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Sacks MS. A Mathematical Model for Postimplant Collagen Remodeling in an Autologous Engineered Pulmonary Arterial Conduit. J Biomech Eng 2024; 146:111006. [PMID: 38980683 PMCID: PMC11369691 DOI: 10.1115/1.4065903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 07/10/2024]
Abstract
This study was undertaken to develop a mathematical model of the long-term in vivo remodeling processes in postimplanted pulmonary artery (PA) conduits. Experimental results from two extant ovine in vivo studies, wherein polyglycolic-acid (PGA)/poly-L-lactic acid tubular conduits were constructed, cell seeded, incubated for 4 weeks, and then implanted in mature sheep to obtain the remodeling data for up to two years. Explanted conduit analysis included detailed novel structural and mechanical studies. Results in both studies indicated that the in vivo conduits remained dimensionally stable up to 80 weeks, so that the conduits maintained a constant in vivo stress and deformation state. In contrast, continued remodeling of the constituent collagen fiber network as evidenced by an increase in effective tissue uniaxial tangent modulus, which then stabilized by one year postimplant. A mesostructural constitute model was then applied to extant planar biaxial mechanical data and revealed several interesting features, including an initial pronounced increase in effective collagen fiber modulus, paralleled by a simultaneous shift toward longer, more uniformly length-distributed collagen fibers. Thus, while the conduit remained dimensionally stable, its internal collagen fibrous structure and resultant mechanical behaviors underwent continued remodeling that stabilized by one year. A time-evolving structural mixture-based mathematical model specialized for this unique form of tissue remodeling was developed, with a focus on time-evolving collagen fiber stiffness as the driver for tissue-level remodeling. The remodeling model was able to fully reproduce (1) the observed tissue-level increases in stiffness by time-evolving simultaneous increases in collagen fiber modulus and lengths, (2) maintenance of the constant collagen fiber angular dispersion, and (3) stabilization of the remodeling processes at one year. Collagen fiber remodeling geometry was directly verified experimentally by histological analysis of the time-evolving collagen fiber crimp, which matches model predictions very closely. Interestingly, the remodeling model indicated that the basis for tissue homeostasis was maintenance of the collagen fiber ensemble stress for all orientations, and not individual collagen fiber stresses. Unlike other growth and remodeling models that traditionally treat changes in the external boundary conditions (e.g., changes in blood pressure) as the primary input stimuli, the driver herein is changes to the internal constituent collagen fiber themselves due to cellular mediated cross-linking.
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Affiliation(s)
- Michael S Sacks
- James T. Willerson Center for Cardiovascular Modeling and Simulation, The Oden Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
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Mushtruk M, Gudzenko M, Palamarchuk I, Vasyliv V, Slobodyanyuk N, Kuts A, Nychyk O, Salavor O, Bober A. Mathematical modeling of the oil extrusion process with pre-grinding of raw materials in a twin-screw extruder. POTRAVINARSTVO 2020. [DOI: 10.5219/1436] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The extrusion process of oil-containing raw materials using a twin-screw extruder is becoming increasingly common in food technology. The problem of high energy costs for the implementation of this process is solved by reducing the resistance of the process mass due to the preliminary grinding of raw materials. The classical theory of extrusion is based mainly on the use of theoretical solutions of mathematical models of processes, which are simplified and allow determining integral parameters using coefficients, the preparation of which for the calculation of the corresponding processes and equipment is a rather complicated and approximate procedure. Mathematical modelling of the movement of the technological medium at the individual stages of the processing of raw materials allows us to determine the analytical dependences for the power and energy parameters of the system and to carry out their effective technical and economic evaluation. Using the methods of mathematical analysis and data processing in the MathCAD software environment, graphical dependences of the power and energy parameters of the research technical system were obtained. By increasing the density of the oil-containing raw materials, which is extruded in the research extruder by 40.5% the pressure force increases by 41%, that is, there is an almost proportional relationship between the pressure force and the density of the processed raw material. With an increase in the angular velocity of the drive shaft ω more than 8 rad.s-1, the pressure force in the research process increases sharply. With an increase in the density of raw materials, it is grinded before extrusion by 40%, the power consumption for the grinding process increases by 2.8 times for the recommended operating mode. Energy losses for pressing completely grinded raw materials are reduced by 2.52 times.
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Rawal A, Sharma S, Singh D, Jangir NK, Saraswat H, Sebők D, Kukovecz A, Hietel D, Dauner M, Onal L. Out-of-plane auxetic nonwoven as a designer meta-biomaterial. J Mech Behav Biomed Mater 2020; 112:104069. [PMID: 32957055 DOI: 10.1016/j.jmbbm.2020.104069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 08/17/2020] [Accepted: 08/25/2020] [Indexed: 11/17/2022]
Abstract
Biomaterials are porous and three-dimensional (3D) templates, which are used as biological substitutes in tissue engineering. Targeting the optimal design of biomaterials requires a synergy between mechanical, porous, mass transport, and biological properties. To address this challenge, we propose a non-periodic meta-biomaterial in the form of an out-of-plane auxetic nonwoven scaffold that possesses a 3D interconnected highly porous structure with remarkable mechanical properties corresponding to conventional nonwoven material. A design strategy of utilizing larger fiber diameters to enhance the porosity and permeability characteristics successfully devised the nonwoven scaffold with an extraordinary out-of-plane auxetic effect. In situ tensile-X-ray microcomputed tomography (microCT) analysis has been carried out to monitor the variation in the morphological characteristics.
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Affiliation(s)
- Amit Rawal
- Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, New Delhi, India.
| | - Sumit Sharma
- Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Danvendra Singh
- Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | | | | | - Dániel Sebők
- University of Szeged, Interdisciplinary Excellence Center, Department of Applied and Environmental Chemistry, Szeged, Hungary
| | - Akos Kukovecz
- University of Szeged, Interdisciplinary Excellence Center, Department of Applied and Environmental Chemistry, Szeged, Hungary
| | - Dietmar Hietel
- Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautern, Germany
| | - Martin Dauner
- Deutsche Institute für Textil- und Faserforschung (DITF), Denkendorf, Germany
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Loerakker S, Ristori T. Computational modeling for cardiovascular tissue engineering: the importance of including cell behavior in growth and remodeling algorithms. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2020; 15:1-9. [PMID: 33997580 PMCID: PMC8105589 DOI: 10.1016/j.cobme.2019.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Understanding cardiovascular growth and remodeling (G&R) is fundamental for designing robust cardiovascular tissue engineering strategies, which enable synthetic or biological scaffolds to transform into healthy living tissues after implantation. Computational modeling, particularly when integrated with experimental research, is key for advancing our understanding, predicting the in vivo evolution of engineered tissues, and efficiently optimizing scaffold designs. As cells are ultimately the drivers of G&R and known to change their behavior in response to mechanical cues, increasing efforts are currently undertaken to capture (mechano-mediated) cell behavior in computational models. In this selective review, we highlight some recent examples that are relevant in the context of cardiovascular tissue engineering and discuss the current and future biological and computational challenges for modeling cell-mediated G&R.
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Affiliation(s)
- Sandra Loerakker
- Department of Biomedical Engineering, Eindhoven University of Technology, Groene Loper Building 15, 5612 AP, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper Building 7, 5612 AJ, Eindhoven, the Netherlands
| | - Tommaso Ristori
- Department of Biomedical Engineering, Eindhoven University of Technology, Groene Loper Building 15, 5612 AP, Eindhoven, the Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Groene Loper Building 7, 5612 AJ, Eindhoven, the Netherlands
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On the homogeneity and isotropy of planar long fibre network computational models. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-2524-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Domaschke S, Morel A, Fortunato G, Ehret AE. Random auxetics from buckling fibre networks. Nat Commun 2019; 10:4863. [PMID: 31653833 PMCID: PMC6961253 DOI: 10.1038/s41467-019-12757-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 09/24/2019] [Indexed: 11/21/2022] Open
Abstract
Auxetic materials have gained increasing interest in the last decades, fostered by auspicious applications in various fields. While the design of new auxetics has largely focused on meta-materials with deterministic, periodically arranged structures, we show here by theoretical and numerical analysis that pronounced auxetic behaviour with negative Poisson's ratios of very large magnitude can occur in random fibre networks with slender, reasonably straight fibre segments that buckle and deflect. We further demonstrate in experiments that such auxetic fibre networks, which increase their thickness by an order of magnitude and more than quintuple their volume when moderately extended, can be produced by electrospinning. Our results thus augment the class of auxetics by a large group of straightforwardly fabricable meta-materials with stochastic microstructure.
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Affiliation(s)
- S Domaschke
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Experimental Continuum Mechanics, 8600, Dübendorf, Switzerland
- ETH Zurich, Institute for Mechanical Systems, 8092, Zürich, Switzerland
| | - A Morel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, 9014, St. Gallen, Switzerland
| | - G Fortunato
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, 9014, St. Gallen, Switzerland
| | - A E Ehret
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Experimental Continuum Mechanics, 8600, Dübendorf, Switzerland.
- ETH Zurich, Institute for Mechanical Systems, 8092, Zürich, Switzerland.
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Salamone S, Schulmann N, Benzerara O, Meyer H, Charitat T, Marques CM. The role of shape disorder in the collective behaviour of aligned fibrous matter. SOFT MATTER 2019; 15:2657-2665. [PMID: 30839978 DOI: 10.1039/c8sm01896k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We study the compression of bundles of aligned macroscopic fibers with intrinsic shape disorder, as found in human hair and in many other natural and man-made systems. We show by a combination of experiments, numerical simulations and theory how the statistical properties of the shapes of the fibers control the collective mechanical behaviour of the bundles. This work paves the way for designing aligned fibrous matter with purposed-designed properties from large numbers of individual strands of selected geometry and rigidity.
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Affiliation(s)
- Salvatore Salamone
- Institut Charles Sadron, Université de Strasbourg, CNRS, 23 rue du Loess, BP 84047 67034 Strasbourg Cedex 2, France.
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A material modeling approach for the effective response of planar soft tissues for efficient computational simulations. J Mech Behav Biomed Mater 2019; 89:168-198. [DOI: 10.1016/j.jmbbm.2018.09.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/22/2018] [Accepted: 09/14/2018] [Indexed: 11/23/2022]
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McEvoy E, Holzapfel GA, McGarry P. Compressibility and Anisotropy of the Ventricular Myocardium: Experimental Analysis and Microstructural Modeling. J Biomech Eng 2018; 140:2678939. [DOI: 10.1115/1.4039947] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Indexed: 11/08/2022]
Abstract
While the anisotropic behavior of the complex composite myocardial tissue has been well characterized in recent years, the compressibility of the tissue has not been rigorously investigated to date. In the first part of this study, we present experimental evidence that passive-excised porcine myocardium exhibits volume change. Under tensile loading of a cylindrical specimen, a volume change of 4.1±1.95% is observed at a peak stretch of 1.3. Confined compression experiments also demonstrate significant volume change in the tissue (loading applied up to a volumetric strain of 10%). In order to simulate the multiaxial passive behavior of the myocardium, a nonlinear volumetric hyperelastic component is combined with the well-established Holzapfel–Ogden anisotropic hyperelastic component for myocardium fibers. This framework is shown to describe the experimentally observed behavior of porcine and human tissues under shear and biaxial loading conditions. In the second part of the study, a representative volumetric element (RVE) of myocardium tissue is constructed to parse the contribution of the tissue vasculature to observed volume change under confined compression loading. Simulations of the myocardium microstructure suggest that the vasculature cannot fully account for the experimentally measured volume change. Additionally, the RVE is subjected to six modes of shear loading to investigate the influence of microscale fiber alignment and dispersion on tissue-scale mechanical behavior.
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Affiliation(s)
- Eoin McEvoy
- Department of Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland e-mail:
| | - Gerhard A. Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz 8010, Austria
- Faculty of Engineering Science and Technology, Norwegian University of Science and Technology (NTNU), Trondheim 7491, Norway e-mail:
| | - Patrick McGarry
- Department of Biomedical Engineering, National University of Ireland Galway, Galway H91 TK33, Ireland e-mail:
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Broders-Bondon F, Nguyen Ho-Bouldoires TH, Fernandez-Sanchez ME, Farge E. Mechanotransduction in tumor progression: The dark side of the force. J Cell Biol 2018; 217:1571-1587. [PMID: 29467174 PMCID: PMC5940296 DOI: 10.1083/jcb.201701039] [Citation(s) in RCA: 184] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 01/19/2018] [Accepted: 02/01/2018] [Indexed: 12/11/2022] Open
Abstract
Broders-Bondon et al. review the pathological mechanical properties of tumor tissues and how abnormal mechanical signals result in oncogenic biochemical signals during tumor progression. Cancer has been characterized as a genetic disease, associated with mutations that cause pathological alterations of the cell cycle, adhesion, or invasive motility. Recently, the importance of the anomalous mechanical properties of tumor tissues, which activate tumorigenic biochemical pathways, has become apparent. This mechanical induction in tumors appears to consist of the destabilization of adult tissue homeostasis as a result of the reactivation of embryonic developmental mechanosensitive pathways in response to pathological mechanical strains. These strains occur in many forms, for example, hypervascularization in late tumors leads to high static hydrodynamic pressure that can promote malignant progression through hypoxia or anomalous interstitial liquid and blood flow. The high stiffness of tumors directly induces the mechanical activation of biochemical pathways enhancing the cell cycle, epithelial–mesenchymal transition, and cell motility. Furthermore, increases in solid-stress pressure associated with cell hyperproliferation activate tumorigenic pathways in the healthy epithelial cells compressed by the neighboring tumor. The underlying molecular mechanisms of the translation of a mechanical signal into a tumor inducing biochemical signal are based on mechanically induced protein conformational changes that activate classical tumorigenic signaling pathways. Understanding these mechanisms will be important for the development of innovative treatments to target such mechanical anomalies in cancer.
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Affiliation(s)
- Florence Broders-Bondon
- Mechanics and Genetics of Embryonic and Tumor Development Group, Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, UMR168, Inserm, Sorbonne Universities, Paris, France
| | - Thanh Huong Nguyen Ho-Bouldoires
- Mechanics and Genetics of Embryonic and Tumor Development Group, Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, UMR168, Inserm, Sorbonne Universities, Paris, France
| | - Maria-Elena Fernandez-Sanchez
- Mechanics and Genetics of Embryonic and Tumor Development Group, Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, UMR168, Inserm, Sorbonne Universities, Paris, France
| | - Emmanuel Farge
- Mechanics and Genetics of Embryonic and Tumor Development Group, Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, UMR168, Inserm, Sorbonne Universities, Paris, France
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Carleton JB, Rodin GJ, Sacks MS. Layered Elastomeric Fibrous Scaffolds: An In-Silico Study of the Achievable Range of Mechanical Behaviors. ACS Biomater Sci Eng 2017; 3:2907-2921. [DOI: 10.1021/acsbiomaterials.7b00308] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- James B. Carleton
- Center
for Cardiovascular Simulation, Institute for Computational Engineering
and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Austin, Texas 78712, United States
| | - Gregory J. Rodin
- Center
for Cardiovascular Simulation, Institute for Computational Engineering
and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Austin, Texas 78712, United States
- Department
of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, 210 East 24th Street, Austin, Texas 78712, United States
| | - Michael S. Sacks
- Center
for Cardiovascular Simulation, Institute for Computational Engineering
and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, Austin, Texas 78712, United States
- Department
of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, 210 East 24th Street, Austin, Texas 78712, United States
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