Pub Date : 2025-11-27DOI: 10.1016/j.jmbbm.2025.107285
Mahsa Salimi Majd , Heiko Tzschätzsch , Tom Meyer , Noah Jaitner , Yang Yang , Neele Hattermann , Alison N. Agres , Georg N. Duda , Steffen Görner , Jürgen Braun , Ingolf Sack , Jing Guo
Determining the biomechanical properties of skeletal muscle in-vivo is challenging due to structural anisotropy. In this study, we developed combined diffusion tensor imaging (DTI) and magnetic resonance elastography (MRE) to quantify direction-dependent biophysical properties of the lower leg muscles and their changes during passive plantarflexion (PF) and dorsiflexion (DF).
Thirteen male volunteers were studied using DTI-MRE. Anisotropic shear-wave-speeds parallel () and perpendicular () to the fiber orientation were reconstructed by aligning MRE vector wave fields to the principal fiber axis with rotation angles obtained from DTI tractography. Isotropic was also calculated without rotation for comparison. Fractional anisotropy (FA), radial (RD) and axial diffusivity (AD) were obtained from DTI.
was higher than in tibialis anterior (TibA), whereas the opposite was observed in posterior soleus (SolP). From PF to DF, and changed significantly in all muscles: TibA (−15 ± 11 %, −15 ± 13 %), SolP (8 ± 12 %, 9 ± 11 %), and gastrocnemius medialis (GasM) (11 ± 15 %, 21 ± 14 %), respectively (all p < 0.05). was only sensitive in TibA (−13 ± 7 %) and GasM (4 ± 11 %), both p < 0.05. For DTI, from PF to DF, FA and RD changed significantly in TibA (−20 ± 12 %, 10 ± 7 %), SolP (26 ± 12 %, −6±6 %), and GasM (19 ± 12 %, −5±7 %), respectively (all p < 0.001). AD only changed in SolP (3 ± 5 %, p < 0.01).
In conclusion, anisotropic MRE was more sensitive to ankle positions in lower leg muscles than isotropic MRE and revealed biomechanical differences between muscle types. In the future, DTI-MRE with anisotropic parameter reconstruction could be used for the detection of subtle structural changes in muscle diseases.
{"title":"Quantification of anisotropic biophysical properties of lower leg muscles at passive dorsiflexion and plantarflexion using magnetic resonance elastography and diffusion tensor imaging","authors":"Mahsa Salimi Majd , Heiko Tzschätzsch , Tom Meyer , Noah Jaitner , Yang Yang , Neele Hattermann , Alison N. Agres , Georg N. Duda , Steffen Görner , Jürgen Braun , Ingolf Sack , Jing Guo","doi":"10.1016/j.jmbbm.2025.107285","DOIUrl":"10.1016/j.jmbbm.2025.107285","url":null,"abstract":"<div><div>Determining the biomechanical properties of skeletal muscle in-vivo is challenging due to structural anisotropy. In this study, we developed combined diffusion tensor imaging (DTI) and magnetic resonance elastography (MRE) to quantify direction-dependent biophysical properties of the lower leg muscles and their changes during passive plantarflexion (PF) and dorsiflexion (DF).</div><div>Thirteen male volunteers were studied using DTI-MRE. Anisotropic shear-wave-speeds parallel (<span><math><mrow><msub><mi>c</mi><mo>∥</mo></msub></mrow></math></span>) and perpendicular (<span><math><mrow><msub><mi>c</mi><mo>⊥</mo></msub></mrow></math></span>) to the fiber orientation were reconstructed by aligning MRE vector wave fields to the principal fiber axis with rotation angles obtained from DTI tractography. Isotropic <span><math><mrow><msub><mi>c</mi><mtext>iso</mtext></msub></mrow></math></span> was also calculated without rotation for comparison. Fractional anisotropy (FA), radial (RD) and axial diffusivity (AD) were obtained from DTI.</div><div><span><math><mrow><msub><mi>c</mi><mo>∥</mo></msub></mrow></math></span> was higher than <span><math><mrow><msub><mi>c</mi><mo>⊥</mo></msub></mrow></math></span> in tibialis anterior (TibA), whereas the opposite was observed in posterior soleus (SolP). From PF to DF, <span><math><mrow><msub><mi>c</mi><mo>⊥</mo></msub></mrow></math></span> and <span><math><mrow><msub><mi>c</mi><mo>∥</mo></msub></mrow></math></span> changed significantly in all muscles: TibA (−15 ± 11 %, −15 ± 13 %), SolP (8 ± 12 %, 9 ± 11 %), and gastrocnemius medialis (GasM) (11 ± 15 %, 21 ± 14 %), respectively (all p < 0.05). <span><math><mrow><msub><mi>c</mi><mtext>iso</mtext></msub></mrow></math></span> was only sensitive in TibA (−13 ± 7 %) and GasM (4 ± 11 %), both p < 0.05. For DTI, from PF to DF, FA and RD changed significantly in TibA (−20 ± 12 %, 10 ± 7 %), SolP (26 ± 12 %, −6±6 %), and GasM (19 ± 12 %, −5±7 %), respectively (all p < 0.001). AD only changed in SolP (3 ± 5 %, p < 0.01).</div><div>In conclusion, anisotropic MRE was more sensitive to ankle positions in lower leg muscles than isotropic MRE and revealed biomechanical differences between muscle types. In the future, DTI-MRE with anisotropic parameter reconstruction could be used for the detection of subtle structural changes in muscle diseases.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107285"},"PeriodicalIF":3.5,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145663127","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}
Pub Date : 2025-11-24DOI: 10.1016/j.jmbbm.2025.107283
Aroj Bhattarai , Gregory P. Reece , Kristy K. Brock , Krishnaswamy Ravi-Chandar
Breast surgery for aesthetic purposes, such as breast augmentation or breast reduction, and breast reconstruction after cancer treatment require an accurate structural (anatomical) and mechanical (functional) understanding of the breast components, including the fascial-ligamentous support system of the breast, to achieve optimal results. This paper aims to provide a comprehensive description of the mechanical behavior of the ligamentous and fascial connective tissues of the human female breast. Fasciae and ligaments obtained from 17 patients between 35 and 85 years of age who were undergoing mastectomy and three female cadavers were tested. Uniaxial tensile tests were conducted, and three constitutive models -- the phenomenological Fung exponential model, the invariant-based anisotropic Gasser-Ogden-Holzapfel model, and the meso-scale structural constitutive model -- were employed to fit the experimental stretch-stress curves. Our results show that the stiffness becomes consistent once collagen fibers are fully stretched, regardless of tissue type or patient factors. This paper presents a comprehensive mechanical characterization of all the connective tissues contributing to the fascial support structures of the breast, collectively termed here as the breast fibro-structural support (BFSS) system. A generalized stress-stretch curve with initial stretch as the only variable effectively captures patient-specific variability.
{"title":"A comprehensive biomechanical material characterization of the human breast fibro-structural support system","authors":"Aroj Bhattarai , Gregory P. Reece , Kristy K. Brock , Krishnaswamy Ravi-Chandar","doi":"10.1016/j.jmbbm.2025.107283","DOIUrl":"10.1016/j.jmbbm.2025.107283","url":null,"abstract":"<div><div>Breast surgery for aesthetic purposes, such as breast augmentation or breast reduction, and breast reconstruction after cancer treatment require an accurate structural (anatomical) and mechanical (functional) understanding of the breast components, including the fascial-ligamentous support system of the breast, to achieve optimal results. This paper aims to provide a comprehensive description of the mechanical behavior of the ligamentous and fascial connective tissues of the human female breast. Fasciae and ligaments obtained from 17 patients between 35 and 85 years of age who were undergoing mastectomy and three female cadavers were tested. Uniaxial tensile tests were conducted, and three constitutive models -- the phenomenological Fung exponential model, the invariant-based anisotropic Gasser-Ogden-Holzapfel model, and the meso-scale structural constitutive model -- were employed to fit the experimental stretch-stress curves. Our results show that the stiffness becomes consistent once collagen fibers are fully stretched, regardless of tissue type or patient factors. This paper presents a comprehensive mechanical characterization of all the connective tissues contributing to the fascial support structures of the breast, collectively termed here as the breast fibro-structural support (BFSS) system. A generalized stress-stretch curve with initial stretch as the only variable effectively captures patient-specific variability.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107283"},"PeriodicalIF":3.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145770384","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}
Pub Date : 2025-11-24DOI: 10.1016/j.jmbbm.2025.107281
Ibrahim El Bojairami , Carlo Santaguida , Salim Al Rawahi , Ahmed Aoude , Mark Driscoll
Introduction
Improper cage placement during spinal interbody fusion surgeries could lead to numerous post-operative complications. Biomechanical factors of such improper placement may result in loss of lumbar lordosis, foraminal stenosis, subsidence, and altered stress distribution to the tissues adjacent to the cage.
Objective
The aim of the present study is to compare three different lumbar interbody cage designs, placed posterior, middle, and anterior, and their biomechanical effect on the aforementioned studied parameter.
Methodology
Cages and MRI-based lumbar spine models were developed using finite elements. A parametric comparative analysis was then designed to explore cage types, height, and location on lumbar lordosis, foraminal area, cage subsidence, along with normal and shear stresses resulting from each cage configuration under a 500 N compression load.
Results
First, the model was validated in light of published data. Simulated results showed that lumbar lordosis and foraminal area are inversely related. The 6-degrees bullet cage showed the highest gain in lordosis (16.5°), while it exhibited a large loss in foraminal area (34.2 mm2). Anterior placement of banana cages, however, showed the best trade-off, effectively recording a 14.5° lordosis gain, a 0.6 mm2 loss in foraminal area, a subsidence as low as 0.27 mm, and a moderate cage stress of 13.6–23.1 MPa.
Conclusions
Reported data favors banana cages for the highest lordosis gains without compromising the other explored biomechanical factors. However, it is still advised to thoroughly consider patient-specific factors at hand, possible complications of foraminal stenosis, cage migration, and endplates wear prior to choosing an appropriate cage morphology and placement.
{"title":"A parametric analysis of interbody fusion cages placement: A finite elements approach comparing lumbar lordosis of bullet and steerable banana cages","authors":"Ibrahim El Bojairami , Carlo Santaguida , Salim Al Rawahi , Ahmed Aoude , Mark Driscoll","doi":"10.1016/j.jmbbm.2025.107281","DOIUrl":"10.1016/j.jmbbm.2025.107281","url":null,"abstract":"<div><h3>Introduction</h3><div>Improper cage placement during spinal interbody fusion surgeries could lead to numerous post-operative complications. Biomechanical factors of such improper placement may result in loss of lumbar lordosis, foraminal stenosis, subsidence, and altered stress distribution to the tissues adjacent to the cage.</div></div><div><h3>Objective</h3><div>The aim of the present study is to compare three different lumbar interbody cage designs, placed posterior, middle, and anterior, and their biomechanical effect on the aforementioned studied parameter.</div></div><div><h3>Methodology</h3><div>Cages and MRI-based lumbar spine models were developed using finite elements. A parametric comparative analysis was then designed to explore cage types, height, and location on lumbar lordosis, foraminal area, cage subsidence, along with normal and shear stresses resulting from each cage configuration under a 500 N compression load.</div></div><div><h3>Results</h3><div>First, the model was validated in light of published data. Simulated results showed that lumbar lordosis and foraminal area are inversely related. The 6-degrees bullet cage showed the highest gain in lordosis (16.5°), while it exhibited a large loss in foraminal area (34.2 mm<sup>2</sup>). Anterior placement of banana cages, however, showed the best trade-off, effectively recording a 14.5° lordosis gain, a 0.6 mm<sup>2</sup> loss in foraminal area, a subsidence as low as 0.27 mm, and a moderate cage stress of 13.6–23.1 MPa.</div></div><div><h3>Conclusions</h3><div>Reported data favors banana cages for the highest lordosis gains without compromising the other explored biomechanical factors. However, it is still advised to thoroughly consider patient-specific factors at hand, possible complications of foraminal stenosis, cage migration, and endplates wear prior to choosing an appropriate cage morphology and placement.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107281"},"PeriodicalIF":3.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615051","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}
Pub Date : 2025-11-24DOI: 10.1016/j.jmbbm.2025.107284
Joyce R. de Souza , Igor P. Mendes Soares , Caroline Anselmi , Prabaha Sikder , Josimeri Hebling , Alexandre L.S. Borges , Eliandra S. Trichês , Marco C. Bottino
This study aimed (1) to develop and characterize 3D-printed hydrogel-based scaffolds composed of sodium alginate and gelatin containing amorphous magnesium phosphate (AMP), and (2) to evaluate the scaffolds’ biological response with alveolar bone–derived mesenchymal stem cells (aBMSCs). Hydrogel inks were prepared with sodium alginate, gelatin, calcium chloride, and varying AMP contents (0 %, 5 %, and 10 %). The scaffolds were fabricated using an extrusion-based 3D bioprinter. First, the formulated hydrogel-based inks were characterized for rheological behavior and printability. After printing, the scaffolds were assessed for morphology, chemical composition, mechanical properties, and swelling/degradation profiles. For in vitro cell-scaffold interaction, scaffolds were seeded with aBMSCs and analyzed for cell viability, matrix mineralization, and osteogenic gene expression via RT-qPCR. Statistical analysis was performed with ANOVA/Sidak or Tukey tests, with confidence intervals (α = 5 %). Rheological analysis showed that all inks exhibited shear-thinning behavior, more pronounced in AMP-containing formulations. Filament drop tests and printability assessments demonstrated filament uniformity and structural fidelity in AMP-containing inks. Morphological analysis revealed well-defined scaffold architecture with regular edges, and SEM confirmed smooth surface morphology with uniform AMP distribution. FTIR spectra displayed characteristic phosphate and polymer bands, while EDS confirmed the presence of magnesium and phosphorus in AMP-containing scaffolds. The swelling behavior increased over 24 h, and all 3D-printed scaffolds fully degraded within 35 days. All formulations supported increased cell viability over time (p ≤ 0.0092). AMP-containing scaffolds enhanced mineralized matrix deposition under osteogenic stimulation (p < 0.0001), particularly in the 10 % AMP group, and promoted upregulation of osteogenic genes (COL1A1, ALPL, and RUNX2). Clinical significance: This study demonstrated that incorporating AMP into alginate-based hydrogels combines printability, biodegradability, and osteoconductive properties. Previous AMP-containing biomaterials lacked optimization for material extrusion-based 3D printing or the synergistic combination with a gelatin-alginate network. This strategy represents an advance in the field, offering a potential biomaterial ink for the fabrication of personalized scaffolds for craniofacial bone regeneration, enabling synergistic modulation of rheology and early osteogenic stimulation.
{"title":"Biodegradable and osteoconductive sodium alginate-gelatin/amorphous magnesium phosphate 3D-printed scaffolds for craniofacial bone regeneration","authors":"Joyce R. de Souza , Igor P. Mendes Soares , Caroline Anselmi , Prabaha Sikder , Josimeri Hebling , Alexandre L.S. Borges , Eliandra S. Trichês , Marco C. Bottino","doi":"10.1016/j.jmbbm.2025.107284","DOIUrl":"10.1016/j.jmbbm.2025.107284","url":null,"abstract":"<div><div>This study aimed (1) to develop and characterize 3D-printed hydrogel-based scaffolds composed of sodium alginate and gelatin containing amorphous magnesium phosphate (AMP), and (2) to evaluate the scaffolds’ biological response with alveolar bone–derived mesenchymal stem cells (aBMSCs). Hydrogel inks were prepared with sodium alginate, gelatin, calcium chloride, and varying AMP contents (0 %, 5 %, and 10 %). The scaffolds were fabricated using an extrusion-based 3D bioprinter. First, the formulated hydrogel-based inks were characterized for rheological behavior and printability. After printing, the scaffolds were assessed for morphology, chemical composition, mechanical properties, and swelling/degradation profiles. For <em>in vitro</em> cell-scaffold interaction, scaffolds were seeded with aBMSCs and analyzed for cell viability, matrix mineralization, and osteogenic gene expression via RT-qPCR. Statistical analysis was performed with ANOVA/Sidak or Tukey tests, with confidence intervals (α = 5 %). Rheological analysis showed that all inks exhibited shear-thinning behavior, more pronounced in AMP-containing formulations. Filament drop tests and printability assessments demonstrated filament uniformity and structural fidelity in AMP-containing inks. Morphological analysis revealed well-defined scaffold architecture with regular edges, and SEM confirmed smooth surface morphology with uniform AMP distribution. FTIR spectra displayed characteristic phosphate and polymer bands, while EDS confirmed the presence of magnesium and phosphorus in AMP-containing scaffolds. The swelling behavior increased over 24 h, and all 3D-printed scaffolds fully degraded within 35 days. All formulations supported increased cell viability over time (p ≤ 0.0092). AMP-containing scaffolds enhanced mineralized matrix deposition under osteogenic stimulation (p < 0.0001), particularly in the 10 % AMP group, and promoted upregulation of osteogenic genes (COL1A1, ALPL, and RUNX2). Clinical significance: This study demonstrated that incorporating AMP into alginate-based hydrogels combines printability, biodegradability, and osteoconductive properties. Previous AMP-containing biomaterials lacked optimization for material extrusion-based 3D printing or the synergistic combination with a gelatin-alginate network. This strategy represents an advance in the field, offering a potential biomaterial ink for the fabrication of personalized scaffolds for craniofacial bone regeneration, enabling synergistic modulation of rheology and early osteogenic stimulation.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107284"},"PeriodicalIF":3.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615052","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}
Accurate detection of tumor boundaries is critical for the success of oncologic surgical intervention. Traditionally, palpation can handover important information for tumor localization based on the tissue mechanical properties, but in Minimally Invasive Surgery no direct access to the tumor for palpation is feasible. For providing a technical analogy, this feasibility-level study focusses on the simplified problem of detection of an inclusion within a homogeneous silicon phantom. We hypothesized that existence of a relatively stiffer inclusion within an elastomer tissue phantom changes vibroacoustic signatures under forced vibration conditions. In comparison with previous studies, in this work the measurement probe was static, and the short-time (1 s) data package analysis targeted at nearly real-time inclusion detection. The inclusion detection problem was cast into a binary classification of the short-time acquired vibroacoustic signals. The method involves a wavelet-based multilayer perceptron neural network (MLP) that is trained in a supervised manner. A micro-electro-mechanical system (MEMS) sensor proximally attached to a solid probe was used to measure the vibroacoustic signals. Phantoms of simulated healthy tissue with stiffer tumor model inclusions were used for experiments and data collection. From the 120 overall number of experiments, 15 % were used as test data to evaluate the performance. The results show inclusion detection F1 score of 75 %, and 77.8 % accuracy related to the confusion matrix, reflecting the model performance on previously unseen data. Performance of the classifier was discussed in terms of various binary classification metrics, and compared with another established classifier, support vector machine (SVM). While the results support the hypothesis of this proof-of-concept study, extensions like improving the electronic system and refining the method with more experiments on biological tissues remain as the future work.
{"title":"Vibroacoustic detection of inclusions in an elastomeric tissue phantom using a multilayer perceptron classifier: A proof-of-concept study","authors":"Mostafa Sayahkarajy , Florian Römer , Hartmut Witte","doi":"10.1016/j.jmbbm.2025.107279","DOIUrl":"10.1016/j.jmbbm.2025.107279","url":null,"abstract":"<div><div>Accurate detection of tumor boundaries is critical for the success of oncologic surgical intervention. Traditionally, palpation can handover important information for tumor localization based on the tissue mechanical properties, but in Minimally Invasive Surgery no direct access to the tumor for palpation is feasible. For providing a technical analogy, this feasibility-level study focusses on the simplified problem of detection of an inclusion within a homogeneous silicon phantom. We hypothesized that existence of a relatively stiffer inclusion within an elastomer tissue phantom changes vibroacoustic signatures under forced vibration conditions. In comparison with previous studies, in this work the measurement probe was static, and the short-time (1 s) data package analysis targeted at nearly real-time inclusion detection. The inclusion detection problem was cast into a binary classification of the short-time acquired vibroacoustic signals. The method involves a wavelet-based multilayer perceptron neural network (MLP) that is trained in a supervised manner. A micro-electro-mechanical system (MEMS) sensor proximally attached to a solid probe was used to measure the vibroacoustic signals. Phantoms of simulated healthy tissue with stiffer tumor model inclusions were used for experiments and data collection. From the 120 overall number of experiments, 15 % were used as test data to evaluate the performance. The results show inclusion detection F1 score of 75 %, and 77.8 % accuracy related to the confusion matrix, reflecting the model performance on previously unseen data. Performance of the classifier was discussed in terms of various binary classification metrics, and compared with another established classifier, support vector machine (SVM). While the results support the hypothesis of this proof-of-concept study, extensions like improving the electronic system and refining the method with more experiments on biological tissues remain as the future work.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107279"},"PeriodicalIF":3.5,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569481","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}
Pub Date : 2025-11-15DOI: 10.1016/j.jmbbm.2025.107277
Dianhao Wu , Zhixian Qiu , Yanshuang Bai , Jingchao Wang , Jie Pan
Background
Inappropriate rotational and feed speed of the rotary nickel-titanium (Ni-Ti) file can cause damage to the root canal wall. Consequently, it is essential to examine the relationships among filing parameters, file stress, and axial force to establish a dependable foundation for the selection of parameters.
Method
A 3D reconstruction of the tooth is executed utilizing CBCT images. The reaming rate of root canal filling is established at 30 % to examine the correlation between Root Canal Preparation (RCP) parameters and damage under critical situations. Utilizing the elastic-plastic model and the Johnson-Cook intrinsic model, the explicit dynamics method of ABAQUS software is employed to simulate the contact stress and axial force at varying feed speeds (1–8 mm/s) and rotational speeds (150–800 rpm). A robotic arm-based filing experimental platform is developed to conduct bionic experiments, which examine the variation of axial filing force with different parameters, and these results are compared with simulation outcomes.
Results
Increased rotational speed and decreased feed speed of the root canal file can diminish the stress and strain on the root canal. The trends and magnitudes of axial force derived from simulation and experiment at varying speeds are comparable (deviation factor = 0.15 %–25.82 %). A rotational speed higher than 350 rpm and a feed speed lower than 6 mm/s are more conducive to stable and safe filing, and the maximum axial force and the maximum stress exhibit a trend analogous.
Conclusion
This study provides a basis for the selection of filing parameters for manual and robot-assisted RCP, thereby improving the safety of clinical preparation.
{"title":"Stress distribution and axial force under different filing parameters during root canal preparation: An in vitro FEA and experimental study","authors":"Dianhao Wu , Zhixian Qiu , Yanshuang Bai , Jingchao Wang , Jie Pan","doi":"10.1016/j.jmbbm.2025.107277","DOIUrl":"10.1016/j.jmbbm.2025.107277","url":null,"abstract":"<div><h3>Background</h3><div>Inappropriate rotational and feed speed of the rotary nickel-titanium (Ni-Ti) file can cause damage to the root canal wall. Consequently, it is essential to examine the relationships among filing parameters, file stress, and axial force to establish a dependable foundation for the selection of parameters.</div></div><div><h3>Method</h3><div>A 3D reconstruction of the tooth is executed utilizing CBCT images. The reaming rate of root canal filling is established at 30 % to examine the correlation between Root Canal Preparation (RCP) parameters and damage under critical situations. Utilizing the elastic-plastic model and the Johnson-Cook intrinsic model, the explicit dynamics method of ABAQUS software is employed to simulate the contact stress and axial force at varying feed speeds (1–8 mm/s) and rotational speeds (150–800 rpm). A robotic arm-based filing experimental platform is developed to conduct bionic experiments, which examine the variation of axial filing force with different parameters, and these results are compared with simulation outcomes.</div></div><div><h3>Results</h3><div>Increased rotational speed and decreased feed speed of the root canal file can diminish the stress and strain on the root canal. The trends and magnitudes of axial force derived from simulation and experiment at varying speeds are comparable (deviation factor = 0.15 %–25.82 %). A rotational speed higher than 350 rpm and a feed speed lower than 6 mm/s are more conducive to stable and safe filing, and the maximum axial force and the maximum stress exhibit a trend analogous.</div></div><div><h3>Conclusion</h3><div>This study provides a basis for the selection of filing parameters for manual and robot-assisted RCP, thereby improving the safety of clinical preparation.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107277"},"PeriodicalIF":3.5,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145552446","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}
Pub Date : 2025-11-13DOI: 10.1016/j.jmbbm.2025.107258
Samyuktha S. Kolluru , Abir Hamdaoui , Hannah F. Rudewick , Samantha G. Zambuto , Michelle L. Oyen
Each year, approximately 30 million Cesarean deliveries are performed globally, involving surgical incisions through the abdomen and uterus, followed by suturing of the uterus and skin after childbirth. The presence of prior uterine incisions disrupts native uterine tissue properties and increases the risk of complications in subsequent pregnancies. Thus, tissue repair scaffolds for this application must promote regeneration and restore the mechanical strength required to withstand the uterine loading. Despite the importance of mechanical considerations in regeneration, the fracture mechanics and energetics of scaffolds for this application have not been systematically characterized. In this work, we developed a novel gelatin methacryloyl–gelatin fiber composite platform by embedding electrospun gelatin fibers of different nanoscale diameters within a hydrogel matrix. Mechanical testing of fiber mats and composites under uniaxial tension and Mode III tearing revealed that fiber diameter strongly influences stiffness, extensibility, and fracture resistance. Further, compared to fiber mats alone, fiber-reinforced composites demonstrate enhanced energy dissipation while retaining physiologically relevant hydration, thereby mimicking native tissue. These results establish critical structure–function relationships in gelatin–based composite systems and highlights their potential as load-bearing scaffolds for uterine tissue repair.
{"title":"Electrospun gelatin fiber–gelatin methacryloyl hydrogel composites for reproductive applications","authors":"Samyuktha S. Kolluru , Abir Hamdaoui , Hannah F. Rudewick , Samantha G. Zambuto , Michelle L. Oyen","doi":"10.1016/j.jmbbm.2025.107258","DOIUrl":"10.1016/j.jmbbm.2025.107258","url":null,"abstract":"<div><div>Each year, approximately 30 million Cesarean deliveries are performed globally, involving surgical incisions through the abdomen and uterus, followed by suturing of the uterus and skin after childbirth. The presence of prior uterine incisions disrupts native uterine tissue properties and increases the risk of complications in subsequent pregnancies. Thus, tissue repair scaffolds for this application must promote regeneration and restore the mechanical strength required to withstand the uterine loading. Despite the importance of mechanical considerations in regeneration, the fracture mechanics and energetics of scaffolds for this application have not been systematically characterized. In this work, we developed a novel gelatin methacryloyl–gelatin fiber composite platform by embedding electrospun gelatin fibers of different nanoscale diameters within a hydrogel matrix. Mechanical testing of fiber mats and composites under uniaxial tension and Mode III tearing revealed that fiber diameter strongly influences stiffness, extensibility, and fracture resistance. Further, compared to fiber mats alone, fiber-reinforced composites demonstrate enhanced energy dissipation while retaining physiologically relevant hydration, thereby mimicking native tissue. These results establish critical structure–function relationships in gelatin–based composite systems and highlights their potential as load-bearing scaffolds for uterine tissue repair.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107258"},"PeriodicalIF":3.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518567","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}
Lamellar and dispersed fibrous collagen networks are organized and maintained via endogenous crosslinks along the superior-inferior and nasal-temporal directions in the stromal regions of corneal tissues. Collagen organization contributes to corneal transparency, tissue integrity, and the surface topography. Ultrastructural changes to the lamellar arrangement of collagen occur in diseases, such as keratoconus and ectasia post refractive surgery, resulting in impaired biomechanical properties, changes to the surface curvature, and irregular astigmatism. Collagen crosslinking with UV-A/riboflavin is used clinically to increase the structural integrity and halt corneal thinning; however it can cause complications in certain cases. Earlier studies suggest that crosslinking mediated by advanced glycation end products (AGE), associated with ageing, may increase corneal stiffness and prevent corneal thinning. The specific links between corneal properties and microstructural network features are however not well established. We used collagenase and non-enzymatic crosslinking using methylglyoxal (MGO) to investigate the effects of collagen content, organization, and crosslinking densities in an ex-vivo goat cornea model. We estimated the collagen contents using a biochemical assay, performed uniaxial mechanical tests, and used histology to quantify the underlying fiber tortuosity in untreated (control) and collagenase/MGO treated groups. We fit the experimental stress-strain data using an exponential strain energy function (SEF) that uses a generalized structure tensor to describe collagen fiber organization in tissues. Our results show that fiber tortuosity increased with collagenase treatment time. AGE-mediated non-enzymatic crosslinking using MGO caused a dramatic increase in the elastic modulus of tissues without significant changes to the fiber tortuosity or overall collagen content. Finally, we obtained scaling relationships linking tissue modulus to collagen volume fraction that may be useful clinically. Changes in fiber tortuosity with collagenase treatment suggest that collagen fiber organization and composition play a key role in regulating mechanobiological properties of the cornea.
{"title":"Collagen content and crosslinks alter the biomechanical properties of corneal tissues","authors":"Anshul Shrivastava , Yogesh Thapliyal , Subhradeep Sarkar , Arkasubhra Ghosh , Namrata Gundiah","doi":"10.1016/j.jmbbm.2025.107276","DOIUrl":"10.1016/j.jmbbm.2025.107276","url":null,"abstract":"<div><div>Lamellar and dispersed fibrous collagen networks are organized and maintained <em>via</em> endogenous crosslinks along the superior-inferior and nasal-temporal directions in the stromal regions of corneal tissues. Collagen organization contributes to corneal transparency, tissue integrity, and the surface topography. Ultrastructural changes to the lamellar arrangement of collagen occur in diseases, such as keratoconus and ectasia post refractive surgery, resulting in impaired biomechanical properties, changes to the surface curvature, and irregular astigmatism. Collagen crosslinking with UV-A/riboflavin is used clinically to increase the structural integrity and halt corneal thinning; however it can cause complications in certain cases. Earlier studies suggest that crosslinking mediated by advanced glycation end products (AGE), associated with ageing, may increase corneal stiffness and prevent corneal thinning. The specific links between corneal properties and microstructural network features are however not well established. We used collagenase and non-enzymatic crosslinking using methylglyoxal (MGO) to investigate the effects of collagen content, organization, and crosslinking densities in an <em>ex-vivo</em> goat cornea model. We estimated the collagen contents using a biochemical assay, performed uniaxial mechanical tests, and used histology to quantify the underlying fiber tortuosity in untreated (control) and collagenase/MGO treated groups. We fit the experimental stress-strain data using an exponential strain energy function (SEF) that uses a generalized structure tensor to describe collagen fiber organization in tissues. Our results show that fiber tortuosity increased with collagenase treatment time. AGE-mediated non-enzymatic crosslinking using MGO caused a dramatic increase in the elastic modulus of tissues without significant changes to the fiber tortuosity or overall collagen content. Finally, we obtained scaling relationships linking tissue modulus to collagen volume fraction that may be useful clinically. Changes in fiber tortuosity with collagenase treatment suggest that collagen fiber organization and composition play a key role in regulating mechanobiological properties of the cornea.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107276"},"PeriodicalIF":3.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145552403","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}
Pub Date : 2025-11-13DOI: 10.1016/j.jmbbm.2025.107271
Eleonora Luzietti , Martina Schembri , Ariel F. Pascaner , Ferdinando Auricchio , Alessandro Caimi , Michele Conti
In recent years, percutaneous procedures are gradually replacing open heart surgery for the treatment of tricuspid valve pathological conditions deploying prosthetic devices (i.e., stent-graft) within the proximal portion of the cava veins. Nevertheless, since there is no comprehensive mechanical characterization of the venous district, the devices exploited in these procedures are very similar to the ones exploited in aortic treatment, involving possible critical periprocedural complications.
According to the international standards adopted for the design of novel vascular devices, this study presents an experimental set-up to investigate the biomechanics of fifteen porcine cava veins with the development of a semi-automatic protocol for compliance testing. During the tests, 2D echo images of the vessel lumen are acquired for different steps within a pressure range of 5–20 mmHg. The acquired pressure-diameter curves of the samples are then derived by a polynomial function, furthermore, the compliance values are obtained using the corresponding equations as well.
The results demonstrate that the cava vein exhibits a hyperelastic behavior, with a nonlinear relationship between pressure and diameter. At low pressures, the veins demonstrate high compliance and reduced stiffness (11.54 ± 4.76 kPa). On the contrary, when pressures exceed the normal physiological range (i.e., greater than 10 mmHg), the veins become stiffer (294.70 ± 233.00 kPa).
The developed set-up, based on an ex-vivo porcine model, proved to be a robust tool for the assessment of vein biomechanics and for preclinical benchmarking of novel venous endovascular devices.
{"title":"Ex-vivo biomechanical characterization of porcine cava vein","authors":"Eleonora Luzietti , Martina Schembri , Ariel F. Pascaner , Ferdinando Auricchio , Alessandro Caimi , Michele Conti","doi":"10.1016/j.jmbbm.2025.107271","DOIUrl":"10.1016/j.jmbbm.2025.107271","url":null,"abstract":"<div><div>In recent years, percutaneous procedures are gradually replacing open heart surgery for the treatment of tricuspid valve pathological conditions deploying prosthetic devices (<em>i.e., stent</em>-<em>graft)</em> within the proximal portion of the cava veins. Nevertheless, since there is no comprehensive mechanical characterization of the venous district, the devices exploited in these procedures are very similar to the ones exploited in aortic treatment, involving possible critical periprocedural complications.</div><div>According to the international standards adopted for the design of novel vascular devices, this study presents an experimental set-up to investigate the biomechanics of fifteen porcine cava veins with the development of a semi-automatic protocol for compliance testing. During the tests, 2D echo images of the vessel lumen are acquired for different steps within a pressure range of 5–20 mmHg. The acquired pressure-diameter curves of the samples are then derived by a polynomial function, furthermore, the compliance values are obtained using the corresponding equations as well.</div><div>The results demonstrate that the cava vein exhibits a hyperelastic behavior, with a nonlinear relationship between pressure and diameter. At low pressures, the veins demonstrate high compliance and reduced stiffness (11.54 ± 4.76 kPa). On the contrary, when pressures exceed the normal physiological range (<em>i.e.,</em> greater than 10 mmHg), the veins become stiffer (294.70 ± 233.00 kPa).</div><div>The developed set-up, based on an <em>ex-vivo</em> porcine model, proved to be a robust tool for the assessment of vein biomechanics and for preclinical benchmarking of novel venous endovascular devices.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107271"},"PeriodicalIF":3.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615176","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}
Pub Date : 2025-11-13DOI: 10.1016/j.jmbbm.2025.107278
Sami Al Shweiki , Stephen J. Ferguson , Ahmed H. Hafez , Naod T. Mogos , Tao Liu , Marwan El-Rich
Universal talus implant has emerged as an innovative solution for talus bone collapse, aiming to retain the clinical benefits of custom total talus replacement while addressing its logistical drawbacks. A subject-specific combined musculoskeletal–finite element (MSK–FE) modeling framework was developed to evaluate two universal talus implant designs during dynamic gait: a purely cobalt chromium (CoCr) implant, and an implant coated with polycarbonate-urethane (PCU), both compared to the native talus. To do so, a MSK simulation of the stance phase of gait was conducted to estimate joint kinematics and joint reaction forces in the ankle complex, with a subsequent dynamic FE simulation performed to assess contact characteristics in terms of contact area and pressure, in cartilages surrounding the talus/implant. The FE model was built directly from the bone geometries of the MSK model to ensure consistency across the study. Results showed that the PCU-coated implant more closely replicated native biomechanics, while the CoCr implant produced consistently higher pressures and smaller contact regions. Normalized RMSE across gait confirmed lower deviation from the native case for the PCU-implant in most joints. These findings highlight the potential of PCU coated implants in improving contact mechanics in articular cartilage as well as the potential of the universal implant topology. This is the first study to dynamically evaluate intra-articular behaviour in all joints surrounding the talus bone during gait, and particularly by analysing the performance of universal talus implants, demonstrating the utility of a MSK-FE approach and offering valuable insights into implant performance under physiological conditions, informing future implant design.
{"title":"Evaluation of a universal talus implant during gait: a combined musculoskeletal and finite element modelling approach","authors":"Sami Al Shweiki , Stephen J. Ferguson , Ahmed H. Hafez , Naod T. Mogos , Tao Liu , Marwan El-Rich","doi":"10.1016/j.jmbbm.2025.107278","DOIUrl":"10.1016/j.jmbbm.2025.107278","url":null,"abstract":"<div><div>Universal talus implant has emerged as an innovative solution for talus bone collapse, aiming to retain the clinical benefits of custom total talus replacement while addressing its logistical drawbacks. A subject-specific combined musculoskeletal–finite element (MSK–FE) modeling framework was developed to evaluate two universal talus implant designs during dynamic gait: a purely cobalt chromium (CoCr) implant, and an implant coated with polycarbonate-urethane (PCU), both compared to the native talus. To do so, a MSK simulation of the stance phase of gait was conducted to estimate joint kinematics and joint reaction forces in the ankle complex, with a subsequent dynamic FE simulation performed to assess contact characteristics in terms of contact area and pressure, in cartilages surrounding the talus/implant. The FE model was built directly from the bone geometries of the MSK model to ensure consistency across the study. Results showed that the PCU-coated implant more closely replicated native biomechanics, while the CoCr implant produced consistently higher pressures and smaller contact regions. Normalized RMSE across gait confirmed lower deviation from the native case for the PCU-implant in most joints. These findings highlight the potential of PCU coated implants in improving contact mechanics in articular cartilage as well as the potential of the universal implant topology. This is the first study to dynamically evaluate intra-articular behaviour in all joints surrounding the talus bone during gait, and particularly by analysing the performance of universal talus implants, demonstrating the utility of a MSK-FE approach and offering valuable insights into implant performance under physiological conditions, informing future implant design.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107278"},"PeriodicalIF":3.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145566908","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}
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