Journal of the Mechanical Behavior of Biomedical Materials最新文献

{"title":"Collagen hydrogels with similar polymer content but different microstructure — A comparative analysis of mechanical response","authors":"Kim Busenhart ,&nbsp;Julie Brun ,&nbsp;Håvar Junker ,&nbsp;Alexander E. Ehret ,&nbsp;Alba Marcellan ,&nbsp;Edoardo Mazza","doi":"10.1016/j.jmbbm.2025.106922","DOIUrl":"10.1016/j.jmbbm.2025.106922","url":null,"abstract":"<div><div>Understanding the mechanical properties of collagen hydrogels is essential for successful applications in tissue engineering and 3D cell culture. This study compares the mechanical behavior of two collagen hydrogel sheets with similar collagen content but different microstructures. One of the differences is that one gel is isotropic while the other has collagen fibers oriented towards the sheet’s plane. Experiments were performed at macro- (uniaxial tension in the sheet plane) and micro-length scale (AFM-based indentation perpendicular to the plane), and a discrete network model was developed to rationalize the observed differences. The experiments showed an order of magnitude difference in the uniaxial stiffness of the two gels. The softer gel exhibited near-incompressible behavior, while the stiffer gel showed a highly contractile response, with Poisson’s ratios around 8. Conversely, the apparent modulus from nano-indentation showed an opposite trend, with higher local stiffness for the gel that was softer in uniaxial tests. The computational model represents the material using a network of bi-linear connectors for the fibrous component and a compressible neo-Hookean material for the surrounding water-rich matrix, assumed to form due to interactions between collagen and water. Under the constraint of equal collagen content, model parameters were tuned to reproduce the observed response of both materials, considering the observed differences in fiber diameter. Importantly, the computations indicate that the difference in collagen orientation cannot explain the observed differences between the mechanical responses of the gels. Successful scaling between the two gels depends on the assumption that, due to their crimped initial state individual fibers primarily experience bending rather than tension when the material is stretched. Moreover, high tensile stretch of the fibers is shown to elicit large lateral contraction. Overall, the results demonstrate the wide range of mechanical properties displayed by hydrogels with similar collagen content, which can be rationalized using discrete models representative of their microstructure.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106922"},"PeriodicalIF":3.3,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463673","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":"Skeletal impacts of dual in vivo compressive axial tibial and ulnar loading in mice","authors":"Olivia N. Reul,&nbsp;Rachel K. Surowiec,&nbsp;Nusaiba N. Chowdhury,&nbsp;Dyann M. Segvich,&nbsp;Joseph M. Wallace","doi":"10.1016/j.jmbbm.2025.106950","DOIUrl":"10.1016/j.jmbbm.2025.106950","url":null,"abstract":"<div><div>The use of compressive axial tibial loading for evaluation of bone adaptation and mechanotransduction has become a common technique in recent years. Despite its popularity, it only produces a single experimental limb per animal which can escalate sample sizes depending on study endpoints. We hypothesized the combination of compressive axial tibial and ulnar loading in a single animal would induce bone formation in loaded limbs, providing two experimental limbs per animal thereby reducing the animals required per study by half. Male and female C57BL/6J mice were purchased at 9 and 19 weeks (wks). Based on sex and age they were divided into 4 groups of N = 17. From each group, N = 5 were sacrificed at 10 and 20 wks for strain gauge calibration. At 11 wks and 21 wks, the left ulnae and right tibiae of the remaining animals (N = 12/group) were loaded 3 days/week for 4 weeks. Tibiae of all groups experienced significant increases in architectural properties due to loading in both trabecular and cortical compartments while there were no significant improvements in the ulna. Female tibiae showed improvements in mechanical properties, but these were not observed in the male tibiae where detrimental impacts were observed. In the ulna, females showed limited mechanical changes due to loading. Contrastingly, loading in males at 11 wks led to decreased mechanical properties while at 21 wks no impacts were observed. Overall, reported beneficial impacts of loading in tibiae were observed in architectural properties but were not maintained in the males’ mechanical properties. Impacts of ulnar loading on architectural and whole bone mechanical properties that have been reported elsewhere were not observed in any groups. These data suggest when architectural and mechanical properties are end points, combined loading is not optimal for reducing the number of animals required per study.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106950"},"PeriodicalIF":3.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420170","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":"Risk of bony endplate failure during vertebral fracture","authors":"Neilesh R. Frings ,&nbsp;Elise F. Morgan","doi":"10.1016/j.jmbbm.2025.106939","DOIUrl":"10.1016/j.jmbbm.2025.106939","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The endplate region of the vertebra, which includes the bony endplate (BEP) and underlying subchondral trabecular bone (STB), is critically involved in vertebral fracture (VF). While evidence abounds that failure initiates in the endplate region, the relative risk of failure of the BEP vs. STB has not been established. In this study, micro-finite element models were constructed of L1 vertebrae (n = 21) that were mechanically tested in a prior study and given experimentally matched boundary conditions corresponding to the vertebra's yield point. Volumes of interest (VOIs) were defined corresponding to the BEP and STB; the remainder was defined as the mid-vertebral body (MVB). The proportion of elements within each VOI that yielded was defined as the VOI yield fraction, and this value divided by the yield fraction of the entire model was defined as the normalized yield fraction. While yield fraction did not differ across VOIs (p = 0.179), normalized yield fraction was greater in the BEP than STB and MVB (p &lt; 0.001), indicating a higher risk of yield in the BEP compared to the other two VOIs. None of the yield fractions was correlated with BEP or STB microstructure, and tension (rather than compression) was the dominant mode of tissue level yield. These findings indicate that the BEP, more so than the STB, is likely the site of VF initiation and that current methods of screening for VF risk, because they omit specific analysis of the BEP, are missing the region that matters the most.&lt;/div&gt;&lt;div&gt;The endplate region of the vertebra, which includes the bony endplate (BEP) and underlying subchondral bone (SB), is critically involved in vertebral fracture (VF). While evidence abounds that failure initiates in the endplate region, the relative risk of failure of the BEP vs. SB has not been established. In this study, micro-finite element models were constructed of L1 vertebrae (n = 21) that had been mechanically tested in a prior study, and they were given experimentally matched boundary conditions corresponding to the vertebra's yield point. Volumes of interest (VOIs) were defined corresponding to the BEP and SB; the remainder was defined as the mid-vertebral body (MVB). The proportion of yielded elements within each VOI was defined as the VOI yield fraction, and this value divided by the yield fraction of the entire model was defined as the normalized yield fraction. While yield fraction did not differ across VOIs (p = 0.179), normalized yield fraction was greater in the BEP than SB and MVB (p &lt; 0.001), indicating a higher risk of yield in the BEP compared to the other two VOIs. None of the yield fractions was correlated with BEP or SB microstructure, and tension (rather than compression) was the dominant mode of tissue level yield. These findings indicate that the BEP, more so than the SB, is likely the site of VF initiation and that current methods of screening for VF risk, because they omit specific analysis of the BEP, are missing the","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106939"},"PeriodicalIF":3.3,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420168","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":"Improving accuracy in assessing osseointegration in small animal bone using specimen-specific additively-manufactured fixtures based on clinical CT imaging","authors":"Maximilian Pestel ,&nbsp;Jürgen Alphonsus ,&nbsp;Stefan Toegel ,&nbsp;Andreas Strassl ,&nbsp;Johannes Herold ,&nbsp;Reinhard Windhager ,&nbsp;Emir Benca","doi":"10.1016/j.jmbbm.2025.106941","DOIUrl":"10.1016/j.jmbbm.2025.106941","url":null,"abstract":"<div><h3>Objective</h3><div>Implant removal is a common method to quantify the level of osseointegration in small animal studies. Due to small implant sizes, precise alignment in removal experiments is crucial to obtain accurate and reproducible results. This study proposes a novel approach using photon counting detector computed tomography (PCD-CT) data and additive manufacturing to improve implant alignment.</div></div><div><h3>Methods</h3><div>A simplified finite element model was designed to investigate the effect of implant misalignment in removal tests. Additionally, the geometry of 43 rat tibiae was assessed utilizing PCD-CT scans, and subsequently specimen-specific positioning fixtures were designed and manufactured using computer-aided design and tabletop 3D printers. The accuracy and precision of the specimen alignment within the fixtures were assessed both visually (current state of the art) and through projectional radiography in both cranial-caudal (CC) and anterior-posterior (AP) projections to quantify true misalignment.</div></div><div><h3>Results</h3><div>Finite element analysis demonstrated that stresses and displacements are sensitive to misalignment, potentially leading to substantial inaccuracies in the implant removal measurements. Statistical analysis of visual assessments revealed poor to moderate inter- and intra-operator variability (0.336 ≤ ICC ≤ 0.625) and low correlation with true misalignment (0.024 ≤ R² ≤ 0.204). Specimen alignment within the fixtures (CC: 0.23 ± 0.46°, AP: 1.00 ± 0.82°) showed improvement in accuracy and precision compared to visual assessments (CC: 0.88 ± 0.92°, AP: 1.11 ± 1.15°).</div></div><div><h3>Conclusion</h3><div>The proposed specimen fixation and alignment, which relies on clinical imaging data and inexpensive 3D printers, offers a cost- and time-effective alternative to visual assessments, which could considerably improve the accuracy and precision in osseointegration assessment.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106941"},"PeriodicalIF":3.3,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453550","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":"Guided neural stem cell differentiation by dynamic loading of 3D printed elastomeric scaffolds","authors":"Yi Yang ,&nbsp;Abdullah Revaha Akdemir ,&nbsp;Rafsan Ahmed Rashik ,&nbsp;Omar Ahmad Shihadeh Khater ,&nbsp;Zijian Weng ,&nbsp;Long Wang ,&nbsp;Ying Zhong ,&nbsp;Nathan D. Gallant","doi":"10.1016/j.jmbbm.2025.106940","DOIUrl":"10.1016/j.jmbbm.2025.106940","url":null,"abstract":"<div><div>The limited regenerative ability of “permanent” cells is a major barrier to treating conditions like spinal cord injury (SCI) and myocardial infarction (MI). The delivery of stem cells, which can generate various cell types, offer potential for personalized therapy with reduced immunoreaction and recovery time. However, restoring function to these tissues also requires new or replacement cells to align properly. Neurons, for example, must organize and extend parallel axons, mimicking their natural structure for directional signal propagation. Current stem cell differentiation methods lack guidance, resulting in randomly distributed axons and limited repair effectiveness. Advancing methods and materials to guide stem cell differentiation into functional, aligned nerve bundles is crucial for improving SCI treatment outcomes. This study aimed to develop an in vitro system to promote aligned neural differentiation by applying cyclic uniaxial tension to PC-12 stem cells adhered to 3D-printed elastic scaffolds. We created a simple loading device which can apply cyclic and controllable stretching force to a scaffold, which in turn transmits uniaxial tension to cells adhered to the scaffold during their differentiation. An elastomer ink for 3D printing scaffolds was formulated and surface treatment processes were investigated to enhance the cell-scaffold adhesion to support the dynamic loading. It was revealed that a corona discharge treatment while the scaffold is soaked with type I collagen can significantly enhance cell adhesion. A range of strain magnitudes and frequencies were revealed to enhance the differentiation of neural tissue derived PC-12 cells to neuron cells and increase the length of their neurites up to 76%. The combination of 3% maximum strain and 1 Hz loading frequency maximized differentiation and neurite extension. These findings demonstrate that dynamic mechanical stimulation enhances neural differentiation and organization, offering an alternative approach for regenerative therapies targeting SCI and similar conditions.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106940"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420898","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":"Relationship between magnetization transfer ratio and axial compressive strain in tibiofemoral articular cartilage","authors":"Emily S. Sullivan ,&nbsp;Andrew Yung ,&nbsp;Jessica Küpper ,&nbsp;Kirsten Bale ,&nbsp;Piotr Kozlowski ,&nbsp;David R. Wilson","doi":"10.1016/j.jmbbm.2025.106937","DOIUrl":"10.1016/j.jmbbm.2025.106937","url":null,"abstract":"<div><h3>Purpose</h3><div>The objective of this study was to determine the relationship between magnetization transfer ratio (MTR) and strain in <em>ex vivo</em> bovine cartilage using 9.4T magnetic resonance imaging (MRI) and to compare this relationship to the relationship between T2 and strain.</div></div><div><h3>Methods</h3><div>A previously designed custom electropneumatic loading device was used to compress together osteochondral blocks of bovine femoral and tibial cartilage and bone within a 9.4T Bruker MRI scanner. Stepwise loads were applied to compress cartilage to targets of 10%, 20% and 30% strain. Images were acquired for unloaded cartilage and after each load had been held constant for 20 min to minimize creep effects. A custom algorithm was used to quantify T2 and MTR (average, by depth, and column wise) in the region of contact, and to calculate axial cartilage strain. Repeated measures correlation was used to investigate potential correlations between MTR and strain, and T2 and strain.</div></div><div><h3>Results</h3><div>Mean MTR vs strain correlations were r_rm = −0.90 (CI = −0.96 to −0.75) in the tibia and r_rm = −0.70 (CI = −0.87 to −0.35) in the femur. Mean T2 vs strain correlations were r_rm = −0.84 (CI = −0.94 to −0.59) in the tibia and r_rm = −0.11 (CI = −0.57 to 0.41) in the femur. Column-wise analyses produced negligible or weak correlations (−0.07 to −0.34 for T2 and MTR).</div></div><div><h3>Conclusions</h3><div>MTR increases with strain in the region of contact, and MTR is more strongly correlated to strain than T2. MTR shows promise as a surrogate measure of strain, especially when averaged over the region of contact.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106937"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463780","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":"Experimental model and simulant for studying blast penetrating injury to the skin","authors":"Thuy-Tien N. Nguyen ,&nbsp;Hirotaka Tsukada ,&nbsp;Gregory R. James ,&nbsp;Iain A. Rankin ,&nbsp;Louise McMenemy ,&nbsp;John Breeze ,&nbsp;Spyros D. Masouros","doi":"10.1016/j.jmbbm.2025.106936","DOIUrl":"10.1016/j.jmbbm.2025.106936","url":null,"abstract":"<div><div>Energised fragments from explosions are the most common wounding mechanism in conflicts and terrorist attacks. Skin covers the vast majority of the human body and is therefore the first anatomical component to be penetrated by fragments, however, its resistance to penetration largely has not been taken into account in models of injury. In this study, an experimental model for ballistic testing of skin is established and a suitable skin simulant for studying resistance to penetration is determined. Fragment-simulating projectiles were fired at human cadaveric skin and skin-simulant candidates. Tissue responses were quantified by evaluating the impact velocity at 50% risk of skin penetration and perforation, and the depth of penetration in cadaveric tissue or skin-simulant candidates. The results identified a 1.5-mm-thick butyl rubber as a suitable skin simulant across the range of threats tested. The findings can help refine assessment of protective systems and predictive models of injury in an effort to improve outcomes of fragment-penetrating injuries.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106936"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420899","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 stress-driven model for bone density evolution in rats during orthodontic tooth movement","authors":"Bin Wu ,&nbsp;Mingna Li ,&nbsp;Fan Yang ,&nbsp;Yi Lu ,&nbsp;Yang Yi ,&nbsp;Mao Liu ,&nbsp;Ke Cheng ,&nbsp;Di Jiang ,&nbsp;Bin Yan","doi":"10.1016/j.jmbbm.2025.106932","DOIUrl":"10.1016/j.jmbbm.2025.106932","url":null,"abstract":"<div><div>Orthodontic bone remodeling simulations offer a scientific foundation for optimizing treatment plans and predicting outcomes in orthodontics. Since alveolar bone exhibits unique regional responses and high sensitivity to tensile and compressive stresses, traditional models often fail to account for these characteristics, limiting their accuracy in predicting the microstructural changes of alveolar bone under external forces. To address this issue, this study proposes a bone remodeling model based on equivalent stress derived from the Mohr strength theory as the mechanical stimulus. The model differentiates tension and compression zones within the alveolar bone and simulates density changes driven by the orthodontic remodeling process: bone formation in tension zone and resorption in compression zone. Orthodontic experiments on rats were conducted to monitor changes in alveolar bone density at 7 and 14 days. Results revealed a density increase of around 3.16% and 9.84% in tension zone and a decrease of approximately 4.86% and 3.61% in compression zone on days 7 and 14, respectively. A comparison between the experimental data and the simulation results of the bone remodeling algorithm demonstrated a consistent trend, validating that the proposed model effectively reflects the dynamic process of bone remodeling. This study provides a new perspective for orthodontic bone remodeling simulations and lays a foundation for further exploration of the mechanisms underlying alveolar bone density changes.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106932"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437301","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":"Exploring hyperelastic material model discovery for human brain cortex: Multivariate analysis vs. artificial neural network approaches","authors":"Jixin Hou ,&nbsp;Nicholas Filla ,&nbsp;Xianyan Chen ,&nbsp;Mir Jalil Razavi ,&nbsp;Dajiang Zhu ,&nbsp;Tianming Liu ,&nbsp;Xianqiao Wang","doi":"10.1016/j.jmbbm.2025.106934","DOIUrl":"10.1016/j.jmbbm.2025.106934","url":null,"abstract":"<div><div>The human brain, characterized by its intricate architecture, exhibits complex mechanical properties that underpin its critical functional capabilities. Traditional computational methods, such as finite element analysis, have been instrumental in uncovering the fundamental mechanisms governing the brain's physical behaviors. However, accurate predictions of brain mechanics require effective constitutive models to represent the nuanced mechanical properties of brain tissue. In this study, we aimed to identify well-suited material models for human brain tissue by leveraging artificial neural network and multiple regression techniques. These methods were applied to a generalized framework of widely accepted classic models, and their respective outcomes were systematically compared. To evaluate model efficacy, all setups were maintained consistent across both approaches, except for strategies employed to mitigate potential overfitting. Our findings reveal that artificial neural networks are capable of automatically identifying accurate constitutive models from given admissible estimators. However, the five-term and two-term neural network models trained under single-mode and multi-mode loading scenarios, respectively, were found to be suboptimal. These models could be further simplified into two-term and single-term formulations using multiple regression, achieving even higher predictive accuracy. This refinement underscores the importance of rigorous cross-validations of regularization parameters in neural network-based methods to ensure globally optimal model selection. Additionally, our study demonstrates that traditional multivariable regression methods, when combined with appropriate information criterion, are also highly effective in discovering optimal constitutive models. These insights contribute to the ongoing development of advanced material constitutive models, particularly for complex biological tissues.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106934"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420171","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":"Mechanical characterization of the human femoral vein wall and its valves","authors":"Kerstin Lebahn ,&nbsp;Jonas Keiler ,&nbsp;Wolfram Schmidt ,&nbsp;Julia Schubert ,&nbsp;Maria Reumann ,&nbsp;Andreas Wree ,&nbsp;Niels Grabow ,&nbsp;Sabine Kischkel","doi":"10.1016/j.jmbbm.2025.106938","DOIUrl":"10.1016/j.jmbbm.2025.106938","url":null,"abstract":"<div><div>For the development of stent-based intraluminal prostheses to treat chronic venous insufficiency, comprehensive knowledge of morphometric and mechanical parameters of the femoral veins (FV) is crucial for an optimized implant design. These data is essential as input for material models for numerical simulations of venous valves prostheses. However, data on mechanical properties of native/unfixed FV tissue are scarce. Unfixed native tissue, though, has limited availableness and durability due to progressing decay. To address these challenges, this study aimed to determine stress-strain behavior and compliance from native specimens of the human FV and its valves from body donations and compared the data to chemically fixed material.</div><div>A large data set has been generated in tensile tests with a total of 313 venous wall and 78 valve leaflet specimens in different fixation groups from a total of 41 body donations. Tensile testing was conducted at cut rectangular specimens in longitudinal as well as circumferential direction of the vein walls and in one specific direction for the valve leaflets. Young's moduli <em>E</em>_<em>1</em> and <em>E</em>_<em>2</em> in two differently defined strain regions, tensile strength <em>R</em>_<em>m</em> and elongation at break <em>A</em> were determined. Additionally, compliance measurements were performed at whole, unfixed vein segments using optical coherence tomography to determine the vessel diameter at increasing intravascular pressure from 20 to 240 mmHg.</div><div>Significant differences were found in the tensile parameters between unfixed tissue and the different fixations (exemplary Young's modulus E₁ in longitudinal direction: <em>E</em>_{<em>1, unfixed</em>} = 5.7 ± 5.1 N/mm², <em>E</em>_{<em>1, FA</em>} = 13.1 ± 11.9 N/mm², <em>E</em>_{<em>1, PFA</em>} = 2.3 ± 1.0 N/mm). A distinct anisotropy of the mechanical properties could only be detected for PFA fixed material when comparing longitudinal and circumferential tensile direction. Resultant mean compliance values over all segments and measuring positions of the vein segments for the analyzed pressure stages were in the range from 18.16 to 3.78 %/100 mmHg and showed a distinct decrease with increasing pressure.</div><div>Fixation (FA, PFA) alters the elastomechanical behavior, but the parameters were still in a similar order of magnitude considering the naturally occurring variability. Thus, testing of fixed tissue appears to be as appropriate as the use of this material for <em>ex vivo</em> testing. The provided material data of femoral veins (longitudinal and circumferential) as well as venous valve leaflets may serve as basis for numerical models, e.g. for the development of artificial venous valves.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106938"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420169","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}