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Shkarin R, Shkarina S, Weinhardt V, Surmenev RA, Surmeneva MA, Shkarin A, Baumbach T, Mikut R. GPU-accelerated ray-casting for 3D fiber orientation analysis. PLoS One 2020; 15:e0236420. [PMID: 32726324 PMCID: PMC7390437 DOI: 10.1371/journal.pone.0236420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/06/2020] [Indexed: 12/01/2022] Open
Abstract
Orientation analysis of fibers is widely applied in the fields of medical, material and life sciences. The orientation information allows predicting properties and behavior of materials to validate and guide a fabrication process of materials with controlled fiber orientation. Meanwhile, development of detector systems for high-resolution non-invasive 3D imaging techniques led to a significant increase in the amount of generated data per a sample up to dozens of gigabytes. Though plenty of 3D orientation estimation algorithms were developed in recent years, neither of them can process large datasets in a reasonable amount of time. This fact complicates the further analysis and makes impossible fast feedback to adjust fabrication parameters. In this work, we present a new method for quantifying the 3D orientation of fibers. The GPU implementation of the proposed method surpasses another popular method for 3D orientation analysis regarding accuracy and speed. The validation of both methods was performed on a synthetic dataset with varying parameters of fibers. Moreover, the proposed method was applied to perform orientation analysis of scaffolds with different fibrous micro-architecture studied with the synchrotron μCT imaging setup. Each acquired dataset of size 600x600x450 voxels was analyzed in less 2 minutes using standard PC equipped with a single GPU.
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Affiliation(s)
- Roman Shkarin
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Automation and Applied Computer Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Svetlana Shkarina
- Physical Materials Science and Composite Materials Centre, Research School of Chemistry & Applied Biomedical Sciences, National Research Tomsk Polytechnic University, Tomsk, Russia
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Venera Weinhardt
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
- Centre for Organismal Studies, COS, Heidelberg University, Heidelberg, Germany
| | - Roman A. Surmenev
- Physical Materials Science and Composite Materials Centre, Research School of Chemistry & Applied Biomedical Sciences, National Research Tomsk Polytechnic University, Tomsk, Russia
| | - Maria A. Surmeneva
- Physical Materials Science and Composite Materials Centre, Research School of Chemistry & Applied Biomedical Sciences, National Research Tomsk Polytechnic University, Tomsk, Russia
| | - Andrei Shkarin
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Tilo Baumbach
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Ralf Mikut
- Institute for Automation and Applied Computer Science, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Lin J, Shi Y, Men Y, Wang X, Ye J, Zhang C. Mechanical Roles in Formation of Oriented Collagen Fibers. TISSUE ENGINEERING PART B-REVIEWS 2020; 26:116-128. [PMID: 31801418 DOI: 10.1089/ten.teb.2019.0243] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Collagen is a structural protein that is widely present in vertebrates, being usually distributed in tissues in the form of fibers. In living organisms, fibers are organized in different orientations in various tissues. As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. The study on mechanics role in formation of oriented collagen fibers enables us to understand how discrete cells use limited molecular materials to create tissues with different structures, thereby promoting our understanding of the mechanism of tissue formation from scratch, from invisible to tangible. However, the current understanding of the mechanism of fiber orientation is still insufficient. In addition, existing fabrication methods of oriented fibers are varied and involve interdisciplinary study, and the achievements of each experiment are favorable to the construction and improvement of the fiber orientation theory. To this end, this review focuses on the preparation methods of oriented fibers and proposes a model explaining the formation process of oriented fibers in tendons based on the existing fiber theory. Impact statement As the structural base in connective tissue and load-bearing tissue, the orientation of collagen fibers plays an extremely important role in the mechanical properties and physiological and biochemical functions. However, the current understanding of the mechanism of fiber orientation is still insufficient, which is greatly responsible for the challenge of functional tissue repair and regeneration. Understanding the mechanism of fiber orientation can promote the successful application of fiber orientation scaffolds in tissue repair and regeneration, as well as providing an insight for the mechanism of tissue histomorphology.
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Affiliation(s)
- Jiexiang Lin
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Yanping Shi
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Yutao Men
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Xin Wang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Jinduo Ye
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
| | - Chunqiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, P.R. China
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3
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Xing F, Li L, Zhou C, Long C, Wu L, Lei H, Kong Q, Fan Y, Xiang Z, Zhang X. Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues. Stem Cells Int 2019; 2019:2180925. [PMID: 31949436 PMCID: PMC6948329 DOI: 10.1155/2019/2180925] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/05/2019] [Indexed: 02/05/2023] Open
Abstract
It is well known that stem cells reside within tissue engineering functional microenvironments that physically localize them and direct their stem cell fate. Recent efforts in the development of more complex and engineered scaffold technologies, together with new understanding of stem cell behavior in vitro, have provided a new impetus to study regulation and directing stem cell fate. A variety of tissue engineering technologies have been developed to regulate the fate of stem cells. Traditional methods to change the fate of stem cells are adding growth factors or some signaling pathways. In recent years, many studies have revealed that the geometrical microenvironment played an essential role in regulating the fate of stem cells, and the physical factors of scaffolds including mechanical properties, pore sizes, porosity, surface stiffness, three-dimensional structures, and mechanical stimulation may affect the fate of stem cells. Chemical factors such as cell-adhesive ligands and exogenous growth factors would also regulate the fate of stem cells. Understanding how these physical and chemical cues affect the fate of stem cells is essential for building more complex and controlled scaffolds for directing stem cell fate.
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Affiliation(s)
- Fei Xing
- Department of Orthopaedics, West China Hospital, Sichuan University, No. 37 Guoxue Lane, Chengdu, 610041 Sichuan, China
| | - Lang Li
- Department of Pediatric Surgery, West China Hospital, Sichuan University, No. 37 Guoxue Lane, Chengdu, 610041 Sichuan, China
| | - Changchun Zhou
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, Sichuan, China
| | - Cheng Long
- Department of Orthopaedics, West China Hospital, Sichuan University, No. 37 Guoxue Lane, Chengdu, 610041 Sichuan, China
| | - Lina Wu
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, Sichuan, China
| | - Haoyuan Lei
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, Sichuan, China
| | - Qingquan Kong
- Department of Orthopaedics, West China Hospital, Sichuan University, No. 37 Guoxue Lane, Chengdu, 610041 Sichuan, China
| | - Yujiang Fan
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, Sichuan, China
| | - Zhou Xiang
- Department of Orthopaedics, West China Hospital, Sichuan University, No. 37 Guoxue Lane, Chengdu, 610041 Sichuan, China
| | - Xingdong Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, 610064 Chengdu, Sichuan, China
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4
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Paten JA, Martin CL, Wanis JT, Siadat SM, Figueroa-Navedo AM, Ruberti JW, Deravi LF. Molecular Interactions between Collagen and Fibronectin: A Reciprocal Relationship that Regulates De Novo Fibrillogenesis. Chem 2019. [DOI: 10.1016/j.chempr.2019.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Li K, Zhang C, Qiu L, Gao L, Zhang X. Advances in Application of Mechanical Stimuli in Bioreactors for Cartilage Tissue Engineering. TISSUE ENGINEERING PART B-REVIEWS 2017; 23:399-411. [PMID: 28463576 DOI: 10.1089/ten.teb.2016.0427] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Articular cartilage (AC) is the weight-bearing tissue in diarthroses. It lacks the capacity for self-healing once there are injuries or diseases due to its avascularity. With the development of tissue engineering, repairing cartilage defects through transplantation of engineered cartilage that closely matches properties of native cartilage has become a new option for curing cartilage diseases. The main hurdle for clinical application of engineered cartilage is how to develop functional cartilage constructs for mass production in a credible way. Recently, impressive hyaline cartilage that may have the potential to provide capabilities for treating large cartilage lesions in the future has been produced in laboratories. The key to functional cartilage construction in vitro is to identify appropriate mechanical stimuli. First, they should ensure the function of metabolism because mechanical stimuli play the role of blood vessels in the metabolism of AC, for example, acquiring nutrition and removing wastes. Second, they should mimic the movement of synovial joints and produce phenotypically correct tissues to achieve the adaptive development between the micro- and macrostructure and function. In this article, we divide mechanical stimuli into three types according to forces transmitted by different media in bioreactors, namely forces transmitted through the liquid medium, solid medium, or other media, then we review and summarize the research status of bioreactors for cartilage tissue engineering (CTE), mainly focusing on the effects of diverse mechanical stimuli on engineered cartilage. Based on current researches, there are several motion patterns in knee joints; but compression, tension, shear, fluid shear, or hydrostatic pressure each only partially reflects the mechanical condition in vivo. In this study, we propose that rolling-sliding-compression load consists of various stimuli that will represent better mechanical environment in CTE. In addition, engineers often ignore the importance of biochemical factors to the growth and development of engineered cartilage. In our point of view, only by fully considering synergistic effects of mechanical and biochemical factors can we find appropriate culture conditions for functional cartilage constructs. Once again, rolling-sliding-compression load under appropriate biochemical conditions may be conductive to realize the adaptive development between the structure and function of engineered cartilage in vitro.
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Affiliation(s)
- Ke Li
- Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China
| | - Chunqiu Zhang
- Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China
| | - Lulu Qiu
- Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China
| | - Lilan Gao
- Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China
| | - Xizheng Zhang
- Tianjin Key Laboratory of Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology , Tianjin, China
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6
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Paten JA, Siadat SM, Susilo ME, Ismail EN, Stoner JL, Rothstein JP, Ruberti JW. Flow-Induced Crystallization of Collagen: A Potentially Critical Mechanism in Early Tissue Formation. ACS NANO 2016; 10:5027-40. [PMID: 27070851 PMCID: PMC6037489 DOI: 10.1021/acsnano.5b07756] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The type I collagen monomer is one of nature's most exquisite and prevalent structural tools. Its 300 nm triple-helical motifs assemble into tough extracellular fibers that transition seamlessly across tissue boundaries and exceed cell dimensions by up to 4 orders of magnitude. In spite of extensive investigation, no existing model satisfactorily explains how such continuous structures are generated and grown precisely where they are needed (aligned in the path of force) by discrete, microscale cells using materials with nanoscale dimensions. We present a simple fiber drawing experiment, which demonstrates that slightly concentrated type I collagen monomers can be "flow-crystallized" to form highly oriented, continuous, hierarchical fibers at cell-achievable strain rates (<1 s(-1)) and physiologically relevant concentrations (∼50 μM). We also show that application of tension following the drawing process maintains the structural integrity of the fibers. While mechanical tension has been shown to be a critical factor driving collagen fibril formation during tissue morphogenesis in developing animals, the precise role of force in the process of building tissue is not well understood. Our data directly couple mechanical tension, specifically the extensional strain rate, to collagen fibril assembly. We further derive a "growth equation" which predicts that application of extensional strains, either globally by developing muscles or locally by fibroblasts, can rapidly drive the fusion of already formed short fibrils to produce long-range, continuous fibers. The results provide a pathway to scalable connective tissue manufacturing and support a mechano-biological model of collagen fibril deposition and growth in vivo.
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Affiliation(s)
- Jeffrey A Paten
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Seyed Mohammad Siadat
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Monica E Susilo
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ebraheim N Ismail
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Jayson L Stoner
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Jonathan P Rothstein
- Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst , 160 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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7
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Susilo ME, Paten JA, Sander EA, Nguyen TD, Ruberti JW. Collagen network strengthening following cyclic tensile loading. Interface Focus 2016; 6:20150088. [DOI: 10.1098/rsfs.2015.0088] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The bulk mechanical properties of tissues are highly tuned to the physiological loads they experience and reflect the hierarchical structure and mechanical properties of their constituent parts. A thorough understanding of the processes involved in tissue adaptation is required to develop multi-scale computational models of tissue remodelling. While extracellular matrix (ECM) remodelling is partly due to the changing cellular metabolic activity, there may also be mechanically directed changes in ECM nano/microscale organization which lead to mechanical tuning. The thermal and enzymatic stability of collagen, which is the principal load-bearing biopolymer in vertebrates, have been shown to be enhanced by force suggesting that collagen has an active role in ECM mechanical properties. Here, we ask how changes in the mechanical properties of a collagen-based material are reflected by alterations in the micro/nanoscale collagen network following cyclic loading. Surprisingly, we observed significantly higher tensile stiffness and ultimate tensile strength, roughly analogous to the effect of work hardening, in the absence of network realignment and alterations to the fibril area fraction. The data suggest that mechanical loading induces stabilizing changes internal to the fibrils themselves or in the fibril–fibril interactions. If such a cell-independent strengthening effect is operational
in vivo
, then it would be an important consideration in any multiscale computational approach to ECM growth and remodelling.
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Affiliation(s)
| | | | - Edward A. Sander
- Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Thao D. Nguyen
- Mechanical Engineering, Johns Hopkins, Baltimore, MD 21218, USA
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8
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Hoogenkamp HR, Bakker GJ, Wolf L, Suurs P, Dunnewind B, Barbut S, Friedl P, van Kuppevelt TH, Daamen WF. Directing collagen fibers using counter-rotating cone extrusion. Acta Biomater 2015; 12:113-121. [PMID: 25462525 DOI: 10.1016/j.actbio.2014.10.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/05/2014] [Accepted: 10/10/2014] [Indexed: 10/24/2022]
Abstract
The bio-inspired engineering of tissue equivalents should take into account anisotropic morphology and the mechanical properties of the extracellular matrix. This especially applies to collagen fibrils, which have various, but highly defined, orientations throughout tissues and organs. There are several methods available to control the alignment of soluble collagen monomers, but the options to direct native insoluble collagen fibers are limited. Here we apply a controlled counter-rotating cone extrusion technology to engineer tubular collagen constructs with defined anisotropy. Driven by diverging inner and outer cone rotation speeds, collagen fibrils from bovine skin were extruded and precipitated onto mandrels as tubes with oriented fibers and bundles, as examined by second harmonic generation microscopy and quantitative image analysis. A clear correlation was found whereby the direction and extent of collagen fiber alignment during extrusion were a function of the shear forces caused by a combination of the cone rotation and flow direction. A gradual change in the fiber direction, spanning +50 to -40°, was observed throughout the sections of the sample, with an average decrease ranging from 2.3 to 2.6° every 10μm. By varying the cone speeds, the collagen constructs showed differences in elasticity and toughness, spanning 900-2000kPa and 19-35mJ, respectively. Rotational extrusion presents an enabling technology to create and control the (an)isotropic architecture of collagen constructs for application in tissue engineering and regenerative medicine.
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9
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Guilak F, Butler DL, Goldstein SA, Baaijens FPT. Biomechanics and mechanobiology in functional tissue engineering. J Biomech 2014; 47:1933-40. [PMID: 24818797 DOI: 10.1016/j.jbiomech.2014.04.019] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 04/17/2014] [Accepted: 04/17/2014] [Indexed: 12/22/2022]
Abstract
The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements.
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Affiliation(s)
- Farshid Guilak
- Departments of Orthopaedic Surgery and Biomedical Engineering, Duke University Medical Center, 375 MSRB, Box 3093, Durham, NC 27710, USA.
| | - David L Butler
- Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Steven A Goldstein
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Frank P T Baaijens
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
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10
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Walters BD, Stegemann JP. Strategies for directing the structure and function of three-dimensional collagen biomaterials across length scales. Acta Biomater 2014; 10:1488-501. [PMID: 24012608 PMCID: PMC3947739 DOI: 10.1016/j.actbio.2013.08.038] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/17/2013] [Accepted: 08/28/2013] [Indexed: 12/16/2022]
Abstract
Collagen type I is a widely used natural biomaterial that has found utility in a variety of biological and medical applications. Its well-characterized structure and role as an extracellular matrix protein make it a highly relevant material for controlling cell function and mimicking tissue properties. Collagen type I is abundant in a number of tissues, and can be isolated as a purified protein. This review focuses on hydrogel biomaterials made by reconstituting collagen type I from a solubilized form, with an emphasis on in vitro studies in which collagen structure can be controlled. The hierarchical structure of collagen from the nanoscale to the macroscale is described, with an emphasis on how structure is related to function across scales. Methods of reconstituting collagen into hydrogel materials are presented, including molding of macroscopic constructs, creation of microscale modules and electrospinning of nanoscale fibers. The modification of collagen biomaterials to achieve the desired structures and functions is also addressed, with particular emphasis on mechanical control of collagen structure, creation of collagen composite materials and crosslinking of collagenous matrices. Biomaterials scientists have made remarkable progress in rationally designing collagen-based biomaterials and in applying them both to the study of biology and for therapeutic benefit. This broad review illustrates recent examples of techniques used to control collagen structure and thereby to direct its biological and mechanical functions.
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Affiliation(s)
- B D Walters
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA
| | - J P Stegemann
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA.
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