Pub Date : 2025-12-02DOI: 10.1016/j.jmbbm.2025.107280
Pierre-Hugo Minster , Clément Parat , Paul Neuville , Damien Carnicelli , Nicolas Morel-Journel , Karine Bruyère-Garnier
The tunica albuginea (TA) is a fibrous connective membrane surrounding the corpora cavernosa (CC), which plays a crucial role in the erection. In case of erectile dysfunction, inflatable penile prothesis (IPP) may be a treatment of choice and mechanical interactions occur between prostheses and these penile tissues. There is still much to be learned about their mechanical behavior to help to improve IPP and penile surgical techniques. This paper presents the characterization of the TA mechanical behavior combined with the observation of its microstructural organization, as well as the mechanical behavior of the cavernous tissue. Uniaxial tensile tests were performed on 40 TA samples and 17 CC samples collected from 5 post mortem human subjects. TA samples were cut along both longitudinal and circumferential directions, and in both proximal and distal regions. Histological slices were produced from biopsies contiguous to the samples to observe the collagen fiber organization in the TA. We observed that this fiber organization usually schematized by 2 layers of perpendicular fibers is more complex, with some dispersion in the fiber orientations and interlacing of the 2 layers. The mechanical characterization of the TA samples revealed no clear anisotropy but different properties for the proximal and distal locations, whereas the CC showed a very low elastic modulus. These data complement those already published and further analysis of the microstructure of the TA will be needed to explain the variability of the mechanical behavior of the TA in view of selecting and identifying nonlinear behavior models.
{"title":"Mechanical and microstructural characterization of the human tunica albuginea","authors":"Pierre-Hugo Minster , Clément Parat , Paul Neuville , Damien Carnicelli , Nicolas Morel-Journel , Karine Bruyère-Garnier","doi":"10.1016/j.jmbbm.2025.107280","DOIUrl":"10.1016/j.jmbbm.2025.107280","url":null,"abstract":"<div><div>The tunica albuginea (TA) is a fibrous connective membrane surrounding the corpora cavernosa (CC), which plays a crucial role in the erection. In case of erectile dysfunction, inflatable penile prothesis (IPP) may be a treatment of choice and mechanical interactions occur between prostheses and these penile tissues. There is still much to be learned about their mechanical behavior to help to improve IPP and penile surgical techniques. This paper presents the characterization of the TA mechanical behavior combined with the observation of its microstructural organization, as well as the mechanical behavior of the cavernous tissue. Uniaxial tensile tests were performed on 40 TA samples and 17 CC samples collected from 5 post mortem human subjects. TA samples were cut along both longitudinal and circumferential directions, and in both proximal and distal regions. Histological slices were produced from biopsies contiguous to the samples to observe the collagen fiber organization in the TA. We observed that this fiber organization usually schematized by 2 layers of perpendicular fibers is more complex, with some dispersion in the fiber orientations and interlacing of the 2 layers. The mechanical characterization of the TA samples revealed no clear anisotropy but different properties for the proximal and distal locations, whereas the CC showed a very low elastic modulus. These data complement those already published and further analysis of the microstructure of the TA will be needed to explain the variability of the mechanical behavior of the TA in view of selecting and identifying nonlinear behavior models.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107280"},"PeriodicalIF":3.5,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784212","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 : 2025-12-02DOI: 10.1016/j.jmbbm.2025.107292
Joy Mojumder , Yuan-Chiao Lu , Alexa M. Diano , Ahmed A. Alshareef , Matthew McGarry , Philip V. Bayly , Curtis L. Johnson , John A. Butman , Dzung L. Pham
Traumatic brain injury (TBI) is a serious health condition that can cause neurological dysfunction to varying degrees depending on the nature of the mechanical insult. In biomechanical studies of TBI under high loading conditions, post-mortem human subjects (PMHS), although difficult to acquire, are often used since ethical concerns prohibit such experiments in living human subjects. Because PMHS brains undergo significant changes following death, it is important to understand the relationship between the mechanical properties of PMHS and living brain tissue. In this study, we performed magnetic resonance elastography (MRE) on three PMHS specimens to estimate the material properties of the cadaveric brain, namely the storage modulus and the loss modulus, as well as the resulting shear stiffness and damping ratio. We also performed longitudinal MRE scans on one of the PMHS brain over the span of two months to investigate the evolution of tissue properties with post-mortem degradation. In comparison to in vivo subjects of age range 70–75 years, a substantially higher stiffness (mean: 5.96 kPa) and lower damping ratio (mean: 0.09) were found in PMHS models. This study also revealed an initial increase in shear stiffness up to the seventh day post-mortem, followed by a steady decrease by the fifty-eighth day. However, the damping ratio displayed an opposite trend to that of shear stiffness. These changes were heterogeneous across brain regions. The collected measurements and analysis elucidate the changes in mechanical properties in post-mortem subjects, and can be used to build and validate computational models of TBI.
{"title":"Characterization of mechanical tissue properties in post-mortem human brain using magnetic resonance elastography","authors":"Joy Mojumder , Yuan-Chiao Lu , Alexa M. Diano , Ahmed A. Alshareef , Matthew McGarry , Philip V. Bayly , Curtis L. Johnson , John A. Butman , Dzung L. Pham","doi":"10.1016/j.jmbbm.2025.107292","DOIUrl":"10.1016/j.jmbbm.2025.107292","url":null,"abstract":"<div><div>Traumatic brain injury (TBI) is a serious health condition that can cause neurological dysfunction to varying degrees depending on the nature of the mechanical insult. In biomechanical studies of TBI under high loading conditions, post-mortem human subjects (PMHS), although difficult to acquire, are often used since ethical concerns prohibit such experiments in living human subjects. Because PMHS brains undergo significant changes following death, it is important to understand the relationship between the mechanical properties of PMHS and living brain tissue. In this study, we performed magnetic resonance elastography (MRE) on three PMHS specimens to estimate the material properties of the cadaveric brain, namely the storage modulus and the loss modulus, as well as the resulting shear stiffness and damping ratio. We also performed longitudinal MRE scans on one of the PMHS brain over the span of two months to investigate the evolution of tissue properties with post-mortem degradation. In comparison to <em>in vivo</em> subjects of age range 70–75 years, a substantially higher stiffness (mean: 5.96 kPa) and lower damping ratio (mean: 0.09) were found in PMHS models. This study also revealed an initial increase in shear stiffness up to the seventh day post-mortem, followed by a steady decrease by the fifty-eighth day. However, the damping ratio displayed an opposite trend to that of shear stiffness. These changes were heterogeneous across brain regions. The collected measurements and analysis elucidate the changes in mechanical properties in post-mortem subjects, and can be used to build and validate computational models of TBI.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107292"},"PeriodicalIF":3.5,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145688900","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 : 2025-12-01DOI: 10.1016/j.jmbbm.2025.107291
Lisa-Marie Skrip , Leonard Boerger , Kilian A. Walter , Alexander Arnold , Lene A. Böhne , Eriselda Keshi , Anna S. Pietsch , Nathanael Raschzok , Timo A. Auer , Uli Fehrenbach , Felix Krenzien , Johann Pratschke , Igor M. Sauer , Jing Guo , Jürgen Braun , Heiko Tzschätzsch , Ingolf Sack , Karl H. Hillebrandt , Simon Moosburner
Objective
Liver transplantation remains the primary treatment for end-stage liver disease, however, a shortage of suitable grafts persists. Factors contributing to this imbalance include insufficient organ quality, which exhibit higher complication rates, exacerbated by static cold storage. Normothermic Machine Perfusion (NMP) is proposed as an alternative, offering dynamic preservation, and quality assessment. This study introduces magnetic resonance elastography (MRE), to evaluate changes of viscoelastic properties of the liver after NMP for quality assessment.
Materials and methods
In this study, using a rat liver NMP model, we investigated whether older age and extended cold ischemia time (CIT) affect liver tissue properties after NMP. Ex vivo MRE measurements were conducted using a multifrequency tabletop 0.5-T MRE with excitation frequencies ranging from 500 Hz to 5300 Hz and viscoelastic model fitting with power-law exponent α.
Results
Samples of 24 Sprague Dawley rat livers were analyzed after 6- or 12-h of cold ischemia time and consequent 6-h NMP. All samples had predominantly viscous-fluid properties (ɑ>0.5). The powerlaw exponent ɑ was the highest in livers from 3-month-old rats and short cold ischemia (0.61, IQR 0.61–0.75) and lowest in long cold ischemia and older liver grafts (0.56, IQR 0.55–0.62; p < 0.001). Furthermore, shear modulus μ was significantly lower in 3-month-old rats and short cold ischemia than all other groups (p < 0.001).
Conclusion
Despite NMP, viscoelastic properties of liver tissues were still slightly impaired after extended CIT. MRE could serve as a diagnostic imaging tool, complementing MRI and pathological evaluation, for assessing the quality of liver grafts after NMP.
目的：肝移植仍然是终末期肝病的主要治疗方法，然而，仍然缺乏合适的移植物。造成这种不平衡的因素包括器官质量不足，这表现出较高的并发症发生率，并因静态冷藏而加剧。常温机器灌注（NMP）被建议作为一种替代方法，提供动态保存和质量评估。本研究引入磁共振弹性成像（MRE）技术，评价NMP后肝脏粘弹性的变化，用于质量评估。材料和方法：本研究采用大鼠肝脏NMP模型，研究年龄和延长冷缺血时间（CIT）对NMP后肝组织特性的影响。体外MRE测量采用多频台式0.5 t MRE，激励频率为500 Hz至5300 Hz，粘弹性模型拟合幂律指数α。结果：24只大鼠肝脏在冷缺血6、12小时后及随后的6小时NMP后进行分析。所有样品都具有主要的粘流体性质（[]> .5]）。3月龄短冷缺血大鼠肝脏的幂律指数最高（0.61，IQR为0.61 ~ 0.75），长冷缺血大鼠肝脏的幂律指数最低（0.56，IQR为0.55 ~ 0.62）；p结论：尽管NMP，延长CIT后肝组织的粘弹性仍有轻微损伤，MRE可作为一种诊断成像工具，补充MRI和病理评价，用于评价NMP后肝移植质量。
{"title":"Assessing age and cold ischemia effects on liver tissue viscoelastic properties: Implications for graft quality assessment with MRE during machine perfusion","authors":"Lisa-Marie Skrip , Leonard Boerger , Kilian A. Walter , Alexander Arnold , Lene A. Böhne , Eriselda Keshi , Anna S. Pietsch , Nathanael Raschzok , Timo A. Auer , Uli Fehrenbach , Felix Krenzien , Johann Pratschke , Igor M. Sauer , Jing Guo , Jürgen Braun , Heiko Tzschätzsch , Ingolf Sack , Karl H. Hillebrandt , Simon Moosburner","doi":"10.1016/j.jmbbm.2025.107291","DOIUrl":"10.1016/j.jmbbm.2025.107291","url":null,"abstract":"<div><h3>Objective</h3><div>Liver transplantation remains the primary treatment for end-stage liver disease, however, a shortage of suitable grafts persists. Factors contributing to this imbalance include insufficient organ quality, which exhibit higher complication rates, exacerbated by static cold storage. Normothermic Machine Perfusion (NMP) is proposed as an alternative, offering dynamic preservation, and quality assessment. This study introduces magnetic resonance elastography (MRE), to evaluate changes of viscoelastic properties of the liver after NMP for quality assessment.</div></div><div><h3>Materials and methods</h3><div>In this study, using a rat liver NMP model, we investigated whether older age and extended cold ischemia time (CIT) affect liver tissue properties after NMP. <em>Ex vivo</em> MRE measurements were conducted using a multifrequency tabletop 0.5-T MRE with excitation frequencies ranging from 500 Hz to 5300 Hz and viscoelastic model fitting with power-law exponent <em>α</em>.</div></div><div><h3>Results</h3><div>Samples of 24 Sprague Dawley rat livers were analyzed after 6- or 12-h of cold ischemia time and consequent 6-h NMP. All samples had predominantly viscous-fluid properties (<em>ɑ</em>>0.5). The powerlaw exponent <em>ɑ</em> was the highest in livers from 3-month-old rats and short cold ischemia (0.61, IQR 0.61–0.75) and lowest in long cold ischemia and older liver grafts (0.56, IQR 0.55–0.62; p < 0.001). Furthermore, shear modulus <em>μ</em> was significantly lower in 3-month-old rats and short cold ischemia than all other groups (p < 0.001).</div></div><div><h3>Conclusion</h3><div>Despite NMP, viscoelastic properties of liver tissues were still slightly impaired after extended CIT. MRE could serve as a diagnostic imaging tool, complementing MRI and pathological evaluation, for assessing the quality of liver grafts after NMP.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107291"},"PeriodicalIF":3.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145679922","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 : 2025-11-29DOI: 10.1016/j.jmbbm.2025.107290
Nikolaus Kronwitter, Angelika Rauch, Sebastian Hahnel, Martin Rosentritt
Aim
This study aimed to evaluate the effects of a translucency-enhancing liquid (TEL) and high-speed sintering (HS) on the mechanical behavior, with a focus on the survival rates and fracture forces of anterior zirconia crowns with different yttria contents.
Materials and methods
Anterior crowns (16 groups, n = 8 per group) were fabricated using four different zirconia materials (3Y-TZP, 4Y-TZP, 5Y-TZP, and multilayer (ML)). The 3Y and 4Y groups were treated with a TEL in three variations: no treatment (NL), two-layer penetration (2L), and four-layer penetration (4L). The 5Y-TZP and ML zirconia crowns served as reference groups without TEL treatment. All specimens underwent either conventional (CS) or high-speed (HS) sintering before being subjected to thermocyclic and mechanical loading (TCML), followed by a load-to-fracture test. Statistics: ANOVA, Bonferroni test, Shapiro-Wilk test, Pearson correlation; α = 0.05.
Results
Three specimens in group 5Y-NL-CS and one in group 4Y-NL-HS failed during TCML. Fracture forces varied significantly between different types of zirconia and decreased with increasing yttria content. While mean fracture forces were not affected by HS or TEL treatment, HS of ML and particularly 5Y-TZP crowns was associated with a higher frequency of crown fractures, indicating material- and condition-specific tendencies of potential clinical relevance.
Conclusion
Within the limitations of this in-vitro study - including the use of PMMA abutments, failures during TCML, and material- and failure-specific differences - all specimens withstood forces exceeding the physiological loads expected in the anterior region. Under these conditions, TEL treatment and HS of 3Y-TZP and 4Y-TZP zirconia appear to allow the rapid fabrication of anterior crowns while maintaining their mechanical performance. As optical parameters were not assessed, any potential aesthetic implications of TEL or HS cannot be inferred.
{"title":"Influence of sintering protocol and translucency-enhancing liquid on the mechanical performance of anterior zirconia crowns","authors":"Nikolaus Kronwitter, Angelika Rauch, Sebastian Hahnel, Martin Rosentritt","doi":"10.1016/j.jmbbm.2025.107290","DOIUrl":"10.1016/j.jmbbm.2025.107290","url":null,"abstract":"<div><h3>Aim</h3><div>This study aimed to evaluate the effects of a translucency-enhancing liquid (TEL) and high-speed sintering (HS) on the mechanical behavior, with a focus on the survival rates and fracture forces of anterior zirconia crowns with different yttria contents.</div></div><div><h3>Materials and methods</h3><div>Anterior crowns (16 groups, n = 8 per group) were fabricated using four different zirconia materials (3Y-TZP, 4Y-TZP, 5Y-TZP, and multilayer (ML)). The 3Y and 4Y groups were treated with a TEL in three variations: no treatment (NL), two-layer penetration (2L), and four-layer penetration (4L). The 5Y-TZP and ML zirconia crowns served as reference groups without TEL treatment. All specimens underwent either conventional (CS) or high-speed (HS) sintering before being subjected to thermocyclic and mechanical loading (TCML), followed by a load-to-fracture test. Statistics: ANOVA, Bonferroni test, Shapiro-Wilk test, Pearson correlation; α = 0.05.</div></div><div><h3>Results</h3><div>Three specimens in group 5Y-NL-CS and one in group 4Y-NL-HS failed during TCML. Fracture forces varied significantly between different types of zirconia and decreased with increasing yttria content. While mean fracture forces were not affected by HS or TEL treatment, HS of ML and particularly 5Y-TZP crowns was associated with a higher frequency of crown fractures, indicating material- and condition-specific tendencies of potential clinical relevance.</div></div><div><h3>Conclusion</h3><div>Within the limitations of this in-vitro study - including the use of PMMA abutments, failures during TCML, and material- and failure-specific differences - all specimens withstood forces exceeding the physiological loads expected in the anterior region. Under these conditions, TEL treatment and HS of 3Y-TZP and 4Y-TZP zirconia appear to allow the rapid fabrication of anterior crowns while maintaining their mechanical performance. As optical parameters were not assessed, any potential aesthetic implications of TEL or HS cannot be inferred.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107290"},"PeriodicalIF":3.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623403","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 : 2025-11-29DOI: 10.1016/j.jmbbm.2025.107289
William W. Hogg, Mueed Jamal, Nathaniel W. Zuckschwerdt, Cohen M. Hess, Susmita Bose, Amit Bandyopadhyay
Additive manufacturing (AM) has been used to process complex one-of-a-kind patient-specific implants, along with on-demand manufacturing with innovative geometries. AM parts are more susceptible to fatigue failure due to inherent porosities than conventionally processed parts. This study investigates the high-cycle rotating bending fatigue behavior of laser powder bed fusion (LPBF) processed Ti6Al4V parts in as-processed and hot isostatically pressed (HIPed) conditions, and compares them to commercially available wrought Ti6Al4V. Ti6Al4V is widely used in orthopedic and dental implants due to its high strength-to-weight ratio, good biocompatibility, and excellent corrosion resistance. To understand the fatigue performance of Ti6Al4V parts, a custom cell was designed to fully immerse the fatigue samples in Dulbecco's Modified Eagle Medium (DMEM) for the duration of the test. The fatigue strength was normalized to the compressive yield strength, and it was found that as-processed samples had the greatest compressive strength but approximately half the relative endurance limit (107 cycles) when compared to wrought and HIPed samples. This inferior fatigue performance of as-processed samples was attributed to porosity defects inherent to the AMed parts. However, it was found through fractography and energy-dispersive spectroscopy (EDS) analyses that these internal defects dominated the fatigue crack initiation in as-processed samples, making DMEM immersion have a minimal effect. The wrought and HIPed samples were susceptible to corrosion fatigue, showing a reduction in endurance limit of 9 % and 6 % in relative strength, respectively. This study highlights the need for in situ corrosion fatigue evaluation of additively manufactured load-bearing implants.
增材制造（AM）已被用于加工复杂的独一无二的患者特定植入物，以及具有创新几何形状的按需制造。由于固有的孔隙率，增材制造零件比传统加工零件更容易疲劳失效。本研究研究了激光粉末床熔合（LPBF）加工Ti6Al4V零件在加工和热等静压（HIPed）条件下的高周旋转弯曲疲劳行为，并将其与市售的锻造Ti6Al4V进行了比较。Ti6Al4V因其高强度重量比、良好的生物相容性和优异的耐腐蚀性而广泛应用于骨科和牙科种植体中。为了了解Ti6Al4V部件的疲劳性能，设计了一个定制池，在测试期间将疲劳样品完全浸入Dulbecco的Modified Eagle Medium （DMEM）中。将疲劳强度归一化为抗压屈服强度，发现加工后的样品具有最大的抗压强度，但与变形和HIPed样品相比，其相对耐久极限（107次循环）约为一半。这种较差的疲劳性能是由于零件固有的气孔缺陷造成的。然而，通过断口分析和能谱分析发现，这些内部缺陷主导了加工样品的疲劳裂纹萌生，使得DMEM浸泡对疲劳裂纹的影响很小。变形试样和HIPed试样易受腐蚀疲劳影响，其相对强度分别下降9%和6%。这项研究强调了对增材制造的承重植入物进行原位腐蚀疲劳评估的必要性。
{"title":"Corrosion-fatigue of additively manufactured Ti6Al4V","authors":"William W. Hogg, Mueed Jamal, Nathaniel W. Zuckschwerdt, Cohen M. Hess, Susmita Bose, Amit Bandyopadhyay","doi":"10.1016/j.jmbbm.2025.107289","DOIUrl":"10.1016/j.jmbbm.2025.107289","url":null,"abstract":"<div><div>Additive manufacturing (AM) has been used to process complex one-of-a-kind patient-specific implants, along with on-demand manufacturing with innovative geometries. AM parts are more susceptible to fatigue failure due to inherent porosities than conventionally processed parts. This study investigates the high-cycle rotating bending fatigue behavior of laser powder bed fusion (LPBF) processed Ti6Al4V parts in as-processed and hot isostatically pressed (HIPed) conditions, and compares them to commercially available wrought Ti6Al4V. Ti6Al4V is widely used in orthopedic and dental implants due to its high strength-to-weight ratio, good biocompatibility, and excellent corrosion resistance. To understand the fatigue performance of Ti6Al4V parts, a custom cell was designed to fully immerse the fatigue samples in Dulbecco's Modified Eagle Medium (DMEM) for the duration of the test. The fatigue strength was normalized to the compressive yield strength, and it was found that as-processed samples had the greatest compressive strength but approximately half the relative endurance limit (10<sup>7</sup> cycles) when compared to wrought and HIPed samples. This inferior fatigue performance of as-processed samples was attributed to porosity defects inherent to the AMed parts. However, it was found through fractography and energy-dispersive spectroscopy (EDS) analyses that these internal defects dominated the fatigue crack initiation in as-processed samples, making DMEM immersion have a minimal effect. The wrought and HIPed samples were susceptible to corrosion fatigue, showing a reduction in endurance limit of 9 % and 6 % in relative strength, respectively. This study highlights the need for <em>in situ</em> corrosion fatigue evaluation of additively manufactured load-bearing implants.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107289"},"PeriodicalIF":3.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145673318","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 : 2025-11-29DOI: 10.1016/j.jmbbm.2025.107288
Katterine N. Rios-Peralta , Afonso J.C. Silva , Ricardo J. Alves-de-Sousa , Kathleen M. Curran , David B. MacManus
Forward head posture (FHP) is a common postural deviation linked to musculoskeletal disorders and altered cervical spine biomechanics. This study used a validated finite element model (C0–T1, THUMS v4.2) to quantify the biomechanical effects of FHP, with validation against cadaveric data for sagittal balance and range of motion in flexion–extension, axial rotation, and lateral bending. Sagittal balance parameters, including craniovertebral angle (CVA), occipital protuberance to C2 (OP–C2), cervical lordosis (C1–C2 and C2–C7), greater occipital nerve (GON), and C2 nerve root (C2–NR), were measured before and after a 2.5 cm anterior head displacement. FHP increased upper cervical lordosis and decreased lower cervical curvature, accompanied by measurable narrowing of neural foraminal spaces (GON and C2–NR) and elevated cortical bone stresses, particularly between C2–C3. These changes reflect compensatory adaptations that may predispose to pain and degeneration, underscoring the need for early intervention strategies to mitigate long-term spinal health impacts.
{"title":"A computational study of forward head posture biomechanics","authors":"Katterine N. Rios-Peralta , Afonso J.C. Silva , Ricardo J. Alves-de-Sousa , Kathleen M. Curran , David B. MacManus","doi":"10.1016/j.jmbbm.2025.107288","DOIUrl":"10.1016/j.jmbbm.2025.107288","url":null,"abstract":"<div><div>Forward head posture (FHP) is a common postural deviation linked to musculoskeletal disorders and altered cervical spine biomechanics. This study used a validated finite element model (C0–T1, THUMS v4.2) to quantify the biomechanical effects of FHP, with validation against cadaveric data for sagittal balance and range of motion in flexion–extension, axial rotation, and lateral bending. Sagittal balance parameters, including craniovertebral angle (CVA), occipital protuberance to C2 (OP–C2), cervical lordosis (C1–C2 and C2–C7), greater occipital nerve (GON), and C2 nerve root (C2–NR), were measured before and after a 2.5 cm anterior head displacement. FHP increased upper cervical lordosis and decreased lower cervical curvature, accompanied by measurable narrowing of neural foraminal spaces (GON and C2–NR) and elevated cortical bone stresses, particularly between C2–C3. These changes reflect compensatory adaptations that may predispose to pain and degeneration, underscoring the need for early intervention strategies to mitigate long-term spinal health impacts.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107288"},"PeriodicalIF":3.5,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145688854","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 : 2025-11-28DOI: 10.1016/j.jmbbm.2025.107286
Swaprakash Yogeshwaran , Leila Donyaparastlivari , Ayda Pormoustafa , Vidhi Patel , Alexander Buffone , Rajarshi Chattaraj , Amir K. Miri
We present an inverse-engineering method for estimating physical forces within cell suspensions in 3D scaffolds during fabrication using fluorescent, lipid-coated microbubbles (MBs) filled with an inert fluorocarbon gas. MBs deform and rupture under significant mechanical pressure. In this work, we applied the compressibility characteristics of the MBs to estimate the forces acting on a cell-laden model during fabrication and handling. MBs were encapsulated in hydrogels and subjected to hydrostatic pressure for a specific period, and we demonstrated how calibration curves are generated to estimate the pressure around each MB. We further studied MB response via conventional ultrasound imaging and theoretical modeling. This work demonstrates a simple, scalable approach for estimating physical loads that biological cells experience during extrusion, injection, and other biofabrication processes.
{"title":"Microbubble-based indirect measurement of cell loading in hydrogel bioinks during handling of 3D models","authors":"Swaprakash Yogeshwaran , Leila Donyaparastlivari , Ayda Pormoustafa , Vidhi Patel , Alexander Buffone , Rajarshi Chattaraj , Amir K. Miri","doi":"10.1016/j.jmbbm.2025.107286","DOIUrl":"10.1016/j.jmbbm.2025.107286","url":null,"abstract":"<div><div>We present an inverse-engineering method for estimating physical forces within cell suspensions in 3D scaffolds during fabrication using fluorescent, lipid-coated microbubbles (MBs) filled with an inert fluorocarbon gas. MBs deform and rupture under significant mechanical pressure. In this work, we applied the compressibility characteristics of the MBs to estimate the forces acting on a cell-laden model during fabrication and handling. MBs were encapsulated in hydrogels and subjected to hydrostatic pressure for a specific period, and we demonstrated how calibration curves are generated to estimate the pressure around each MB. We further studied MB response via conventional ultrasound imaging and theoretical modeling. This work demonstrates a simple, scalable approach for estimating physical loads that biological cells experience during extrusion, injection, and other biofabrication processes.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107286"},"PeriodicalIF":3.5,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145727528","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 : 2025-11-28DOI: 10.1016/j.jmbbm.2025.107287
Farshid Shojaeianforoud , Alexander M. Venezie , Jose E. Rubio , Jaques Reifman , Brittany Coats , Kenneth L. Monson
Repeated traumatic brain injury (TBI) is a significant concern among military personnel, athletes, and abuse victims. However, little is known about the mechanisms that drive the brain's apparent increase in injury susceptibility with repeated loading. One critical factor may be the softening of cerebral blood vessels, which are significantly stiffer than brain tissue and influence its mechanical response during trauma. In this study, we employed a finite element model of a Göttingen minipig head to investigate how progressive vascular softening influences strain changes in brain tissue during both repeated blast and rapid rotation. The model incorporated pig-specific anatomical detail and material properties, including detailed cerebral vasculature. Simulations included six repeated exposures of either blast overpressure or coronal or sagittal rotations at varying severity levels. Additional “no-vasculature” (NV) cases were included for each loading condition to benchmark the mechanical contribution of blood vessels. Vessel softening was applied after each exposure based on previous experiments on Göttingen minipig cerebral arteries. While blast exposures did not generate sufficient strain to induce vessel softening, rotational events led to progressively increasing brain strain with repetition, especially in regions adjacent to softened vessels. These increases progressed toward the NV condition with repetition, consistent with diminishing structural support by softened vessels. Results also showed increasing risk of vessel rupture and axonal injury with repetition. These findings elucidate the biomechanical role of vessel softening in repeated TBI and suggest that even sub-failure vessel damage may exacerbate brain strain in repeated exposures and elevate injury risk.
{"title":"TBI-induced vessel softening increases brain susceptibility to injury with repeated head trauma","authors":"Farshid Shojaeianforoud , Alexander M. Venezie , Jose E. Rubio , Jaques Reifman , Brittany Coats , Kenneth L. Monson","doi":"10.1016/j.jmbbm.2025.107287","DOIUrl":"10.1016/j.jmbbm.2025.107287","url":null,"abstract":"<div><div>Repeated traumatic brain injury (TBI) is a significant concern among military personnel, athletes, and abuse victims. However, little is known about the mechanisms that drive the brain's apparent increase in injury susceptibility with repeated loading. One critical factor may be the softening of cerebral blood vessels, which are significantly stiffer than brain tissue and influence its mechanical response during trauma. In this study, we employed a finite element model of a Göttingen minipig head to investigate how progressive vascular softening influences strain changes in brain tissue during both repeated blast and rapid rotation. The model incorporated pig-specific anatomical detail and material properties, including detailed cerebral vasculature. Simulations included six repeated exposures of either blast overpressure or coronal or sagittal rotations at varying severity levels. Additional “no-vasculature” (NV) cases were included for each loading condition to benchmark the mechanical contribution of blood vessels. Vessel softening was applied after each exposure based on previous experiments on Göttingen minipig cerebral arteries. While blast exposures did not generate sufficient strain to induce vessel softening, rotational events led to progressively increasing brain strain with repetition, especially in regions adjacent to softened vessels. These increases progressed toward the NV condition with repetition, consistent with diminishing structural support by softened vessels. Results also showed increasing risk of vessel rupture and axonal injury with repetition. These findings elucidate the biomechanical role of vessel softening in repeated TBI and suggest that even sub-failure vessel damage may exacerbate brain strain in repeated exposures and elevate injury risk.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107287"},"PeriodicalIF":3.5,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145688875","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 : 2025-11-27DOI: 10.1016/j.jmbbm.2025.107282
Jan Saip Aunan-Diop , José Bonilla , Bo Halle , Christian Bonde Pedersen , Ancuta Ioana Friismose , Bo Mussmann , Frantz Rom Poulsen
Tumor consistency influences meningioma handling during surgery, but systematic biomechanical classifications are lacking. In this prospective study, 129 tumor slices from 20 meningiomas underwent amplitude-sweep oscillatory rheometry (1–100% strain, 1 Hz) to characterize storage modulus (G′), loss modulus (G″), damping (tan δ), yield strain, and strain stiffening. Curves were normalized, embedded by principal component analysis, and subjected to unsupervised clustering. Three reproducible viscoelastic phenotypes were identified (Cluster A: 29%, B: 61%, C: 9%) that differed significantly across baseline stiffness, stiffening slope, yield strain, and damping (all q < 1 × 10-7). Cluster C, defined by high stiffness and elevated dissipation, was strongly associated with intraoperative hard grading (OR 82.8, 95% CI 11.0–623.2, p < 0.0001). Tumor-level stiffness index correlated with overall consistency (ρ = 0.48, p = 0.033), and the hard-phenotype fraction tracked both maximum (ρ = 0.54, p = 0.013) and minimum consistency (ρ = 0.53, p = 0.017). Entropy-based heterogeneity did not predict surgical consistency range. Clustering robustness was confirmed by bootstrap (ARI 0.81) and leave-one-tumor-out analysis (ARI 0.79). These findings suggest a quantitative biomechanical classification of meningiomas directly linked to operative handling.
肿瘤一致性影响手术中脑膜瘤的处理，但缺乏系统的生物力学分类。在这项前瞻性研究中，来自20个脑膜瘤的129个肿瘤切片进行了振幅扫描振荡流变仪（1-100%应变，1 Hz）来表征存储模量（G'），损耗模量（G″），阻尼（tan δ），屈服应变和应变硬化。曲线归一化，主成分分析嵌入，并进行无监督聚类。确定了三种可重复的粘弹性表型（A组：29%，B组：61%，C组：9%），它们在基线刚度、加劲斜率、屈服应变和阻尼（均为q -7）之间存在显著差异。C组，定义为高刚度和高耗散，与术中硬度分级密切相关（OR 82.8, 95% CI 11.0-623.2, p . 522）
{"title":"Viscoelastic phenotyping of meningiomas reveals biomechanical classes and intratumoral heterogeneity","authors":"Jan Saip Aunan-Diop , José Bonilla , Bo Halle , Christian Bonde Pedersen , Ancuta Ioana Friismose , Bo Mussmann , Frantz Rom Poulsen","doi":"10.1016/j.jmbbm.2025.107282","DOIUrl":"10.1016/j.jmbbm.2025.107282","url":null,"abstract":"<div><div>Tumor consistency influences meningioma handling during surgery, but systematic biomechanical classifications are lacking. In this prospective study, 129 tumor slices from 20 meningiomas underwent amplitude-sweep oscillatory rheometry (1–100% strain, 1 Hz) to characterize storage modulus (G′), loss modulus (G″), damping (tan δ), yield strain, and strain stiffening. Curves were normalized, embedded by principal component analysis, and subjected to unsupervised clustering. Three reproducible viscoelastic phenotypes were identified (Cluster A: 29%, B: 61%, C: 9%) that differed significantly across baseline stiffness, stiffening slope, yield strain, and damping (all q < 1 × 10<sup>-7</sup>). Cluster C, defined by high stiffness and elevated dissipation, was strongly associated with intraoperative hard grading (OR 82.8, 95% CI 11.0–623.2, p < 0.0001). Tumor-level stiffness index correlated with overall consistency (ρ = 0.48, p = 0.033), and the hard-phenotype fraction tracked both maximum (ρ = 0.54, p = 0.013) and minimum consistency (ρ = 0.53, p = 0.017). Entropy-based heterogeneity did not predict surgical consistency range. Clustering robustness was confirmed by bootstrap (ARI 0.81) and leave-one-tumor-out analysis (ARI 0.79). These findings suggest a quantitative biomechanical classification of meningiomas directly linked to operative handling.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"174 ","pages":"Article 107282"},"PeriodicalIF":3.5,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145650639","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 : 2025-11-27DOI: 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}
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