Electrospun polymeric fibres are promising materials for biomedical applications, owing to their biocompatibility, biodegradability, and ability to be assembled into a non-woven fibrous mesh. In particular, continuous filaments can be produced and subsequently assembled into multi-filament braided structures for ligament and tendon tissue repair. In these applications, characterising the evolution of the mechanical properties of the filament as it degrades is of primary importance. The role of applied mechanical loads during the degradation process also needs to be understood. In this study, we characterised the hydrolytic degradation behaviour of pre-stretched electrospun filaments made of poly(- caprolactone) (PCL) in buffer saline solution at 45 °C for up to 5 weeks, considering both non-loaded and loaded conditions. We show that PCL filaments degrade significantly over this relatively short time period, with non-loaded specimens showing a 21 % reduction in molecular weight after 5 weeks of exposure. Tensile loads applied during degradation further accelerate the degradation rate, with filaments subjected to a 25 g load showing a 33 % reduction in molecular weight over the same time period. Applied loads also impact the mechanical properties of the degraded specimens, causing an increase in elastic modulus and strength but a sharp decrease in elongation at break with exposure time. Our findings have implications for the design of PCL electrospun constructs in load bearing biomedical applications.
{"title":"Hydrolytic degradation behaviour of electrospun poly(ɛ-caprolactone) filaments for biological tissue repair","authors":"Thales Zanetti Ferreira , Huanming Chen , Kaili Chen , Pierre-Alexis Mouthuy , Laurence Brassart","doi":"10.1016/j.jmbbm.2025.107308","DOIUrl":"10.1016/j.jmbbm.2025.107308","url":null,"abstract":"<div><div>Electrospun polymeric fibres are promising materials for biomedical applications, owing to their biocompatibility, biodegradability, and ability to be assembled into a non-woven fibrous mesh. In particular, continuous filaments can be produced and subsequently assembled into multi-filament braided structures for ligament and tendon tissue repair. In these applications, characterising the evolution of the mechanical properties of the filament as it degrades is of primary importance. The role of applied mechanical loads during the degradation process also needs to be understood. In this study, we characterised the hydrolytic degradation behaviour of pre-stretched electrospun filaments made of poly(<span><math><mi>ɛ</mi></math></span>- caprolactone) (PCL) in buffer saline solution at 45 °C for up to 5 weeks, considering both non-loaded and loaded conditions. We show that PCL filaments degrade significantly over this relatively short time period, with non-loaded specimens showing a 21 % reduction in molecular weight after 5 weeks of exposure. Tensile loads applied during degradation further accelerate the degradation rate, with filaments subjected to a 25 g load showing a 33 % reduction in molecular weight over the same time period. Applied loads also impact the mechanical properties of the degraded specimens, causing an increase in elastic modulus and strength but a sharp decrease in elongation at break with exposure time. Our findings have implications for the design of PCL electrospun constructs in load bearing biomedical applications.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107308"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717154","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 : 2026-03-01Epub Date: 2025-12-06DOI: 10.1016/j.jmbbm.2025.107305
Mahdi Bodaghi , Saman Jolaiy , Kaveh Rahmani , Sheng Li , Fei Gao , Ali Zolfagharian
Prosthetic comfort depends on how the residual limb, liner, and socket share load. A crab-inspired auxetic metamaterial is introduced and applied to transtibial liners and sockets, with region-specific and fully auxetic variants benchmarked against conventional interfaces. Patient CT/3D scans guided anatomically targeted components. Auxetic lattices were additively manufactured in TPU (liners) and PA-12 (sockets). Cyclic compression experiments calibrated material models, and finite-element analyses quantified interface stresses and energy metrics. Across four sensitive liner regions, a four-zone auxetic TPU liner cut peak von Mises stresses by up to 60 %, and a fully auxetic liner by up to 65 %, relative to silicone/EL50 baselines. In sockets, a PA-12 design with two auxetic zones reduced peak stresses by ∼40–45 % versus ABS, while a fully auxetic socket achieved ∼80 % reductions with higher specific energy absorption. These findings indicate that bioinspired auxetics, integrated where anatomy needs compliance, improve pressure redistribution and mass-efficient energy management. The workflow from imaging to lattice design, printing, testing, and simulation was validated and is compatible with multi-jet fusion, enabling patient-specific prosthetic interfaces suitable for clinical translation.
{"title":"Bioinspired auxetic metamaterial liners and sockets for transtibial prostheses: Energy absorption and stress redistribution","authors":"Mahdi Bodaghi , Saman Jolaiy , Kaveh Rahmani , Sheng Li , Fei Gao , Ali Zolfagharian","doi":"10.1016/j.jmbbm.2025.107305","DOIUrl":"10.1016/j.jmbbm.2025.107305","url":null,"abstract":"<div><div>Prosthetic comfort depends on how the residual limb, liner, and socket share load. A crab-inspired auxetic metamaterial is introduced and applied to transtibial liners and sockets, with region-specific and fully auxetic variants benchmarked against conventional interfaces. Patient CT/3D scans guided anatomically targeted components. Auxetic lattices were additively manufactured in TPU (liners) and PA-12 (sockets). Cyclic compression experiments calibrated material models, and finite-element analyses quantified interface stresses and energy metrics. Across four sensitive liner regions, a four-zone auxetic TPU liner cut peak von Mises stresses by up to 60 %, and a fully auxetic liner by up to 65 %, relative to silicone/EL50 baselines. In sockets, a PA-12 design with two auxetic zones reduced peak stresses by ∼40–45 % versus ABS, while a fully auxetic socket achieved ∼80 % reductions with higher specific energy absorption. These findings indicate that bioinspired auxetics, integrated where anatomy needs compliance, improve pressure redistribution and mass-efficient energy management. The workflow from imaging to lattice design, printing, testing, and simulation was validated and is compatible with multi-jet fusion, enabling patient-specific prosthetic interfaces suitable for clinical translation.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107305"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145717193","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 : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.jmbbm.2025.107318
Victoria Haines , Jennifer Helen Edwards , Anthony Herbert
Rupture of the anterior cruciate ligament is a common sports-related injury that lacks intrinsic healing capacity, often necessitating surgical intervention. Our group has developed a new graft biomaterial, the decellularised porcine super flexor tendon (pSFT), designed to mitigate immune rejection post-implantation by removing cellular components. The current 26-day decellularisation process attenuates the mechanical properties of the graft, potentially disrupting the structural micro-cues that influence cell repopulation and integration. This study investigates a shortened 4-day protocol to determine whether mechanical properties are preserved more closely to native, unprocessed tissue.
Histological analysis and DNA quantification confirmed effective cell removal for both the 26-day and 4-day protocols. Native, 26-day processed, and 4-day processed grafts were mechanically evaluated through stress relaxation and failure testing. Following stress relaxation testing, several Maxwell-Weichert viscoelastic parameters were found to significantly differ between 26-day and native groups (E0, E1, E2 & τ2), whereas between 4-day and native groups fewer significant differences were found (E1 & E2). Following failure testing, again several parameters were found to significantly differ between 26-day and native groups (PFAIL, UTS, Elinear and εT), whereas between 4-day and native groups only one parameter was significantly different (Elinear).
These findings indicate that the 4-day decellularisation process better preserves the native tissue mechanical properties, potentially reducing structural alterations and improving suitability for anterior cruciate ligament replacement.
{"title":"Evaluation of a novel 4-day decellularisation protocol for porcine flexor tendons: A comparative study with a 26-day process","authors":"Victoria Haines , Jennifer Helen Edwards , Anthony Herbert","doi":"10.1016/j.jmbbm.2025.107318","DOIUrl":"10.1016/j.jmbbm.2025.107318","url":null,"abstract":"<div><div>Rupture of the anterior cruciate ligament is a common sports-related injury that lacks intrinsic healing capacity, often necessitating surgical intervention. Our group has developed a new graft biomaterial, the decellularised porcine super flexor tendon (pSFT), designed to mitigate immune rejection post-implantation by removing cellular components. The current 26-day decellularisation process attenuates the mechanical properties of the graft, potentially disrupting the structural micro-cues that influence cell repopulation and integration. This study investigates a shortened 4-day protocol to determine whether mechanical properties are preserved more closely to native, unprocessed tissue.</div><div>Histological analysis and DNA quantification confirmed effective cell removal for both the 26-day and 4-day protocols. Native, 26-day processed, and 4-day processed grafts were mechanically evaluated through stress relaxation and failure testing. Following stress relaxation testing, several Maxwell-Weichert viscoelastic parameters were found to significantly differ between 26-day and native groups (E<sub>0</sub>, E<sub>1</sub>, E<sub>2</sub> & τ<sub>2</sub>), whereas between 4-day and native groups fewer significant differences were found (E<sub>1</sub> & E<sub>2</sub>). Following failure testing, again several parameters were found to significantly differ between 26-day and native groups (P<sub>FAIL</sub>, UTS, E<sub>linear</sub> and ε<sub>T</sub>), whereas between 4-day and native groups only one parameter was significantly different (E<sub>linear</sub>).</div><div>These findings indicate that the 4-day decellularisation process better preserves the native tissue mechanical properties, potentially reducing structural alterations and improving suitability for anterior cruciate ligament replacement.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107318"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837305","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 : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.jmbbm.2025.107310
Ritika Raj Menghani , Karthik Tappa , Peiyan Li , Katelyn Kevorkian , Alexander F. Mericli , Valerae O. Lewis , Justin E. Bird , Raudel Avila
Spino-pelvic reconstruction following extended hemipelvectomy is a highly complex surgical procedure with significant variability in biomechanics between patients due to differences in surgical techniques. Despite its clinical significance, experimentally identifying the key biomechanical factors that govern the integrity of the reconstructed pelvis remains challenging. To address this, we developed a multiscale computational modeling framework, ranging from 1D beam theory and 2D composite trusses to anatomically accurate 3D reconstructions, to systematically evaluate the biomechanical trade-offs of bone graft selection in spino-pelvic reconstructions. Anatomically accurate, three-dimensional finite element models, reconstructed from postoperative CT imaging, were developed to simulate stress distributions in both bone and implant components of the reconstructed pelvis under quasi-static sitting conditions, representing the postoperative recovery phase. Two key choices were systematically evaluated: bone graft selection and implant material properties. Comparative analysis of tibial, femoral, and fibular grafts demonstrates that the femoral graft provides superior mechanical performance due to its larger cross-sectional area. The tibial graft exhibits approximately twice the stress level of the femur, while the fibular graft experiences stresses nearly three times higher, indicating limited suitability for structural reconstruction. Implant material analysis reveals that titanium and stainless steel minimize stress accumulation and reduce the risk of mechanical failure, making them preferable under high-load conditions. In contrast, polymer-based implants mitigate stress shielding and may be advantageous when bone remodeling is a priority. Together, these findings offer new insight into spino-pelvic reconstruction strategies and support simulation-driven design optimization to improve future outcomes for patients undergoing these complex procedures.
{"title":"Mechanics of bone graft and implant choices for spino-pelvic reconstruction following combined hemipelvectomy, sacrectomy and L5 vertebrectomy","authors":"Ritika Raj Menghani , Karthik Tappa , Peiyan Li , Katelyn Kevorkian , Alexander F. Mericli , Valerae O. Lewis , Justin E. Bird , Raudel Avila","doi":"10.1016/j.jmbbm.2025.107310","DOIUrl":"10.1016/j.jmbbm.2025.107310","url":null,"abstract":"<div><div>Spino-pelvic reconstruction following extended hemipelvectomy is a highly complex surgical procedure with significant variability in biomechanics between patients due to differences in surgical techniques. Despite its clinical significance, experimentally identifying the key biomechanical factors that govern the integrity of the reconstructed pelvis remains challenging. To address this, we developed a multiscale computational modeling framework, ranging from 1D beam theory and 2D composite trusses to anatomically accurate 3D reconstructions, to systematically evaluate the biomechanical trade-offs of bone graft selection in spino-pelvic reconstructions. Anatomically accurate, three-dimensional finite element models, reconstructed from postoperative CT imaging, were developed to simulate stress distributions in both bone and implant components of the reconstructed pelvis under quasi-static sitting conditions, representing the postoperative recovery phase. Two key choices were systematically evaluated: bone graft selection and implant material properties. Comparative analysis of tibial, femoral, and fibular grafts demonstrates that the femoral graft provides superior mechanical performance due to its larger cross-sectional area. The tibial graft exhibits approximately twice the stress level of the femur, while the fibular graft experiences stresses nearly three times higher, indicating limited suitability for structural reconstruction. Implant material analysis reveals that titanium and stainless steel minimize stress accumulation and reduce the risk of mechanical failure, making them preferable under high-load conditions. In contrast, polymer-based implants mitigate stress shielding and may be advantageous when bone remodeling is a priority. Together, these findings offer new insight into spino-pelvic reconstruction strategies and support simulation-driven design optimization to improve future outcomes for patients undergoing these complex procedures.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107310"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746284","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 : 2026-03-01Epub 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":"2026-03-01","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 : 2026-03-01Epub Date: 2025-12-16DOI: 10.1016/j.jmbbm.2025.107311
K. Zouggar , D. Guerraiche , K. Guerraiche , K. Bendine , M.W. Harmel , K. Madani , R.D.S.G. Campilho
The present research investigates the impact of carbon-filler reinforcement on the thermo-mechanical characteristics of polyamide 12 (PA12) during Selective Laser Sintering (SLS) for the production of specific cranial implants. A complete thermo-mechanical finite element analysis was developed using user subroutines (DFLUX, UMAT, and UEPActivationVol) from a commercial software Abaqus for modeling variations of temperature, warpage, crystallization kinetics, shrinkage, and residual stresses accumulation during the complete layer-wise sintering fabrication process. The model underwent quantitative validation against experimental benchmarks, demonstrating dimensional deviations of less than 5 % and warpage prediction errors below 15 %, thereby affirming its predictive reliability. The validated framework was subsequently utilized to compare neat PA12 with a 35 % carbon filler-reinforced composite (PA12CF35). The research results suggest that PA12CF35 displays a 26 % improvement in solidification speed, a 17.5 % decrease in shrinkage, and an estimated 5 % enhancement in warpage resistance compared to PA12. The use of carbon fillers improves thermal conductivity and reduces the peak temperature by 3.4 %, allowing more uniform melting and cooling across consecutive layers. Additionally, PA12CF35 exhibits a 7.7 % decrease in residual stress, resulting in improved structural stiffness and dimensional stability post-solidification.
The assessed results reveal that the designed model approach efficiently guides process optimization and composite design in polymer-based SLS. The enhanced thermo-mechanical properties of PA12CF35 underscore its suitability for advanced cranial implants developed via additive manufacturing.
{"title":"Benchmarking PA12 and PA12CF35 for selective laser sintering of patient-specific implants: a thermo-mechanical analysis","authors":"K. Zouggar , D. Guerraiche , K. Guerraiche , K. Bendine , M.W. Harmel , K. Madani , R.D.S.G. Campilho","doi":"10.1016/j.jmbbm.2025.107311","DOIUrl":"10.1016/j.jmbbm.2025.107311","url":null,"abstract":"<div><div>The present research investigates the impact of carbon-filler reinforcement on the thermo-mechanical characteristics of polyamide 12 (PA12) during Selective Laser Sintering (SLS) for the production of specific cranial implants. A complete thermo-mechanical finite element analysis was developed using user subroutines (DFLUX, UMAT, and UEPActivationVol) from a commercial software Abaqus for modeling variations of temperature, warpage, crystallization kinetics, shrinkage, and residual stresses accumulation during the complete layer-wise sintering fabrication process. The model underwent quantitative validation against experimental benchmarks, demonstrating dimensional deviations of less than 5 % and warpage prediction errors below 15 %, thereby affirming its predictive reliability. The validated framework was subsequently utilized to compare neat PA12 with a 35 % carbon filler-reinforced composite (PA12CF35). The research results suggest that PA12CF35 displays a 26 % improvement in solidification speed, a 17.5 % decrease in shrinkage, and an estimated 5 % enhancement in warpage resistance compared to PA12. The use of carbon fillers improves thermal conductivity and reduces the peak temperature by 3.4 %, allowing more uniform melting and cooling across consecutive layers. Additionally, PA12CF35 exhibits a 7.7 % decrease in residual stress, resulting in improved structural stiffness and dimensional stability post-solidification.</div><div>The assessed results reveal that the designed model approach efficiently guides process optimization and composite design in polymer-based SLS. The enhanced thermo-mechanical properties of PA12CF35 underscore its suitability for advanced cranial implants developed via additive manufacturing.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107311"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145795540","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 : 2026-03-01Epub 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":"2026-03-01","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 : 2026-03-01Epub 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":"2026-03-01","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 : 2026-03-01Epub Date: 2025-12-29DOI: 10.1016/j.jmbbm.2025.107329
Mohamad Hassan Taherian , Thi Anh Le , Anh Van Thi Le , Dung My Thi Dang , Tin Chanh Duc Doan , Chien Mau Dang , Martin Bolduc
Hydroxyapatite (HA)–Bioglass® (45S) nanocomposites were fabricated via two-step sintering (TSS) to optimize densification, phase stability, and mechanical performance for potential bone regeneration applications. Composite nanopowders were prepared by a sol–gel route, compacted into pellets, and subjected to a TSS protocol with systematically varied temperatures and holding times. The selected two-step sintering (TSS2) parameters were identified as an initial temperature of 1150 °C with a 15 min hold, followed by a seconday treatment at 1050 °C for 25 h, which yielded the best balance of densification and phase stability. X-ray diffraction and scanning electron microscopy revealed that HA remained the primary phase, while β-tricalcium phosphate (β-TCP) formation increased with Bioglass® content, enhancing fracture toughness via crack-bridging and transformation-induced local compressive stresses. Bulk density and nanoindentation measurements showed that Bioglass® acted as an effective sintering aid, promoting densification and improving hardness, elastic modulus, and toughness. Among the studied compositions, the 10 wt% Bioglass® composite processed under selected TSS2 conditions exhibited the highest density and superior mechanical properties, while maintaining nanoscale grains (<100 nm). These results demonstrate that controlled TSS can effectively tailor the microstructure and performance of HA– Bioglass® composites, offering a promising strategy for advanced bioceramic implants.
{"title":"Controlled microstructural evolution of Hydroxyapatite–Bioglass® nanocomposites via two-step sintering","authors":"Mohamad Hassan Taherian , Thi Anh Le , Anh Van Thi Le , Dung My Thi Dang , Tin Chanh Duc Doan , Chien Mau Dang , Martin Bolduc","doi":"10.1016/j.jmbbm.2025.107329","DOIUrl":"10.1016/j.jmbbm.2025.107329","url":null,"abstract":"<div><div>Hydroxyapatite (HA)–Bioglass® (45S) nanocomposites were fabricated via two-step sintering (TSS) to optimize densification, phase stability, and mechanical performance for potential bone regeneration applications. Composite nanopowders were prepared by a sol–gel route, compacted into pellets, and subjected to a TSS protocol with systematically varied temperatures and holding times. The selected two-step sintering (TSS2) parameters were identified as an initial temperature of 1150 °C with a 15 min hold, followed by a seconday treatment at 1050 °C for 25 h, which yielded the best balance of densification and phase stability. X-ray diffraction and scanning electron microscopy revealed that HA remained the primary phase, while β-tricalcium phosphate (β-TCP) formation increased with Bioglass® content, enhancing fracture toughness via crack-bridging and transformation-induced local compressive stresses. Bulk density and nanoindentation measurements showed that Bioglass® acted as an effective sintering aid, promoting densification and improving hardness, elastic modulus, and toughness. Among the studied compositions, the 10 wt% Bioglass® composite processed under selected TSS2 conditions exhibited the highest density and superior mechanical properties, while maintaining nanoscale grains (<100 nm). These results demonstrate that controlled TSS can effectively tailor the microstructure and performance of HA– Bioglass® composites, offering a promising strategy for advanced bioceramic implants.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"175 ","pages":"Article 107329"},"PeriodicalIF":3.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880596","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 : 2026-03-01Epub 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":"2026-03-01","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}
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