Pub Date : 2025-01-08DOI: 10.1016/j.jmbbm.2025.106887
Michael Werner , Welf-Guntram Drossel , Sabine Löffler , Niels Hammer
When conducting biomechanical testing or clinical training using embalmed human soft tissues, it is essential to understand their impact on biomechanical properties and their time dependence. Previous studies have investigated this influence, but specific variations over different embalming durations have not been thoroughly addressed to date.
Ninety-seven human iliotibial band specimens were obtained from nine donors. All specimens were embalmed in ethanol-glycerin for varying durations: one day, eight days, and fourteen days. Prior to the mechanical trials, the specimens underwent osmotic water adjustment, tapering and standardized clamping. Uniaxial tensile tests were conducted to determine elastic modulus, ultimate tensile strength, and ultimate strain. Surface strain measurements were performed using a digital image correlation system.
Ethanol-glycerin embalming of soft tissues significantly affects ultimate strain after one day of submersion time, elastic modulus after eight days, and the ultimate tensile strength after fourteen days. For applications requiring consistent and reliable material properties reflecting a (supra-)vital state, caution is advised against using embalmed tissues even following short submersion durations in ethanol-glycerin.
{"title":"Time-dependent effects of ethanol-glycerin embalming on iliotibial band biomechanics","authors":"Michael Werner , Welf-Guntram Drossel , Sabine Löffler , Niels Hammer","doi":"10.1016/j.jmbbm.2025.106887","DOIUrl":"10.1016/j.jmbbm.2025.106887","url":null,"abstract":"<div><div>When conducting biomechanical testing or clinical training using embalmed human soft tissues, it is essential to understand their impact on biomechanical properties and their time dependence. Previous studies have investigated this influence, but specific variations over different embalming durations have not been thoroughly addressed to date.</div><div>Ninety-seven human iliotibial band specimens were obtained from nine donors. All specimens were embalmed in ethanol-glycerin for varying durations: one day, eight days, and fourteen days. Prior to the mechanical trials, the specimens underwent osmotic water adjustment, tapering and standardized clamping. Uniaxial tensile tests were conducted to determine elastic modulus, ultimate tensile strength, and ultimate strain. Surface strain measurements were performed using a digital image correlation system.</div><div>Ethanol-glycerin embalming of soft tissues significantly affects ultimate strain after one day of submersion time, elastic modulus after eight days, and the ultimate tensile strength after fourteen days. For applications requiring consistent and reliable material properties reflecting a (supra-)vital state, caution is advised against using embalmed tissues even following short submersion durations in ethanol-glycerin.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106887"},"PeriodicalIF":3.3,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143019000","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 : 2025-01-02DOI: 10.1016/j.jmbbm.2024.106882
Jonah M. Dimnik , Kurt H. Wilde , W. Brent Edwards
The rabbit is a popular experimental model in orthopaedic biomechanics due to the presence of natural Haversian remodeling, allowing for better translational relevance to the mechanobiology of human bone over traditional rodent models. Although rabbits are often used with computational modeling approaches such as the finite element (FE) method, a validated and widely agreed upon density–elasticity relationship, which is required to make subject-specific predictions, does not exist. Therefore, the purpose of this study was to determine and validate an accurate density–elasticity relationship for rabbit hindlimb bones using mathematical optimization. Fourteen tibiae and thirteen femora were harvested from New Zealand White Rabbits, imaged with computed tomography (CT), and cyclically loaded in uniaxial compression while strain gauge rosette data were recorded. The CT images were processed into subject-specific FE models which were used in a Nelder–Mead optimization routine to determine a density–elasticity relationship that minimized the error between experimentally measured and FE-predicted principal strains. Optimizations were performed for the tibiae and femora independently, and for both bones combined. A subset of 4 tibiae and 4 femora that were excluded from the optimization were then used to validate the derived relationships. All equations that were determined by the initial optimization exhibited a type of relationship with strong correlations (Tibiae: ; Femora: ; Combined: ) and good agreement. The validation groups yielded similar results with strong correlations (Tibiae: ; Femora: ; Combined: ). These findings suggest that any of the derived density–elasticity relationships are suitable for computational modeling of the rabbit hindlimb and that a single relationship could be used for the whole rabbit hindlimb in studies where greater computational efficiency is necessary.
{"title":"Optimization of the density–elasticity relationship for rabbit hindlimb bones","authors":"Jonah M. Dimnik , Kurt H. Wilde , W. Brent Edwards","doi":"10.1016/j.jmbbm.2024.106882","DOIUrl":"10.1016/j.jmbbm.2024.106882","url":null,"abstract":"<div><div>The rabbit is a popular experimental model in orthopaedic biomechanics due to the presence of natural Haversian remodeling, allowing for better translational relevance to the mechanobiology of human bone over traditional rodent models. Although rabbits are often used with computational modeling approaches such as the finite element (FE) method, a validated and widely agreed upon density–elasticity relationship, which is required to make subject-specific predictions, does not exist. Therefore, the purpose of this study was to determine and validate an accurate density–elasticity relationship for rabbit hindlimb bones using mathematical optimization. Fourteen tibiae and thirteen femora were harvested from New Zealand White Rabbits, imaged with computed tomography (CT), and cyclically loaded in uniaxial compression while strain gauge rosette data were recorded. The CT images were processed into subject-specific FE models which were used in a Nelder–Mead optimization routine to determine a density–elasticity relationship that minimized the error between experimentally measured and FE-predicted principal strains. Optimizations were performed for the tibiae and femora independently, and for both bones combined. A subset of 4 tibiae and 4 femora that were excluded from the optimization were then used to validate the derived relationships. All equations that were determined by the initial optimization exhibited a <span><math><mrow><mi>Y</mi><mo>=</mo><mi>X</mi></mrow></math></span> type of relationship with strong correlations (Tibiae: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>96</mn></mrow></math></span>; Femora: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>85</mn></mrow></math></span>; Combined: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>90</mn></mrow></math></span>) and good agreement. The validation groups yielded similar results with strong correlations (Tibiae: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>94</mn></mrow></math></span>; Femora: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>87</mn></mrow></math></span>; Combined: <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>91</mn></mrow></math></span>). These findings suggest that any of the derived density–elasticity relationships are suitable for computational modeling of the rabbit hindlimb and that a single relationship could be used for the whole rabbit hindlimb in studies where greater computational efficiency is necessary.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106882"},"PeriodicalIF":3.3,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142934198","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 : 2025-01-02DOI: 10.1016/j.jmbbm.2024.106884
Nipa Khair , Sanchita Bhat , Sakhawat Hossan Robel , Srujana Joshi , Katie Vinterella , Lakshmi Dasi , Susan James
Hyaluronic acid-enhanced polyethylene polymeric TAVR shows excellent in vivo anti-calcific, anti-thrombotic, and in vitro hydrodynamic performance. However, during durability testing, impact wear and fatigue cause early valve failure. Heart valve durability can be improved by strengthening the leaflet with fiber reinforcement. A thin plastic sheet is assembled into a cylindrical form by welding two ends, which never fails during accelerated wear testing (ISO 5840-2005). The weld at the commissure post region of the leaflet (ROI) is mechanically stronger than the rest of the leaflet, which protects this region. Braided polyester fibers are embedded on the leaflet regions of the commissure post perpendicular to the valve circumference, mimicking the weld but at a much higher strength. Leaflet durability skyrockets from a few million cycles to 73 million and comparable hemodynamics performances. The entire cardiac cycle of the heart valve with embedded fibers of varying angles, lengths, and numbers is simulated in Finite Element Analysis (FEA) to study their effects on leaflet maximum principal stress and leaflet opening dynamics. Horizontal fibers wrap the leaflet 360° to relax the leaflet completely during peak diastolic. However, the leaflet has a higher coaptation gap and lower geometric orifice area (GOA). The heart valve with embedded horizontal fibers is physically manufactured and tested in an in vitro flow loop and wear tester, which shows improved durability but compromised hemodynamics. The parametric study further predicts that 12 mm long fibers covering only the commissure post region of the leaflet have low principal stress, maximum GOA, and fastest opening as the spring-like fibers help leaflet opening.
{"title":"Parametric finite element modeling of reinforced polymeric leaflets for improved durability","authors":"Nipa Khair , Sanchita Bhat , Sakhawat Hossan Robel , Srujana Joshi , Katie Vinterella , Lakshmi Dasi , Susan James","doi":"10.1016/j.jmbbm.2024.106884","DOIUrl":"10.1016/j.jmbbm.2024.106884","url":null,"abstract":"<div><div>Hyaluronic acid-enhanced polyethylene polymeric TAVR shows excellent <em>in vivo</em> anti-calcific, anti-thrombotic, and <em>in vitro</em> hydrodynamic performance. However, during durability testing, impact wear and fatigue cause early valve failure. Heart valve durability can be improved by strengthening the leaflet with fiber reinforcement. A thin plastic sheet is assembled into a cylindrical form by welding two ends, which never fails during accelerated wear testing (ISO 5840-2005). The weld at the commissure post region of the leaflet (ROI) is mechanically stronger than the rest of the leaflet, which protects this region. Braided polyester fibers are embedded on the leaflet regions of the commissure post perpendicular to the valve circumference, mimicking the weld but at a much higher strength. Leaflet durability skyrockets from a few million cycles to 73 million and comparable hemodynamics performances. The entire cardiac cycle of the heart valve with embedded fibers of varying angles, lengths, and numbers is simulated in Finite Element Analysis (FEA) to study their effects on leaflet maximum principal stress and leaflet opening dynamics. Horizontal fibers wrap the leaflet 360° to relax the leaflet completely during peak diastolic. However, the leaflet has a higher coaptation gap and lower geometric orifice area (GOA). The heart valve with embedded horizontal fibers is physically manufactured and tested in an <em>in vitro</em> flow loop and wear tester, which shows improved durability but compromised hemodynamics. The parametric study further predicts that 12 mm long fibers covering only the commissure post region of the leaflet have low principal stress, maximum GOA, and fastest opening as the spring-like fibers help leaflet opening.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106884"},"PeriodicalIF":3.3,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142974143","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}
Bioabsorbable polymer microneedles are highly attractive as modernized medical devices for efficient yet safe transdermal drug delivery and biofluid biopsy. In this study, the elastoplastic deformation of polymer microneedles, having a high aspect ratio (over 5–10), is investigated using poly(lactic) acid polymer approved by the United States Food and Drug Administration to be generally considered safe. Microneedle geometries are comprehensively analyzed for tip geometries comprising the tip diameter (ϕt) and tip taper length (lt) of 100 designs. Elastoplastic analysis is conducted using the finite element method to determine the typical geometries of the polymer microneedles to avoid elastoplastic deformation accompanied by fatal fracture based on the mechanical properties of the polymer materials. The design principles of microneedle geometries based on polymer material properties are important guidelines for developing polymer microneedles, overcoming their mechanical weakness, and ensuring excellent functions.
生物可吸收聚合物微针作为高效安全的经皮给药和生物液体活检的现代化医疗器械具有很高的吸引力。本研究采用经美国食品药品监督管理局（Food and Drug Administration）普遍认为安全的聚（乳酸）聚合物，研究高纵横比（大于5-10）聚合物微针的弹塑性变形。综合分析了微针的几何形状，包括100种设计的尖端直径（ϕt）和尖端锥度长度（lt）。基于高分子材料的力学性能，采用有限元法进行弹塑性分析，确定聚合物微针的典型几何形状，避免聚合物微针发生弹塑性变形并导致致命断裂。基于高分子材料特性的微针几何设计原则是开发聚合物微针、克服其机械缺陷、保证其优良功能的重要指导原则。
{"title":"Mechanical finite element analysis of needle tip shape to develop insertable polymer-based microneedle without plastic deformation","authors":"Hiroaki Takehara , Mizuki Inada , Yukihiro Kanda , Takanori Ichiki","doi":"10.1016/j.jmbbm.2025.106885","DOIUrl":"10.1016/j.jmbbm.2025.106885","url":null,"abstract":"<div><div>Bioabsorbable polymer microneedles are highly attractive as modernized medical devices for efficient yet safe transdermal drug delivery and biofluid biopsy. In this study, the elastoplastic deformation of polymer microneedles, having a high aspect ratio (over 5–10), is investigated using poly(lactic) acid polymer approved by the United States Food and Drug Administration to be generally considered safe. Microneedle geometries are comprehensively analyzed for tip geometries comprising the tip diameter (<em>ϕ</em><sub><em>t</em></sub>) and tip taper length (<em>l</em><sub><em>t</em></sub>) of 100 designs. Elastoplastic analysis is conducted using the finite element method to determine the typical geometries of the polymer microneedles to avoid elastoplastic deformation accompanied by fatal fracture based on the mechanical properties of the polymer materials. The design principles of microneedle geometries based on polymer material properties are important guidelines for developing polymer microneedles, overcoming their mechanical weakness, and ensuring excellent functions.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106885"},"PeriodicalIF":3.3,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143018988","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 : 2025-01-02DOI: 10.1016/j.jmbbm.2024.106880
Youxin Li , Bingmei Shao , Zhan Liu
Objective
This study aims to investigate adhesive damage caused by the synergistic effects of polymerization shrinkage and occlusal forces via finite element analysis (FEA), based on damage mechanics with the cohesive zone model (CZM). The objective is to obtain the adhesive damage distribution and investigate how the material properties of resin composite impact adhesive damage.
Methods
A 3D reconstruction model of an mandibular first molar was constructed through CBCT imaging, and a Class V cavity was prepared using computer-aided engineering (CAE) software. Common clinical resin composite and an universal adhesive were selected for restorative filling. A 3D FEA was performed, incorporating the pre-stress induced by polymerization shrinkage of the resin composite, followed by occlusal forces. The cohesive zone model (CZM) was employed to represent the adhesive damage. To emphasize the impact of synergistic loading on adhesive damage, three types of loads were separately applied to the model: polymerization shrinkage, occlusal forces, and combined loading. Subsequently, three clinical resin composites with varying polymerization shrinkage and elastic modulus were used as restorative materials. Sensitivity analysis was conducted on dozens of hypothetical materials to provide definitive results.
Results
Polymerization shrinkage was undergone by the cured resin composite, resulting in extensive adhesive damage. Occlusal forces induced microdamage in regions already damaged by shrinkage stress, especially in the gingival wall. Predictably, the regions with severe adhesive damage were prone to marginal microleakage. The properties of the resin composite can affect adhesive damage. The adhesive damage with bulk-fill resin composite was milder than that with flowable and conventional resin composite. The extent of adhesive damage correlated markedly positively with the polymerization shrinkage of the resin composite and mildly positively with its elastic modulus.
Significance
Adhesive damage has been directly implicated in marginal microleakage. The cohesive zone model (CZM) can effectively elucidate the distribution of adhesive damage and provide a clear representation of the impact of varying material properties of resin composite on adhesive damage.
{"title":"Adhesive damage of class V restorations under shrinkage stress and occlusal forces using cohesive zone modeling","authors":"Youxin Li , Bingmei Shao , Zhan Liu","doi":"10.1016/j.jmbbm.2024.106880","DOIUrl":"10.1016/j.jmbbm.2024.106880","url":null,"abstract":"<div><h3>Objective</h3><div>This study aims to investigate adhesive damage caused by the synergistic effects of polymerization shrinkage and occlusal forces via finite element analysis (FEA), based on damage mechanics with the cohesive zone model (CZM). The objective is to obtain the adhesive damage distribution and investigate how the material properties of resin composite impact adhesive damage.</div></div><div><h3>Methods</h3><div>A 3D reconstruction model of an mandibular first molar was constructed through CBCT imaging, and a Class V cavity was prepared using computer-aided engineering (CAE) software. Common clinical resin composite and an universal adhesive were selected for restorative filling. A 3D FEA was performed, incorporating the pre-stress induced by polymerization shrinkage of the resin composite, followed by occlusal forces. The cohesive zone model (CZM) was employed to represent the adhesive damage. To emphasize the impact of synergistic loading on adhesive damage, three types of loads were separately applied to the model: polymerization shrinkage, occlusal forces, and combined loading. Subsequently, three clinical resin composites with varying polymerization shrinkage and elastic modulus were used as restorative materials. Sensitivity analysis was conducted on dozens of hypothetical materials to provide definitive results.</div></div><div><h3>Results</h3><div>Polymerization shrinkage was undergone by the cured resin composite, resulting in extensive adhesive damage. Occlusal forces induced microdamage in regions already damaged by shrinkage stress, especially in the gingival wall. Predictably, the regions with severe adhesive damage were prone to marginal microleakage. The properties of the resin composite can affect adhesive damage. The adhesive damage with bulk-fill resin composite was milder than that with flowable and conventional resin composite. The extent of adhesive damage correlated markedly positively with the polymerization shrinkage of the resin composite and mildly positively with its elastic modulus.</div></div><div><h3>Significance</h3><div>Adhesive damage has been directly implicated in marginal microleakage. The cohesive zone model (CZM) can effectively elucidate the distribution of adhesive damage and provide a clear representation of the impact of varying material properties of resin composite on adhesive damage.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106880"},"PeriodicalIF":3.3,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967371","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 : 2025-01-02DOI: 10.1016/j.jmbbm.2025.106886
Virginia Fregona , Giulia Luraghi , Behrooz Fereidoonnezhad , Frank J.H. Gijsen , Charles B.L.M. Majoie , Jose Felix Rodríguez Matas , Francesco Migliavacca
Endovascular thrombectomy (EVT) aims at restoring blood flow in case of acute ischemic stroke by removing the thrombus occluding a large cerebral artery. During the procedure with stent-retriever, the thrombus is captured within the device, which is then retrieved, subjecting the thrombus to several forces, potentially leading to its fragmentation. In silico studies, along with mechanical characterisation of thrombi, can enhance our understanding of the EVT, helping the development of new devices and interventional strategies. Our group previously validated a numerical approach to study EVT able to account for thrombus fragmentation. In this study, the same methodology was employed to explore the applicability of the chosen failure criterion to EVT simulations and the impact of thrombus composition on the outcome of the in silico procedure. For the first time, human clot analogues experimental data were applied to this methodology. Clot analogues of three different compositions were tested, and a material model incorporating failure was calibrated, followed by a verification analysis. Finally, the calibrated material model was used to perform EVT simulations, combining the three tested thrombus compositions with three different stent retriever models. The experimental tests confirmed a compression-tension asymmetry in the stress-strain curves, showing decreasing stiffness with increasing the red blood cell (RBC) content. Applying the resulting material models to EVT simulations demonstrated: (i) the dependency of the failure criterion on the thrombus mesh size, (ii) a greater tendency for RBC-rich thrombi to fragment, and (iii) increased difficulty in retrieving RBC-poor thrombi compared to RBC-rich thrombi.
{"title":"Impact of thrombus composition on virtual thrombectomy procedures using human clot analogues mechanical data","authors":"Virginia Fregona , Giulia Luraghi , Behrooz Fereidoonnezhad , Frank J.H. Gijsen , Charles B.L.M. Majoie , Jose Felix Rodríguez Matas , Francesco Migliavacca","doi":"10.1016/j.jmbbm.2025.106886","DOIUrl":"10.1016/j.jmbbm.2025.106886","url":null,"abstract":"<div><div>Endovascular thrombectomy (EVT) aims at restoring blood flow in case of acute ischemic stroke by removing the thrombus occluding a large cerebral artery. During the procedure with stent-retriever, the thrombus is captured within the device, which is then retrieved, subjecting the thrombus to several forces, potentially leading to its fragmentation. <em>In silico</em> studies, along with mechanical characterisation of thrombi, can enhance our understanding of the EVT, helping the development of new devices and interventional strategies. Our group previously validated a numerical approach to study EVT able to account for thrombus fragmentation. In this study, the same methodology was employed to explore the applicability of the chosen failure criterion to EVT simulations and the impact of thrombus composition on the outcome of the <em>in silico</em> procedure. For the first time, human clot analogues experimental data were applied to this methodology. Clot analogues of three different compositions were tested, and a material model incorporating failure was calibrated, followed by a verification analysis. Finally, the calibrated material model was used to perform EVT simulations, combining the three tested thrombus compositions with three different stent retriever models. The experimental tests confirmed a compression-tension asymmetry in the stress-strain curves, showing decreasing stiffness with increasing the red blood cell (RBC) content. Applying the resulting material models to EVT simulations demonstrated: (i) the dependency of the failure criterion on the thrombus mesh size, (ii) a greater tendency for RBC-rich thrombi to fragment, and (iii) increased difficulty in retrieving RBC-poor thrombi compared to RBC-rich thrombi.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106886"},"PeriodicalIF":3.3,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142928945","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 : 2025-01-01DOI: 10.1016/j.jmbbm.2024.106831
Richard Johannes Best , Andrei Sotnikov , Hagen Schmidt , Igor Zlotnikov
{"title":"Corrigendum to “Elastic constants of biogenic calcium carbonate” (155), 106570","authors":"Richard Johannes Best , Andrei Sotnikov , Hagen Schmidt , Igor Zlotnikov","doi":"10.1016/j.jmbbm.2024.106831","DOIUrl":"10.1016/j.jmbbm.2024.106831","url":null,"abstract":"","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"161 ","pages":"Article 106831"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696311","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 : 2024-12-31DOI: 10.1016/j.jmbbm.2024.106883
Ben M. Ferguson , Jonathan R. Clark , Qing Li
In a tissue-engineered bone scaffold implant, the process of neo-tissue ingrowth and remodelling into hard lamellar bone occurs slowly; it typically requires a period of several months to a year (or more) to complete. This research considers the design optimisation of a scaffold's unit cell geometry for the purpose of accelerating the rate at which neo-tissue forms in the porous network of the scaffold (ingrowth), and hence, reduce the length of time to complete the bone ingrowth process. In this study, the basic structure of the scaffold is the Schwarz Primitive (P) surface unit cell, selected for its compelling biomechanical and permeability characteristics. The geometry of the scaffold is varied using two parameters (namely iso-value, k, and spatial period, a) within the surface equation defining the Schwarz P-surface unit cell. In total, sixteen different unit cell geometries are considered here with the porosity ranging from 50% to 82%.
The design objectives for the scaffold are to (i) enhance mechanobiological stimulus conditions conducive to bone apposition and (ii) enhance permeability to improve the transport of nutrients/oxygen and metabolities to and from the sites of neo-tissue formation throughout the porous scaffold. The independent design variables ( and ) of the periodic unit cell geometry are optimised to best satisfy the design objectives of appositional mechanobiological stimulus and biotransporting permeability. First, a reconstructed sheep mandible computed tomographic (CT)-based finite element (FE) analysis model is used to relate the strain energy density and mechanobiological stimulus to the design variables. Next, a computational fluid dynamics (CFD) model of a 5 × 5 × 5 unit cell scaffold is developed to relate the distributions of pressure and fluid velocity to the design variables. Then, surrogate modelling is undertaken in which bivariate cubic polynomial response surfaces are fitted to the FE and CFD analysis output data to form mathematical functions of each objective with respect to the two design variables. Finally, a multiobjective optimisation algorithm is invoked to determine the best trade-off between the competing design objectives of mechanobiological stimulus and biofluidic permeability. The novel design of the scaffold structure is anticipated to provide a better biomechanical and biotransport environment for tissue regeneration.
{"title":"Scaffold geometries designed to promote bone ingrowth by enhancing mechanobiological stimulation and biotransportation - A multiobjective optimisation approach","authors":"Ben M. Ferguson , Jonathan R. Clark , Qing Li","doi":"10.1016/j.jmbbm.2024.106883","DOIUrl":"10.1016/j.jmbbm.2024.106883","url":null,"abstract":"<div><div>In a tissue-engineered bone scaffold implant, the process of neo-tissue ingrowth and remodelling into hard lamellar bone occurs slowly; it typically requires a period of several months to a year (or more) to complete. This research considers the design optimisation of a scaffold's unit cell geometry for the purpose of accelerating the rate at which neo-tissue forms in the porous network of the scaffold (ingrowth), and hence, reduce the length of time to complete the bone ingrowth process. In this study, the basic structure of the scaffold is the Schwarz Primitive (P) surface unit cell, selected for its compelling biomechanical and permeability characteristics. The geometry of the scaffold is varied using two parameters (namely iso-value, <em>k</em>, and spatial period, <em>a</em>) within the surface equation defining the Schwarz P-surface unit cell. In total, sixteen different unit cell geometries are considered here with the porosity ranging from 50% to 82%.</div><div>The design objectives for the scaffold are to (i) enhance mechanobiological stimulus conditions conducive to bone apposition and (ii) enhance permeability to improve the transport of nutrients/oxygen and metabolities to and from the sites of neo-tissue formation throughout the porous scaffold. The independent design variables (<span><math><mrow><mi>k</mi></mrow></math></span> and <span><math><mrow><mi>a</mi></mrow></math></span>) of the periodic unit cell geometry are optimised to best satisfy the design objectives of appositional mechanobiological stimulus and biotransporting permeability. First, a reconstructed sheep mandible computed tomographic (CT)-based finite element (FE) analysis model is used to relate the strain energy density and mechanobiological stimulus to the design variables. Next, a computational fluid dynamics (CFD) model of a 5 × 5 × 5 unit cell scaffold is developed to relate the distributions of pressure and fluid velocity to the design variables. Then, surrogate modelling is undertaken in which bivariate cubic polynomial response surfaces are fitted to the FE and CFD analysis output data to form mathematical functions of each objective with respect to the two design variables. Finally, a multiobjective optimisation algorithm is invoked to determine the best trade-off between the competing design objectives of mechanobiological stimulus and biofluidic permeability. The novel design of the scaffold structure is anticipated to provide a better biomechanical and biotransport environment for tissue regeneration.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106883"},"PeriodicalIF":3.3,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143328667","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 : 2024-12-28DOI: 10.1016/j.jmbbm.2024.106871
Jessica Faber , Jan Hinrichsen , Anahita Ahmadi Soufivand , Hsuan-Heng Lu , Tanja Rosenberger , Emine Karakaya , Rainer Detsch , Aldo R. Boccaccini , Silvia Budday
Extrusion-based 3D bioprinting is one of the most promising and widely used technologies in bioprinting. However, the development of bioprintable, biocompatible bioinks with tailored mechanical and biological properties remains a major challenge in this field. Alginate dialdehyde–gelatin (ADA–GEL) hydrogels face these difficulties and enable to tune the mechanical properties depending on the degree of oxidation ( DO) of ADA. Here, we present a holistic approach for characterizing the influence of the DO on the mechanical properties of ADA–GEL hydrogels under multiple loading modes, compression, tension, and torsional shear in the large-strain regime. We evaluate complex mechanical characteristics including nonlinearity, hysteresis, conditioning, and stress relaxation. We calibrate hyperelastic material models to determine the corresponding material parameters inversely. Our results confirm that decreasing the DO of ionically crosslinked ADA–GEL hydrogels leads to an increase in stiffness, more distinct nonlinearity, more pronounced hysteresis, and minor preconditioning effects, while the relaxation behavior is slightly affected. The fabrication technique – molding or printing – does only slightly affect the complex mechanical properties and stress relaxation behavior. Ionically and enzymatically dual-crosslinked ADA–GEL hydrogels showed higher stresses during cyclic loading and less viscous effects during stress relaxation in all three loading modes. We conclude that the DO and the crosslinking procedure are crucial parameters to tune the mechanical behavior of ADA–GEL hydrogels. Careful choice of these parameters might facilitate the fabrication of biomaterials that closely mimic the properties of native tissues for advanced tissue engineering applications.
{"title":"Tuning the mechanical properties of alginate dialdehyde–gelatin (ADA–GEL) bioinks for bioprinting approaches by varying the degree of oxidation","authors":"Jessica Faber , Jan Hinrichsen , Anahita Ahmadi Soufivand , Hsuan-Heng Lu , Tanja Rosenberger , Emine Karakaya , Rainer Detsch , Aldo R. Boccaccini , Silvia Budday","doi":"10.1016/j.jmbbm.2024.106871","DOIUrl":"10.1016/j.jmbbm.2024.106871","url":null,"abstract":"<div><div>Extrusion-based 3D bioprinting is one of the most promising and widely used technologies in bioprinting. However, the development of bioprintable, biocompatible bioinks with tailored mechanical and biological properties remains a major challenge in this field. Alginate dialdehyde–gelatin (ADA–GEL) hydrogels face these difficulties and enable to tune the mechanical properties depending on the degree of oxidation (<span><math><mtext>%</mtext></math></span> DO) of ADA. Here, we present a holistic approach for characterizing the influence of the <span><math><mtext>%</mtext></math></span> DO on the mechanical properties of ADA–GEL hydrogels under multiple loading modes, compression, tension, and torsional shear in the large-strain regime. We evaluate complex mechanical characteristics including nonlinearity, hysteresis, conditioning, and stress relaxation. We calibrate hyperelastic material models to determine the corresponding material parameters inversely. Our results confirm that decreasing the <span><math><mtext>%</mtext></math></span> DO of ionically crosslinked ADA–GEL hydrogels leads to an increase in stiffness, more distinct nonlinearity, more pronounced hysteresis, and minor preconditioning effects, while the relaxation behavior is slightly affected. The fabrication technique – molding or printing – does only slightly affect the complex mechanical properties and stress relaxation behavior. Ionically and enzymatically dual-crosslinked ADA–GEL hydrogels showed higher stresses during cyclic loading and less viscous effects during stress relaxation in all three loading modes. We conclude that the <span><math><mtext>%</mtext></math></span> DO and the crosslinking procedure are crucial parameters to tune the mechanical behavior of ADA–GEL hydrogels. Careful choice of these parameters might facilitate the fabrication of biomaterials that closely mimic the properties of native tissues for advanced tissue engineering applications.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106871"},"PeriodicalIF":3.3,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143177251","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 : 2024-12-27DOI: 10.1016/j.jmbbm.2024.106881
Celia Hughes , Alix Whelan , David O'Reilly , Evelyn M. Campbell , Caitríona Lally
Aortic stenosis is a prevalent disease that is treated with either mechanical or bioprosthetic valve replacement devices. However, these implants can experience problems with either functionality in the case of mechanical valves or long-term durability in the case of bioprosthetic valves. To enhance next generation prosthetic valves, such as biomimetic polymeric valves, an improved understanding of the native aortic valve leaflet structure and mechanical response is required to provide much needed benchmarks for future device development. This study aims to provide such information through imaging and mechanical testing of porcine aortic valve leaflet tissue. Using second harmonic generation imaging on cleared tissue it is shown that the fibre orientations are dependent on the leaflet type (left coronary, right coronary, non-coronary), while fibre crimp is not solely dependent on either of these factors. Uniaxial tensile testing of the leaflets and their layers showed that the ventricularis layer is stiffer than the fibrosa but the fibrosa dominates the mechanical response of the whole leaflet due to its higher thickness. Overall, this work provides a detailed assessment of the native porcine aortic valve leaflets’ microstructure and mechanical response, delivering key information to aid the design and manufacture of future bioinspired valve implant devices.
{"title":"Aortic valve leaflet assessment to inform novel bioinspired materials: Understanding the impact of collagen fibres on the tissue's mechanical behaviour","authors":"Celia Hughes , Alix Whelan , David O'Reilly , Evelyn M. Campbell , Caitríona Lally","doi":"10.1016/j.jmbbm.2024.106881","DOIUrl":"10.1016/j.jmbbm.2024.106881","url":null,"abstract":"<div><div>Aortic stenosis is a prevalent disease that is treated with either mechanical or bioprosthetic valve replacement devices. However, these implants can experience problems with either functionality in the case of mechanical valves or long-term durability in the case of bioprosthetic valves. To enhance next generation prosthetic valves, such as biomimetic polymeric valves, an improved understanding of the native aortic valve leaflet structure and mechanical response is required to provide much needed benchmarks for future device development. This study aims to provide such information through imaging and mechanical testing of porcine aortic valve leaflet tissue. Using second harmonic generation imaging on cleared tissue it is shown that the fibre orientations are dependent on the leaflet type (left coronary, right coronary, non-coronary), while fibre crimp is not solely dependent on either of these factors. Uniaxial tensile testing of the leaflets and their layers showed that the ventricularis layer is stiffer than the fibrosa but the fibrosa dominates the mechanical response of the whole leaflet due to its higher thickness. Overall, this work provides a detailed assessment of the native porcine aortic valve leaflets’ microstructure and mechanical response, delivering key information to aid the design and manufacture of future bioinspired valve implant devices.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"163 ","pages":"Article 106881"},"PeriodicalIF":3.3,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142974141","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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