Four-dimensional imaging and quantification of viscous flow sintering within a 3D printed bioactive glass scaffold using synchrotron X-ray tomography

Nommeots‐Nomm, Amy; Ligorio, Cosimo; Bodey, Andrew J.; Cai, Biao; Jones, Julian R.; Lee, Peter; Poologasundarampillai, Gowsihan

doi:10.1016/j.mtadv.2019.100011

Cited by 18 publications

(26 citation statements)

References 62 publications

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“…The fracture plan propagating from the upper strut through the underlying layer in the same proves that the consolidation process took place between different filaments, with good fusion between layers. In this regard, a detailed description of viscous flow sintering within robocast 13–93 bioactive glass scaffolds was provided elsewhere [29].…”

Section: Resultsmentioning

confidence: 99%

Robocasting of SiO2-Based Bioactive Glass Scaffolds with Porosity Gradient for Bone Regeneration and Potential Load-Bearing Applications

et al. 2019

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: Additive manufacturing of bioactive glasses has recently attracted high interest in the field of regenerative medicine as a versatile class of fabrication methods to process bone substitute materials. In this study, melt-derived glass particles from the SiO2-P2O5-CaO-MgO-Na2O-K2O system were used to fabricate bioactive scaffolds with graded porosity by robocasting. A printable ink made of glass powder and Pluronic F-127 (binder) was extruded into a grid-like three-dimensional structure with bimodal porosity, i.e., the inner part of the scaffold had macropores with smaller size compared to the periphery. The crystallization behavior of the glass powder was studied by hot-stage microscopy, differential thermal analysis, and X-ray diffraction; the scaffolds were sintered at a temperature below the onset of crystallization so that amorphous structures could be obtained. Scaffold architecture was investigated by scanning electron microscopy and microtomographic analysis that allowed quantifying the microstructural parameters. In vitro tests in Kokubo’s simulated body fluid (SBF) confirmed the apatite-forming ability (i.e., bioactivity) of the scaffolds. The compressive strength was found to slightly decrease during immersion in SBF up to 4 weeks but still remained comparable to that of human cancellous bone. The pH and concentration of released ions in SBF were also measured at each time point. Taken together, these results (favorable porosity, mechanical strength, and in vitro bioactivity) show great promise for the potential application of these robocast scaffolds in bone defect repair.

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Section: Resultsmentioning

confidence: 99%

Robocasting of SiO2-Based Bioactive Glass Scaffolds with Porosity Gradient for Bone Regeneration and Potential Load-Bearing Applications

et al. 2019

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“…The use of polyethylene particles [25] and rice husk [26] allow obtaining strong scaffolds that are potentially suitable for use in high-load-bearing defect sites or even for the replacement of cortical bone; on the other hand, these porous implants typically suffer from low pore interconnectivity, which limits the permeation of biological fluids, cell colonization, and vascularization with obvious impairment of osteointegration.Implementation of additive manufacturing techniques (AMTs) has recently opened new horizons in the fabrication of bioactive glass and ceramic scaffolds [27]. AMTs allow accurate control, tailoring, and reproducibility of scaffold features and pore/strut architecture, as well as an easy scalability to the industrial level [28]. Albeit the equipment for selective laser sintering [29] and stereolithography [30] still requires high investment costs, relatively affordable 3D printers are available on the market and can be customized on demand or in-house [31].…”

mentioning

confidence: 99%

“…Implementation of additive manufacturing techniques (AMTs) has recently opened new horizons in the fabrication of bioactive glass and ceramic scaffolds [27]. AMTs allow accurate control, tailoring, and reproducibility of scaffold features and pore/strut architecture, as well as an easy scalability to the industrial level [28]. Albeit the equipment for selective laser sintering [29] and stereolithography [30] still requires high investment costs, relatively affordable 3D printers are available on the market and can be customized on demand or in-house [31].…”

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confidence: 99%

Dolomite-Foamed Bioactive Silicate Scaffolds for Bone Tissue Repair

et al. 2020

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The use of three-dimensional (3D) scaffolds is recognized worldwide as a valuable biomedical approach for promoting tissue regeneration in critical-size bone defects. Over the last 50 years, bioactive glasses have been intensively investigated in a wide range of different clinical applications, from orthopedics to soft tissue healing. Bioactive glasses exhibit the unique capability to chemically bond to the host tissue and, furthermore, their processing versatility makes them very appealing due to the availability of different manufacturing techniques for the production of porous and interconnected synthetic bone grafts able to support new tissue growth over the whole duration of the treatment. As a novel contribution to the broad field of scaffold manufacturing, we report here an effective and relatively easy method to produce silicate glass-derived scaffolds by using, for the first time in the biomedical field, dolomite powder as a foaming agent for the formation of 3D bone-like porous structures. Morphological/structural features, crystallization behavior, and in vitro bioactivity in a simulated body fluid (SBF) were investigated. All the tested scaffolds were found to fulfil the minimum requirements that a scaffold for osseous repair should exhibit, including porosity (65–83 vol.%) and compressive strength (1.3–3.9 MPa) comparable to those of cancellous bone, as well as hydroxyapatite-forming ability (bioactivity). This study proves the suitability of a dolomite-foaming method for the production of potentially suitable bone grafts based on bioactive glass systems.

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“…The platform integrates a unified feature extraction, quality prediction, and decision-making algorithm by visualizing crucial aspects of laser processes that enable the operator's feedback to the system. The current study regards the Laser Welding case; however, the platform can be easily adapted to accommodate the monitoring imaging systems of other applications, besides any training and validation, as mentioned in [7][8][9][10] extending by these means the cognitive capacity of the platform, such as additive manufacturing/laser metal deposition and cutting.…”

Section: Discussionmentioning

confidence: 99%

“…Monitoring and quality control systems are critical and necessary tools in order for production results to be kept in desired boundaries [6] and be able to deal with changing conditions without requiring a complex and time-consuming manual setup. In this regard, systems for monitoring of Laser AM and 3D printing processes based on X-ray imaging have been developed allowing the exploitation of novel process insights [7,8]. Furthermore, in the case of metal droplet fusion processes, industrial computer tomography scanning is utilized for defect identification of the fabricated parts [9,10].…”

Section: Introductionmentioning

confidence: 99%

A three-stage quality diagnosis platform for laser-based manufacturing processes

Stavropoulos

Papacharalampopoulos

Stavridis

et al. 2020

Int J Adv Manuf Technol

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Diagnosis systems for laser processing are being integrated into industry. However, their readiness level is still questionable under the prism of the Industry’s 4.0 design principles for interoperability and intuitive technical assistance. This paper presents a novel multifunctional, web-based, real-time quality diagnosis platform, in the context of a laser welding application, fused with decision support, data visualization, storing, and post-processing functionalities. The platform’s core considers a quality assessment module, based upon a three-stage method which utilizes feature extraction and machine learning techniques for weld defect detection and quality prediction. A multisensorial configuration streams image data from the weld pool to the module in which a statistical and geometrical method is applied for selecting the input features for the classification model. A Hidden Markov Model is then used to fuse this information with earlier results for a decision to be made on the basis of maximum likelihood. The outcome is fed through web services in a tailored User Interface. The platform’s operation has been validated with real data.

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Four-dimensional imaging and quantification of viscous flow sintering within a 3D printed bioactive glass scaffold using synchrotron X-ray tomography

Cited by 18 publications

References 62 publications

Robocasting of SiO2-Based Bioactive Glass Scaffolds with Porosity Gradient for Bone Regeneration and Potential Load-Bearing Applications

Robocasting of SiO2-Based Bioactive Glass Scaffolds with Porosity Gradient for Bone Regeneration and Potential Load-Bearing Applications

Dolomite-Foamed Bioactive Silicate Scaffolds for Bone Tissue Repair

A three-stage quality diagnosis platform for laser-based manufacturing processes

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