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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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De Cet A, D'Andrea L, Gastaldi D, Baino F, Verné E, Örlygsson G, Vena P. Micro-CT imaging and finite element models reveal how sintering temperature affects the microstructure and strength of bioactive glass-derived scaffolds. Sci Rep 2024; 14:969. [PMID: 38200047 PMCID: PMC10781744 DOI: 10.1038/s41598-023-50255-5] [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: 07/08/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
This study focuses on the finite element simulation and micromechanical characterization of bioactive glass-ceramic scaffolds using Computed micro Tomography ([Formula: see text]CT) imaging. The main purpose of this work is to quantify the effect of sintering temperature on the morphometry and mechanical performance of the scaffolds. In particular, the scaffolds were produced using a novel bioactive glass material (47.5B) through foam replication, applying six different sintering temperatures. Through [Formula: see text]CT imaging, detailed three-dimensional images of the scaffold's internal structure are obtained, enabling the extraction of important geometric features and how these features change with sintering temperature. A finite element model is then developed based on the [Formula: see text]CT images to simulate the fracture process under uniaxial compression loading. The model incorporates scaffold heterogeneity and material properties-also depending on sintering temperature-to capture the mechanical response, including crack initiation, propagation, and failure. Scaffolds sintered at temperatures equal to or higher than 700 [Formula: see text]C exhibit two-scale porosity, with micro and macro pores. Finite element analyses revealed that the dual porosity significantly affects fracture mechanisms, as micro-pores attract cracks and weaken strength. Interestingly, scaffolds sintered at high temperatures, the overall strength of which is higher due to greater intrinsic strength, showed lower normalized strength compared to low-temperature scaffolds. By using a combined strategy of finite element simulation and [Formula: see text]CT-based characterization, bioactive glass-ceramic scaffolds can be optimized for bone tissue engineering applications by learning more about their micromechanical characteristics and fracture response.
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Affiliation(s)
- Anna De Cet
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Laboratory of Biological Structure Mechanics (LaBS)-Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Luca D'Andrea
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Laboratory of Biological Structure Mechanics (LaBS)-Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Dario Gastaldi
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Laboratory of Biological Structure Mechanics (LaBS)-Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Francesco Baino
- Institute of Materials Physics and Engineering, Department of Applied Science and Technology-Politecnico di Torino, 10129, Turin, Italy
| | - Enrica Verné
- Institute of Materials Physics and Engineering, Department of Applied Science and Technology-Politecnico di Torino, 10129, Turin, Italy
| | | | - Pasquale Vena
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Laboratory of Biological Structure Mechanics (LaBS)-Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.
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da Silva RBP, Biguetti CC, Munerato MS, Siqueira RL, Zanotto ED, Kudo GHA, Simionato GB, Bacelar ACZ, Ortiz RC, Ferreira-Junior JS, Rangel-Junior IG, Matsumoto MA. Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration. J Biomed Mater Res B Appl Biomater 2024; 112:e35340. [PMID: 37929804 DOI: 10.1002/jbm.b.35340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/28/2023] [Accepted: 09/18/2023] [Indexed: 11/07/2023]
Abstract
Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-β. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-β) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-β+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.
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Affiliation(s)
| | - Claudia Cristina Biguetti
- Regenerative Medicine Laboratory, School of Podiatric Medicine, The University of Texas Rio Grande Valley - UTRGV, Harlingen, Texas, USA
| | | | - Renato Luis Siqueira
- Department of Material Engineering, São Carlos Federal University, São Paulo, Brazil
| | - Edgard Dutra Zanotto
- Department of Material Engineering, São Carlos Federal University, São Paulo, Brazil
| | | | - Gustavo Baroni Simionato
- Department of Basic Sciences, São Paulo State University (Unesp), School of Dentistry, Araçatuba, Brazil
| | - Ana Carolina Zucon Bacelar
- Department of Basic Sciences, São Paulo State University (Unesp), School of Dentistry, Araçatuba, Brazil
| | - Rafael Carneiro Ortiz
- Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru, Brazil
| | | | - Idelmo Garcia Rangel-Junior
- Department of Diagnosis and Surgery, São Paulo State University (Unesp), School of Dentistry, Araçatuba, Brazil
| | - Mariza Akemi Matsumoto
- Department of Basic Sciences, São Paulo State University (Unesp), School of Dentistry, Araçatuba, Brazil
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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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De Luca S, Verdoliva V, Kargozar S, Baino F. Bioactive Glass-Ceramic Scaffolds Coated with Hyaluronic Acid-Fatty Acid Conjugates: A Feasibility Study. J Funct Biomater 2023; 14:jfb14010026. [PMID: 36662073 PMCID: PMC9866274 DOI: 10.3390/jfb14010026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023] Open
Abstract
Promoting bone healing is a key challenge in our society that can be tackled by developing new implantable biomaterials provided with regenerative properties. In this work, the coating of three-dimensional porous glass-derived scaffolds with hyaluronic acid (HA)-fatty acids was investigated for the first time. The starting scaffolds, based on bioactive silicate glass, were produced by foam replication followed by sintering; then, HA-palmitate and HA-oleate conjugate coatings were deposited on the scaffold struts through a dipping procedure. FT-IR analysis confirmed the successful deposition of the coatings on the surface and struts of the scaffolds, the foam-like architecture of which was maintained as assessed by SEM investigations. The in vitro bioactivity of the HA-fatty-acid-coated scaffolds was studied by immersion tests in simulated body fluid and the subsequent evaluation of hydroxyapatite formation. The deposition of the polymeric coating did not inhibit the apatite-forming ability of scaffolds, as revealed by the formation of nanostructured hydroxyapatite agglomerates 48 h from immersion. These promising results motivate further investigation of these novel bioactive systems, which are expected to combine the bone-bonding properties of the glass with the wound-healing promotion carried out by the polymeric conjugates.
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Affiliation(s)
- Stefania De Luca
- Institute of Biostructures and Bioimaging, National Research Council, 80134 Naples, Italy
| | - Valentina Verdoliva
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Via Vivaldi 43, 81100 Caserta, Italy
| | - Saeid Kargozar
- Tissue Engineering Research Group (TERG), Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad 917794-8564, Iran
| | - Francesco Baino
- Institute of Materials Physics and Engineering, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
- Correspondence:
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Tulyaganov DU, Fiume E, Akbarov A, Ziyadullaeva N, Murtazaev S, Rahdar A, Massera J, Verné E, Baino F. In Vivo Evaluation of 3D-Printed Silica-Based Bioactive Glass Scaffolds for Bone Regeneration. J Funct Biomater 2022; 13:jfb13020074. [PMID: 35735929 PMCID: PMC9224601 DOI: 10.3390/jfb13020074] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 05/29/2022] [Accepted: 06/02/2022] [Indexed: 01/04/2023] Open
Abstract
Bioactive glasses are often designed as porous implantable templates in which newly-formed bone can grow in three dimensions (3D). This research work aims to investigate the bone regenerative capability of silicate bioactive glass scaffolds produced by robocasting in comparison with powder and granule-like materials (oxide system: 47.5SiO2-10Na2O-10K2O-10MgO-20CaO-2.5P2O5, mol.%). Morphological and compositional analyses performed by scanning electron microscopy (SEM), combined with energy dispersive spectroscopy (EDS) after the bioactivity studies in a simulated body fluid (SBF) confirmed the apatite-forming ability of the scaffolds, which is key to allowing bone-bonding in vivo. The scaffolds exhibited a clear osteogenic effect upon implantation in rabbit femur and underwent gradual resorption followed by ossification. Full resorption in favor of new bone growth was achieved within 6 months. Osseous defect healing was accompanied by the formation of mature bone with abundant osteocytes and bone marrow cells. These in vivo results support the scaffold’s suitability for application in bone tissue engineering and show promise for potential translation to clinical assessment.
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Affiliation(s)
- Dilshat U. Tulyaganov
- Department of Natural-Mathematical Sciences, Turin Polytechnic University in Tashkent, Tashkent 100095, Uzbekistan;
| | - Elisa Fiume
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 Turin, Italy; (E.F.); (E.V.)
| | - Avzal Akbarov
- Department of Prosthodontics, Tashkent State Dental Institute, Tashkent 100047, Uzbekistan; (A.A.); (N.Z.); (S.M.)
| | - Nigora Ziyadullaeva
- Department of Prosthodontics, Tashkent State Dental Institute, Tashkent 100047, Uzbekistan; (A.A.); (N.Z.); (S.M.)
| | - Saidazim Murtazaev
- Department of Prosthodontics, Tashkent State Dental Institute, Tashkent 100047, Uzbekistan; (A.A.); (N.Z.); (S.M.)
| | - Abbas Rahdar
- Department of Physics, University of Zabol, Zabol 98613-35856, Iran;
| | - Jonathan Massera
- Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland;
| | - Enrica Verné
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 Turin, Italy; (E.F.); (E.V.)
| | - Francesco Baino
- Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 Turin, Italy; (E.F.); (E.V.)
- Correspondence:
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Schiavi A, Fiume E, Orlygsson G, Schwentenwein M, Verné E, Baino F. High-reliability data processing and calculation of microstructural parameters in hydroxyapatite scaffolds produced by vat photopolymerization. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2022.06.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Duan X, Li N, Chen X, Zhu N. Characterization of Tissue Scaffolds Using Synchrotron Radiation Microcomputed Tomography Imaging. Tissue Eng Part C Methods 2021; 27:573-588. [PMID: 34670397 DOI: 10.1089/ten.tec.2021.0155] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Distinguishing from other traditional imaging, synchrotron radiation microcomputed tomography (SR-μCT) imaging allows for the visualization of three-dimensional objects of interest in a nondestructive and/or in situ way with better spatial resolution, deep penetration, relatively fast speed, and/or high contrast. SR-μCT has been illustrated promising for visualizing and characterizing tissue scaffolds for repairing or replacing damaged tissue or organs in tissue engineering (TE), which is of particular advance for longitudinal monitoring and tracking the success of scaffolds once implanted in animal models and/or human patients. This article presents a comprehensive review on recent studies of characterization of scaffolds based on SR-μCT and takes scaffold architectural properties, mechanical properties, degradation, swelling and wettability, and biological properties as five separate sections to introduce SR-μCT wide applications. We also discuss and highlight the unique opportunities of SR-μCT in various TE applications; conclude this article with the suggested future research directions, including the prospective applications of SR-μCT, along with its challenges and methods for improvement in the field of TE.
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Affiliation(s)
- Xiaoman Duan
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
| | - Naitao Li
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
| | - Xiongbiao Chen
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
- Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
| | - Ning Zhu
- Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
- Department of Chemical and Biological Engineering, College of Engineering, University of Saskatchewan, Saskatoon, Canada
- Canadian Light Source, Saskatoon, Canada
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Biological Evaluation of a New Sodium-Potassium Silico-Phosphate Glass for Bone Regeneration: In Vitro and In Vivo Studies. MATERIALS 2021; 14:ma14164546. [PMID: 34443069 PMCID: PMC8400910 DOI: 10.3390/ma14164546] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/01/2021] [Accepted: 08/10/2021] [Indexed: 12/27/2022]
Abstract
In vitro and in vivo studies are fundamental steps in the characterization of new implantable materials to preliminarily assess their biological response. The present study reports the in vitro and in vivo characterizations of a novel experimental silicate bioactive glass (BG) (47.5B, 47.5SiO2-10Na2O-10K2O-10MgO-20CaO-2.5P2O5 mol.%). Cytocompatibility tests were performed using human mature osteoblasts (U2OS), human mesenchymal stem cells (hMSCs) and human endothelial cells (EA.hy926). The release of the early osteogenic alkaline phosphatase (ALP) marker suggested strong pro-osteogenic properties, as the amount was comparable between hMSCs cultivated onto BG surface and cells cultivated onto polystyrene control. Similarly, real-time PCR revealed that the osteogenic collagen I gene was overexpressed in cells cultivated onto BG surface without biochemical induction. Acute toxicity tests for the determination of the median lethal dose (LD50) allowed classifying the analyzed material as a slightly toxic substance with LD50 = 4522 ± 248 mg/kg. A statistically significant difference in bone formation was observed in vivo through comparing the control (untreated) group and the experimental one, proving a clear osteogenic effect induced by the implantation at the defect site. Complete resorption of 47.5B powder was observed after only 3 months in favor of newly formed tissue, thus confirming the high osteostimulatory potential of 47.5B glass.
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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: 19] [Impact Index Per Article: 6.3] [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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Sintering Behavior of a Six-Oxide Silicate Bioactive Glass for Scaffold Manufacturing. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10228279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The intrinsic brittleness of bioactive glasses (BGs) is one of the main barriers to the widespread use of three-dimensional porous BG-derived bone grafts (scaffolds) in clinical practice. Among all the available strategies for improving the mechanical properties of BG-based scaffolds, strut densification upon sintering treatments at high temperatures represents a relatively easy approach, but its implementation might lead to undesired and poorly predictable decrease in porosity, mass transport properties and bioactivity resulting from densification and devitrification phenomena occurring in the material upon heating. The aim of the present work was to investigate the sinter-crystallization of a highly bioactive SiO2-P2O5-CaO–MgO–Na2O–K2O glass (47.5B composition) in reference to its suitability for the fabrication of bonelike foams. The thermal behavior of 47.5B glass particles was investigated upon sintering at different temperatures in the range of 600–850 °C by means of combined thermal analyses (differential thermal analysis (DTA) and hot-stage microscopy (HSM)). Then, XRD measurements were carried out to identify crystalline phases developed upon sintering. Finally, porous scaffolds were produced by a foam replica method in order to evaluate the effect of the sintering temperature on the mechanical properties under compression loading conditions. Assessing a relationship between mechanical properties and sintering temperature, or in other words between scaffold performance and fabrication process, is a key step towards the rationale design of optimized scaffolds for tissue repair.
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