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1 – 10 of 141Sarbjit Kaur, Niraj Bala and Charu Khosla
The biomaterials are natural or synthetic materials used to improve quality of life either by replacing tissue/organ or assisting their function in medical field. The purpose of…
Abstract
Purpose
The biomaterials are natural or synthetic materials used to improve quality of life either by replacing tissue/organ or assisting their function in medical field. The purpose of the study is to analyze the hydroxyapatite (HAP), HAP-TiO2 (25 percent) composite coatings deposited on 316 LSS by High Velocity Flame Spray (HVFS) technique.
Design/methodology/approach
The coatings exhibit almost uniform and dense microstructure with porosity (HAP = 0.153 and HAP-TiO2 composite = 0.138). Electrochemical corrosion testing was done on the uncoated and coated specimens in Ringer solution (SBF). As-sprayed coatings were characterized by XRD, SEM/EDS and cross-sectional X-ray mapping techniques before and after dipping in Ringer solution. Microhardness of composite coating (568.8 MPa) was found to be higher than HAP coating (353 MPa).
Findings
During investigations, it was observed that the corrosion resistance of steel was found to have increased after the deposition of HAP and HAP-TiO2 composite coatings. Thus, coatings serve as an effective diffusion barrier to prohibit the diffusion of ions from the SBF into the substrate. Composite coatings have been found to be more corrosion resistant as compared to HAP coating in the simulated body fluid.
Research limitations/implications
It has been concluded that corrosion resistance of HAP as well as composite coating is because of the desirable microstructural changes such as low porosity high microhardness and flat splat structures in coatings as compared to bare specimen.
Practical implications
This study is useful in the selection of biomedical implants.
Social implications
This study is useful in the field of biomaterials.
Originality/value
No reported literature on corrosion behavior of HAP+ 25%- TiO2 has been noted till now using flame spray technique. The main focus of the study is to investigate the HAP as well as composite coatings for biomedical applications.
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M.M. Savalani, L. Hao, P.M. Dickens, Y. Zhang, K.E. Tanner and R.A. Harris
Hydroxyapatite‐polymer composite materials are being researched for the development of low‐load bearing implants because of their bioactive and osteoconductive properties, while…
Abstract
Purpose
Hydroxyapatite‐polymer composite materials are being researched for the development of low‐load bearing implants because of their bioactive and osteoconductive properties, while avoiding modulus mismatch found in homogenous materials. For the direct production of hydroxyapatite‐polymer composite implants, selective laser sintering (SLS) has been used and various parameters and their effects on the physical properties (micro and macro morphologies) have been investigated. The purpose of this paper is to identify the most influential parameters on the micro and macro pore morphologies of sintered hydroxyapatite‐polymer composites.
Design/methodology/approach
A two‐level full factorial experiment was designed to evaluate the effects of the various processing parameters and their effects on the physical properties, including open porosity, average pore width and the percentage of pores which could enable potential bone regeneration and ingrowth of the sintered parts. The density of the sintered parts was measured by weight and volume; optical microscopy combined with the interception method was used to determine the average pore size and proportion of pores suitable to enable bone regeneration.
Findings
It was found that the effect of build layer thickness was the most influential parameter with respect to physical and pore morphology features. Consequently, it is found that the energy density equation with the layer thickness parameter provides a better estimation of part porosity of composite structures than the energy density equation without the layer thickness parameter. However, further work needs to be conducted to overcome the existing error of variance.
Originality/value
This work is the first step in identifying the most significant SLS parameters and their effects on the porosity, micro and macro pore morphologies of the fabricated parts. This is an important step in the further development of implants which may be required.
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Fangfang Sun, Tianze Wang and Yong Yang
Rapid prototyping (RP) technology is widely used in many fields in recent years. Bone tissue engineering (TE) is an interdisciplinary field involving life sciences, engineering…
Abstract
Purpose
Rapid prototyping (RP) technology is widely used in many fields in recent years. Bone tissue engineering (TE) is an interdisciplinary field involving life sciences, engineering and materials science. Hydroxyapatite (HAp) are similar to natural bone and it has been extensively studied due to its excellent biocompatibility and osteoconductivity. This paper aims to review nanoscaled HAp-based scaffolds with high porosity fabricated by various RP methods for bone regeneration.
Design/methodology/approach
The review focused on the fabrication methods of HAp composite scaffolds through RP techniques. The paper summarized the evaluation of these scaffolds on the basis of their biocompatibility and biodegradability through in vitro and in vivo tests. Finally, a summary and perspectives on this active area of research are provided.
Findings
HAp composite scaffold fabricated by RP methods has been widely used in bone TE and it has been deeply studied by researchers during the past two decades. However, its brittleness and difficulty in processing have largely limited its wide application in TE. Therefore, the formability of HAp combined with biocompatible organic materials and fabrication techniques could be effectively enhanced, and it can be used in bone TE applications finally.
Originality/value
This review paper presented a comprehensive study of the various types of HAp composite scaffold fabricated by RP technologies and introduced their potential application in bone TE, as well as future roadmap and perspective.
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Hanxiao Wang, Marco Domingos and Fabio Scenini
The purpose of this paper is to study the effect of nano hydroxyapatite (HA) and graphene oxide (GO) particles on thermal and mechanical performances of 3D printed…
Abstract
Purpose
The purpose of this paper is to study the effect of nano hydroxyapatite (HA) and graphene oxide (GO) particles on thermal and mechanical performances of 3D printed poly(ε-caprolactone) (PCL) filaments used in bone tissue engineering (BTE).
Design/methodology/approach
Raw materials were prepared by melt blending, followed by 3D printing via 3D Discovery (regenHU Ltd., CH) with all fabricating parameters kept constant. Filaments, including pure PCL, PCL/HA and PCL/GO, were tested under the same conditions. Several techniques were used to mechanically, thermally and microstructurally evaluate properties of these filaments, including differential scanning calorimetry, tensile test, nano indentation and scanning electron microscope.
Findings
Results show that both HA and GO nano particles are capable of improving mechanical performance of PCL. Enhanced mechanical properties of PCL/HA result from reinforcing effect of HA, while a different mechanism is observed in PCL/GO, where degree of crystallinity plays an important role. In addition, GO is more efficient at enhancing mechanical performance of PCL compared with HA.
Originality/value
For the first time, a systematic study about effects of nano HA and GO particles on bioactive scaffolds produced by additive manufacturing for BTE applications is conducted in this work. Mechanical and thermal behaviors of each sample, pure PCL, PCL/HA and PCL/GO, are reported, correlated and compared with literature.
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Jatender Pal Singh, Pulak M. Pandey and Anita Kamra Verma
Scaffolds are essentially required to have open porous structure for facilitating bone to grow. They are generally placed on those bone defective/fractured sites which are more…
Abstract
Purpose
Scaffolds are essentially required to have open porous structure for facilitating bone to grow. They are generally placed on those bone defective/fractured sites which are more prone to compressive loading. Open porous structure lacks in strength in comparison to solid. Selective laser sintering (SLS) process is prominently used for fabrication of polymer/composite scaffolds. So, this paper aims to study for fabrication of three-dimensional open porous scaffolds with enhanced strength, process parameters of SLS of a biocompatible material are required to be optimized.
Design/methodology/approach
Regular open porous structures with suitable pore size as per computer-aided design models were fabricated using SLS. Polyamide (PA-2200) was used to fabricate the specimen/scaffold. To optimize the strength of the designed structure, response surface methodology was used to design the experiments. Specimens as per ASTM D695 were fabricated using SLS and compressive testing was carried out. Analysis of variance was done for estimating contribution of individual process parameters. Optimized process parameters were obtained using a trust region algorithm and correlated with experimental results. Accuracy of the fabricated specimen/scaffold was also assessed in terms of IT grades. In vitro cell culture on the fabricated structures confirmed the biocompatibility of polyamide (PA-2200).
Findings
Optimized process parameters for open cell process structures were obtained and confirmed experimentally. Laser power, hatch spacing and layer thickness have contributed more in the porous part’s strength than scan speed. The accuracy of the order of IT16 has been found for all functional dimensions. Cell growth and proliferation confirmed biocompatibility of polyamide (PA-2200) for scaffold applications.
Originality/value
This paper demonstrates the biocompatibility of PA-2200 for scaffold applications. The optimized process parameters of SLS process for open cell structure having pore size 1.2 × 1.2 mm2 with strut diameter of 1 mm have been obtained. The accuracy of the order of IT16 was obtained at the optimized process factors.
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Abstract
Purpose
Additive manufacturing (AM) or solid freeform fabrication (SFF) technique is extensively used to produce intrinsic 3D structures with high accuracy. Its significant contributions in the field of tissue engineering (TE) have significantly increased in the recent years. TE is used to regenerate or repair impaired tissues which are caused by trauma, disease and injury in human body. There are a number of novel materials such as polymers, ceramics and composites, which possess immense potential for production of scaffolds. However, the major challenge is in developing those bioactive and patient-specific scaffolds, which have a required controlled design like pore architecture with good interconnectivity, optimized porosity and microstructure. Such design not only supports cell proliferation but also promotes good adhesion and differentiation. However, the traditional techniques fail to fulfill all the required specific properties in tissue scaffold. The purpose of this study is to report the review on AM techniques for the fabrication of TE scaffolds.
Design/methodology/approach
The present review paper provides a detailed analysis of the widely used AM techniques to construct tissue scaffolds using stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), binder jetting (BJ) and advanced or hybrid additive manufacturing methods.
Findings
Subsequently, this study also focuses on understanding the concepts of TE scaffolds and their characteristics, working principle of scaffolds fabrication process. Besides this, mechanical properties, characteristics of microstructure, in vitro and in vivo analysis of the fabricated scaffolds have also been discussed in detail.
Originality/value
The review paper highlights the way forward in the area of additive manufacturing applications in TE field by following a systematic review methodology.
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Nataraj Poomathi, Sunpreet Singh, Chander Prakash, Arjun Subramanian, Rahul Sahay, Amutha Cinappan and Seeram Ramakrishna
In the past decade, three-dimensional (3D) printing has gained attention in areas such as medicine, engineering, manufacturing art and most recently in education. In biomedical…
Abstract
Purpose
In the past decade, three-dimensional (3D) printing has gained attention in areas such as medicine, engineering, manufacturing art and most recently in education. In biomedical, the development of a wide range of biomaterials has catalysed the considerable role of 3D printing (3DP), where it functions as synthetic frameworks in the form of scaffolds, constructs or matrices. The purpose of this paper is to present the state-of-the-art literature coverage of 3DP applications in tissue engineering (such as customized scaffoldings and organs, and regenerative medicine).
Design/methodology/approach
This review focusses on various 3DP techniques and biomaterials for tissue engineering (TE) applications. The literature reviewed in the manuscript has been collected from various journal search engines including Google Scholar, Research Gate, Academia, PubMed, Scopus, EMBASE, Cochrane Library and Web of Science. The keywords that have been selected for the searches were 3 D printing, tissue engineering, scaffoldings, organs, regenerative medicine, biomaterials, standards, applications and future directions. Further, the sub-classifications of the keyword, wherever possible, have been used as sectioned/sub-sectioned in the manuscript.
Findings
3DP techniques have many applications in biomedical and TE (B-TE), as covered in the literature. Customized structures for B-TE applications are easy and cost-effective to manufacture through 3DP, whereas on many occasions, conventional technologies generally become incompatible. For this, this new class of manufacturing must be explored to further capabilities for many potential applications.
Originality/value
This review paper presents a comprehensive study of the various types of 3DP technologies in the light of their possible B-TE application as well as provides a future roadmap.
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Neha Choudhary, Chandrachur Ghosh, Varun Sharma, Partha Roy and Pradeep Kumar
The purpose of this paper is to fabricate the scaffolds with different pore architectures using additive manufacturing and analyze its mechanical and biological properties for…
Abstract
Purpose
The purpose of this paper is to fabricate the scaffolds with different pore architectures using additive manufacturing and analyze its mechanical and biological properties for bone tissue engineering applications.
Design/methodology/approach
The polylactic acid (PLA)/composite filament were fabricated through single screw extrusion and scaffolds were printed with four different pore architectures, i.e. circle, square, triangle and parallelogram with fused deposition modelling. Afterwards, scaffolds were coated with hydroxyapatite (HA) using dip coating technique. Various physical and thermo-mechanical tests have been conducted to confirm the feasibility. Furthermore, the biological tests were conducted with MG63 fibroblast cell lines to investigate the biocompatibility of the developed scaffolds.
Findings
The scaffolds were successfully printed with different pore architectures. The pore size of the scaffolds was found to be nearly 1,500 µm, and porosity varied between 53% and 63%. The fabricated circular pore architecture resulted in highest average compression strength of 13.7 MPa and modulus of 525 MPa. The characterizations showed the fidelity of the work. After seven days of cell culture, it was observed that the developed composites were non-toxic and supported cellular activities. The coating of HA made the scaffolds bioactive, showing higher wettability, degradation and high cellular responses.
Originality/value
The research attempts highlight the development of novel biodegradable and biocompatible polymer (PLA)/bioactive ceramic (Al2O3) composite for additive manufacturing with application in the tissue engineering field.
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Fouad Al Bayaty, Mazen M. Jamil Al-Obaidi, Anissa Lokman, Suhaila Yazid and Omar Emad Ibrahim
This study examines the osteoconductive and healing capabilities of locally implanted synthetic hydroxyapatite (sHAp) derived from eggshells in the central incisor sockets of rats.
Abstract
Purpose
This study examines the osteoconductive and healing capabilities of locally implanted synthetic hydroxyapatite (sHAp) derived from eggshells in the central incisor sockets of rats.
Design/methodology/approach
Toxicity experiments were conducted in vitro and in vivo, to testify the safety dosage of sHAp. Around 24 mature male Sprague–Dawley (SD) rats had their upper central incisors extracted. The rats were placed into three groups of eight rats each: Group 1: the sockets of extracted central incisors were left unfilled (control), Group 2: filled up with commercially available hydroxyapatite (HAp) and Group 3: implanted with sHAp locally retrieved from eggshells. After extraction, four rats from each group were sacrificed at 2nd and 4th weeks. Maxillary tissue sections were obtained and stained with hematoxylin and eosin (H&E) and Masson’s trichome (MT) staining. Anti-osteocalcin (OCN) and proliferating cell nuclear antigen (PCNA) were used primary antibodies for immunohistochemistry (IHC) special labeling.
Findings
The results showed that the locally implanted sHAp was non-toxic and safe in cell lines (human osteoblast and fibroblast) and animals. Histological analysis of H&E, MT and IHC showed that the sockets treated with locally implanted sHAp from eggshells were filled with new bone tissue of comparable thickness to other groups.
Originality/value
This unique technique uses locally implanted eggshell-derived sHAp with osteoconductive characteristics. In an in vivo model, sHAps increased OCN and PCNA expression to improve bone repair.
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Asif Ur Rehman, Pedro Navarrete-Segado, Metin U. Salamci, Christine Frances, Mallorie Tourbin and David Grossin
The consolidation process and morphology evolution in ceramics-based additive manufacturing (AM) are still not well-understood. As a way to better understand the ceramic selective…
Abstract
Purpose
The consolidation process and morphology evolution in ceramics-based additive manufacturing (AM) are still not well-understood. As a way to better understand the ceramic selective laser sintering (SLS), a dynamic three-dimensional computational model was developed to forecast thermal behavior of hydroxyapatite (HA) bioceramic.
Design/methodology/approach
AM has revolutionized automotive, biomedical and aerospace industries, among many others. AM provides design and geometric freedom, rapid product customization and manufacturing flexibility through its layer-by-layer technique. However, a very limited number of materials are printable because of rapid melting and solidification hysteresis. Melting-solidification dynamics in powder bed fusion are usually correlated with welding, often ignoring the intrinsic properties of the laser irradiation; unsurprisingly, the printable materials are mostly the well-known weldable materials.
Findings
The consolidation mechanism of HA was identified during its processing in a ceramic SLS device, then the effect of the laser energy density was studied to see how it affects the processing window. Premature sintering and sintering regimes were revealed and elaborated in detail. The full consolidation beyond sintering was also revealed along with its interaction to baseplate.
Originality/value
These findings provide important insight into the consolidation mechanism of HA ceramics, which will be the cornerstone for extending the range of materials in laser powder bed fusion of ceramics.
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