ) and Insertion Torque (IT)—are indirect measures. While these methods provide insights into the overall mechanical behavior of the bone-implant system, they do not account for the impact of implant morphology on the surrounding bone. The method presented here aims to analyze the peri-implant bone using image analysis and volume correlation techniques combined with computed tomography to assess the bone strain field and densification resulting from dental implant placement. The study utilized two types of implants with distinct designs—one cylindrical and the other self-tapping—on five iliac crest bone samples harvested from butcher pigs. The results indicated that the self-tapping implant caused significantly greater bone densification near the implant compared to the cylindrical one (46% of densification in the first 30 μm, against 21% for cylindrical implant). Additionally, the volume of strained peri-implant bone appeared to be larger for the self-tapping implant (38% of the volume was mechanically affected above 0,5% VM strains for self-tapping implant, against 31% for the cylindrical implant), though this difference was not statistically significant. Furthermore, established descriptors from the literature struggled to effectively differentiate between the two implant types. Despite the study's limitations, the proposed method shows promise for distinguishing implants based on the densification and deformation of peri-implant bone, and can serve as a complementary approach to standard ISQ and IT measurements.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"167 ","pages":"Article 106966"},"PeriodicalIF":3.3,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619359","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}

{"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}