Purpose
To develop a novel 3D printable polyether ether ketone (PEEK)-hydroxyapatite (HA)-magnesium orthosilicate (Mg
2
SiO
4
) composite material with enhanced properties for potential use in ...tumour, osteoporosis and other spinal conditions. We aim to evaluate biocompatibility and imaging compatibility of the material.
Methods
Materials were prepared in three different compositions, namely composite A: 75 weight % PEEK, 20 weight % HA, 5 weight % Mg
2
SiO
4
; composite B: 70 weight% PEEK, 25 weight % HA, 5 weight % Mg
2
SiO
4
; and composite C: 65 weight % PEEK, 30 weight % HA, 5 weight % Mg
2
SiO
4
. The materials were processed to obtain 3D printable filament. Biomechanical properties were analysed as per ASTM standards and biocompatibility of the novel material was evaluated using indirect and direct cell cytotoxicity tests. Cell viability of the novel material was compared to PEEK and PEEK-HA materials. The novel material was used to 3D print a standard spine cage. Furthermore, the CT and MR imaging compatibility of the novel material cage vs PEEK and PEEK-HA cages were evaluated using a phantom setup.
Results
Composite A resulted in optimal material processing to obtain a 3D printable filament, while composite B and C resulted in non-optimal processing. Composite A enhanced cell viability up to ~ 20% compared to PEEK and PEEK-HA materials. Composite A cage generated minimal/no artefacts on CT and MR imaging and the images were comparable to that of PEEK and PEEK-HA cages.
Conclusion
Composite A demonstrated superior bioactivity vs PEEK and PEEK-HA materials and comparable imaging compatibility vs PEEK and PEEK-HA. Therefore, our material displays an excellent potential to manufacture spine implants with enhanced mechanical and bioactive property.
The complex and hierarchical structure with high vascularization of human bone limits the applications of traditional bone tissue engineering, especially in large bone defects. Progress in ...nanotechnology and 3D printing has opened new opportunities for bone tissue engineering. Nanoparticles possess unique size-dependent physicochemical and mechanical properties, such as bone scaffold enhancement, drug delivery ability, and bioimaging ability, that are rarely detected in bulk components. Nanoparticles with these features have enabled us to create multi-functional bone scaffolds within a single system. At the same time, 3D printing can make the scaffolds with fully customizable designs. These nanoparticle-embedded 3D printed scaffolds used in bone tissue engineering have tremendous potential to enhance bone regeneration and healing. The previous review paper covered the functions and applications of metallic and metal oxide nanoparticles in bone tissue engineering. This review paper aims to cover the most recent bone tissue engineering applications based on different ceramic nanoparticles in 3D printed scaffolds. This paper also summarizes the capabilities and limitations of the multi-functional ceramic nanoparticles, and potential future improvement solutions.
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Instrumentation during metastatic spine tumor surgery (MSTS) provides stability to the spinal column in patients with pathologic fracture or iatrogenic instability produced while undergoing extensive ...decompression. Titanium is the current implant material of choice in MSTS. However, it hinders radiotherapy planning and generates artifacts, with magnetic resonance imaging and computed tomography scans used for postoperative evaluation of tumor recurrence and/or complications. The high modulus of elasticity of titanium (110 GPa) results in stress shielding, which may lead to construct failure at the bone–implant interface. Polyether ether ketone (PEEK), a thermoplastic polymer, is an emerging alternative to titanium for use in MSTS. The modulus of elasticity of PEEK (3.6 GPa) is close to that of cortical bone (17–21 GPa), resulting in minimal stress shielding. Its radiolucent and nonmetallic properties cause minimal interference with magnetic resonance imaging and computed tomography scans. PEEK also causes low-dose perturbation for radiotherapy planning. However, PEEK has reduced bioactivity with bone and lacks sufficient rigidity to be used as rods in MSTS. The reduced bioactivity of PEEK may be addressed by 1) surface modification (introducing porosity or bioactive coating with hydroxyapatite HA or titanium) and 2) forming composites with HA/titanium. The mechanical properties of PEEK may be improved by forming composites with HA or carbon fiber. Despite these modifications, all PEEK and PEEK-based implants are difficult to handle and contour intraoperatively. Our review provides a comprehensive overview of PEEK and modified PEEK implants, with a description of their properties and limitations, potentially serving as a basis for their future development and use in MSTS.
Bioelectricity has been a fundamental property of all living organisms. With electrical stimulation, living cells can interact with their microenvironments, which makes electrical stimulation highly ...beneficial for various biomedical applications. However, traditional electrical stimulation mainly relies on bulky and complex equipment, which may not be ideal due to the restriction of movement, limited battery lifetime, uncomfortable wearing, and potential unfriendly to the environment. The advent of triboelectric nanogenerators (TENGs) has helped to resolve the existing limitations. TENGs are effective energy harvesting systems that use a mix of triboelectrification and electrostatic induction to create electrical energy from kinetic energy. TENGs deliver self‐powered electrical stimulation to bone cells for functional regulation or bone regeneration, serve as sensors to detect biological signals or movements, or act as a power source for other biomedical devices. TENGs can be employed in various applications, including enhancing bone regeneration, providing sensing function, slowing bone aging, and curing implant‐related infections. The recent applications of TENGs in bone tissue engineering are reviewed, and the drawbacks of the TENGs are discussed. Finally, the existing challenges and future roadmap for developing TENGs are presented.
Triboelectric nanogenerators (TENGs) are effective and cutting‐edge energy harvesting systems that can deliver self‐powered electrical stimulation to bone cells for functional regulation or bone regeneration, serve as sensors to detect biological signals or movements, and act as a power source for other biomedical devices. Besides bone tissue engineering, TENGs also have great potential in other biomedical applications.
4D Printing
In article number 2206486 by Guiwei Li and co‐workers, a 4D printing method to endow non‐shapememory metallic materials with active properties is presented, which can realize the shape ...changing of selected areas during or after forming process owing to stress release generated. The methodology opens new avenues to create metallic shape‐morphing 3D structures for high‐performance engineering applications. Specifically, the 2D part precursor can be turned into fitting a 3D structure by laser stimulation to repair the gap of the space station.
•As compared to 316 L SS, Fe-based BMG exhibits optimal mechanical properties, adequate corrosion resistance, and excellent biocompatibility.•regardless of the various processing parameters, nearly ...fully amorphous structures specimen can be produced by SLM.•At the same energy density, the hardness and elastic modulus can be varied by adjusting laser power and scanning speed.•Lower processing parameters (at the same energy) can generate Fe-based BMG with a rougher surface, which can release more beneficial ions for better biocompatibility.
The unique properties of bulk metallic glass (BMG) render it an excellent material for bone-implant applications. BMG samples are difficult to produce directly because of the critical cooling rate of molding. Advancements in additive manufacturing technologies, such as selective laser melting (SLM), have enabled the development of BMG. The successful production of materials via SLM relies significantly on the processing parameters; meanwhile, the overall energy density affects the crystallization and, thus, the final properties. Therefore, to further determine the effects of the processing parameters, SLM is performed in this study to print Fe-based BMG with different properties three dimensionally using selected processing parameters but a constant energy density. The printed amorphous Fe-based BMG outperforms the typical 316 L stainless steel (316 L SS) in terms of mechanical properties and corrosion resistance. Moreover, observations from nanoindentation tests indicate that the hardness and elastic modulus of the Fe-based BMG can be customized explicitly by adjusting the SLM processing parameters. Indirect cytotoxicity results show that the Fe-based BMG can enhance the viability of SAOS2 cells, as compared with 316 L SS. These intriguing results show that Fe-based BMG should be investigated further for orthopedic implant applications.
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To develop a novel 3D printable polyether ether ketone (PEEK)-hydroxyapatite (HA)-magnesium orthosilicate (Mg
SiO
) composite material with enhanced properties for potential use in tumour, ...osteoporosis and other spinal conditions. We aim to evaluate biocompatibility and imaging compatibility of the material.
Materials were prepared in three different compositions, namely composite A: 75 weight % PEEK, 20 weight % HA, 5 weight % Mg
SiO
; composite B: 70 weight% PEEK, 25 weight % HA, 5 weight % Mg
SiO
; and composite C: 65 weight % PEEK, 30 weight % HA, 5 weight % Mg
SiO
. The materials were processed to obtain 3D printable filament. Biomechanical properties were analysed as per ASTM standards and biocompatibility of the novel material was evaluated using indirect and direct cell cytotoxicity tests. Cell viability of the novel material was compared to PEEK and PEEK-HA materials. The novel material was used to 3D print a standard spine cage. Furthermore, the CT and MR imaging compatibility of the novel material cage vs PEEK and PEEK-HA cages were evaluated using a phantom setup.
Composite A resulted in optimal material processing to obtain a 3D printable filament, while composite B and C resulted in non-optimal processing. Composite A enhanced cell viability up to ~ 20% compared to PEEK and PEEK-HA materials. Composite A cage generated minimal/no artefacts on CT and MR imaging and the images were comparable to that of PEEK and PEEK-HA cages.
Composite A demonstrated superior bioactivity vs PEEK and PEEK-HA materials and comparable imaging compatibility vs PEEK and PEEK-HA. Therefore, our material displays an excellent potential to manufacture spine implants with enhanced mechanical and bioactive property.
A process planning (PP) problem is defined as to determine a set of operation-methods (machine, tool, and set-up configuration) that can convert the given stock to the designed part. Essentially, the ...PP problem involves the simultaneous decision making of two tasks: operation-method selection and sequencing. This is a combinatorial optimisation problem and it is difficult to find the best solution in a reasonable amount of time. In this article, an optimisation approach based on particle swarm optimisation (PSO) is proposed to solve the PP problem. Due to the characteristic of discrete process planning solution space and the continuous nature of the original PSO, a novel solution representation scheme is introduced for the application of PSO in solving the PP problem. Moreover, two kinds of local search algorithms are incorporated and interweaved with PSO evolution to improve the best solution in each generation. The numerical experiments and analysis have demonstrated that the proposed algorithm is capable of gaining a good quality solution in an efficient way.
Bioprinting is a novel technology that has a greater potential to revolutionize the field of tissue engineering and regenerative medicine. The growth of this technology is commendable and the ...applications explored are far and wide, including skin printing, orthopedics, cardiovascular applications, dental and maxillofacial applications, cancer research, and personalized medicine. Bioprinting is moving from tissue printing toward printing of functional organs. Although printing fully functional organ cannot be expected to be achieved in this decade, given the challenges and complexities, diligent efforts are taken by researchers around the world to realize this ambitious goal. Asia has contributed its share to the global bioprinting research community. A keyword search in Scopus with “bioprinting” showed that Asia has 30% share of the research publications in the past decade (2008-2018), the details are shown in table below.
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