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Gabetti S, Masante B, Schiavi A, Scatena E, Zenobi E, Israel S, Sanginario A, Del Gaudio C, Audenino A, Morbiducci U, Massai D. Adaptable test bench for ASTM-compliant permeability measurement of porous scaffolds for tissue engineering. Sci Rep 2024; 14:1722. [PMID: 38242930 PMCID: PMC10799031 DOI: 10.1038/s41598-024-52159-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/15/2024] [Indexed: 01/21/2024] Open
Abstract
Intrinsic permeability describes the ability of a porous medium to be penetrated by a fluid. Considering porous scaffolds for tissue engineering (TE) applications, this macroscopic variable can strongly influence the transport of oxygen and nutrients, the cell seeding process, and the transmission of fluid forces to the cells, playing a crucial role in determining scaffold efficacy. Thus, accurately measuring the permeability of porous scaffolds could represent an essential step in their optimization process. In literature, several methods have been proposed to characterize scaffold permeability. Most of the currently adopted approaches to assess permeability limit their applicability to specific scaffold structures, hampering protocols standardization, and ultimately leading to incomparable results among different laboratories. The content of novelty of this study is in the proposal of an adaptable test bench and in defining a specific testing protocol, compliant with the ASTM International F2952-22 guidelines, for reliable and repeatable measurements of the intrinsic permeability of TE porous scaffolds. The developed permeability test bench (PTB) exploits the pump-based method, and it is composed of a modular permeability chamber integrated within a closed-loop hydraulic circuit, which includes a peristaltic pump and pressure sensors, recirculating demineralized water. A specific testing protocol was defined for characterizing the pressure drop associated with the scaffold under test, while minimizing the effects of uncertainty sources. To assess the operational capabilities and performance of the proposed test bench, permeability measurements were conducted on PLA scaffolds with regular (PS) and random (RS) micro-architecture and on commercial bovine bone matrix-derived scaffolds (CS) for bone TE. To validate the proposed approach, the scaffolds were as well characterized using an alternative test bench (ATB) based on acoustic measurements, implementing a blind randomized testing procedure. The consistency of the permeability values measured using both the test benches demonstrated the reliability of the proposed approach. A further validation of the PTB's measurement reliability was provided by the agreement between the measured permeability values of the PS scaffolds and the theory-based predicted permeability value. Once validated the proposed PTB, the performed measurements allowed the investigation of the scaffolds' transport properties. Samples with the same structure (guaranteed by the fused-deposition modeling technique) were characterized by similar permeability values, and CS and RS scaffolds showed permeability values in agreement with the values reported in the literature for bovine trabecular bone. In conclusion, the developed PTB and the proposed testing protocol allow the characterization of the intrinsic permeability of porous scaffolds of different types and dimensions under controlled flow regimes, representing a powerful tool in view of providing a reliable and repeatable framework for characterizing and optimizing scaffolds for TE applications.
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Affiliation(s)
- Stefano Gabetti
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy
| | - Beatrice Masante
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy
- Department of Surgical Sciences, CIR-Dental School, University of Turin, Turin, Italy
| | - Alessandro Schiavi
- Applied Metrology and Engineering Division, INRiM-National Institute of Metrological Research, Turin, Italy
| | | | | | - Simone Israel
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy
| | - Alessandro Sanginario
- Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
| | | | - Alberto Audenino
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy
| | - Umberto Morbiducci
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy
| | - Diana Massai
- Department of Mechanical and Aerospace Engineering and PolitoBIOMed Lab, Politecnico di Torino, Corso Duca Degli Abruzzi, 24, 10129, Turin, Italy.
- Centro 3R, Interuniversity Center for the Promotion of the 3Rs Principles in Teaching and Research, Turin, Italy.
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Toosi S, Javid-Naderi MJ, Tamayol A, Ebrahimzadeh MH, Yaghoubian S, Mousavi Shaegh SA. Additively manufactured porous scaffolds by design for treatment of bone defects. Front Bioeng Biotechnol 2024; 11:1252636. [PMID: 38312510 PMCID: PMC10834686 DOI: 10.3389/fbioe.2023.1252636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 12/20/2023] [Indexed: 02/06/2024] Open
Abstract
There has been increasing attention to produce porous scaffolds that mimic human bone properties for enhancement of tissue ingrowth, regeneration, and integration. Additive manufacturing (AM) technologies, i.e., three dimensional (3D) printing, have played a substantial role in engineering porous scaffolds for clinical applications owing to their high level of design and fabrication flexibility. To this end, this review article attempts to provide a detailed overview on the main design considerations of porous scaffolds such as permeability, adhesion, vascularisation, and interfacial features and their interplay to affect bone regeneration and osseointegration. Physiology of bone regeneration was initially explained that was followed by analysing the impacts of porosity, pore size, permeability and surface chemistry of porous scaffolds on bone regeneration in defects. Importantly, major 3D printing methods employed for fabrication of porous bone substitutes were also discussed. Advancements of MA technologies have allowed for the production of bone scaffolds with complex geometries in polymers, composites and metals with well-tailored architectural, mechanical, and mass transport features. In this way, a particular attention was devoted to reviewing 3D printed scaffolds with triply periodic minimal surface (TPMS) geometries that mimic the hierarchical structure of human bones. In overall, this review enlighten a design pathway to produce patient-specific 3D-printed bone substitutions with high regeneration and osseointegration capacity for repairing large bone defects.
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Affiliation(s)
- Shirin Toosi
- Stem Cell and Regenerative Medicine Center, Mashhad University of Medical Science, Mashhad, Iran
| | - Mohammad Javad Javid-Naderi
- Department of Medical Biotechnology and Nanotechnology, Faculty of Medicine, Mashhad University of Medical Science, Mashhad, Iran
| | - Ali Tamayol
- Department of Biomedical Engineering, University of Connecticut Health Center, Farmington, CT, United States
| | | | - Sima Yaghoubian
- Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Ali Mousavi Shaegh
- Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
- Laboratory for Microfluidics and Medical Microsystems, BuAli Research Institute, Mashhad University of Medical Science, Mashhad, Iran
- Clinical Research Unit, Ghaem Hospital, Mashhad University of Medical Science, Mashhad, Iran
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3
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Bouakaz I, Drouet C, Grossin D, Cobraiville E, Nolens G. Hydroxyapatite 3D-printed scaffolds with Gyroid-Triply periodic minimal surface porous structure: Fabrication and an in vivo pilot study in sheep. Acta Biomater 2023; 170:580-595. [PMID: 37673232 DOI: 10.1016/j.actbio.2023.08.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 09/08/2023]
Abstract
Bone repair is a major challenge in regenerative medicine, e.g. for large defects. There is a need for bioactive, highly percolating bone substitutes favoring bone ingrowth and tissue healing. Here, a modern 3D printing approach (VAT photopolymerization) was exploited to fabricate hydroxyapatite (HA) scaffolds with a Gyroid-"Triply periodic minimal surface" (TPMS) porous structure (65% porosity, 90.5% HA densification) inspired from trabecular bone. Percolation and absorption capacities were analyzed in gaseous and liquid conditions. Mechanical properties relevant to guided bone regeneration in non-load bearing sites, as for maxillofacial contour reconstruction, were evidenced from 3-point bending tests and macrospherical indentation. Scaffolds were implanted in a clinically-relevant large animal model (sheep femur), over 6 months, enabling thorough analyses at short (4 weeks) and long (26 weeks) time points. In vivo performances were systematically compared to the bovine bone-derived Bio-OssⓇ standard. The local tissue response was examined thoroughly by semi-quantitative histopathology. Results demonstrated the absence of toxicity. Bone healing was assessed by bone dynamics analysis through epifluorescence using various fluorochromes and quantitative histomorphometry. Performant bone regeneration was evidenced with similar overall performances to the control, although the Gyroid biomaterial slightly outperformed Bio-OssⓇ at early healing time in terms of osteointegration and appositional mineralization. This work is considered a pilot study on the in vivo evaluation of TPMS-based 3D porous scaffolds in a large animal model, for an extended period of time, and in comparison to a clinical standard. Our results confirm the relevance of such scaffolds for bone regeneration in view of clinical practice. STATEMENT OF SIGNIFICANCE: Bone repair, e.g. for large bone defects or patients with defective vascularization is still a major challenge. Highly percolating TPMS porous structures have recently emerged, but no in vivo data were reported on a large animal model of clinical relevance and comparing to an international standard. Here, we fabricated TPMS scaffolds of HA, determined their chemical, percolation and mechanical features, and ran an in-depth pilot study in the sheep with a systematic comparison to the Bio-OssⓇ reference. Our results clearly show the high bone-forming capability of such scaffolds, with outcomes even better than Bio-OssⓇ at short implantation time. This preclinical work provides quantitative data validating the relevance of such TMPS porous scaffolds for bone regeneration in view of clinical evaluation.
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Affiliation(s)
- Islam Bouakaz
- CERHUM - PIMW, 4000 Liège, Belgium; CIRIMAT, Université de Toulouse, CNRS / Toulouse INP / UT3, 31030 Toulouse, France
| | - Christophe Drouet
- CIRIMAT, Université de Toulouse, CNRS / Toulouse INP / UT3, 31030 Toulouse, France.
| | - David Grossin
- CIRIMAT, Université de Toulouse, CNRS / Toulouse INP / UT3, 31030 Toulouse, France
| | | | - Grégory Nolens
- CERHUM - PIMW, 4000 Liège, Belgium; Faculty of Medicine, University of Namur, 5000 Namur, Belgium.
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Kong D, Wang Q, Huang J, Zhang Z, Wang X, Han Q, Shi Y, Ji R, Li Y. Design and manufacturing of biomimetic scaffolds for bone repair inspired by bone trabeculae. Comput Biol Med 2023; 165:107369. [PMID: 37625259 DOI: 10.1016/j.compbiomed.2023.107369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/13/2023] [Accepted: 08/12/2023] [Indexed: 08/27/2023]
Abstract
Porous scaffold (PorS) implants, particularly those that mimic the structural features of natural cancellous bone (NCanB), are increasingly essential for the treatment of large-area bone defects. However, the mechanical properties of NCanB-based bionic bone scaffold (BioS) and its performance as a bone repair material have not been fully explored. This study investigates the effect of bionic structure parameters on the mechanical properties and bone reconstruction performance of BioS. Using laser powder bed fusion (L-PBF) technology, different BioS with various structural parameters were created and evaluated using Micro-CT, compression testing, Finite Element (FE) Simulation, and computational fluid dynamics (CFD), and compared to commonly used clinical PorS. Assess the capacity of the BioS scaffold to support and enhance bone reconstruction following implantation through the evaluation of its mechanical properties, permeability, and fluid shear stress (FSS). BioS-85-90 and BioS-80-50 showed suitable mechanical properties, performed well in FE simulation of implantation, demonstrated outstanding abilities for osteoinductive ingrowth and bone tissue differentiation, and proved to be reliable materials for the reconstruction of bone defects. Therefore, BioS shows significant potential for clinical application as a bone reconstruction material, providing a solid foundation for the integration of tissue engineering and bionic design.
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Affiliation(s)
- Deyin Kong
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China
| | - Qing Wang
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China
| | - Jiangeng Huang
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China
| | - Zhihui Zhang
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China; Liaoning Academy of Materials, Shenyang 110167, China.
| | - Xiebin Wang
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan, China
| | - Qing Han
- Department of Orthopedics, Second Hospital of Jilin University, Changchun, China
| | - Yanbin Shi
- School of Mechanical & Automotive Engineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Ran Ji
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China
| | - Yiling Li
- Key Laboratory of Bionic Engineering, Ministry of Education, College of Biological and Agricultural Engineering, Jilin University, Changchun, China
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5
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Alvarado-Hernández F, Mihalcea E, Jimenez O, Macías R, Olmos L, López-Baltazar EA, Guevara-Martinez S, Lemus-Ruiz J. Design of Ti64/Ta Hybrid Materials by Powder Metallurgy Mimicking Bone Structure. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4372. [PMID: 37374557 DOI: 10.3390/ma16124372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023]
Abstract
This work reports on the fabrication of a novel two-layer material composed of a porous tantalum core and a dense Ti6Al4V (Ti64) shell by powder metallurgy. The porous core was obtained by mixing Ta particles and salt space-holders to create large pores, the green compact was obtained by pressing. The sintering behavior of the two-layer sample was studied by dilatometry. The interface bonding between the Ti64 and Ta layers was analyzed by SEM, and the pore characteristics were analyzed by computed microtomography. Images showed that two distinct layers were obtained with a bonding achieved by the solid-state diffusion of Ta particles into Ti64 during sintering. The formation of β-Ti and α' martensitic phases confirmed the diffusion of Ta. The pore size distribution was in the size range of 80 to 500 µm, and a permeability value of 6 × 10-10 m2 was close to the trabecular bones one. The mechanical properties of the component were dominated mainly by the porous layer, and Young's modulus of 16 GPa was in the range of bones. Additionally, the density of this material (6 g/cm3) was much lower than the one of pure Ta, which helps to reduce the weight for the desired applications. These results indicate that structurally hybridized materials, also known as composites, with specific property profiles can improve the response to osseointegration for bone implant applications.
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Affiliation(s)
| | - Elena Mihalcea
- Unidad Académica de Ingeniería I, Universidad Autónoma de Zacatecas, Zacatecas 98000, Mexico
| | - Omar Jimenez
- CUCEI, Universidad de Guadalajara, Zapopan 45100, Mexico
| | - Rogelio Macías
- Tecnológico Nacional de México (IT Morelia), DEPI, Morelia 58120, Mexico
| | - Luis Olmos
- INICIT, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58060, Mexico
| | | | | | - José Lemus-Ruiz
- IIMM, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58060, Mexico
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6
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Ozulumba T, Montalbine AN, Ortiz-Cárdenas JE, Pompano RR. New tools for immunologists: models of lymph node function from cells to tissues. Front Immunol 2023; 14:1183286. [PMID: 37234163 PMCID: PMC10206051 DOI: 10.3389/fimmu.2023.1183286] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 04/20/2023] [Indexed: 05/27/2023] Open
Abstract
The lymph node is a highly structured organ that mediates the body's adaptive immune response to antigens and other foreign particles. Central to its function is the distinct spatial assortment of lymphocytes and stromal cells, as well as chemokines that drive the signaling cascades which underpin immune responses. Investigations of lymph node biology were historically explored in vivo in animal models, using technologies that were breakthroughs in their time such as immunofluorescence with monoclonal antibodies, genetic reporters, in vivo two-photon imaging, and, more recently spatial biology techniques. However, new approaches are needed to enable tests of cell behavior and spatiotemporal dynamics under well controlled experimental perturbation, particularly for human immunity. This review presents a suite of technologies, comprising in vitro, ex vivo and in silico models, developed to study the lymph node or its components. We discuss the use of these tools to model cell behaviors in increasing order of complexity, from cell motility, to cell-cell interactions, to organ-level functions such as vaccination. Next, we identify current challenges regarding cell sourcing and culture, real time measurements of lymph node behavior in vivo and tool development for analysis and control of engineered cultures. Finally, we propose new research directions and offer our perspective on the future of this rapidly growing field. We anticipate that this review will be especially beneficial to immunologists looking to expand their toolkit for probing lymph node structure and function.
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Affiliation(s)
- Tochukwu Ozulumba
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States
| | - Alyssa N. Montalbine
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, United States
| | - Jennifer E. Ortiz-Cárdenas
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States
- Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Rebecca R. Pompano
- Department of Chemistry, University of Virginia, Charlottesville, VA, United States
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States
- Carter Immunology Center and University of Virginia (UVA) Cancer Center, University of Virginia School of Medicine, Charlottesville, VA, United States
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7
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Cell–scaffold interactions in tissue engineering for oral and craniofacial reconstruction. Bioact Mater 2023; 23:16-44. [DOI: 10.1016/j.bioactmat.2022.10.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/22/2022] [Accepted: 10/30/2022] [Indexed: 11/09/2022] Open
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The Effect of Tortuosity on Permeability of Porous Scaffold. Biomedicines 2023; 11:biomedicines11020427. [PMID: 36830961 PMCID: PMC9953537 DOI: 10.3390/biomedicines11020427] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/25/2023] [Accepted: 01/26/2023] [Indexed: 02/05/2023] Open
Abstract
In designing porous scaffolds, permeability is essential to consider as a function of cell migration and bone tissue regeneration. Good permeability has been achieved by mimicking the complexity of natural cancellous bone. In this study, a porous scaffold was developed according to the morphological indices of cancellous bone (porosity, specific surface area, thickness, and tortuosity). The computational fluid dynamics method analyzes the fluid flow through the scaffold. The permeability values of natural cancellous bone and three types of scaffolds (cubic, octahedron pillar, and Schoen's gyroid) were compared. The results showed that the permeability of the Negative Schwarz Primitive (NSP) scaffold model was similar to that of natural cancellous bone, which was in the range of 2.0 × 10-11 m2 to 4.0 × 10-10 m2. In addition, it was observed that the tortuosity parameter significantly affected the scaffold's permeability and shear stress values. The tortuosity value of the NSP scaffold was in the range of 1.5-2.8. Therefore, tortuosity can be manipulated by changing the curvature of the surface scaffold radius to obtain a superior bone tissue engineering construction supporting cell migration and tissue regeneration. This parameter should be considered when making new scaffolds, such as our NSP. Such efforts will produce a scaffold architecturally and functionally close to the natural cancellous bone, as demonstrated in this study.
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Evans LM, Sözümert E, Keenan BE, Wood CE, du Plessis A. A Review of Image-Based Simulation Applications in High-Value Manufacturing. ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING : STATE OF THE ART REVIEWS 2023; 30:1495-1552. [PMID: 36685137 PMCID: PMC9847465 DOI: 10.1007/s11831-022-09836-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/15/2022] [Indexed: 06/17/2023]
Abstract
Image-Based Simulation (IBSim) is the process by which a digital representation of a real geometry is generated from image data for the purpose of performing a simulation with greater accuracy than with idealised Computer Aided Design (CAD) based simulations. Whilst IBSim originates in the biomedical field, the wider adoption of imaging for non-destructive testing and evaluation (NDT/NDE) within the High-Value Manufacturing (HVM) sector has allowed wider use of IBSim in recent years. IBSim is invaluable in scenarios where there exists a non-negligible variation between the 'as designed' and 'as manufactured' state of parts. It has also been used for characterisation of geometries too complex to accurately draw with CAD. IBSim simulations are unique to the geometry being imaged, therefore it is possible to perform part-specific virtual testing within batches of manufactured parts. This novel review presents the applications of IBSim within HVM, whereby HVM is the value provided by a manufactured part (or conversely the potential cost should the part fail) rather than the actual cost of manufacturing the part itself. Examples include fibre and aggregate composite materials, additive manufacturing, foams, and interface bonding such as welding. This review is divided into the following sections: Material Characterisation; Characterisation of Manufacturing Techniques; Impact of Deviations from Idealised Design Geometry on Product Design and Performance; Customisation and Personalisation of Products; IBSim in Biomimicry. Finally, conclusions are drawn, and observations made on future trends based on the current state of the literature.
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Affiliation(s)
- Llion Marc Evans
- Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN UK
- United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB UK
| | - Emrah Sözümert
- Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN UK
| | - Bethany E. Keenan
- Cardiff School of Engineering, Cardiff University, Cardiff, CF24 3AA UK
| | - Charles E. Wood
- School of Mechanical & Design Engineering, University of Portsmouth, Portsmouth, PO1 3DJ UK
| | - Anton du Plessis
- Object Research Systems, Montreal, H3B 1A7 Canada
- Research Group 3DInnovation, Stellenbosch University, Stellenbosch, 7602 South Africa
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10
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Zhao Z, Li J, Yao D, Wei Y. Mechanical and permeability properties of porous scaffolds developed by a Voronoi tessellation for bone tissue engineering. J Mater Chem B 2022; 10:9699-9712. [PMID: 36398681 DOI: 10.1039/d2tb01478e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Irregular porous structures for guided bone regeneration applications have gained increasing attention as they are similar to human bone and more suitable for bone tissue growth. However, pore irregularity as a critical characteristic has been poorly explored. This study proposed a method for parametrically designing porous scaffolds based on a Voronoi tessellation which were manufactured by selective laser sintering (SLS) using the polyamide 12 (PA12) material. The deformation mechanism and energy absorption properties of the prepared Voronoi scaffolds were investigated by quasi-static compression experiments. The results demonstrated that the Voronoi scaffold underwent bending deformation subsequent to transverse expansion under compression, and the Voronoi scaffold simultaneously had been indicated to be effective in improving the carrying capacity and energy absorption performance. Subsequently, computational fluid dynamics (CFD) and cell proliferation tests were introduced to comprehensively assess the influence of the scaffolds on cell growth. CFD analysis showed that the permeability of the surveyed scaffolds is between 3.65 × 10-8 and 12.05 × 10-8 m2 similar to that of natural cancellous bone. The cell test expressed that the scaffold exhibits good cell activity, which can be used to promote cell adhesion and migration with superior potential for development and application.
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Affiliation(s)
- Ze Zhao
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.
| | - Junchao Li
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.
| | - Dingrou Yao
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.
| | - Yuan Wei
- College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.
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Sodium Alginate/Chitosan Scaffolds for Cardiac Tissue Engineering: The Influence of Its Three-Dimensional Material Preparation and the Use of Gold Nanoparticles. Polymers (Basel) 2022; 14:polym14163233. [PMID: 36015490 PMCID: PMC9414310 DOI: 10.3390/polym14163233] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 11/17/2022] Open
Abstract
Natural biopolymer scaffolds and conductive nanomaterials have been widely used in cardiac tissue engineering; however, there are still challenges in the scaffold fabrication, which include enhancing nutrient delivery, biocompatibility and properties that favor the growth, maturation and functionality of the generated tissue for therapeutic application. In the present work, different scaffolds prepared with sodium alginate and chitosan (alginate/chitosan) were fabricated with and without the addition of metal nanoparticles and how their fabrication affects cardiomyocyte growth was evaluated. The scaffolds (hydrogels) were dried by freeze drying using calcium gluconate as a crosslinking agent, and two types of metal nanoparticles were incorporated, gold (AuNp) and gold plus sodium alginate (AuNp+Alg). A physicochemical characterization of the scaffolds was carried out by swelling, degradation, permeability and infrared spectroscopy studies. The results show that the scaffolds obtained were highly porous (>90%) and hydrophilic, with swelling percentages of around 3000% and permeability of the order of 1 × 10−8 m2. In addition, the scaffolds proposed favored adhesion and spheroid formation, with cardiac markers expression such as tropomyosin, troponin I and cardiac myosin. The incorporation of AuNp+Alg increased cardiac protein expression and cell proliferation, thus demonstrating their potential use in cardiac tissue engineering.
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12
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Hydrogels as Corneal Stroma Substitutes for In Vitro Evaluation of Drug Ocular Permeation. Pharmaceutics 2022; 14:pharmaceutics14040850. [PMID: 35456684 PMCID: PMC9027330 DOI: 10.3390/pharmaceutics14040850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
Hydrogels are complex hydrophilic structures, consisting of crosslinked homopolymers or copolymers insoluble in water. Due to their controllable bio-physicochemical properties mimicking the morphology of the native extracellular matrix, they are a key part of a lot of research fields, including medicine, pharmaceutics, and tissue engineering. This paper was focused on the preparation and characterization of hydrogels from different blends of polyvinyl alcohol (PVA) with microcrystalline cellulose (MCC) and gelatin (GEL) at various ratios, and from gelatin and chitosan alone to understand their feasibility of utilizing as corneal stroma substitutes in permeability tests for drug candidate molecules in early stages of their development. The characterization was carried out by differential scanning calorimetry, electron microscopy (SEM), water content, mass loss, water permeability, wettability, and tensile stress–strain tests. After the physicochemical characterization, PVA/MCC blend and chitosan proved to be the most promising constructs, showing negligible mass loss after immersion in aqueous medium for two weeks and low hydrodynamic permeability. They were then employed in drug molecules permeation studies and these data were compared to that obtained through excised tissues. The results obtained showed that PVA/MCC hydrogels have similar mechanical and permeability properties to corneal stroma.
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13
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Fattahi E, Taheri S, Schilling AF, Becker T, Pörtner R. Generation and evaluation of input values for computational analysis of transport processes within tissue cultures. Eng Life Sci 2022; 22:681-698. [PMID: 36348656 PMCID: PMC9635004 DOI: 10.1002/elsc.202100128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/27/2022] [Accepted: 02/11/2022] [Indexed: 11/15/2022] Open
Abstract
Techniques for tissue culture have seen significant advances during the last decades and novel 3D cell culture systems have become available. To control their high complexity, experimental techniques and their Digital Twins (modelling and computational tools) are combined to link different variables to process conditions and critical process parameters. This allows a rapid evaluation of the expected product quality. However, the use of mathematical simulation and Digital Twins is critically dependent on the precise description of the problem and correct input parameters. Errors here can lead to dramatically wrong conclusions. The intention of this review is to provide an overview of the state‐of‐the‐art and remaining challenges with respect to generating input values for computational analysis of mass and momentum transport processes within tissue cultures. It gives an overview on relevant aspects of transport processes in tissue cultures as well as modelling and computational tools to tackle these problems. Further focus is on techniques used for the determination of cell‐specific parameters and characterization of culture systems, including sensors for on‐line determination of relevant parameters. In conclusion, tissue culture techniques are well‐established, and modelling tools are technically mature. New sensor technologies are on the way, especially for organ chips. The greatest remaining challenge seems to be the proper addressing and handling of input parameters required for mathematical models. Following Good Modelling Practice approaches when setting up and validating computational models is, therefore, essential to get to better estimations of the interesting complex processes inside organotypic tissue cultures in the future.
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Affiliation(s)
- Ehsan Fattahi
- Chair of Brewing and Beverage Technology TUM School of Life Sciences Technische Universität München Freising Germany
| | - Shahed Taheri
- Department of Trauma Surgery Orthopaedics and Plastic Surgery University Medical Center Göttingen Göttingen Germany
| | - Arndt F. Schilling
- Department of Trauma Surgery Orthopaedics and Plastic Surgery University Medical Center Göttingen Göttingen Germany
| | - Thomas Becker
- Chair of Brewing and Beverage Technology TUM School of Life Sciences Technische Universität München Freising Germany
| | - Ralf Pörtner
- Institute of Bioprocess and Biosystems Engineering Hamburg University of Technology Hamburg Germany
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14
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Lopez Marquez A, Gareis IE, Dias FJ, Gerhard C, Lezcano MF. Methods to Characterize Electrospun Scaffold Morphology: A Critical Review. Polymers (Basel) 2022; 14:polym14030467. [PMID: 35160457 PMCID: PMC8839183 DOI: 10.3390/polym14030467] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/06/2022] [Accepted: 01/19/2022] [Indexed: 12/10/2022] Open
Abstract
Electrospun scaffolds can imitate the hierarchical structures present in the extracellular matrix, representing one of the main concerns of modern tissue engineering. They are characterized in order to evaluate their capability to support cells or to provide guidelines for reproducibility. The issues with widely used methods for morphological characterization are discussed in order to provide insight into a desirable methodology for electrospun scaffold characterization. Reported methods include imaging and physical measurements. Characterization methods harbor inherent limitations and benefits, and these are discussed and presented in a comprehensive selection matrix to provide researchers with the adequate tools and insights required to characterize their electrospun scaffolds. It is shown that imaging methods present the most benefits, with drawbacks being limited to required costs and expertise. By making use of more appropriate characterization, researchers will avoid measurements that do not represent their scaffolds and perhaps might discover that they can extract more characteristics from their scaffold at no further cost.
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Affiliation(s)
- Alex Lopez Marquez
- Faculty of Engineering and Health, University of Applied Sciences and Arts, 37085 Gottingen, Germany; (A.L.M.); (C.G.)
| | - Iván Emilio Gareis
- Laboratorio de Cibernética, Departamento de Bioingeniería, Facultad de Ingeniería, Universidad Nacional de Entre Ríos, Oro Verde 3100, Argentina;
| | - Fernando José Dias
- Research Centre for Dental Sciences CICO, Department of Integral Adults Dentistry, Dental School, Universidad de La Frontera, Temuco 4811230, Chile;
| | - Christoph Gerhard
- Faculty of Engineering and Health, University of Applied Sciences and Arts, 37085 Gottingen, Germany; (A.L.M.); (C.G.)
| | - María Florencia Lezcano
- Laboratorio de Cibernética, Departamento de Bioingeniería, Facultad de Ingeniería, Universidad Nacional de Entre Ríos, Oro Verde 3100, Argentina;
- Research Centre for Dental Sciences CICO, Department of Integral Adults Dentistry, Dental School, Universidad de La Frontera, Temuco 4811230, Chile;
- Correspondence:
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15
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Novel dual-flow perfusion bioreactor for in vitro pre-screening of nanoparticles delivery: design, characterization and testing. Bioprocess Biosyst Eng 2021; 44:2361-2374. [PMID: 34304344 DOI: 10.1007/s00449-021-02609-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
An advanced dual-flow perfusion bioreactor with a simple and compact design was developed and evaluated as a potential apparatus to reduce the gap between animal testing and drug administration to human subjects in clinical trials. All the experimental tests were carried out using an ad hoc Poly Lactic Acid (PLLA) scaffold synthesized via Thermally Induced Phase Separation (TIPS). The bioreactor shows a tunable radial flow throughout the microporous matrix of the scaffold. The radial perfusion was quantified both with permeability tests and with a mathematical model, applying a combination of Darcy's Theory, Bernoulli's Equation, and Poiseuille's Law. Finally, a diffusion test allowed to investigate the efficacy of the radial flow using Polymeric Fluorescent Nanoparticles (FNPs) mimicking drug/colloidal carriers. These tests confirmed the ability of our bioreactor to create a uniform distribution of particles inside porous matrices. All the findings candidate our system as a potential tool for drug pre-screening testing with a cost and time reduction over animal models.
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16
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Fu M, Wang F, Lin G. Design and research of bone repair scaffold based on two-way fluid-structure interaction. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 204:106055. [PMID: 33784546 DOI: 10.1016/j.cmpb.2021.106055] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Porous bone repair scaffolds are an important method of repairing bone defects. Fluid flow in the scaffold plays a vital role in tissue differentiation and permeability and fluid shear stress (FSS) are two important factors. The differentiation of bone tissue depends on the osteogenic differentiation of cells, FSS affects cell proliferation and differentiation, and permeability affects the transportation of nutrients and metabolic waste. Therefore, it is necessary to better understand and analyze the FSS on the cell surface and the permeability of the scaffold to obtain better osteogenic performance. METHODS In this study, computational fluid dynamics (CFD) was used to analyze fluid flow in the scaffold. Three structures and nine scaffold unit cell models were designed and the cell models were loaded onto the scaffold surface. Considering cell deformability, the two-way fluid-structure interaction (FSI) method was used to evaluate the FSS on the cell surface. RESULTS The simulation results showed that as the pore size of the scaffold increases, its permeability increases and the FSS decreases. The FSS received on the cell surface was much larger than scaffold surface. Moreover the FSS on the cell surface was distributed in steps. CONCLUSIONS The results showed the permeability of all models matches that of human bone tissue. Based on the cell surface FSS as the criterion, it was found that the spherical-560 scaffold exhibited the best osteogenic performance. This provided a strategy to design a better bone repair scaffold from biological aspects.
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Affiliation(s)
- Mengguang Fu
- School of Mechanical and Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
| | - Fei Wang
- School of Mechanical and Automotive Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
| | - Guimei Lin
- School of Pharmaceutical Science, Shandong University, Jinan 250012, China
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17
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Foam Replica Method in the Manufacturing of Bioactive Glass Scaffolds: Out-of-Date Technology or Still Underexploited Potential? MATERIALS 2021; 14:ma14112795. [PMID: 34073945 PMCID: PMC8197364 DOI: 10.3390/ma14112795] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 01/19/2023]
Abstract
Since 2006, the foam replica method has been commonly recognized as a valuable technology for the production of highly porous bioactive glass scaffolds showing three-dimensional, open-cell structures closely mimicking that of natural trabecular bone. Despite this, there are important drawbacks making the usage of foam-replicated glass scaffolds a difficult achievement in clinical practice; among these, certainly the high operator-dependency of the overall manufacturing process is one of the most crucial, limiting the scalability to industrial production and, thus, the spread of foam-replicated synthetic bone substitutes for effective use in routine management of bone defect. The present review opens a window on the versatile world of the foam replica technique, focusing the dissertation on scaffold properties analyzed in relation to various processing parameters, in order to better understand which are the real issues behind the bottleneck that still puts this technology on the Olympus of the most used techniques in laboratory practice, without moving, unfortunately, to a more concrete application. Specifically, scaffold morphology, mechanical and mass transport properties will be reviewed in detail, considering the various templates proposed till now by several research groups all over the world. In the end, a comprehensive overview of in vivo studies on bioactive glass foams will be provided, in order to put an emphasis on scaffold performances in a complex three-dimensional environment.
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18
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Brown DM, Pardue MT, Ethier CR. A biphasic approach for characterizing tensile, compressive and hydraulic properties of the sclera. J R Soc Interface 2021; 18:20200634. [PMID: 33468024 PMCID: PMC7879763 DOI: 10.1098/rsif.2020.0634] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/15/2020] [Indexed: 11/12/2022] Open
Abstract
Measuring the biomechanical properties of the mouse sclera is of great interest: altered scleral properties are features of many common ocular pathologies, and the mouse is a powerful tool for studying genetic factors in disease, yet the small size of the mouse eye and its thin sclera make experimental measurements in the mouse difficult. Here, a poroelastic material model is used to analyse data from unconfined compression testing of both pig and mouse sclera, and the tensile modulus, compressive modulus and permeability of the sclera are obtained at three levels of compressive strain. Values for all three properties were comparable to previously reported values measured by tests specific for each property. The repeatability of the approach was evaluated using a test-retest experimental paradigm on pig sclera, and tensile stiffness and permeability measurements were found to be reasonably repeatable. The intrinsic material properties of the mouse sclera were measured for the first time. Tensile stiffness and permeability of the sclera in both species were seen to be dependent on the state of compressive strain. We conclude that unconfined compression testing of sclera, when analysed with poroelastic theory, is a powerful tool to phenotype mouse scleral changes in future genotype-phenotype association studies.
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Affiliation(s)
- Dillon M. Brown
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
- Atlanta Veterans Affairs Healthcare System, 1670 Clairmont Rd, Atlanta, GA, 30033, USA
| | - Machelle T. Pardue
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
- Atlanta Veterans Affairs Healthcare System, 1670 Clairmont Rd, Atlanta, GA, 30033, USA
| | - C. Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
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19
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Fiume E, Schiavi A, Orlygsson G, Bignardi C, Verné E, Baino F. Comprehensive assessment of bioactive glass and glass-ceramic scaffold permeability: experimental measurements by pressure wave drop, modelling and computed tomography-based analysis. Acta Biomater 2021; 119:405-418. [PMID: 33091624 DOI: 10.1016/j.actbio.2020.10.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/10/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022]
Abstract
Proper microstructural and transport properties are fundamental requirements for a suitable scaffold design and realization in tissue engineering applications. Scaffold microstructure (i.e. pore size, shape and distribution) and transport properties (i.e. intrinsic permeability), are commonly recognized as the key parameters related to the biological performance, such as cell attachment, penetration depth and tissue vascularization. While pore characteristics are relatively easy to asses, accurate and reliable evaluation of permeability still remains a challenge. In the present study, the microstructural properties of foam-replicated bioactive glass-derived scaffolds (basic composition 47.5SiO2-2.5P2O5-20CaO-10MgO-10Na2O-10K2O mol.%) were determined as function of the sintering temperature within the range 600-850°C, identified on the basis of thermal analyses that were previously performed on the material. Scaffolds with total porosity between 55 and 84 vol.% and trabecular-like architecture were obtained, with pore morphological features varying according to the sintering temperature. Mathematical modelling, supported by micro-computed tomography (μ-CT) imaging, was implemented to selectively investigate the effect of different pore features on intrinsic permeability, which was determined by laminar airflow alternating pressure wave drop measurements and found to be within 0.051-2.811·10-10 m2. The calculated effective porosity of the scaffolds was in the range of 46 to 66 vol.%, while the average pore diameter assessed by μ-CT varied between 220 and 780 μm, where the values in the lower range were observed for higher sintering temperatures (750-850°C). Experimental results were critically discussed by means of a robust statistical analysis. Finally, the complete microstructural characterization of the scaffolds was achieved by applying the general constitutive equation based on Forchheimer's theory.
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20
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Yang Y, Abdalla S. Scaffolds of Macroporous Tannin Spray With Human-Induced Pluripotent Stem Cells. Front Bioeng Biotechnol 2020; 8:951. [PMID: 33178667 PMCID: PMC7593690 DOI: 10.3389/fbioe.2020.00951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/23/2020] [Indexed: 12/04/2022] Open
Abstract
Skeletal defects resulting from trauma and disease represent a major clinical problem worldwide exacerbated further by global population growth and an increasing number of elderly people. As treatment options are limited, bone tissue engineering opens the doors to start an infinite amount of tissue/bone biomaterials having excellent therapeutic potential for the management of clinical cases characterized by severe bone loss. Bone engineering relies on the use of compliant biomaterial scaffolds, osteocompetent cells, and biologically active agents. In fact, we are interested to use a new natural material, tannin. Among other materials, porous tannin spray-dried powder (PTSDP) has been approved for human use. We use PTSDP as reconstructive materials with low cost, biocompatibility, and potential ability to be replaced by bone in vivo. In this study, macro PTSDP scaffolds with defined geometry, porosity, and mechanical properties are manufactured using a combination of casting technology and porogen leaching, by mixing PTSDP and hydroxyapatite Ca10(PO4)6(OH)2 with polyethylene glycol macroparticles. Our results show that the scaffolds developed in this work support attachment, long-term viability, and osteogenic differentiation of human-induced pluripotent stem cell-derived mesenchymal progenitors. The combination of select macroporous PTSDP scaffolds with patient-specific osteocompetent cells offers new opportunities to grow autologous bone grafts with enhanced clinical potential for complex skeletal reconstructions.
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Affiliation(s)
- Yongbo Yang
- Department of Orthopedics (Spine), Xinxiang Central Hospital, Xinxiang City, China
| | - Soliman Abdalla
- Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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21
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Carbonaro D, Putame G, Castaldo C, Meglio FD, Siciliano K, Belviso I, Romano V, Sacco AM, Schonauer F, Montagnani S, Audenino AL, Morbiducci U, Gallo D, Massai D. A low-cost scalable 3D-printed sample-holder for agitation-based decellularization of biological tissues. Med Eng Phys 2020; 85:7-15. [DOI: 10.1016/j.medengphy.2020.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 07/31/2020] [Accepted: 09/12/2020] [Indexed: 12/01/2022]
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22
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Santos J, Pires T, Gouveia BP, Castro AP, Fernandes PR. On the permeability of TPMS scaffolds. J Mech Behav Biomed Mater 2020; 110:103932. [DOI: 10.1016/j.jmbbm.2020.103932] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/03/2020] [Accepted: 06/10/2020] [Indexed: 10/23/2022]
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23
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Guo Z, Grijpma D, Poot A. Leachable Poly(Trimethylene Carbonate)/CaCO 3 Composites for Additive Manufacturing of Microporous Vascular Structures. MATERIALS 2020; 13:ma13153435. [PMID: 32759759 PMCID: PMC7435882 DOI: 10.3390/ma13153435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/10/2020] [Accepted: 07/27/2020] [Indexed: 01/21/2023]
Abstract
The aim of this work was to fabricate microporous poly(trimethylene carbonate) (PTMC) vascular structures by stereolithography (SLA) for applications in tissue engineering and organ models. Leachable CaCO3 particles with an average size of 0.56 μm were used as porogens. Composites of photocrosslinkable PTMC and CaCO3 particles were cast on glass plates, crosslinked by ultraviolet light treatment and leached in watery HCl solutions. In order to obtain interconnected pore structures, the PTMC/CaCO3 composites had to contain at least 30 vol % CaCO3. Leached PTMC films had porosities ranging from 33% to 71% and a pore size of around 0.5 μm. The mechanical properties of the microporous PTMC films matched with those of natural blood vessels. Resins based on PTMC/CaCO3 composites with 45 vol % CaCO3 particles were formulated and successfully used to build vascular structures of various shapes and sizes by SLA. The intrinsic permeabilities of the microporous PTMC films and vascular structures were at least one order of magnitude higher than reported for the extracellular matrix, indicating no mass transfer limitations in the case of cell seeding.
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24
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Tupin S, Ohta M. Assessing Porous Media Permeability in Non-Darcy Flow: A Re-Evaluation Based on the Forchheimer Equation. MATERIALS 2020; 13:ma13112535. [PMID: 32503159 PMCID: PMC7321472 DOI: 10.3390/ma13112535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 12/20/2022]
Abstract
In a recent paper published in Materials (Castro et al., 2019), the permeability evaluation of triple periodic minimum surface samples was carried out experimentally. Darcy's law was used under unsuitable conditions, resulting in an underestimation of the results. In this comment, we highlight the problem and propose a new estimation of the permeability using the Forchheimer equation, which is better suited to the experimental conditions.
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25
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Conrad TL, Roeder RK. Effects of porogen morphology on the architecture, permeability, and mechanical properties of hydroxyapatite whisker reinforced polyetheretherketone scaffolds. J Mech Behav Biomed Mater 2020; 106:103730. [DOI: 10.1016/j.jmbbm.2020.103730] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/08/2020] [Accepted: 03/13/2020] [Indexed: 11/16/2022]
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26
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Erickson CB, Newsom JP, Fletcher NA, Feuer ZM, Yu Y, Rodriguez‐Fontan F, Hadley Miller N, Krebs MD, Payne KA. In vivo degradation rate of alginate–chitosan hydrogels influences tissue repair following physeal injury. J Biomed Mater Res B Appl Biomater 2020; 108:2484-2494. [DOI: 10.1002/jbm.b.34580] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/14/2020] [Accepted: 01/25/2020] [Indexed: 01/15/2023]
Affiliation(s)
- Christopher B. Erickson
- Department of OrthopedicsUniversity of Colorado Anschutz Medical Campus Aurora Colorado
- Department of BioengineeringUniversity of Colorado Anschutz Medical Campus Aurora Colorado
| | - Jake P. Newsom
- Department of Chemical and Biological EngineeringColorado School of Mines Golden Colorado
| | - Nathan A. Fletcher
- Department of Chemical and Biological EngineeringColorado School of Mines Golden Colorado
| | - Zachary M. Feuer
- Gates Center for Regenerative MedicineUniversity of Colorado Anschutz Medical Campus Aurora Colorado
| | - Yangyi Yu
- Department of OrthopedicsUniversity of Colorado Anschutz Medical Campus Aurora Colorado
- Department of Orthopaedic SurgeryThe First Affiliated Hospital of Zhengzhou University Zhengzhou China
| | | | - Nancy Hadley Miller
- Department of OrthopedicsUniversity of Colorado Anschutz Medical Campus Aurora Colorado
| | - Melissa D. Krebs
- Department of Chemical and Biological EngineeringColorado School of Mines Golden Colorado
| | - Karin A. Payne
- Department of OrthopedicsUniversity of Colorado Anschutz Medical Campus Aurora Colorado
- Gates Center for Regenerative MedicineUniversity of Colorado Anschutz Medical Campus Aurora Colorado
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27
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Ramazanilar M, Mojra A. Characterization of breast tissue permeability for detection of vascular breast tumors: An in vitro study. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 107:110222. [PMID: 31761188 DOI: 10.1016/j.msec.2019.110222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 09/14/2019] [Accepted: 09/17/2019] [Indexed: 01/20/2023]
Abstract
The biological tissue could be considered as a porous matrix filled with the interstitial fluid. The tumoral tissue has a different permeability from the healthy tissue. With regard to this knowledge, the main objective of the present study is to study the tissue permeability as a diagnostic parameter for the detection of breast cancer. To this end, the healthy and the cancerous specimens of the breast tissue are taken from 17 female cases. All cancerous tumors are in the vascular phase of the growth. The samples undergo a uniaxial compression test by a robotic system while the strain rate is set to remain unchanged. Using the stress and the strain rate data, the strain-dependent permeability is determined, which is an exponential function of the strain level. The permeability function is identified by the initial permeability at the zero compressive strain and a material constant. Results show that the initial permeability of the healthy breast tissue is significantly different from the corresponding value for the cancerous tissue. For all cancerous samples, the permeability is less than the healthy tissue samples; as 40-70% reduction in the initial permeability is observed compared to the healthy breast tissue. The evaluation of the permeability between the healthy and the cancerous specimens is accompanied by the biopsy reports and observing structural images of the specimens using environmental scanning electron microscope. Based on the results, the permeability is suggested to have a diagnostic application for the detection of vascular breast tumors.
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Affiliation(s)
- M Ramazanilar
- Department of Mechanical Engineering, K. N. Toosi University of Technology, 15 Pardis St., Tehran, 1991943344, Iran.
| | - A Mojra
- Department of Mechanical Engineering, K. N. Toosi University of Technology, 15 Pardis St., Tehran, 1991943344, Iran.
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28
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Eufrásio-da-Silva T, Ruiz-Hernandez E, O'Dwyer J, Picazo-Frutos D, Duffy GP, Murphy BP. Enhancing medial layer recellularization of tissue-engineered blood vessels using radial microchannels. Regen Med 2019; 14:1013-1028. [PMID: 31746270 DOI: 10.2217/rme-2019-0011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aim: Cell repopulation of tissue-engineered vascular grafts (TEVGs) from decellularized arterial scaffolds is limited by dense concentric tunica media layers which impede cells migrating radially between the layers. We aimed to develop and validate a new microneedle device to modify decellularized carotid arteries with radial microchannels to enhance medial layer repopulation. Material & methods: Modified decellularized porcine arteries were seeded with rat mesenchymal stem cells using either standard longitudinal injection, or a dual vacuum-perfusion bioreactor. Mechanical tests were used to assess the arterial integrity following modification. Results & conclusion: The method herein achieved radial recellularization of arteries in vitro without significant loss of mechanical integrity, Thus, we report a novel method for successful radial repopulation of decellularized carotid artery-based tissue-engineered vascular grafts.
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Affiliation(s)
- Tatiane Eufrásio-da-Silva
- Department of Anatomy, Tissue Engineering Research Group (TERG), Royal College of Surgeons in Ireland (RCSI), Dublin, Ireland.,Trinity Centre for Biomedical Engineering (TCBE), Trinity Biomedical Sciences Institute, TCD, Dublin, Ireland.,Advanced Materials & BioEngineering Research Centre (AMBER), RCSI & TCD, Dublin, Ireland
| | - Eduardo Ruiz-Hernandez
- Advanced Materials & BioEngineering Research Centre (AMBER), RCSI & TCD, Dublin, Ireland.,School of Pharmacy & Pharmaceutical Sciences, Trinity College Dublin (TCD), Dublin, Ireland
| | - Joanne O'Dwyer
- Department of Anatomy, Tissue Engineering Research Group (TERG), Royal College of Surgeons in Ireland (RCSI), Dublin, Ireland.,School of Pharmacy, RCSI, Dublin, Ireland.,Anatomy, School of Medicine, College of Medicine Nursing & Health Sciences, National University of Ireland Galway, Galway, Ireland
| | - Dolores Picazo-Frutos
- Department of Anatomy, Tissue Engineering Research Group (TERG), Royal College of Surgeons in Ireland (RCSI), Dublin, Ireland.,School of Pharmacy, RCSI, Dublin, Ireland
| | - Garry P Duffy
- Department of Anatomy, Tissue Engineering Research Group (TERG), Royal College of Surgeons in Ireland (RCSI), Dublin, Ireland.,Trinity Centre for Biomedical Engineering (TCBE), Trinity Biomedical Sciences Institute, TCD, Dublin, Ireland.,Advanced Materials & BioEngineering Research Centre (AMBER), RCSI & TCD, Dublin, Ireland.,Anatomy, School of Medicine, College of Medicine Nursing & Health Sciences, National University of Ireland Galway, Galway, Ireland
| | - Bruce P Murphy
- Trinity Centre for Biomedical Engineering (TCBE), Trinity Biomedical Sciences Institute, TCD, Dublin, Ireland.,Advanced Materials & BioEngineering Research Centre (AMBER), RCSI & TCD, Dublin, Ireland.,Department of Mechanical & Manufacturing Engineering, TCD, Dublin, Ireland
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Frati C, Graiani G, Barbani N, Madeddu D, Falco A, Quaini F, Lazzeri L, Cascone MG, Rosellini E. Reinforced alginate/gelatin sponges functionalized by avidin/biotin-binding strategy: a novel cardiac patch. J Biomater Appl 2019; 34:975-987. [PMID: 31684794 DOI: 10.1177/0885328219886029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Caterina Frati
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Gallia Graiani
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Niccoletta Barbani
- Department of Civil and Industrial Engineering, University of Pisa, Pisa, Italy
| | - Denise Madeddu
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Angela Falco
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Federico Quaini
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Luigi Lazzeri
- Department of Civil and Industrial Engineering, University of Pisa, Pisa, Italy
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Biodegradable nanocomposite Fe–Ag load-bearing scaffolds for bone healing. J Mech Behav Biomed Mater 2019; 98:246-254. [DOI: 10.1016/j.jmbbm.2019.06.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 06/07/2019] [Accepted: 06/30/2019] [Indexed: 12/18/2022]
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Li Y, Jahr H, Pavanram P, Bobbert FSL, Paggi U, Zhang XY, Pouran B, Leeflang MA, Weinans H, Zhou J, Zadpoor AA. Additively manufactured functionally graded biodegradable porous iron. Acta Biomater 2019; 96:646-661. [PMID: 31302295 DOI: 10.1016/j.actbio.2019.07.013] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/03/2019] [Accepted: 07/09/2019] [Indexed: 11/28/2022]
Abstract
Additively manufactured (AM) functionally graded porous metallic biomaterials offer unique opportunities to satisfy the contradictory design requirements of an ideal bone substitute. However, no functionally graded porous structures have ever been 3D-printed from biodegradable metals, even though biodegradability is crucial both for full tissue regeneration and for the prevention of implant-associated infections in the long term. Here, we present the first ever report on AM functionally graded biodegradable porous metallic biomaterials. We made use of a diamond unit cell for the topological design of four different types of porous structures including two functionally graded structures and two reference uniform structures. Specimens were then fabricated from pure iron powder using selective laser melting (SLM), followed by experimental and computational analyses of their permeability, dynamic biodegradation behavior, mechanical properties, and cytocompatibility. It was found that the topological design with functional gradients controlled the fluid flow, mass transport properties and biodegradation behavior of the AM porous iron specimens, as up to 4-fold variations in permeability and up to 3-fold variations in biodegradation rate were observed for the different experimental groups. After 4 weeks of in vitro biodegradation, the AM porous scaffolds lost 5-16% of their weight. This falls into the desired range of biodegradation rates for bone substitution and confirms our hypothesis that topological design could indeed accelerate the biodegradation of otherwise slowly degrading metals, like iron. Even after 4 weeks of biodegradation, the mechanical properties of the specimens (i.e., E = 0.5-2.1 GPa, σy = 8-48 MPa) remained within the range of the values reported for trabecular bone. Design-dependent cell viability did not differ from gold standard controls for up to 48 h. This study clearly shows the great potential of AM functionally graded porous iron as a bone substituting material. Moreover, we demonstrate that complex topological design permits the control of mechanical properties, degradation behavior of AM porous metallic biomaterials. STATEMENT OF SIGNIFICANCE: No functionally graded porous structures have ever been 3D-printed from biodegradable metals, even though biodegradability is crucial both for full tissue regeneration and for the prevention of implant-associated infections in the long term. Here, we present the first report on 3D-printed functionally graded biodegradable porous metallic biomaterials. Our results suggest that topological design in general, and functional gradients in particular can be used as an important tool for adjusting the biodegradation behavior of AM porous metallic biomaterials. The biodegradation rate and mass transport properties of AM porous iron can be increased while maintaining the bone-mimicking mechanical properties of these biomaterials. The observations reported here underline the importance of proper topological design in the development of AM porous biodegradable metals.
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Affiliation(s)
- Y Li
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands.
| | - H Jahr
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany; Department of Orthopedic Surgery, Maastricht UMC+, Maastricht 6202 AZ, The Netherlands
| | - P Pavanram
- Department of Anatomy and Cell Biology, University Hospital RWTH Aachen, Aachen 52074, Germany
| | - F S L Bobbert
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - U Paggi
- 3D Systems - LayerWise NV, Grauwmeer 14, Leuven 3001, Belgium; KU Leuven Department of Mechanical Engineering, Kasteelpark Arenberg 44, Leuven 3001, Belgium
| | - X-Y Zhang
- Department of Mechanical Engineering, Tsinghua University, Beijing 10004, China
| | - B Pouran
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
| | - M A Leeflang
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - H Weinans
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands; Department of Orthopedics, UMC Utrecht, Heidelberglaan 100, Utrecht 3584CX, The Netherlands
| | - J Zhou
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
| | - A A Zadpoor
- Department of Biomechanical Engineering, Delft University of Technology, Delft 2628 CD, The Netherlands
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Lutzweiler G, Barthes J, Koenig G, Kerdjoudj H, Mayingi J, Boulmedais F, Schaaf P, Drenckhan W, Vrana NE. Modulation of Cellular Colonization of Porous Polyurethane Scaffolds via the Control of Pore Interconnection Size and Nanoscale Surface Modifications. ACS APPLIED MATERIALS & INTERFACES 2019; 11:19819-19829. [PMID: 31074959 DOI: 10.1021/acsami.9b04625] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Full-scale cell penetration within porous scaffolds is required to obtain functional connective tissue components in tissue engineering applications. For this aim, we produced porous polyurethane structures with well-controlled pore and interconnection sizes. Although the influence of the pore size on cellular behavior is widely studied, we focused on the impact of the size of the interconnections on the colonization by NIH 3T3 fibroblasts and Wharton's jelly-derived mesenchymal stem cells (WJMSCs). To render the material hydrophilic and allow good material wettability, we treated the material either by plasma or by polydopamine (PDA) coating. We show that cells weakly adhere on these surfaces. Keeping the average pore diameter constant at 133 μm, we compare two structures, one with LARGE (52 μm) and one with SMALL (27 μm) interconnection diameters. DNA quantification and extracellular matrix (ECM) production reveal that larger interconnections is more suitable for cells to move across the scaffold and form a three-dimensional cellular network. We argue that LARGE interconnections favor cell communication between different pores, which then favors the production of the ECM. Moreover, PDA treatment shows a truly beneficial effect on fibroblast viability and on matrix production, whereas plasma treatment shows the same effect for WJMSCs. We, therefore, claim that both pore interconnection size and surface treatment play a significant role to improve the quality of integration of tissue engineering scaffolds.
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Affiliation(s)
- G Lutzweiler
- Institut National de la Santé et de la Recherche Medicale, UMR_S 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Faculté de Chirurgie Dentaire , Université de Strasbourg , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
- Université de Strasbourg, CNRS, Institut Charles Sadron , 23 rue de Loess , 67034 Strasbourg , France
| | - J Barthes
- Protip Medical SAS , 8 Place de l'Hôpital , 67000 Strasbourg , France
| | - G Koenig
- Institut National de la Santé et de la Recherche Medicale, UMR_S 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Faculté de Chirurgie Dentaire , Université de Strasbourg , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
| | - H Kerdjoudj
- EA 4691, Biomateŕiaux et Inflammation en Site Osseux (BIOS), SFR-CAP Santé (FED4231), Université de Reims Champagne Ardenne , 51100 Reims , France
- UFR d'Odontologie, Université de Reims Champagne Ardenne , 51100 Reims , France
| | - J Mayingi
- Cetim Grand Est , 24a Rue d'Alsace , 67400 Illkirch-Graffenstaden , France
| | - F Boulmedais
- Université de Strasbourg, CNRS, Institut Charles Sadron , 23 rue de Loess , 67034 Strasbourg , France
| | - P Schaaf
- Institut National de la Santé et de la Recherche Medicale, UMR_S 1121 , 11 rue Humann , 67085 Strasbourg Cedex , France
- Faculté de Chirurgie Dentaire , Université de Strasbourg , 8 rue Sainte Elisabeth , 67000 Strasbourg , France
| | - W Drenckhan
- Université de Strasbourg, CNRS, Institut Charles Sadron , 23 rue de Loess , 67034 Strasbourg , France
| | - N E Vrana
- Protip Medical SAS , 8 Place de l'Hôpital , 67000 Strasbourg , France
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Permeability versus Design in TPMS Scaffolds. MATERIALS 2019; 12:ma12081313. [PMID: 31013656 PMCID: PMC6515433 DOI: 10.3390/ma12081313] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/15/2019] [Accepted: 04/20/2019] [Indexed: 11/17/2022]
Abstract
Scaffolds for bone tissue engineering are porous structures that serve as support for cellular growth and, therefore, new tissue formation. The present work assessed the influence of the porous architecture of triply periodic minimal surface (TPMS) scaffolds on their macroscopic permeability behavior, combining numerical and experimental methods. The TPMS scaffolds considered were Schwartz D, Schwartz P, and Gyroid, which have been previously studied for bone tissue engineering, with 70% porosity. On the experimental side, these scaffolds were produced by MultiJet 3D printing and tested for fluid passage to calculate their permeability through Darcy’s Law. On the numerical side, finite element (FE) models of the scaffolds were simulated on ABAQUS® for fluid passage under compression to assess potential fluid concentration spots. The outcomes revealed that the design of the unit cell had a noticeable effect on both calculated permeability and FE computed fluid flow velocity, regardless of the identical porosity, with the Gyroid scaffold having higher permeability and the Schwartz P a lower probability of fluid trapping. Schwartz D had the worst outcomes in both testing modalities, so these scaffolds would most likely be the last choice for promoting cell differentiation onto bone cells. Gyroid and Schwartz P would be up for selection depending on the application and targeted bone tissue.
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Baino F, Barberi J, Fiume E, Orlygsson G, Massera J, Verné E. Robocasting of Bioactive SiO 2-P 2O 5-CaO-MgO-Na 2O-K 2O Glass Scaffolds. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:5153136. [PMID: 31098008 PMCID: PMC6487107 DOI: 10.1155/2019/5153136] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/12/2019] [Indexed: 11/21/2022]
Abstract
Bioactive silicate glass scaffolds were fabricated by a robocasting process in which all the movements of the printing head were programmed by compiling a script (text file). A printable ink made of glass powder and Pluronic F-127, acting as a binder, was extruded to obtain macroporous scaffolds with a grid-like three-dimensional structure. The scaffold architecture was investigated by scanning electron microscopy and microtomographic analysis, which allowed quantifying the microstructural parameters (pore size 150-180 μm and strut diameter 300 μm). In vitro tests in simulated body fluid (SBF) confirmed the apatite-forming ability (i.e., bioactivity) of the scaffolds. The compressive strength (around 10 MPa for as-produced scaffolds) progressively decreased during immersion in SBF (3.3 MPa after 4 weeks) but remains acceptable for bone repair applications. Taken together, these results (adequate porosity and mechanical strength as well as bioactivity) support the potential suitability of the prepared scaffolds for bone substitution.
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Affiliation(s)
- Francesco Baino
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
| | - Jacopo Barberi
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
| | - Elisa Fiume
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
- Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Turin, Italy
| | - Gissur Orlygsson
- Department of Materials, Biotechnology and Energy, Innovation Center Iceland (ICI), Reykjavik, Iceland
| | - Jonathan Massera
- Faculty of Medicine and Health Technology, University of Tampere, Tampere, Finland
| | - Enrica Verné
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, Turin, Italy
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Entezari A, Roohani I, Li G, Dunstan CR, Rognon P, Li Q, Jiang X, Zreiqat H. Architectural Design of 3D Printed Scaffolds Controls the Volume and Functionality of Newly Formed Bone. Adv Healthc Mater 2019; 8:e1801353. [PMID: 30536610 DOI: 10.1002/adhm.201801353] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/17/2018] [Indexed: 02/01/2023]
Abstract
The successful regeneration of functional bone tissue in critical-size defects remains a significant clinical challenge. To address this challenge, synthetic bone scaffolds are widely developed, but remarkably few are translated to the clinic due to poor performance in vivo. Here, it is demonstrated how architectural design of 3D printed scaffolds can improve in vivo outcomes. Ceramic scaffolds with different pore sizes and permeabilities, but with similar porosity and interconnectivity, are implanted in rabbit calvaria for 12 weeks, and then the explants are harvested for microcomputed tomography evaluation of the volume and functionality of newly formed bone. The results indicate that scaffold pores should be larger than 390 µm with an upper limit of 590 µm to enhance bone formation. It is also demonstrated that a bimodal pore topology-alternating large and small pores-enhances the volume and functionality of new bone substantially. Moreover, bone formation results indicate that stiffness of new bone is highly influenced by the scaffold's permeability in the direction concerned. This study demonstrates that manipulating pore size and permeability in a 3D printed scaffold architecture provides a useful strategy for enhancing bone regeneration outcomes.
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Affiliation(s)
- Ali Entezari
- Australian Research Council Centre in Innovative BioEngineering School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW 2006 Australia
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
| | - Iman Roohani
- School of Chemistry University of New South Wales NSW 2052 Australia
| | - Guanglong Li
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
- Department of Prosthodontics Oral Bioengineering and Regenerative Medicine Lab Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine 639 Zhizaoju Road Shanghai 200011 China
| | - Colin R. Dunstan
- Australian Research Council Centre in Innovative BioEngineering School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW 2006 Australia
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
| | - Pierre Rognon
- School of Civil Engineering University of Sydney NSW 2006 Australia
| | - Qing Li
- Australian Research Council Centre in Innovative BioEngineering School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW 2006 Australia
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
| | - Xinquan Jiang
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
- Department of Prosthodontics Oral Bioengineering and Regenerative Medicine Lab Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine 639 Zhizaoju Road Shanghai 200011 China
| | - Hala Zreiqat
- Australian Research Council Centre in Innovative BioEngineering School of Aerospace Mechanical and Mechatronic Engineering University of Sydney NSW 2006 Australia
- Shanghai‐Sydney Joint Bioengineering and Regenerative Medicine Lab at Shanghai JiaoTong Shanghai 200011 China
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36
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Offeddu GS, Axpe E, Harley BAC, Oyen ML. Relationship between permeability and diffusivity in polyethylene glycol hydrogels. AIP ADVANCES 2018; 8:105006. [PMID: 30345162 PMCID: PMC6172138 DOI: 10.1063/1.5036999] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/10/2018] [Indexed: 05/22/2023]
Abstract
The transport properties of hydrogels largely affect their performance in biomedical applications ranging from cell culture scaffolds to drug delivery systems. Solutes can move through the polymer mesh as a result of concentration gradients in the interstitial fluid or pressure gradients that move the fluid and solutes simultaneously. The relationship between the two modalities of transport in hydrogels can provide insight for the design of materials that can function effectively in the dynamic conditions experienced in vitro and in vivo, yet this correlation has not been previously elucidated. Here, fluorescence recovery after photobleaching (FRAP) is used to measure the diffusivity of dextran molecules of different size within polyethylene glycol hydrogels. Spherical indentation analyzed in a poroelastic framework is used to measure the permeability to fluid flow of the same hydrogels. It is found that while the diffusivity varies with exp(ξ -2), where ξ is the mesh size of the hydrogels, it also varies with exp(k -1), where k is the intrinsic permeability. For the same hydrogel structure, diffusive transport is affected by the solute size, while convective transport is unaffected. As spherical indentation is a reliable, quick and non-destructive testing method for hydrated soft materials, the relationship provides the means to faster assessment of the transport properties of hydrogels and, ultimately, of their effective use in biomedical applications.
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Affiliation(s)
- G. S. Offeddu
- The Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, United Kingdom
| | - E. Axpe
- The Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, United Kingdom
| | - B. A. C. Harley
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 110 Roger Adams Lab., 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - M. L. Oyen
- The Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, United Kingdom
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37
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Pawelec KM, Koffler J, Shahriari D, Galvan A, Tuszynski MH, Sakamoto J. Microstructure and in vivo characterization of multi-channel nerve guidance scaffolds. ACTA ACUST UNITED AC 2018; 13:044104. [PMID: 29411711 DOI: 10.1088/1748-605x/aaad85] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In a previous study, we demonstrated a novel manufacturing approach to fabricate multi-channel scaffolds (MCS) for use in spinal cord injuries (SCI). In the present study, we extended similar materials processing technology to fabricate significantly longer (5X) porous poly caprolactone (PCL) MCS and evaluated their efficacy in 1 cm sciatic peripheral nerve injury (PNI) model. Due to the increase in MCS dimensions and the challenges that may arise in a longer nerve gap model, microstructural characterization involved MCS wall permeability to assess nutrient flow, topography, and microstructural uniformity to evaluate the potential for homogeneous linear axon guidance. It was determined that the wall permeability dramatically varied from 0.02 ± 0.01 × 10-13 to 21.7 ± 11.4 × 10-13 m2 for 50% and 70% porous PCL, respectively. Using interferometry, the porous PCL surface roughness was determined to be 10.7 ± 1.2 μm, which is believed to be sufficient to promote cell integration. Using micro computed tomography, the 3D MCS microstructure was determined to be uniform over 1 cm with an open lumen volume of 44.6% ± 3.6%. In vivo implantation, in the rat sciatic nerve model, over 4 weeks, demonstrated that MCS scaffolds maintained structural integrity, were biocompatible, and supported linear axon guidance and distal end egress over 1 cm. Taken together, this study demonstrated that MCS technology previously developed for the SCI is also relevant to longer nerve gap PNI.
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Affiliation(s)
- K M Pawelec
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, United States of America
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Ramírez-Rodríguez GB, Montesi M, Panseri S, Sprio S, Tampieri A, Sandri M. * Biomineralized Recombinant Collagen-Based Scaffold Mimicking Native Bone Enhances Mesenchymal Stem Cell Interaction and Differentiation. Tissue Eng Part A 2017. [PMID: 28637399 DOI: 10.1089/ten.tea.2017.0028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The need of synthetic bone grafts that recreate from macro- to nanoscale level the biochemical and biophysical cues of bone extracellular matrix has been a major driving force for the development of new generation of biomaterials. In this study, synthetic bone substitutes have been synthesized via biomimetic mineralization of a recombinant collagen type I-derived peptide (RCP), enriched in tri-amino acid sequence arginine-glycine-aspartate (RGD). Three-dimensional (3D) isotropic porous scaffolds of three different compositions are developed by freeze-drying: non-mineralized (RCP, as a control), mineralized (Ap/RCP), and mineralized scaffolds in the presence of magnesium (MgAp/RCP) that closely imitate bone composition. The effect of mineral phase on scaffold pore size, porosity, and permeability, as well as on their in vitro kinetic degradation, is evaluated. The ultimate goal is to investigate how chemical (i.e., surface chemistry and ion release from scaffold) together with physical signals (i.e., surface nanotopography) conferred via biomimetic mineralization can persuade and guide mesenchymal stem cell (MSC) interaction and fate. The three scaffold compositions showed optimum pore size and porosity for osteoconduction, without significant differences between them. The degradation tests confirmed that MgAp/RCP scaffolds presented higher reactivity under physiological condition compared to Ap/RCP ones. The in vitro study revealed an enhanced cell growth and proliferation on MgAp/RCP scaffolds at day 7, 14, and 21. Furthermore, MgAp/RCP scaffolds potentially promoted cell migration through the inner areas reaching the bottom of the scaffold after 14 days. MSCs cultured on MgAp/RCP scaffolds displayed higher gene and protein expressions of osteogenic markers when comparing them with the results of those MSCs grown on RCP or Ap/RCP scaffolds. This work highlights that mineralization of recombinant collagen mimicking bone mineral composition and morphology is a versatile approach to design smart scaffold interface in a 3D model guiding MSC fate.
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Affiliation(s)
| | - Monica Montesi
- Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR) , Faenza, Italy
| | - Silvia Panseri
- Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR) , Faenza, Italy
| | - Simone Sprio
- Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR) , Faenza, Italy
| | - Anna Tampieri
- Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR) , Faenza, Italy
| | - Monica Sandri
- Institute of Science and Technology for Ceramics (ISTEC), National Research Council (CNR) , Faenza, Italy
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Nasrollahzadeh N, Applegate LA, Pioletti DP. Development of an Effective Cell Seeding Technique: Simulation, Implementation, and Analysis of Contributing Factors. Tissue Eng Part C Methods 2017; 23:485-496. [PMID: 28602135 DOI: 10.1089/ten.tec.2017.0108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cell seeding in a biomaterial is an important process for tissue engineering applications. It helps to modulate tissue formation or to control initial conditions for mechanobiological studies. The compression release-induced suction (CRIS) seeding technique leads to active infiltration of the cell suspension toward the central region of the scaffold. Its effectiveness, however, may significantly vary depending on several controlling factors such as the rate of loading and unloading or scaffold architecture. We utilized a 2D axisymmetric finite element model to numerically evaluate the influence of a seeding loading regime on suction pressure and infiltration velocity of the cell suspension. The in vitro application of optimized CRIS seeding obtained from simulation showed significant effectiveness over a static seeding method. As simulation results predicted, the permeability of the scaffold directly influenced CRIS seeding effectiveness in vitro. By supplementing an optimized CRIS loading regime with slow rotation after seeding treatment, cell distribution through thickness was improved especially for scaffolds showing low permeability. Finally, we systematically analyzed the relative importance of permeability, thickness, or coating on cell seeding efficiency and uniformity using a full factorial design of experiments. We observed that permeability has a higher impact on the CRIS seeding than scaffold coating and thickness.
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Affiliation(s)
- Naser Nasrollahzadeh
- 1 Laboratory of Biomechanical Orthopedics, Institute of Bioengineering , EPFL, Lausanne, Switzerland
| | - Lee Ann Applegate
- 2 Regenerative Therapy Unit, Plastic and Reconstructive Surgery, University Hospital of Lausanne (CHUV) , Lausanne, Switzerland
| | - Dominique P Pioletti
- 1 Laboratory of Biomechanical Orthopedics, Institute of Bioengineering , EPFL, Lausanne, Switzerland
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40
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Pawelec KM, van Boxtel HA, Kluijtmans SG. Ice-templating of anisotropic structures with high permeability. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 76:628-636. [DOI: 10.1016/j.msec.2017.03.142] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 12/01/2022]
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41
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Blanquer SBG, Werner M, Hannula M, Sharifi S, Lajoinie GPR, Eglin D, Hyttinen J, Poot AA, Grijpma DW. Surface curvature in triply-periodic minimal surface architectures as a distinct design parameter in preparing advanced tissue engineering scaffolds. Biofabrication 2017; 9:025001. [DOI: 10.1088/1758-5090/aa6553] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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42
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Shamekhi MA, Rabiee A, Mirzadeh H, Mahdavi H, Mohebbi-Kalhori D, Baghaban Eslaminejad M. Fabrication and characterization of hydrothermal cross-linked chitosan porous scaffolds for cartilage tissue engineering applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 80:532-542. [PMID: 28866197 DOI: 10.1016/j.msec.2017.03.194] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 12/22/2016] [Accepted: 03/21/2017] [Indexed: 01/13/2023]
Abstract
The use of various chemical cross-linking agents for the improvement of scaffolds physical and mechanical properties is a common practical method, which is limited by cytotoxicity effects. Due to exerting contract type forces, chondrocytes are known to implement shrinkage on the tissue engineered constructs, which can be avoided by the scaffold cross-linking. In the this research, chitosan scaffolds are cross-linked with hydrothermal treatment with autoclave sterilization time of 0, 10, 20 and 30min, to avoid the application of the traditional chemical toxic materials. The optimization studies with gel content and crosslink density measurements indicate that for 20min sterilization time, the gel content approaches to ~80%. The scaffolds are fully characterized by the conventional techniques such as SEM, porosity and permeability, XRD, compression, thermal analysis and dynamic mechanical thermal analysis (DMTA). FT-IR studies shows that autoclave inter-chain cross-linking reduces the amine group absorption at 1560cm-1 and increase the absorption of N-acetylated groups at 1629cm-1. It is anticipated, that this observation evidenced by chitosan scaffold browning upon autoclave cross-linking is an indication of the familiar maillard reaction between amine moieties and carbonyl groups. The biodegradation rate analysis shows that chitosan scaffolds with lower concentrations, possess suitable degradation rate for cartilage tissue engineering applications. In addition, cytotoxicity analysis shows that fabricated scaffolds are biocompatible. The human articular chondrocytes seeding into 3D cross-linked scaffolds shows a higher viability and proliferation in comparison with the uncross-linked samples and 2D controls. Investigation of cell morphology on the scaffolds by SEM, shows a more spherical morphology of chondrocytes on the cross-linked scaffolds for 21days of in vitro culture.
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Affiliation(s)
- Mohammad Amin Shamekhi
- Novel Drug Delivery Systems and Biomaterial Department, Science Faculty, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Ahmad Rabiee
- Polymer Science Department, Iran Polymer and Petrochemical Institute, Tehran, Iran.
| | - Hamid Mirzadeh
- Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, 424 Hafez Avenue, Tehran, Iran.
| | - Hamid Mahdavi
- Novel Drug Delivery Systems and Biomaterial Department, Science Faculty, Iran Polymer and Petrochemical Institute, Tehran, Iran
| | - Davod Mohebbi-Kalhori
- Chemical Engineering Department, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran
| | - Mohamadreza Baghaban Eslaminejad
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
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43
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Experimental method to characterize the strain dependent permeability of tissue engineering scaffolds. J Biomech 2016; 49:3749-3752. [DOI: 10.1016/j.jbiomech.2016.09.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 09/13/2016] [Accepted: 09/16/2016] [Indexed: 11/20/2022]
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Offeddu GS, Ashworth JC, Cameron RE, Oyen ML. Structural determinants of hydration, mechanics and fluid flow in freeze-dried collagen scaffolds. Acta Biomater 2016; 41:193-203. [PMID: 27255358 DOI: 10.1016/j.actbio.2016.05.024] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/18/2016] [Accepted: 05/13/2016] [Indexed: 11/16/2022]
Abstract
UNLABELLED Freeze-dried scaffolds provide regeneration templates for a wide range of tissues, due to their flexibility in physical and biological properties. Control of structure is crucial for tuning such properties, and therefore scaffold functionality. However, the common approach of modeling these scaffolds as open-cell foams does not fully account for their structural complexity. Here, the validity of the open-cell model is examined across a range of physical characteristics, rigorously linking morphology to hydration and mechanical properties. Collagen scaffolds with systematic changes in relative density were characterized using Scanning Electron Microscopy, X-ray Micro-Computed Tomography and spherical indentation analyzed in a time-dependent poroelastic framework. Morphologically, all scaffolds were mid-way between the open- and closed-cell models, approaching the closed-cell model as relative density increased. Although pore size remained constant, transport pathway diameter decreased. Larger collagen fractions also produced greater volume swelling on hydration, although the change in pore diameter was constant, and relatively small at ∼6%. Mechanically, the dry and hydrated scaffold moduli varied quadratically with relative density, as expected of open-cell materials. However, the increasing pore wall closure was found to determine the time-dependent nature of the hydrated scaffold response, with a decrease in permeability producing increasingly elastic rather than viscoelastic behavior. These results demonstrate that characterizing the deviation from the open-cell model is vital to gain a full understanding of scaffold biophysical properties, and provide a template for structural studies of other freeze-dried biomaterials. STATEMENT OF SIGNIFICANCE Freeze-dried collagen sponges are three-dimensional microporous scaffolds that have been used for a number of exploratory tissue engineering applications. The characterization of the structure-properties relationships of these scaffolds is necessary to understand their biophysical behavior in vivo. In this work, the relationship between morphology and physical properties in the dry and hydrated states was investigated across a range of solid concentrations in the scaffolds. The quantitative results provided can aid the design of scaffolds with a target trade-off between mechanical properties and structural features important for their biological activity.
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Affiliation(s)
- G S Offeddu
- Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, UK; Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FF, UK
| | - J C Ashworth
- Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FF, UK
| | - R E Cameron
- Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FF, UK
| | - M L Oyen
- Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, UK.
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45
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Cell structure, stiffness and permeability of freeze-dried collagen scaffolds in dry and hydrated states. Acta Biomater 2016; 33:166-175. [PMID: 26827778 DOI: 10.1016/j.actbio.2016.01.041] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/22/2015] [Accepted: 01/27/2016] [Indexed: 02/03/2023]
Abstract
Scaffolds for tissue engineering applications should be highly permeable to support mass transfer requirements while providing a 3-D template for the encapsulated biological cells. High porosity and cell interconnectivity result in highly compliant scaffolds. Overstraining occurs easily with such compliant materials and can produce misleading results. In this paper, the cell structure of freeze-dried collagen scaffolds, in both dry and hydrated states, was characterised using X-ray tomography and 2-photon confocal microscopy respectively. Measurements have been made of the scaffold's Young's modulus using conventional mechanical testing and a customised see-saw testing configuration. Specific permeability was measured under constant pressure gradient and compared with predictions. The collagen scaffolds investigated here have a coarse cell size (∼100-150 μm) and extensive connectivity between adjacent cells (∼10-30 μm) in both dry and hydrated states. The Young's modulus is very low, of the order of 10 kPa when dry and 1 kPa when hydrated. There is only a single previous study concerning the specific permeability of (hydrated) collagen scaffolds, despite its importance in nutrient diffusion, waste removal and cell migration. The experimentally measured value reported here (5 × 10(-)(10)m(2)) is in good agreement with predictions based on Computational Fluid Dynamics simulation and broadly consistent with the Carman-Kozeny empirical estimate. It is however about three orders of magnitude higher than the single previously-reported value and this discrepancy is attributed at least partly to the high pressure gradient imposed in the previous study. STATEMENT OF SIGNIFICANCE The high porosity and interconnectivity of tissue engineering scaffolds result in highly compliant structures (ie large deflections under low applied loads). Characterisation is essential if these scaffolds are to be systematically optimised. Scaffold overstraining during characterisation can lead to misleading results. In this study, the stiffness (in dry and hydrated states) and specific permeability of freeze-dried collagen scaffolds have been measured using techniques customised for low stiffness structures. The scaffold cell structure is investigated using X-ray computed tomography, which has been applied previously to visualise such materials, without extracting any structural parameters or simulating fluid flow. These are carried out in this work. 2-photon confocal microscopy is used for the first time to study the structure in hydrated state.
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46
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Applications of Computational Modelling and Simulation of Porous Medium in Tissue Engineering. COMPUTATION 2016. [DOI: 10.3390/computation4010007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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47
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Hunckler MD, Tilley JMR, Roeder RK. Molecular transport in collagenous tissues measured by gel electrophoresis. J Biomech 2015; 48:4087-4092. [PMID: 26482732 DOI: 10.1016/j.jbiomech.2015.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 09/29/2015] [Accepted: 10/04/2015] [Indexed: 10/22/2022]
Abstract
Molecular transport in tissues is important for drug delivery, nutrient supply, waste removal, cell signaling, and detecting tissue degeneration. Therefore, the objective of this study was to investigate gel electrophoresis as a simple method to measure molecular transport in collagenous tissues. The electrophoretic mobility of charged molecules in tissue samples was measured from relative differences in the velocity of a cationic dye passing through an agarose gel in the absence and presence of a tissue section embedded within the gel. Differences in electrophoretic mobility were measured for the transport of a molecule through different tissues and tissue anisotropy, or the transport of different sized molecules through the same tissue. Tissue samples included tendon and fibrocartilage from the proximal (tensile) and distal (compressive) regions of the bovine flexor tendon, respectively, and bovine articular cartilage. The measured electrophoretic mobility was greatest in the compressive region of the tendon (fibrocartilage), followed by the tensile region of tendon, and lowest in articular cartilage, reflecting differences in the composition and organization of the tissues. The anisotropy of tendon was measured by greater electrophoretic mobility parallel compared with perpendicular to the predominate collagen fiber orientation. Electrophoretic mobility also decreased with increased molecular size, as expected. Therefore, the results of this study suggest that gel electrophoresis may be a useful method to measure differences in molecular transport within various tissues, including the effects of tissue type, tissue anisotropy, and molecular size.
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Affiliation(s)
- Michael D Hunckler
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jennifer M R Tilley
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Ryan K Roeder
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA.
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Villa MM, Wang L, Huang J, Rowe DW, Wei M. Improving the permeability of lyophilized collagen-hydroxyapatite scaffolds for cell-based bone regeneration with a gelatin porogen. J Biomed Mater Res B Appl Biomater 2015; 104:1580-1590. [PMID: 26305733 DOI: 10.1002/jbm.b.33387] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/14/2014] [Accepted: 01/09/2015] [Indexed: 11/08/2022]
Abstract
Bone tissue engineering using biomaterial scaffolds and culture-expanded osteoprogenitor cells has been demonstrated in several studies; however, it is not yet a clinical reality. One challenge is the optimal design of scaffolds for cell delivery and the identification of scaffold parameters that can delineate success and failure in vivo. Motivated by a previous experiment in which a batch of lyophilized collagen-hydroxyapatite (HA) scaffolds displayed modest bone formation in vivo, despite having large pores and high porosity, we began to investigate the effect of scaffold permeability on bone formation. Herein, we fabricated scaffolds with a permeability of 2.17 ± 1.63 × 10-9 m4 /(N s) and fourfold higher using a sacrificial gelatin porogen. Scaffolds were seeded with mouse bone marrow stromal cells carrying a fluorescent reporter for osteoblast differentiation and implanted into critical-size calvarial defects in immunodeficient mice. The porogen scaffold group containing a 1:1 ratio of solids to beads was significantly more radiopaque than the scaffold group without the bead porogen 3 weeks after implantation. Quantitative histomorphometry uncovered the same trend between the 1:1 group and scaffolds without porogen found in the radiographic data; however, this was not statistically significant here. Taken together, the X-ray and histology suggest that the 1:1 ratio of porogen to scaffold solids, resulting in a fourfold increase in permeability, may enhance bone formation when compared to scaffolds without porogen. Scaffold permeability can be a useful quality control measure before implantation and this practice should improve the consistency and efficacy of cell-based bone tissue engineering. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1580-1590, 2016.
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Affiliation(s)
- Max M Villa
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut, 06269
| | - Liping Wang
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut, 06030
| | - Jianping Huang
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut, 06030
| | - David W Rowe
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut, 06030
| | - Mei Wei
- Department of Materials Science and Engineering, Institute of Materials Science, University of Connecticut, Storrs, Connecticut, 06269.
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Three-Dimensional Modelling inside a Differential Pressure Laminar Flow Bioreactor Filled with Porous Media. BIOMED RESEARCH INTERNATIONAL 2015; 2015:320280. [PMID: 26301245 PMCID: PMC4537716 DOI: 10.1155/2015/320280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 07/05/2015] [Indexed: 12/22/2022]
Abstract
A three-dimensional computational fluid dynamics- (CFD-) model based on a differential pressure laminar flow bioreactor prototype was developed to further examine performance under changing culture conditions. Cell growth inside scaffolds was simulated by decreasing intrinsic permeability values and led to pressure build-up in the upper culture chamber. Pressure release by an integrated bypass system allowed continuation of culture. The specific shape of the bioreactor culture vessel supported a homogenous flow profile and mass flux at the scaffold level at various scaffold permeabilities. Experimental data showed an increase in oxygen concentration measured inside a collagen scaffold seeded with human mesenchymal stem cells when cultured in the perfusion bioreactor after 24 h compared to static culture in a Petri dish (dynamic: 11% O2 versus static: 3% O2). Computational fluid simulation can support design of bioreactor systems for tissue engineering application.
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Wang Y, Meng H, Yuan X, Peng J, Guo Q, Lu S, Wang A. Fabrication and in vitro evaluation of an articular cartilage extracellular matrix-hydroxyapatite bilayered scaffold with low permeability for interface tissue engineering. Biomed Eng Online 2014; 13:80. [PMID: 24950704 PMCID: PMC4084593 DOI: 10.1186/1475-925x-13-80] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/17/2014] [Indexed: 12/28/2022] Open
Abstract
Background Osteochondral interface regeneration is challenging for functional and integrated cartilage repair. Various layered scaffolds have been used to reconstruct the complex interface, yet the influence of the permeability of the layered structure on cartilage defect healing remains largely unknown. Methods We designed and fabricated a novel bilayered scaffold using articular cartilage extracellular matrix (ACECM) and hydroxyapatite (HAp), involving a porous, oriented upper layer and a dense, mineralised lower layer. By optimising the HAp/ACECM ratio, differing pore sizes and porosities were obtained simultaneously in the two layers. To evaluate the effects of permeability on cell behaviour, rabbit chondrocytes were seeded. Results Morphological observations demonstrated that a gradual interfacial region was formed with pore sizes varying from 128.2 ± 20.3 to 21.2 ± 3.1 μm. The permeability of the bilayered scaffold decreased with increasing compressive strain and HAp content. Mechanical tests indicated that the interface was stable to bearing compressive and shear loads. Accordingly, the optimum HAp/ACECM ratio (7 w/v%) in the layer to mimic native calcified cartilage was found. Chondrocytes could not penetrate the interface and resided only in the upper layer, where they showed high cellularity and abundant matrix deposition. Conclusions Our findings suggest that a bilayered scaffold with low permeability, rather than complete isolation, represents a promising candidate for osteochondral interface tissue engineering.
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Affiliation(s)
| | | | | | | | | | | | - Aiyuan Wang
- Institute of Orthopaedics, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, China.
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