Pub Date : 2025-02-07DOI: 10.1016/j.jmbbm.2025.106927
Xingyue Wang , Susu Wang , Akoumay Tehoungue , Yurong Li , Xiang Li , Yanhui , Mingkun Zhu , Guozheng Zhang , Yeshun Zhang
Oxidative stress and infection significantly obstruct the process of diabetic wound healing. Herein, we developed a new sericin hydrogel with excellent antioxidative and antimicrobial features for the treatment of diabetic wounds. This hydrogel was prepared from a native sericin solution collected from silk fibroin-deficient mutant silkworm bodies; it also possesses exceptional ductility, high transparency, and excellent biocompatibility, enabling the hydrogel dressing to effectively eliminate excessive reactive oxygen species, while preventing bacterial infections within the diabetic wound microenvironment. Additionally, the hydrogel facilitates real-time monitoring of wounds and surgical sutures. Furthermore, it demonstrates pH-responsive swelling and degradation properties, along with a microporous structure, which collectively foster a moist, flexible, and breathable environment conducive to tissue regeneration, thereby promoting wound healing. Moreover, the hydrogel promotes the adhesion and proliferation of NIH3T3 cells, and in vivo studies highlight its ability to expedite wound healing. These findings suggest that the formic acid-treated sericin hydrogel dressing holds great promise as an advanced solution for managing diabetic wounds.
{"title":"A robust visualized sericin hydrogel dressing with excellent antioxidative and antimicrobial activities facilitates diabetic wound healing","authors":"Xingyue Wang , Susu Wang , Akoumay Tehoungue , Yurong Li , Xiang Li , Yanhui , Mingkun Zhu , Guozheng Zhang , Yeshun Zhang","doi":"10.1016/j.jmbbm.2025.106927","DOIUrl":"10.1016/j.jmbbm.2025.106927","url":null,"abstract":"<div><div>Oxidative stress and infection significantly obstruct the process of diabetic wound healing. Herein, we developed a new sericin hydrogel with excellent antioxidative and antimicrobial features for the treatment of diabetic wounds. This hydrogel was prepared from a native sericin solution collected from silk fibroin-deficient mutant silkworm bodies; it also possesses exceptional ductility, high transparency, and excellent biocompatibility, enabling the hydrogel dressing to effectively eliminate excessive reactive oxygen species, while preventing bacterial infections within the diabetic wound microenvironment. Additionally, the hydrogel facilitates real-time monitoring of wounds and surgical sutures. Furthermore, it demonstrates pH-responsive swelling and degradation properties, along with a microporous structure, which collectively foster a moist, flexible, and breathable environment conducive to tissue regeneration, thereby promoting wound healing. Moreover, the hydrogel promotes the adhesion and proliferation of NIH3T3 cells, and in vivo studies highlight its ability to expedite wound healing. These findings suggest that the formic acid-treated sericin hydrogel dressing holds great promise as an advanced solution for managing diabetic wounds.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106927"},"PeriodicalIF":3.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395882","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 : 2025-02-06DOI: 10.1016/j.jmbbm.2025.106929
Joyce R. de Souza , Caroline Anselmi , Lais M. Cardoso , Letícia T. Kito , Alexandre H. dos Reis-Prado , Pedro H.C. de Oliveira , Renan Dal-Fabbro , Maedeh Rahimnejad , Tiago M.B. Campos , Luciano T.A. Cintra , Alexandre L.S. Borges , Marco C. Bottino
Bone regeneration remains a critical challenge in regenerative medicine, particularly in dentistry, where conditions such as periodontal disease and trauma can lead to significant bone defects. Traditional treatment methods, such as autogenous bone grafting, face limitations, including donor site morbidity and postoperative complications. Recent advancements in biomaterials, particularly silk fibroin-based scaffolds, have shown promise due to their excellent biocompatibility and tunable mechanical properties. Incorporating bioactive glass and metal ions, such as cobalt, into these scaffolds can enhance osteogenic properties and antibacterial effects, creating an optimal environment for bone regeneration. The primary objective of this study was to develop and characterize SilkMA/silicated-chlorinated cobalt-doped bioactive glass composites with the potential for bone regeneration applications. Utilizing the sol-gel method, we synthesized cobalt-doped bioglass, enhancing its bioactivity and antibacterial properties. Mechanical testing, swelling assessments, degradation analysis, and in vitro evaluations using alveolar bone-derived mesenchymal stem cells (aBMSCs) demonstrated the scaffolds' cytocompatibility and favorable physical properties. The structural integrity of the electrospun fibers was confirmed through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy analyses. Incorporating bioglass reduced swelling ratios, while in vitro assays showed that cobalt ions effectively inhibited the biofilm formation of Porphyromonas gingivalis. In vivo analysis using hematoxylin-eosin and von Kossa (vK) staining demonstrated that the SilkMA + 20% BGCo scaffold elicited a minimal inflammatory response, confirming its biocompatibility. However, the absence of positively stained structures in the vK analysis indicated its lack of mineralization potential. In sum, SilkMA/BGCo scaffolds showed promising in vitro potential for bone tissue regeneration and excellent biocompatibility in vivo despite lacking calcium deposition. Further studies with alternative in vivo models are needed to confirm their efficacy.
{"title":"Electrospun SilkMA/silicate-chlorinated cobalt-doped bioactive glass composite for bone regeneration","authors":"Joyce R. de Souza , Caroline Anselmi , Lais M. Cardoso , Letícia T. Kito , Alexandre H. dos Reis-Prado , Pedro H.C. de Oliveira , Renan Dal-Fabbro , Maedeh Rahimnejad , Tiago M.B. Campos , Luciano T.A. Cintra , Alexandre L.S. Borges , Marco C. Bottino","doi":"10.1016/j.jmbbm.2025.106929","DOIUrl":"10.1016/j.jmbbm.2025.106929","url":null,"abstract":"<div><div>Bone regeneration remains a critical challenge in regenerative medicine, particularly in dentistry, where conditions such as periodontal disease and trauma can lead to significant bone defects. Traditional treatment methods, such as autogenous bone grafting, face limitations, including donor site morbidity and postoperative complications. Recent advancements in biomaterials, particularly silk fibroin-based scaffolds, have shown promise due to their excellent biocompatibility and tunable mechanical properties. Incorporating bioactive glass and metal ions, such as cobalt, into these scaffolds can enhance osteogenic properties and antibacterial effects, creating an optimal environment for bone regeneration. The primary objective of this study was to develop and characterize SilkMA/silicated-chlorinated cobalt-doped bioactive glass composites with the potential for bone regeneration applications. Utilizing the sol-gel method, we synthesized cobalt-doped bioglass, enhancing its bioactivity and antibacterial properties. Mechanical testing, swelling assessments, degradation analysis, and <em>in vitro</em> evaluations using alveolar bone-derived mesenchymal stem cells (aBMSCs) demonstrated the scaffolds' cytocompatibility and favorable physical properties. The structural integrity of the electrospun fibers was confirmed through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy analyses. Incorporating bioglass reduced swelling ratios, while <em>in vitro</em> assays showed that cobalt ions effectively inhibited the biofilm formation of <em>Porphyromonas gingivalis</em>. <em>In vivo</em> analysis using hematoxylin-eosin and von Kossa (vK) staining demonstrated that the SilkMA + 20% BGCo scaffold elicited a minimal inflammatory response, confirming its biocompatibility. However, the absence of positively stained structures in the vK analysis indicated its lack of mineralization potential. In sum, SilkMA/BGCo scaffolds showed promising <em>in vitro</em> potential for bone tissue regeneration and excellent biocompatibility <em>in vivo</em> despite lacking calcium deposition. Further studies with alternative <em>in vivo</em> models are needed to confirm their efficacy.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106929"},"PeriodicalIF":3.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372384","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 : 2025-02-05DOI: 10.1016/j.jmbbm.2025.106904
Fatemeh Khorami , Numaira Obaid , Carolyn J. Sparrey
Hip injuries are a frequent outcome of falls. Studying the biomechanics of hip injuries requires a comprehensive understanding of soft tissue properties and their responses to external loads. Particularly, muscle activity is crucial in arresting a fall and is likely to affect soft tissue properties. Failing to consider muscle activation might result in incorrect conclusions regarding the processes underlying injuries and the efficacy of preventive strategies. Soft tissue response is also affected by loading rate, sex, and mechanical testing protocols, highlighting the need for precise experimental design and interpretation.
Forty individuals (age = 25.53 ± 3.41 years) were recruited (20 males and 20 females) to investigate the hip soft tissue response during a high-speed cyclic indentation testing. Muscle activity was recorded using electromyography (EMG) and soft tissue thickness was measured using ultrasound imaging. Peak force, energy, and tissue stiffness were measured using tissue indentation.
The hip soft tissue exhibited hysteresis and was nonlinear during loading. Sex differences in trochanteric soft tissue stiffness resulted in males having 38% higher peak force than females and absorbed energy was 32% higher in the active state than the passive state (in combined participants).
Characterizing the range of tissue responses for in vivo hip soft tissues emphasizes the natural variability in healthy human tissues and the need to consider the range of tissue behaviors in models, not just the average response. Both sex and muscle activation increased tissue mechanical variability and need to be considered in future physical and computational models of hip impact.
{"title":"Sex differences in in vivo soft tissue compressive properties of the human hip in young adults: a comparison between passive vs active state","authors":"Fatemeh Khorami , Numaira Obaid , Carolyn J. Sparrey","doi":"10.1016/j.jmbbm.2025.106904","DOIUrl":"10.1016/j.jmbbm.2025.106904","url":null,"abstract":"<div><div>Hip injuries are a frequent outcome of falls. Studying the biomechanics of hip injuries requires a comprehensive understanding of soft tissue properties and their responses to external loads. Particularly, muscle activity is crucial in arresting a fall and is likely to affect soft tissue properties. Failing to consider muscle activation might result in incorrect conclusions regarding the processes underlying injuries and the efficacy of preventive strategies. Soft tissue response is also affected by loading rate, sex, and mechanical testing protocols, highlighting the need for precise experimental design and interpretation.</div><div>Forty individuals (age = 25.53 ± 3.41 years) were recruited (20 males and 20 females) to investigate the hip soft tissue response during a high-speed cyclic indentation testing. Muscle activity was recorded using electromyography (EMG) and soft tissue thickness was measured using ultrasound imaging. Peak force, energy, and tissue stiffness were measured using tissue indentation.</div><div>The hip soft tissue exhibited hysteresis and was nonlinear during loading. Sex differences in trochanteric soft tissue stiffness resulted in males having 38% higher peak force than females and absorbed energy was 32% higher in the active state than the passive state (in combined participants).</div><div>Characterizing the range of tissue responses for in vivo hip soft tissues emphasizes the natural variability in healthy human tissues and the need to consider the range of tissue behaviors in models, not just the average response. Both sex and muscle activation increased tissue mechanical variability and need to be considered in future physical and computational models of hip impact.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106904"},"PeriodicalIF":3.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the effects of tensile and compressive stresses on peri-implant bone remodeling activity. Titanium implants were inserted into the extracted maxillary molar sites of four-week-old male mice and allowed to heal. A sustained load of 0.9 N, inclined at 30° from palatal to buccal, was applied for 30 min daily over 7 days. Non-loaded implants served as a controls. Non-demineralized sections parallel to the occlusal plane were prepared 150 μm below the alveolar crest, and bone morphometry parameters related to bone resorption and formation were measured within a 120 μm-wide peri-implant region, divided into distal, buccal, mesial, and palatal quarters. Stress distribution was calculated using an animal-specific three-dimensional (3D) finite element (FE) model based on microfocus CT data. In the buccal quarter, where compressive stress was statistically higher than in the other quarters, and the mesial quarter, where tensile stress was greater than that in the other quarters, bone remodeling parameters increased significantly upon loading (p < 0.05), aligning with previous in vivo findings that mechanical stress influences bone-related cell activity. However, no significant parameter changes were observed in the distal quarter, where both tensile and compressive stresses were higher than those in the other quarters. This suggested regional suppression of remodeling activity by a simultaneous concentration of tension and compression. These findings offer crucial insights into the preservation and maintenance of the peri-implant bone under mechanical stress from occlusal forces, highlighting the role of stress distribution in bone remodeling.
{"title":"Effects of tensile and compressive stress on bone resorption and formation parameters surrounding dental implants","authors":"Bin Li , Natsuko Murakami , Cangyou Xie , Yuki Mouri , Hitomi Matsuno , Hisami Okawara , Kazuhiro Aoki , Noriyuki Wakabayashi","doi":"10.1016/j.jmbbm.2025.106928","DOIUrl":"10.1016/j.jmbbm.2025.106928","url":null,"abstract":"<div><div>This study investigates the effects of tensile and compressive stresses on peri-implant bone remodeling activity. Titanium implants were inserted into the extracted maxillary molar sites of four-week-old male mice and allowed to heal. A sustained load of 0.9 N, inclined at 30° from palatal to buccal, was applied for 30 min daily over 7 days. Non-loaded implants served as a controls. Non-demineralized sections parallel to the occlusal plane were prepared 150 μm below the alveolar crest, and bone morphometry parameters related to bone resorption and formation were measured within a 120 μm-wide peri-implant region, divided into distal, buccal, mesial, and palatal quarters. Stress distribution was calculated using an animal-specific three-dimensional (3D) finite element (FE) model based on microfocus CT data. In the buccal quarter, where compressive stress was statistically higher than in the other quarters, and the mesial quarter, where tensile stress was greater than that in the other quarters, bone remodeling parameters increased significantly upon loading (p < 0.05), aligning with previous <em>in vivo</em> findings that mechanical stress influences bone-related cell activity. However, no significant parameter changes were observed in the distal quarter, where both tensile and compressive stresses were higher than those in the other quarters. This suggested regional suppression of remodeling activity by a simultaneous concentration of tension and compression. These findings offer crucial insights into the preservation and maintenance of the peri-implant bone under mechanical stress from occlusal forces, highlighting the role of stress distribution in bone remodeling.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106928"},"PeriodicalIF":3.3,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395820","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 : 2025-02-03DOI: 10.1016/j.jmbbm.2025.106924
Sarah Emille Gomes da Silva , Bianca Cristina Dantas da Silva , Anne Heloyse Teixeira Crispim , Amanda Maria de Oliveira Dal Piva , Cornelis Johannes Kleverlaan , Rodrigo Othávio de Assunção e Souza
Purpose
To evaluate the effect of different finishing/polishing procedures and glaze on the surface roughness, flexure strength, and microstructure of an ultratranslucent zirconia (UZ) submitted aging.
Methodology
Two hundred and forty (240) UZ bars were sintered (8 × 2 × 1 mm) and treated according to the factors (n = 15): Type of finishing/polishing procedure (Control - Ctrl; Ultra-fine Diamond Burr - FG; Medium grit diamond burr- MG; Stone Bur - Stone; Rubber - Rub; FG + Rub; MG + Rub; Stone + Rub), and “Glaze” (Without and With - Gl). The bars were hydrothermally degraded (24 h, 127 °C, 1.7 bar), submitted to roughness analysis and 3-point mini flexural strength (FS) test. Scanning Electron Microscopy (SEM), X-ray Diffraction (XDR), and Weibull analysis were performed. Data were analyzed by 2-way ANOVA and Tukey test (5%).
Results
Finishing/Polishing’ and its interaction with ‘Glaze’ were statistically significant (P < 0.0001) for FS, unlike ‘Glaze’ alone (P = 0.8827). Rub (602.11 MPaA), Stone + Rub (555.50 MPaAB), and Ctrl (621.72 MPaA) showed superior FS, while FG_GL showed the lowest FS. Stone + Rub showed the highest Weibull modulus (13.15a). Ctrl_Gl (0.18 ± 0.02F μm) and Ctrl + Rub_Gl (0.29 ± 0.07F μm) showed the lowest roughness. Glaze (0.48B) reduced the roughness of the groups that did not receive it (1.56A), with MG (2.60 ± 0.69A μm) and FG (2.50 ± 0.7A μm) exhibiting rougher surfaces.
Conclusions
Rubber polishers are ideal for minor adjustments to UZ while Stone followed by rubber is effective for greater abrasion without compromising mechanical strength. The application of glaze did not reduce mechanical strength and resulted in lower surface roughness compared to the non-glazed groups, with the exception of the FG groups.
{"title":"Effect of different finishing/polishing techniques and glaze application on the flexural strength of ultratranslucent zirconia after hydrothermal aging","authors":"Sarah Emille Gomes da Silva , Bianca Cristina Dantas da Silva , Anne Heloyse Teixeira Crispim , Amanda Maria de Oliveira Dal Piva , Cornelis Johannes Kleverlaan , Rodrigo Othávio de Assunção e Souza","doi":"10.1016/j.jmbbm.2025.106924","DOIUrl":"10.1016/j.jmbbm.2025.106924","url":null,"abstract":"<div><h3>Purpose</h3><div>To evaluate the effect of different finishing/polishing procedures and glaze on the surface roughness, flexure strength, and microstructure of an ultratranslucent zirconia (UZ) submitted aging.</div></div><div><h3>Methodology</h3><div>Two hundred and forty (240) UZ bars were sintered (8 × 2 × 1 mm) and treated according to the factors (n = 15): Type of finishing/polishing procedure (Control - Ctrl; Ultra-fine Diamond Burr - FG; Medium grit diamond burr- MG; Stone Bur - Stone; Rubber - Rub; FG + Rub; MG + Rub; Stone + Rub), and “Glaze” (Without and With - Gl). The bars were hydrothermally degraded (24 h, 127 °C, 1.7 bar), submitted to roughness analysis and 3-point mini flexural strength (FS) test. Scanning Electron Microscopy (SEM), X-ray Diffraction (XDR), and Weibull analysis were performed. Data were analyzed by 2-way ANOVA and Tukey test (5%).</div></div><div><h3>Results</h3><div>Finishing/Polishing’ and its interaction with ‘Glaze’ were statistically significant (P < 0.0001) for FS, unlike ‘Glaze’ alone (P = 0.8827). Rub (602.11 MPa<sup>A</sup>), Stone + Rub (555.50 MPa<sup>AB</sup>), and Ctrl (621.72 MPa<sup>A</sup>) showed superior FS, while FG_GL showed the lowest FS. Stone + Rub showed the highest Weibull modulus (13.15<sup>a</sup>). Ctrl_Gl (0.18 ± 0.02<sup>F</sup> μm) and Ctrl + Rub_Gl (0.29 ± 0.07<sup>F</sup> μm) showed the lowest roughness. Glaze (0.48<sup>B</sup>) reduced the roughness of the groups that did not receive it (1.56<sup>A</sup>), with MG (2.60 ± 0.69<sup>A</sup> μm) and FG (2.50 ± 0.7<sup>A</sup> μm) exhibiting rougher surfaces.</div></div><div><h3>Conclusions</h3><div>Rubber polishers are ideal for minor adjustments to UZ while Stone followed by rubber is effective for greater abrasion without compromising mechanical strength. The application of glaze did not reduce mechanical strength and resulted in lower surface roughness compared to the non-glazed groups, with the exception of the FG groups.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106924"},"PeriodicalIF":3.3,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372338","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 : 2025-02-01DOI: 10.1016/j.jmbbm.2025.106925
Nodoka Iwasaki , Benjamin Morrison , Aikaterina Karali , Marta Roldo , Gordon Blunn
The muscle-tendon junction (MTJ) is a specialized interface that facilitates the transmission of force from the muscle to the tendon which has been implicated in muscle strains and tears. Understanding the transmission of forces and the strain generated in the MTJ is therefore important. For the first time, we report the 3D full-field strain distribution across the muscle-tendon junction (MTJ) using in-situ tensile testing and confocal microscopy coupled with digital volume correlation (DVC). This approach allowed us to measure the mechanical behaviour of the MTJ at the fibre/fascicle level. Acridine orange (AO) in 70% ethanol was used to enhance the contrast of the mouse Achilles-gastrocnemius MTJ, and the specimens were rehydrated prior to the tensile testing, which was performed using custom made tensile rig that fitted under the confocal microscopy. The 3D full-field strain distribution was obtained using DVC, where the strain changes were measured from confocal images taken with the MTJ under preload (0.4 N) and loaded (0.8 N and 1.2 N) representing 2.7- and 4-times body weight. High strain concentration was observed at the junction for both 0.8 N and 1.2 N loads. At the junction, the first principal stain (εp1), shear strain (γ) and von Mises strain (εVM) reached 15.2, 34.2 and 19.2% respectively. This study allowed us to measure fascicle level strain distribution at the MTJ. Using histology, microtears at the MTJ were seen in specimens loaded with 1.2 N which were associated with von Mises strain concentration in the adjacent region. The microtears occurred in regions where the strain level was between 8 and 15%. This study developed a methodology to determine high-resolution strain distribution at the MTJ and has the potential to be used to analyse the strain at the cellular level using higher magnification objectives.
{"title":"Measuring full-field strain of the muscle-tendon junction using confocal microscopy combined with digital volume correlation","authors":"Nodoka Iwasaki , Benjamin Morrison , Aikaterina Karali , Marta Roldo , Gordon Blunn","doi":"10.1016/j.jmbbm.2025.106925","DOIUrl":"10.1016/j.jmbbm.2025.106925","url":null,"abstract":"<div><div>The muscle-tendon junction (MTJ) is a specialized interface that facilitates the transmission of force from the muscle to the tendon which has been implicated in muscle strains and tears. Understanding the transmission of forces and the strain generated in the MTJ is therefore important. For the first time, we report the 3D full-field strain distribution across the muscle-tendon junction (MTJ) using in-situ tensile testing and confocal microscopy coupled with digital volume correlation (DVC). This approach allowed us to measure the mechanical behaviour of the MTJ at the fibre/fascicle level. Acridine orange (AO) in 70% ethanol was used to enhance the contrast of the mouse Achilles-gastrocnemius MTJ, and the specimens were rehydrated prior to the tensile testing, which was performed using custom made tensile rig that fitted under the confocal microscopy. The 3D full-field strain distribution was obtained using DVC, where the strain changes were measured from confocal images taken with the MTJ under preload (0.4 N) and loaded (0.8 N and 1.2 N) representing 2.7- and 4-times body weight. High strain concentration was observed at the junction for both 0.8 N and 1.2 N loads. At the junction, the first principal stain (ε<sub>p1</sub>), shear strain (γ) and von Mises strain (ε<sub>VM</sub>) reached 15.2, 34.2 and 19.2% respectively. This study allowed us to measure fascicle level strain distribution at the MTJ. Using histology, microtears at the MTJ were seen in specimens loaded with 1.2 N which were associated with von Mises strain concentration in the adjacent region. The microtears occurred in regions where the strain level was between 8 and 15%. This study developed a methodology to determine high-resolution strain distribution at the MTJ and has the potential to be used to analyse the strain at the cellular level using higher magnification objectives.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106925"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.jmbbm.2025.106926
Mahmuda R. Arshee , Ritwik Shukla , Jie Li , Umnia Doha , Indrani C. Bagchi , Ayelet Ziv-Gal , Amy J. Wagoner Johnson
This study investigates the structural and mechanical changes in uterine collagen following exposure to propylparaben (PP) using a combined methodology of Second Harmonic Generation (SHG) microscopy, Nanoindentation (NI), and Atomic Force Microscopy (AFM). SHG analysis identified significant disorganization in collagen fibril orientation in the circumferential layer and heterogeneous distribution of regions with elevated forward to backward ratios (F/B) across all uterine layers due to PP exposure. High F/B can indicate multiple potential fibril-level changes like thickened fibrils, higher crosslinking, fibril disorganization - changes not fully decipherable by SHG alone. Recognizing this limitation, the study employs NI and AFM to provide complementary mechanical and nanoscale insights. NI revealed increased indentation modulus in the exposed uteri, suggesting increased stiffness. Co-registration of the indentation response with SHG parameters uncovered that elevated F/B regions show enhanced mechanical stiffness, suggesting a fibrotic transformation following chronic PP exposure. AFM was specifically performed on regions identified by SHG as having low or high F/B, providing the necessary nanoscale resolution to elucidate the structural changes in fibrils that are likely responsible for the observed alterations. AFM confirmed the presence of disordered and entangled collagen fibrils in the circumferential layer in all regions and an increase in fibril diameter in the high F/B regions in the PP-exposed uteri. Together, these findings demonstrate significant alterations in collagen architecture due to PP exposure, revealing disruptions at both the fiber and fibril levels and highlighting the potential for broader applications of the multi-scale, multi-modal approach in collagenous tissue studies.
{"title":"Impact of paraben on uterine collagen: An integrated and targeted Correlative approach using second harmonic generation microscopy, nanoindentation, and atomic force microscopy","authors":"Mahmuda R. Arshee , Ritwik Shukla , Jie Li , Umnia Doha , Indrani C. Bagchi , Ayelet Ziv-Gal , Amy J. Wagoner Johnson","doi":"10.1016/j.jmbbm.2025.106926","DOIUrl":"10.1016/j.jmbbm.2025.106926","url":null,"abstract":"<div><div>This study investigates the structural and mechanical changes in uterine collagen following exposure to propylparaben (PP) using a combined methodology of Second Harmonic Generation (SHG) microscopy, Nanoindentation (NI), and Atomic Force Microscopy (AFM). SHG analysis identified significant disorganization in collagen fibril orientation in the circumferential layer and heterogeneous distribution of regions with elevated forward to backward ratios (F/B) across all uterine layers due to PP exposure. High F/B can indicate multiple potential fibril-level changes like thickened fibrils, higher crosslinking, fibril disorganization - changes not fully decipherable by SHG alone. Recognizing this limitation, the study employs NI and AFM to provide complementary mechanical and nanoscale insights. NI revealed increased indentation modulus in the exposed uteri, suggesting increased stiffness. Co-registration of the indentation response with SHG parameters uncovered that elevated F/B regions show enhanced mechanical stiffness, suggesting a fibrotic transformation following chronic PP exposure. AFM was specifically performed on regions identified by SHG as having low or high F/B, providing the necessary nanoscale resolution to elucidate the structural changes in fibrils that are likely responsible for the observed alterations. AFM confirmed the presence of disordered and entangled collagen fibrils in the circumferential layer in all regions and an increase in fibril diameter in the high F/B regions in the PP-exposed uteri. Together, these findings demonstrate significant alterations in collagen architecture due to PP exposure, revealing disruptions at both the fiber and fibril levels and highlighting the potential for broader applications of the multi-scale, multi-modal approach in collagenous tissue studies.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106926"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-31DOI: 10.1016/j.jmbbm.2025.106899
Maria Herbster , Bernd Garke , Karsten Harnisch , Oliver Michael , Alexandra Lieb , Ulf Betke , Mandy Könnecke , Andreas Heyn , Paulina Kriegel , Henrike Thärichen , Jessica Bertrand , Manja Krüger , Thorsten Halle
Due to their excellent biocompatibility, favorable strength-to-weight ratio and mechanical properties, Ti-based alloys are most commonly used for long-term implants in the human body. Nevertheless, low wear resistance and increased degradation due to corrosion under critical in vivo conditions impair the service life of these implants. This fact opens the potential for optimization, which can be exploited by chemical alloying with Cr.
This study investigates the effect of Cr alloying on the mechanical, tribological, corrosion properties and cytocompatibility of cp Ti and TiAl6V4 alloys. Argon-arc melting was used to cast binary and quaternary specimens of varying Cr content (0.1, 0.2, 0.4, 1, 2, 4, 8, 10, 15 and 20 m%). After homogenization (1100 °C, 30 min), microstructures were characterized by means of XRD and EBSD and correlated with mechanical properties using hardness and compression tests. At up to 2 m% Cr, a martensitic α′ microstructure is formed. A Cr content of 4 m% reveals two phase α’ + β alloys. Alloying with ≥8 m% Cr results in complete β phase, whereas the significantly reduced fracture compression indicates the formation of metastable ω phase for Cr content of 8–10 m%. Based on XPS analysis, a change in the composition of the passive layers by incorporation of Cr2O3 and CrOx is verified. These modified passive layers result in a reduction in corrosion current densities under mimicked severe inflammatory conditions (PBS with HCl and H2O2). In addition, the tribological behavior is significantly improved by a reduced wear rate for binary Ti-2/4Cr and quaternary TiAlV-4/8Cr alloys. Cell viability is not inhibited by Cr alloying, but reduced calcification is observed for all Cr modified specimens. These findings highlight the tremendous potential of Ti alloying with Cr for improved implant properties, with the alloy range of 2–4 m% Cr being the most suitable.
{"title":"Effects of Cr addition on Ti implant alloys (Ti-Cr/Ti-Al-V-Cr) to enhance corrosion and wear resistance","authors":"Maria Herbster , Bernd Garke , Karsten Harnisch , Oliver Michael , Alexandra Lieb , Ulf Betke , Mandy Könnecke , Andreas Heyn , Paulina Kriegel , Henrike Thärichen , Jessica Bertrand , Manja Krüger , Thorsten Halle","doi":"10.1016/j.jmbbm.2025.106899","DOIUrl":"10.1016/j.jmbbm.2025.106899","url":null,"abstract":"<div><div>Due to their excellent biocompatibility, favorable strength-to-weight ratio and mechanical properties, Ti-based alloys are most commonly used for long-term implants in the human body. Nevertheless, low wear resistance and increased degradation due to corrosion under critical <em>in vivo</em> conditions impair the service life of these implants. This fact opens the potential for optimization, which can be exploited by chemical alloying with Cr.</div><div>This study investigates the effect of Cr alloying on the mechanical, tribological, corrosion properties and cytocompatibility of cp Ti and TiAl6V4 alloys. Argon-arc melting was used to cast binary and quaternary specimens of varying Cr content (0.1, 0.2, 0.4, 1, 2, 4, 8, 10, 15 and 20 m%). After homogenization (1100 °C, 30 min), microstructures were characterized by means of XRD and EBSD and correlated with mechanical properties using hardness and compression tests. At up to 2 m% Cr, a martensitic α′ microstructure is formed. A Cr content of 4 m% reveals two phase α’ + β alloys. Alloying with ≥8 m% Cr results in complete β phase, whereas the significantly reduced fracture compression indicates the formation of metastable ω phase for Cr content of 8–10 m%. Based on XPS analysis, a change in the composition of the passive layers by incorporation of Cr<sub>2</sub>O<sub>3</sub> and CrO<sub>x</sub> is verified. These modified passive layers result in a reduction in corrosion current densities under mimicked severe inflammatory conditions (PBS with HCl and H<sub>2</sub>O<sub>2</sub>). In addition, the tribological behavior is significantly improved by a reduced wear rate for binary Ti-2/4Cr and quaternary TiAlV-4/8Cr alloys. Cell viability is not inhibited by Cr alloying, but reduced calcification is observed for all Cr modified specimens. These findings highlight the tremendous potential of Ti alloying with Cr for improved implant properties, with the alloy range of 2–4 m% Cr being the most suitable.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106899"},"PeriodicalIF":3.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-31DOI: 10.1016/j.jmbbm.2025.106909
C. Davis , B. Zambrano-Roman , R. Sridhar , A. Jastram , S. Chakraborty , D. Zawieja , M.R. Moreno
Reproducing the in vivo physiologic conditions and biomechanical environment to stimulate natural growth and behavior of lymphatic endothelial cells (LECs) is critical in studying the lymphatic system and its response to stimuli. In vitro studies that deconstruct the biomechanical environment, e.g. independently incorporate flow-induced shear stress or membrane strain have demonstrated the significance of mechanotransduction in LECs (and vascular endothelial cells). Such studies have facilitated the investigation of intracellular signaling pathways stimulated by a particular mechanical cue but do not accurately reproduce natural physiologic behavior of in vivo LECs given the absence of other natural mechanical cues. In this study, we present a novel experimental device designed to reconstruct the in vivo biomechanical environment, i.e. a device that enables the simultaneous application of flow-induced shear stress and cyclic stretching of LECs in vitro. The device is uniquely capable of simulating physiologically-relevant conditions for lymphatic endothelial cells, such as low-flow, high-strain scenarios. Using this device, we observed that, like vascular ECs, LECs aligned in the direction of fluid shear stress when steady flow was applied. In our case the behavior was observed under conditions closer to the physiological mean flow in the lymphatic vessels than vascular levels of shear stress. When concurrent cyclic stretching was applied, the alignment in the direction of flow and perpendicular to the uniaxial stretch was detected in a substantially shortened timeframe. Additionally, the distribution of alignment angles was more closely clustered around 90° under the flow/stretch scenario after 6 h than the 24 h flow only scenario, perhaps indicating a greater sensitivity to cyclic stretching than to fluid shear stress in the morphological alignment response of LECs. We also observed alignment of cell nuclei and F-actin filaments in Human Dermal Lymphatic Endothelial Cells (HDLECs) after only 6 h of combined flow and stretch. These observations underscore the importance of including both sources of mechanical stress when studying the growth and behavior of LECs.
{"title":"A bioreactor for in vitro studies of lymphatic endothelial cells with simultaneous fluid shear stress and membrane strain","authors":"C. Davis , B. Zambrano-Roman , R. Sridhar , A. Jastram , S. Chakraborty , D. Zawieja , M.R. Moreno","doi":"10.1016/j.jmbbm.2025.106909","DOIUrl":"10.1016/j.jmbbm.2025.106909","url":null,"abstract":"<div><div>Reproducing the <em>in vivo</em> physiologic conditions and biomechanical environment to stimulate natural growth and behavior of lymphatic endothelial cells (LECs) is critical in studying the lymphatic system and its response to stimuli. <em>In vitro</em> studies that deconstruct the biomechanical environment, e.g. independently incorporate flow-induced shear stress or membrane strain have demonstrated the significance of mechanotransduction in LECs (and vascular endothelial cells). Such studies have facilitated the investigation of intracellular signaling pathways stimulated by a particular mechanical cue but do not accurately reproduce natural physiologic behavior of <em>in vivo</em> LECs given the absence of other natural mechanical cues. In this study, we present a novel experimental device designed to reconstruct the <em>in vivo</em> biomechanical environment, i.e. a device that enables the simultaneous application of flow-induced shear stress and cyclic stretching of LECs <em>in vitro</em>. The device is uniquely capable of simulating physiologically-relevant conditions for lymphatic endothelial cells, such as low-flow, high-strain scenarios. Using this device, we observed that, like vascular ECs, LECs aligned in the direction of fluid shear stress when steady flow was applied. In our case the behavior was observed under conditions closer to the physiological mean flow in the lymphatic vessels than vascular levels of shear stress. When concurrent cyclic stretching was applied, the alignment in the direction of flow and perpendicular to the uniaxial stretch was detected in a substantially shortened timeframe. Additionally, the distribution of alignment angles was more closely clustered around 90° under the flow/stretch scenario after 6 h than the 24 h flow only scenario, perhaps indicating a greater sensitivity to cyclic stretching than to fluid shear stress in the morphological alignment response of LECs. We also observed alignment of cell nuclei and F-actin filaments in Human Dermal Lymphatic Endothelial Cells (HDLECs) after only 6 h of combined flow and stretch. These observations underscore the importance of including both sources of mechanical stress when studying the growth and behavior of LECs.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106909"},"PeriodicalIF":3.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350113","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 : 2025-01-30DOI: 10.1016/j.jmbbm.2025.106908
Emmanuel Eghan-Acquah , Alireza Y. Bavil , Laura E. Diamond , Rod Barrett , Christopher P. Carty , Martina Barzan , David Bade , Azadeh Nasseri , David G. Lloyd , David J. Saxby , Stefanie Feih
Finite element analysis (FEA) is nowadays a pivotal tool in orthopaedic research for personalized virtual surgery planning. Despite its widespread use, a comprehensive evaluation of the effect of boundary conditions on the simulation of physiological mechanics in implanted bone is currently lacking. This study assesses the impact of boundary conditions and femur geometry on predicted femur mechanics. It focuses on an isolated implanted femur, partially imaged, from a paediatric patient with femoral varus who underwent a proximal femoral osteotomy. By employing FEA of the femur under motion with loading scenarios informed by personalized neuromusculoskeletal modelling, this study evaluated implant and bone mechanics across three femur model configurations (full-femur, proximal half-femur, and distally synthesized full-femur) with two boundary condition approaches (biomechanical and fixed distal). The biomechanical boundary condition was validated against the gold standard inertia relief method for the natural femur and thereafter exploited as the benchmark against the other implanted femur model configurations. The distally synthesized full-femur with biomechanical boundary conditions performed best and closely predicted bone-implant micromotion (R2 = 0.99, nRMSE = 0.3%), risk of implant yield (<1% variance from the benchmark model), and interfragmentary movement (R2 = 1, nRMSE = 6%). The half-femur model with biomechanical boundary conditions overpredicted the risk of yield and interfragmentary movements by 17% and 15.8%, respectively. The fixed distal constraint method significantly overestimated the risk of implant yield in both half and synthesized full-femur models by 157% and 170%, respectively. These findings underscore the critical importance of selecting appropriate boundary conditions in the FEA of implanted femur models and advocate for the synthesis of the missing portion of the femur coupled with the biomechanical boundary conditions for more accurate predictions of bone and implant mechanics. Such insights are expected to enhance the physiological plausibility and reliability of orthopaedic research and clinical practices, especially when managing proximal femoral osteotomies.
{"title":"Evaluation of boundary conditions for predicting femoral bone-implant mechanics during gait in the absence of comprehensive medical imaging","authors":"Emmanuel Eghan-Acquah , Alireza Y. Bavil , Laura E. Diamond , Rod Barrett , Christopher P. Carty , Martina Barzan , David Bade , Azadeh Nasseri , David G. Lloyd , David J. Saxby , Stefanie Feih","doi":"10.1016/j.jmbbm.2025.106908","DOIUrl":"10.1016/j.jmbbm.2025.106908","url":null,"abstract":"<div><div>Finite element analysis (FEA) is nowadays a pivotal tool in orthopaedic research for personalized virtual surgery planning. Despite its widespread use, a comprehensive evaluation of the effect of boundary conditions on the simulation of physiological mechanics in implanted bone is currently lacking. This study assesses the impact of boundary conditions and femur geometry on predicted femur mechanics. It focuses on an isolated implanted femur, partially imaged, from a paediatric patient with femoral varus who underwent a proximal femoral osteotomy. By employing FEA of the femur under motion with loading scenarios informed by personalized neuromusculoskeletal modelling, this study evaluated implant and bone mechanics across three femur model configurations (full-femur, proximal half-femur, and distally synthesized full-femur) with two boundary condition approaches (biomechanical and fixed distal). The biomechanical boundary condition was validated against the gold standard inertia relief method for the natural femur and thereafter exploited as the benchmark against the other implanted femur model configurations. The distally synthesized full-femur with biomechanical boundary conditions performed best and closely predicted bone-implant micromotion (R<sup>2</sup> = 0.99, nRMSE = 0.3%), risk of implant yield (<1% variance from the benchmark model), and interfragmentary movement (R<sup>2</sup> = 1, nRMSE = 6%). The half-femur model with biomechanical boundary conditions overpredicted the risk of yield and interfragmentary movements by 17% and 15.8%, respectively. The fixed distal constraint method significantly overestimated the risk of implant yield in both half and synthesized full-femur models by 157% and 170%, respectively. These findings underscore the critical importance of selecting appropriate boundary conditions in the FEA of implanted femur models and advocate for the synthesis of the missing portion of the femur coupled with the biomechanical boundary conditions for more accurate predictions of bone and implant mechanics. Such insights are expected to enhance the physiological plausibility and reliability of orthopaedic research and clinical practices, especially when managing proximal femoral osteotomies.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106908"},"PeriodicalIF":3.3,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143328668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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