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Mechanical, compositional and morphological characterisation of the human male urethra for the development of a biomimetic tissue engineered urethral scaffold. Biomaterials 2021; 269:120651. [PMID: 33476892 DOI: 10.1016/j.biomaterials.2021.120651] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/31/2020] [Accepted: 12/31/2020] [Indexed: 12/11/2022]
Abstract
This study addresses a crucial gap in the literature by characterising the relationship between urethral tissue mechanics, composition and gross structure. We then utilise these data to develop a biomimetic urethral scaffold with physical properties that more accurately mimic the native tissue than existing gold standard scaffolds; small intestinal submucosa (SIS) and urinary bladder matrix (UBM). Nine human urethra samples were mechanically characterised using pressure-diameter and uniaxial extension testing. The composition and gross structure of the tissue was determined using immunohistological staining. A pressure stiffening response is observed during the application of intraluminal pressure. The elastic and viscous tissue responses to extension are free of regional or directional variance. The elastin and collagen content of the tissue correlates significantly with tissue mechanics. Building on these data, a biomimetic urethral scaffold was fabricated from collagen and elastin in a ratio that mimics the composition of the native tissue. The resultant scaffold is comprised of a dense inner layer and a porous outer layer that structurally mimic the submucosa and corpus spongiosum layers of the native tissue, respectively. The porous outer layer facilitated more uniform cell infiltration relative to SIS and UBM when implanted subcutaneously (p < 0.05). The mechanical properties of the biomimetic scaffold better mimic the native tissue compared to SIS and UBM. The tissue characterisation data presented herein paves the way for the development of biomimetic urethral grafts, and the novel scaffold we develop demonstrates positive findings that warrant further in vivo evaluation.
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Vélez-Rendón D, Pursell ER, Shieh J, Valdez-Jasso D. Relative Contributions of Matrix and Myocytes to Biaxial Mechanics of the Right Ventricle in Pulmonary Arterial Hypertension. J Biomech Eng 2019; 141:091011. [PMID: 31299076 DOI: 10.1115/1.4044225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Indexed: 01/15/2023]
Abstract
Pulmonary arterial hypertension (PAH) commonly leads to right ventricular (RV) hypertrophy and fibrosis that affect the mechanical properties of the RV myocardium (MYO). To investigate the effects of PAH on the mechanics of the RV MYO and extracellular matrix (ECM), we compared RV wall samples, isolated from rats in which PAH was induced using the SuHx protocol, with samples from control animals before and after the tissues were decellularized. Planar biaxial mechanical testing, a technique first adapted to living soft biological tissues by Fung, was performed on intact and decellularized samples. Fung's anisotropic exponential strain energy function fitted the full range of biaxial test results with high fidelity in control and PAH samples both before and after they were decellularized. Mean RV myocardial apex-to-outflow tract and circumferential stresses during equibiaxial strain were significantly greater in PAH than control samples. Mean RV ECM circumferential but not apex-to-outflow tract stresses during equibiaxial strain were significantly greater in the PAH than control group. The ratio of ECM to myocardial stresses at matched strains did not change significantly between groups. Circumferential stresses were significantly higher than apex-to-outflow tract stresses for all groups. These findings confirm the predictions of a mathematical model based on changes in RV hemodynamics and morphology in rat PAH, and may provide a foundation for a new constitutive analysis of the contributions of ECM remodeling to changes in RV filling properties during PAH.
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Affiliation(s)
- Daniela Vélez-Rendón
- Department of Bioengineering,University of Illinois at Chicago,Chicago, IL 60607
| | - Erica R Pursell
- Bioengineering Department,University of California San Diego,La Jolla, CA 92122
| | - Justin Shieh
- Bioengineering Department,University of California San Diego,La Jolla, CA 92122
| | - Daniela Valdez-Jasso
- Bioengineering Department,University of California, San Diego,La Jolla, CA 92122e-mail:
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3
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Wahlsten A, Pensalfini M, Stracuzzi A, Restivo G, Hopf R, Mazza E. On the compressibility and poroelasticity of human and murine skin. Biomech Model Mechanobiol 2019; 18:1079-1093. [PMID: 30806838 DOI: 10.1007/s10237-019-01129-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/09/2019] [Indexed: 01/09/2023]
Abstract
A total of 37 human and 33 murine skin samples were subjected to uniaxial monotonic, cyclic, and relaxation experiments. Detailed analysis of the three-dimensional kinematic response showed that skin volume is significantly reduced as a consequence of a tensile elongation. This behavior is most pronounced in monotonic but persists in cyclic tests. The dehydration associated with volume loss depends on the osmolarity of the environment, so that tension relaxation changes as a consequence of modifying the ionic strength of the environmental bath. Similar to ex vivo observations, complementary in vivo stretching experiments on human volar forearms showed strong in-plane lateral contraction. A biphasic homogenized model is proposed which allows representing all relevant features of the observed mechanical response.
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Affiliation(s)
- Adam Wahlsten
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland.
| | - Marco Pensalfini
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland
| | - Alberto Stracuzzi
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland
| | - Gaetana Restivo
- Department of Dermatology, University Hospital Zurich, 8091, Zurich, Switzerland
| | - Raoul Hopf
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland.,Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, Institute for Mechanical Systems, ETH Zurich, 8092, Zurich, Switzerland. .,Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland.
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White EJ, Cunnane EM, McMahon M, Walsh MT, Coffey JC, O'Sullivan L. Mechanical characterisation of porcine non-intestinal colorectal tissues for innovation in surgical instrument design. Proc Inst Mech Eng H 2018; 232:796-806. [PMID: 30035663 DOI: 10.1177/0954411918788595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
This article presents an investigation into the mechanical properties of porcine mesocolon, small intestinal mesentery, fascia, and peritoneum tissues to generate a preliminary database of the mechanical characteristics of these tissues as surrogates for human tissue. No study has mechanically characterised porcine tissue correlates of the mesentery and associated structures. The samples were tested to determine the strength, stretch at failure, and stiffness of each tissue. The results indicated that porcine mesenteric and associated tissues visually resembled corresponding human tissues and had similar tactile characteristics, according to an expert colorectal surgeon. Stiffness values ranged from 0.088 MPa to 6.858 MPa across all tissues, with fascia being the weakest, and mesentery and peritoneum being the strongest. Failure stress values ranged from 0.336 MPa to 6.517 MPa, and failure stretch values ranged from 1.766 to 3.176, across all tissues. These mechanical data can serve as reference baseline data upon which future work can expand.
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Affiliation(s)
- Eoin J White
- 1 School of Design, University of Limerick, Limerick, Ireland
| | - Eoghan M Cunnane
- 2 School of Engineering, University of Limerick, Limerick, Ireland
| | - Muireann McMahon
- 1 School of Design, University of Limerick, Limerick, Ireland.,3 Health Research Institute, University of Limerick, Limerick, Ireland
| | - Michael T Walsh
- 2 School of Engineering, University of Limerick, Limerick, Ireland.,3 Health Research Institute, University of Limerick, Limerick, Ireland.,4 Bernal Institute, University of Limerick, Limerick, Ireland
| | - J Calvin Coffey
- 3 Health Research Institute, University of Limerick, Limerick, Ireland.,5 Graduate Entry Medical School, University of Limerick, Limerick, Ireland.,6 Department of Colorectal Surgery, University Hospitals Limerick, Limerick, Ireland
| | - Leonard O'Sullivan
- 1 School of Design, University of Limerick, Limerick, Ireland.,3 Health Research Institute, University of Limerick, Limerick, Ireland
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Davis NF, Mulvihill JJE, Mulay S, Cunnane EM, Bolton DM, Walsh MT. Urinary Bladder vs Gastrointestinal Tissue: A Comparative Study of Their Biomechanical Properties for Urinary Tract Reconstruction. Urology 2017; 113:235-240. [PMID: 29197522 DOI: 10.1016/j.urology.2017.11.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 10/14/2017] [Accepted: 11/18/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To evaluate the mechanical properties of gastrointestinal (GI) tissue segments and to compare them with the urinary bladder for urinary tract reconstruction. METHODS Urinary bladders and GI tissue segments were sourced from porcine models (n = 6, 7 months old [5 male; 1 female]). Uniaxial planar tension tests were performed on bladder tissue, and Cauchy stress-stretch ratio responses were compared with stomach, jejunum, ileum, and colonic GI tissue. RESULTS The biomechanical properties of the bladder differed significantly from jejunum, ileum, and colonic GI tissue. Young modulus (kPa-measure of stiffness) of the GI tissue segments was on average 3.07-fold (±0.21 standard error) higher than bladder tissue (P < .01), and the strain at Cauchy stress of 50 kPa for bladder tissues was on average 2.27-fold (±0.20) higher than GI tissues. There were no significant differences between the averaged stretch ratio and Young modulus of the horizontal and vertical directions of bladder tissue (315.05 ± 49.64 kPa and 283.62 ± 57.04, respectively, P = .42). However, stomach tissues were 1.09- (±0.17) and 0.85- (±0.03) fold greater than bladder tissues for Young modulus and strain at 50 kPa, respectively. CONCLUSION An ideal urinary bladder replacement biomaterial should demonstrate mechanical equivalence to native tissue. Our findings demonstrate that GI tissue does not meet these mechanical requirements. Knowledge on the biomechanical properties of bladder and GI tissue may improve development opportunities for more suitable urologic reconstructive biomaterials.
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Affiliation(s)
- N F Davis
- Department of Urology, The Austin Hospital, Melbourne, Victoria, Australia.
| | - J J E Mulvihill
- School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Limerick, Ireland
| | - S Mulay
- School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Limerick, Ireland
| | - E M Cunnane
- School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Limerick, Ireland
| | - D M Bolton
- Department of Urology, The Austin Hospital, Melbourne, Victoria, Australia
| | - M T Walsh
- School of Engineering, Bernal Institute and the Health Research Institute, University of Limerick, Limerick, Ireland
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Cunnane EM, Mulvihill JJE, Barrett HE, Hennessy MM, Kavanagh EG, Walsh MT. Mechanical properties and composition of carotid and femoral atherosclerotic plaques: A comparative study. J Biomech 2016; 49:3697-3704. [PMID: 27776741 DOI: 10.1016/j.jbiomech.2016.09.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/27/2016] [Accepted: 09/30/2016] [Indexed: 01/25/2023]
Abstract
This study compares the mechanical properties of excised carotid and femoral human plaques and also develops a predictor of these properties based on plaque composition. Circumferential planar tension tests were performed on 24 carotid and 16 femoral plaque samples. Composition was characterised using Fourier Transform Infrared spectroscopy. Stretch at failure, strength, and stiffness are significantly higher in the carotid group (P=.012, P<.001 and P=.002, respectively). The ratio of calcified to lipid plaque content demonstrates the strongest correlation with the stretch at failure and strength (R2=.285, P<.001 and R2=.347, P<.001). No composition based parameter correlates significantly with stiffness. The significantly different mechanical properties of the two groups aids in explaining the varying endovascular treatment outcomes clinically observed in these vessels. Furthermore, determining the ratio of calcified to lipid plaque content may be useful in predicting individual plaque mechanical response to endovascular treatment.
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Affiliation(s)
- Eoghan M Cunnane
- School of Engineering, Bernal Institute, and the Health Research Institute, University of Limerick, Ireland
| | - John J E Mulvihill
- School of Engineering, Bernal Institute, and the Health Research Institute, University of Limerick, Ireland
| | - Hilary E Barrett
- School of Engineering, Bernal Institute, and the Health Research Institute, University of Limerick, Ireland
| | - Mairead M Hennessy
- Department of Vascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Eamon G Kavanagh
- Department of Vascular Surgery, University Hospital Limerick, Limerick, Ireland
| | - Michael T Walsh
- School of Engineering, Bernal Institute, and the Health Research Institute, University of Limerick, Ireland.
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Hopf R, Bernardi L, Menze J, Zündel M, Mazza E, Ehret A. Experimental and theoretical analyses of the age-dependent large-strain behavior of Sylgard 184 (10:1) silicone elastomer. J Mech Behav Biomed Mater 2016; 60:425-437. [DOI: 10.1016/j.jmbbm.2016.02.022] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/11/2016] [Accepted: 02/13/2016] [Indexed: 12/24/2022]
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Maurer MM, Röhrnbauer B, Feola A, Deprest J, Mazza E. Prosthetic Meshes for Repair of Hernia and Pelvic Organ Prolapse: Comparison of Biomechanical Properties. MATERIALS 2015. [PMCID: PMC5455575 DOI: 10.3390/ma8052794] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study aims to compare the mechanical behavior of synthetic meshes used for pelvic organ prolapse (POP) and hernia repair. The analysis is based on a comprehensive experimental protocol, which included uniaxial and biaxial tension, cyclic loading and testing of meshes in dry conditions and embedded into an elastomer matrix. Implants are grouped as POP or hernia meshes, as indicated by the manufacturer, and their stiffness in different loading configurations, area density and porosity are compared. Hernia meshes might be expected to be stiffer, since they are implanted into a stiffer tissue (abdominal wall) than POP meshes (vaginal wall). Contrary to this, hernia meshes have a generally lower secant stiffness than POP meshes. For example, DynaMesh PRS, a POP mesh, is up to two orders of magnitude stiffer in all tested configurations than DynaMesh ENDOLAP, a hernia mesh. Additionally, lighter, large pore implants might be expected to be more compliant, which was shown to be generally not true. In particular, Restorelle, the lightest mesh with the largest pores, is less compliant in the tested configurations than Surgipro, the heaviest, small-pore implant. Our study raises the question of defining a meaningful design target for meshes in terms of mechanical biocompatibility.
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Affiliation(s)
- Manfred M. Maurer
- Institute of Mechanical Systems, ETH Zurich, Leonhardstrasse 21, Zurich 8092, Switzerland; E-Mails: (B.R.); (E.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +41-44-6339228; Fax: +41-44-6321145
| | - Barbara Röhrnbauer
- Institute of Mechanical Systems, ETH Zurich, Leonhardstrasse 21, Zurich 8092, Switzerland; E-Mails: (B.R.); (E.M.)
| | - Andrew Feola
- Center for Surgical Technologies, Faculty of Medicine, Universitair Ziekenhuis “Gasthuisberg” Leuven, Katholieke Universiteit Leuven, Leuven 3000, Belgium; E-Mails: (A.F.); (J.D.)
| | - Jan Deprest
- Center for Surgical Technologies, Faculty of Medicine, Universitair Ziekenhuis “Gasthuisberg” Leuven, Katholieke Universiteit Leuven, Leuven 3000, Belgium; E-Mails: (A.F.); (J.D.)
| | - Edoardo Mazza
- Institute of Mechanical Systems, ETH Zurich, Leonhardstrasse 21, Zurich 8092, Switzerland; E-Mails: (B.R.); (E.M.)
- Empa—Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf 8600, Switzerland
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Perrini M, Mauri A, Ehret AE, Ochsenbein-Kölble N, Zimmermann R, Ehrbar M, Mazza E. Mechanical and microstructural investigation of the cyclic behavior of human amnion. J Biomech Eng 2015; 137:061010. [PMID: 25780908 DOI: 10.1115/1.4030054] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Indexed: 11/08/2022]
Abstract
The structural and mechanical integrity of amnion is essential to prevent preterm premature rupture (PPROM) of the fetal membrane. In this study, the mechanical response of human amnion to repeated loading and the microstructural mechanisms determining its behavior were investigated. Inflation and uniaxial cyclic tests were combined with corresponding in situ experiments in a multiphoton microscope (MPM). Fresh unfixed amnion was imaged during loading and changes in thickness and collagen orientation were quantified. Mechanical and in situ experiments revealed differences between the investigated configurations in the deformation and microstructural mechanisms. Repeated inflation induces a significant but reversible volume change and is characterized by high energy dissipation. Under uniaxial tension, volume reduction is associated with low energy, unrecoverable in-plane fiber reorientation.
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10
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Mauri A, Ehret AE, Perrini M, Maake C, Ochsenbein-Kölble N, Ehrbar M, Oyen ML, Mazza E. Deformation mechanisms of human amnion: Quantitative studies based on second harmonic generation microscopy. J Biomech 2015; 48:1606-13. [PMID: 25805698 DOI: 10.1016/j.jbiomech.2015.01.045] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 01/31/2015] [Indexed: 11/15/2022]
Abstract
Multiphoton microscopy has proven to be a versatile tool to analyze the three-dimensional microstructure of the fetal membrane and the mechanisms of deformation on the length scale of cells and the collagen network. In the present contribution, dedicated microscopic tools for in situ mechanical characterization of tissue under applied mechanical loads and the related methods for data interpretation are presented with emphasis on new stepwise monotonic uniaxial experiments. The resulting microscopic parameters are consistent with previous ones quantified for cyclic and relaxation tests, underlining the reliability of these techniques. The thickness reduction and the substantial alignment of collagen fiber bundles in the compact and fibroblast layer starting at very small loads are highlighted, which challenges the definition of a reference configuration in terms of a force threshold. The findings presented in this paper intend to inform the development of models towards a better understanding of fetal membrane deformation and failure, and thus of related problems in obstetrics and other clinical conditions.
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Affiliation(s)
- Arabella Mauri
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
| | - Alexander E Ehret
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Michela Perrini
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; Department of Obstetrics, University Hospital Zürich, 8091 Zurich, Switzerland
| | - Caroline Maake
- Institute of Anatomy, University of Zurich, 8057 Zurich, Switzerland
| | | | - Martin Ehrbar
- Department of Obstetrics, University Hospital Zürich, 8091 Zurich, Switzerland
| | - Michelle L Oyen
- Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ, UK
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; Swiss Federal Laboratories for Materials Science and Technology, EMPA, 8600 Dübendorf, Switzerland
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Mauri A, Perrini M, Ehret AE, De Focatiis DSA, Mazza E. Time-dependent mechanical behavior of human amnion: macroscopic and microscopic characterization. Acta Biomater 2015; 11:314-23. [PMID: 25240983 DOI: 10.1016/j.actbio.2014.09.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/19/2014] [Accepted: 09/10/2014] [Indexed: 11/16/2022]
Abstract
Characterizing the mechanical response of the human amnion is essential to understand and to eventually prevent premature rupture of fetal membranes. In this study, a large set of macroscopic and microscopic mechanical tests have been carried out on fresh unfixed amnion to gain insight into the time-dependent material response and the underlying mechanisms. Creep and relaxation responses of amnion were characterized in macroscopic uniaxial tension, biaxial tension and inflation configurations. For the first time, these experiments were complemented by microstructural information from nonlinear laser scanning microscopy performed during in situ uniaxial relaxation tests. The amnion showed large tension reduction during relaxation and small inelastic strain accumulation in creep. The short-term relaxation response was related to a concomitant in-plane and out-of-plane contraction, and was dependent on the testing configuration. The microscopic investigation revealed a large volume reduction at the beginning, but no change of volume was measured long-term during relaxation. Tension-strain curves normalized with respect to the maximum strain were highly repeatable in all configurations and allowed the quantification of corresponding characteristic parameters. The present data indicate that dissipative behavior of human amnion is related to two mechanisms: (i) volume reduction due to water outflow (up to ∼20 s) and (ii) long-term dissipative behavior without macroscopic deformation and no systematic global reorientation of collagen fibers.
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Affiliation(s)
- Arabella Mauri
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
| | - Michela Perrini
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; Department of Obstetrics, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Alexander E Ehret
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Davide S A De Focatiis
- Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland; Swiss Federal Laboratories for Materials Science and Technology, EMPA, 8600 Dübendorf, Switzerland
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Maurer M, Röhrnbauer B, Feola A, Deprest J, Mazza E. Mechanical biocompatibility of prosthetic meshes: A comprehensive protocol for mechanical characterization. J Mech Behav Biomed Mater 2014; 40:42-58. [DOI: 10.1016/j.jmbbm.2014.08.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/29/2014] [Accepted: 08/10/2014] [Indexed: 11/27/2022]
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Weickenmeier J, Jabareen M. Elastic-viscoplastic modeling of soft biological tissues using a mixed finite element formulation based on the relative deformation gradient. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:1238-62. [PMID: 24817477 DOI: 10.1002/cnm.2654] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/27/2014] [Accepted: 05/04/2014] [Indexed: 05/17/2023]
Abstract
The characteristic highly nonlinear, time-dependent, and often inelastic material response of soft biological tissues can be expressed in a set of elastic-viscoplastic constitutive equations. The specific elastic-viscoplastic model for soft tissues proposed by Rubin and Bodner (2002) is generalized with respect to the constitutive equations for the scalar quantity of the rate of inelasticity and the hardening parameter in order to represent a general framework for elastic-viscoplastic models. A strongly objective integration scheme and a new mixed finite element formulation were developed based on the introduction of the relative deformation gradient-the deformation mapping between the last converged and current configurations. The numerical implementation of both the generalized framework and the specific Rubin and Bodner model is presented. As an example of a challenging application of the new model equations, the mechanical response of facial skin tissue is characterized through an experimental campaign based on the suction method. The measurement data are used for the identification of a suitable set of model parameters that well represents the experimentally observed tissue behavior. Two different measurement protocols were defined to address specific tissue properties with respect to the instantaneous tissue response, inelasticity, and tissue recovery.
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Affiliation(s)
- J Weickenmeier
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
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HUANG HSIAOYINGSHADOW, HUANG SIYAO, FRAZIER COLINP, PRIM PETERM, HARRYSSON OLA. DIRECTIONAL BIOMECHANICAL PROPERTIES OF PORCINE SKIN TISSUE. J MECH MED BIOL 2014. [DOI: 10.1142/s0219519414500699] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Skin is a multilayered composite material and composed principally of the proteins collagen, elastic fibers and fibroblasts. The direction-dependent material properties of skin tissue is important for physiological functions like skin expansion. The current study has developed methods to characterize the directional biomechanical properties of porcine skin tissues as studies have shown that pigs represent a useful animal model due to similarities between porcine and human skin. It is observed that skin tissue has a nonlinear anisotropy biomechanical behavior, where the parameters of material modulus is 378 ± 160 kPa in the preferred-fiber direction and 65.96 ± 40.49 kPa in the cross-fiber direction when stretching above 30% strain equibiaxially. The result from the study provides methods of characterizing biaxial mechanical properties of skin tissue, as the collagen fiber direction appears to be one of the primary determinants of tissue anisotropy.
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Affiliation(s)
| | - SIYAO HUANG
- Mechanical and Aerospace Engineering Department, North Carolina State University, USA
| | - COLIN P. FRAZIER
- Mechanical and Aerospace Engineering Department, North Carolina State University, USA
| | - PETER M. PRIM
- Fitts Department of Industrial and Systems Engineering, North Carolina State University, USA
| | - OLA HARRYSSON
- Fitts Department of Industrial and Systems Engineering, North Carolina State University, USA
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15
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Böl M, Ehret AE, Leichsenring K, Weichert C, Kruse R. On the anisotropy of skeletal muscle tissue under compression. Acta Biomater 2014; 10:3225-34. [PMID: 24636829 DOI: 10.1016/j.actbio.2014.03.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 02/18/2014] [Accepted: 03/04/2014] [Indexed: 11/28/2022]
Abstract
This paper deals with the role of the muscle fibres and extracellular matrix (ECM) components when muscle tissue is subjected to compressive loads. To this end, dissected tissue samples were tested in compression modes which induced states of fibres in compression (I), in tension (II) or at constant length (III), respectively. A comparison of the stress responses indicated that the tissue behaviour is significantly different for these modes, including differences between the modes (I) and (III). This contradicts the paradigm of many constitutive models that the stress response can be decomposed into an isotropic part relating to the ECM and an anisotropic fibre part the contribution of which can be neglected under compression. Conversely, the results provide experimental evidence that there is an anisotropic contribution of the fibre direction to the compressive stress. Interpreting these results in terms of recent microscopical studies, potential connections between the observed behaviour and the structure of muscle ECM are established.
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Affiliation(s)
- Markus Böl
- Institute of Solid Mechanics, Technische Universität Braunschweig, 38106 Braunschweig, Germany.
| | - Alexander E Ehret
- Institute of Solid Mechanics, Technische Universität Braunschweig, 38106 Braunschweig, Germany; Institute of Mechanical Systems, ETH Zurich, 8092 Zurich, Switzerland
| | - Kay Leichsenring
- Institute of Solid Mechanics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Christine Weichert
- Institute of Solid Mechanics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Roland Kruse
- Institute of Solid Mechanics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
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Buerzle W, Mazza E. On the deformation behavior of human amnion. J Biomech 2013; 46:1777-83. [DOI: 10.1016/j.jbiomech.2013.05.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/15/2013] [Accepted: 05/20/2013] [Indexed: 11/28/2022]
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17
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Zöllner AM, Holland MA, Honda KS, Gosain AK, Kuhl E. Growth on demand: reviewing the mechanobiology of stretched skin. J Mech Behav Biomed Mater 2013; 28:495-509. [PMID: 23623569 DOI: 10.1016/j.jmbbm.2013.03.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/15/2013] [Accepted: 03/19/2013] [Indexed: 02/03/2023]
Abstract
Skin is a highly dynamic, autoregulated, living system that responds to mechanical stretch through a net gain in skin surface area. Tissue expansion uses the concept of controlled overstretch to grow extra skin for defect repair in situ. While the short-term mechanics of stretched skin have been studied intensely by testing explanted tissue samples ex vivo, we know very little about the long-term biomechanics and mechanobiology of living skin in vivo. Here we explore the long-term effects of mechanical stretch on the characteristics of living skin using a mathematical model for skin growth. We review the molecular mechanisms by which skin responds to mechanical loading and model their effects collectively in a single scalar-valued internal variable, the surface area growth. This allows us to adopt a continuum model for growing skin based on the multiplicative decomposition of the deformation gradient into a reversible elastic and an irreversible growth part. To demonstrate the inherent modularity of this approach, we implement growth as a user-defined constitutive subroutine into the general purpose implicit finite element program Abaqus/Standard. To illustrate the features of the model, we simulate the controlled area growth of skin in response to tissue expansion with multiple filling points in time. Our results demonstrate that the field theories of continuum mechanics can reliably predict the manipulation of thin biological membranes through mechanical overstretch. Our model could serve as a valuable tool to rationalize clinical process parameters such as expander geometry, expander size, filling volume, filling pressure, and inflation timing to minimize tissue necrosis and maximize patient comfort in plastic and reconstructive surgery. While initially developed for growing skin, our model can easily be generalized to arbitrary biological structures to explore the physiology and pathology of stretch-induced growth of other living systems such as hearts, arteries, bladders, intestines, ureters, muscles, and nerves.
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Röhrnbauer B, Mazza E. A non-biological model system to simulate the in vivo mechanical behavior of prosthetic meshes. J Mech Behav Biomed Mater 2013; 20:305-15. [DOI: 10.1016/j.jmbbm.2013.01.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 01/15/2013] [Accepted: 01/28/2013] [Indexed: 10/27/2022]
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Mauri A, Zeisberger SM, Hoerstrup SP, Mazza E. Analysis of the Uniaxial and Multiaxial Mechanical Response of a Tissue-Engineered Vascular Graft. Tissue Eng Part A 2013; 19:583-92. [DOI: 10.1089/ten.tea.2012.0075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Arabella Mauri
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Steffen M. Zeisberger
- Swiss Center for Regenerative Medicine (SCRM), University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Department of Surgical Research and Clinic for Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Simon P. Hoerstrup
- Swiss Center for Regenerative Medicine (SCRM), University Hospital Zurich and University of Zurich, Zurich, Switzerland
- Department of Surgical Research and Clinic for Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Edoardo Mazza
- Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
- Swiss Federal Laboratories for Materials Science and Technology, EMPA, Duebendorf, Switzerland
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On the mechanical behaviour of carotid artery plaques: the influence of curve-fitting experimental data on numerical model results. Biomech Model Mechanobiol 2012. [DOI: 10.1007/s10237-012-0457-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Böl M, Kruse R, Ehret AE, Leichsenring K, Siebert T. Compressive properties of passive skeletal muscle—The impact of precise sample geometry on parameter identification in inverse finite element analysis. J Biomech 2012; 45:2673-9. [DOI: 10.1016/j.jbiomech.2012.08.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 08/15/2012] [Accepted: 08/15/2012] [Indexed: 10/27/2022]
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Gerhardt LC, Schmidt J, Sanz-Herrera J, Baaijens F, Ansari T, Peters G, Oomens C. A novel method for visualising and quantifying through-plane skin layer deformations. J Mech Behav Biomed Mater 2012; 14:199-207. [DOI: 10.1016/j.jmbbm.2012.05.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 05/10/2012] [Accepted: 05/22/2012] [Indexed: 10/28/2022]
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