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Snellings J, Keshi E, Tang P, Daneshgar A, Willma EC, Haderer L, Klein O, Krenzien F, Malinka T, Asbach P, Pratschke J, Sauer IM, Braun J, Sack I, Hillebrandt K. Solid fraction determines stiffness and viscosity in decellularized pancreatic tissues. Biomater Adv 2022; 139:212999. [PMID: 35882147 DOI: 10.1016/j.bioadv.2022.212999] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/05/2022] [Accepted: 06/20/2022] [Indexed: 05/29/2023]
Abstract
The role of extracellular matrix (ECM) composition and turnover in mechano-signaling and the metamorphic fate of cells seeded into decellularized tissue can be elucidated by recent developments in non-invasive imaging and biotechnological analysis methods. Because these methods allow accurate quantification of the composition and structural integrity of the ECM, they can be critical in establishing standardized decellularization protocols. This study proposes quantification of the solid fraction, the single-component fraction and the viscoelasticity of decellularized pancreatic tissues using compact multifrequency magnetic resonance elastography (MRE) to assess the efficiency and quality of decellularization protocols. MRE of native and decellularized pancreatic tissues showed that viscoelasticity parameters depend according to a power law on the solid fraction of the decellularized matrix. The parameters can thus be used as highly sensitive markers of the mechanical integrity of soft tissues. Compact MRE allows consistent and noninvasive quantification of the viscoelastic properties of decellularized tissue. Such a method is urgently needed for the standardized monitoring of decellularization processes, evaluation of mechanical ECM properties, and quantification of the integrity of solid structural elements remaining in the decellularized tissue matrix.
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Affiliation(s)
- Joachim Snellings
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Eriselda Keshi
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Peter Tang
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Assal Daneshgar
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Esther C Willma
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Luna Haderer
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Oliver Klein
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Center for Regenerative Therapies, Charitéplatz 1, 10117 Berlin, Germany
| | - Felix Krenzien
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany at Charité - Universitätsmedizin Berlin, BIH Acadamy, Clinician Scientist Program, Charitéplatz 1, 10117 Berlin, Germany
| | - Thomas Malinka
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Patrick Asbach
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Johann Pratschke
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
| | - Igor M Sauer
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
| | - Jürgen Braun
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute for Medical Informatics, Charitéplatz 1, 10117 Berlin, Germany
| | - Ingolf Sack
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany.
| | - Karl Hillebrandt
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany at Charité - Universitätsmedizin Berlin, BIH Acadamy, Clinician Scientist Program, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
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Zhou B, Zhang X. Comparison of five viscoelastic models for estimating viscoelastic parameters using ultrasound shear wave elastography. J Mech Behav Biomed Mater 2018; 85:109-116. [PMID: 29879581 DOI: 10.1016/j.jmbbm.2018.05.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/09/2018] [Accepted: 05/29/2018] [Indexed: 01/09/2023]
Abstract
The purpose of this study is to compare five viscoelastic models (Voigt, Maxwell, standard linear solid, spring-pot, and fractional Voigt models) for estimating viscoelastic properties based on ultrasound shear wave elastography measurements. We performed the forward problem analysis, the inverse problem analysis, and experiments. In the forward problem analysis, the shear wave speeds at different frequencies were calculated using the Voigt model for given shear elasticity and varying shear viscosity. In the inverse problem analysis, the viscoelastic parameters were estimated from the given wave speeds for the five viscoelastic models using the least-square regression. The experiment was performed in a tissue-mimicking phantom. A local harmonic vibration was generated via a mechanical shaker on the phantom at five frequencies (100, 150, 200, 250, and 300 Hz) and an ultrasound transducer was used to capture the tissue motion. Shear wave speed of the phantom was measured using the ultrasound shear wave elastography technique. The parameters for different viscoelastic models for the phantom were identified. For both analytical and experimental studies, ratios of storage to loss modulus as a function of excitation frequency for different viscoelastic models were calculated. We found that the Voigt and fractional Voigt models fit well with the shear wave speed - frequency and ratio of storage to loss modulus - frequency relationships both in analytical and experimental studies.
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Affiliation(s)
- Boran Zhou
- Department of Radiology, Mayo Clinic College of Medicine, 200 1st St SW, Rochester, MN 55905, USA
| | - Xiaoming Zhang
- Department of Radiology, Mayo Clinic College of Medicine, 200 1st St SW, Rochester, MN 55905, USA.
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Mattei G, Gruca G, Rijnveld N, Ahluwalia A. The nano-epsilon dot method for strain rate viscoelastic characterisation of soft biomaterials by spherical nano-indentation. J Mech Behav Biomed Mater 2015; 50:150-9. [PMID: 26143307 DOI: 10.1016/j.jmbbm.2015.06.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 06/12/2015] [Accepted: 06/15/2015] [Indexed: 11/16/2022]
Abstract
Nano-indentation is widely used for probing the micromechanical properties of materials. Based on the indentation of surfaces using probes with a well-defined geometry, the elastic and viscoelastic constants of materials can be determined by relating indenter geometry and measured load and displacement to parameters which represent stress and deformation. Here we describe a method to derive the viscoelastic properties of soft hydrated materials at the micro-scale using constant strain rates and stress-free initial conditions. Using a new self-consistent definition of indentation stress and strain and corresponding unique depth-independent expression for indentation strain rate, the epsilon dot method, which is suitable for bulk compression testing, is transformed to nano-indentation. We demonstrate how two materials can be tested with a displacement controlled commercial nano-indentor using the nano-espilon dot method (nano-ε̇M) to give values of instantaneous and equilibrium elastic moduli and time constants with high precision. As samples are tested in stress-free initial conditions, the nano-ε̇M could be useful for characterising the micro-mechanical behaviour of soft materials such as hydrogels and biological tissues at cell length scales.
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Affiliation(s)
- G Mattei
- Research Centre "E. Piaggio", University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy
| | - G Gruca
- Optics11, De Boelelaan 108, 1081 HV Amsterdam, The Netherlands
| | - N Rijnveld
- Optics11, De Boelelaan 108, 1081 HV Amsterdam, The Netherlands
| | - A Ahluwalia
- Research Centre "E. Piaggio", University of Pisa, Largo Lucio Lazzarino 1, 56122 Pisa, Italy.
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