scholarly journals Fractal Design Boosts Extrusion-Based 3D Printing of Bone-Mimicking Radial-Gradient Scaffolds

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Huawei Qu ◽  
Zhenyu Han ◽  
Zhigang Chen ◽  
Lan Tang ◽  
Chongjian Gao ◽  
...  

Although extrusion-based three-dimensional (EB-3D) printing technique has been widely used in the complex fabrication of bone tissue-engineered scaffolds, a natural bone-like radial-gradient scaffold by this processing method is of huge challenge and still unmet. Inspired by a typical fractal structure of Koch snowflake, for the first time, a fractal-like porous scaffold with a controllable hierarchical gradient in the radial direction is presented via fractal design and then implemented by EB-3D printing. This radial-gradient structure successfully mimics the radially gradual decrease in porosity of natural bone from cancellous bone to cortical bone. First, we create a design-to-fabrication workflow with embedding the graded data on basis of fractal design into digital processing to instruct the extrusion process of fractal-like scaffolds. Further, by a combination of suitable extruded inks, a series of bone-mimicking scaffolds with a 3-iteration fractal-like structure are fabricated to demonstrate their superiority, including radial porosity, mechanical property, and permeability. This study showcases a robust strategy to overcome the limitations of conventional EB-3D printers for the design and fabrication of functionally graded scaffolds, showing great potential in bone tissue engineering.

2020 ◽  
Vol 6 (1) ◽  
pp. 57-69
Author(s):  
Amirhosein Fathi ◽  
Farzad Kermani ◽  
Aliasghar Behnamghader ◽  
Sara Banijamali ◽  
Masoud Mozafari ◽  
...  

AbstractOver the last years, three-dimensional (3D) printing has been successfully applied to produce suitable substitutes for treating bone defects. In this work, 3D printed composite scaffolds of polycaprolactone (PCL) and strontium (Sr)- and cobalt (Co)-doped multi-component melt-derived bioactive glasses (BGs) were prepared for bone tissue engineering strategies. For this purpose, 30% of as-prepared BG particles (size <38 μm) were incorporated into PCL, and then the obtained composite mix was introduced into a 3D printing machine to fabricate layer-by-layer porous structures with the size of 12 × 12 × 2 mm3.The scaffolds were fully characterized through a series of physico-chemical and biological assays. Adding the BGs to PCL led to an improvement in the compressive strength of the fabricated scaffolds and increased their hydrophilicity. Furthermore, the PCL/BG scaffolds showed apatite-forming ability (i.e., bioactivity behavior) after being immersed in simulated body fluid (SBF). The in vitro cellular examinations revealed the cytocompatibility of the scaffolds and confirmed them as suitable substrates for the adhesion and proliferation of MG-63 osteosarcoma cells. In conclusion, 3D printed composite scaffolds made of PCL and Sr- and Co-doped BGs might be potentially-beneficial bone replacements, and the achieved results motivate further research on these materials.


Author(s):  
Verma Walker, MLIS

Three-dimensional (3D) printing is opening new opportunities in biomedicine by enabling creative problem solving, faster prototyping of ideas, advances in tissue engineering, and customized patient solutions. The National Institutes of Health (NIH) Library purchased a Makerbot Replicator 2 3D printer to give scientists a chance to try out this technology. To launch the service, the library offered training, conducted a survey on service model preferences, and tracked usage and class attendance. 3D printing was very popular, with new lab equipment prototypes being the most common model type. Most survey respondents indicated they would use the service again and be willing to pay for models. There was high interest in training for 3D modeling, which has a steep learning curve. 3D printers also require significant care and repairs. NIH scientists are using 3D printing to improve their research, and it is opening new avenues for problem solving in labs. Several scientists found the 3D printer so helpful they bought one for their labs. Having a printer in a central and open location like a library can help scientists, doctors, and students learn how to use this technology in their work.


Author(s):  
Laxmi Poudel ◽  
Chandler Blair ◽  
Jace McPherson ◽  
Zhenghui Sha ◽  
Wenchao Zhou

Abstract While three-dimensional (3D) printing has been making significant strides over the past decades, it still trails behind mainstream manufacturing due to its lack of scalability in both print size and print speed. Cooperative 3D printing (C3DP) is an emerging technology that holds the promise to mitigate both of these issues by having a swarm of printhead-carrying mobile robots working together to finish a single print job cooperatively. In our previous work, we have developed a chunk-based printing strategy to enable the cooperative 3D printing with two fused deposition modeling (FDM) mobile 3D printers, which allows each of them to print one chunk at a time without interfering with the other and the printed part. In this paper, we present a novel method in discretizing the continuous 3D printing process, where the desired part is discretized into chunks, resulting in multi-stage 3D printing process. In addition, the key contribution of this study is the first working scaling strategy for cooperative 3D printing based on simple heuristics, called scalable parallel arrays of robots for 3DP (SPAR3), which enables many mobile 3D printers to work together to reduce the total printing time for large prints. In order to evaluate the performance of the printing strategy, a framework is developed based on directed dependency tree (DDT), which provides a mathematical and graphical description of dependency relationships and sequence of printing tasks. The graph-based framework can be used to estimate the total print time for a given print strategy. Along with the time evaluation metric, the developed framework provides us with a mathematical representation of geometric constraints that are temporospatially dynamic and need to be satisfied in order to achieve collision-free printing for any C3DP strategy. The DDT-based evaluation framework is then used to evaluate the proposed SPAR3 strategy. The results validate the SPAR3 as a collision-free strategy that can significantly shorten the printing time (about 11 times faster with 16 robots for the demonstrated examples) in comparison with the traditional 3D printing with single printhead.


2014 ◽  
Vol 2 (38) ◽  
pp. 6611-6618 ◽  
Author(s):  
Jun Yang ◽  
Teng Long ◽  
Nan-Fei He ◽  
Ya-Ping Guo ◽  
Zhen-An Zhu ◽  
...  

A chitosan/bioglass three-dimensional porous scaffold with excellent biocompatibility and mechanical properties has been developed for the treatment of bone defects.


2020 ◽  
Author(s):  
Alexander Vladimirovich Dektyarev ◽  
Pavel Gennadievich Zobov ◽  
Pavel Romanovich Grishin ◽  
Vladimir Nikolaevich Morozov

Abstract The relevance of the work is determined by a fundamentally new direction of 3D printing in the manufacture of ship models for hydrodynamic testing. In this paper, we study the towing drag of a model of a small boat manufactured using additive three-dimensional printing technologies. Based on the dimensions of the 3D printers used and the technological parameters of working with them, as well as the design features of the test pool, small-sized vessels of a series of kayaks, kayaks and canoes, which are of sufficient length, but not too wide and high, were investigated as a prototype of the future model, which is ideal under the methods of additive manufacturing. A base of prototypes of vessels of this class has been compiled and a rationale has been given for the choice of the prototype vessel itself for research, including an analysis of the design of the vessels presented, the availability of design and technological documentation, as well as technological schemes for manufacturing the model. A 3D model of the vessel was developed, its optimization for 3D printing and analysis of geometric shapes for deviations from ITTC requirements. The study of deviations of the geometric shapes of the ship model from shrinkage deformations was carried out using 3D scanning with the development of a technological scheme for describing this process. When developing a 3D model, in the process of 3D printing, as well as processing the results of 3D scanning, modern software tools — FreeShip, Autodesk Inventor, Cloud Compare, and others — were used in the work. In the manufacture of the model, the new DPA adhesive compound formula was used, able to provide durable joints for PLA plastic products. It was found that the measurements prove the possibility of using 3D printing for the production of ship models for hydrodynamic testing, subject to all the nuances of the technology.


Author(s):  
N. Kirillova ◽  
A. Alekseeva ◽  
A. Egorova

Additive technologies that allow creating volume objects of different complexity are becoming popular in different industries. There is an increase in the scale of introduction of 3D printing technologies in the construction industry, including in the production of ceramic products. With the help of modern additive technologies, different models, products and designs are created. They can be complex and can be made from different materials. Experts are wondering what the future holds for additive technologies in construction, as well as in ceramic production, as these technologies can save resources, reduce the time of the technological process and form complex shapes. The article presents an analytical review of the global application of additive technologies in construction, as well as in the manufacture of ceramic products. The advantages and disadvantages, the possibilities of 3D printing are considered. The creation of ceramic three-dimensional products is still a rare area of additive technologies that requires research. The production of ceramic products, superior to other materials in terms of high temperature strength, hardness, chemical and thermal resistance, has a high potential for the use of additive technologies. The types of construction 3D printers and raw materials for them are analyzed. The results of a study of the properties of clay raw materials of the Sannikovsky, Namtsyrsky and Kangalassky deposits of the Republic of Sakha (Yakutia) are presented.


2020 ◽  
Vol 39 (1) ◽  
pp. 243-261
Author(s):  
Lori Lioce ◽  
Kimberly Budisalich ◽  
Darlene A. Showalter

Though three-dimensional (3D) printing is often touted as cutting-edge technology, it actually made its appearance in the 1980s. Since then, this technology has made significant progress from its humble origins of layering polymers to create simple structures to the more sophisticated printing with elements such as metals used to create complex structures for aircraft. This technology has advanced and been finely tuned largely in thanks to the engineering profession. The variance within the printers, software, and printing material allows for broad application beyond engineering and manufacturing. Healthcare and academic applications are beginning to get traction. The National Institutes of Health has established a platform for sharing 3D ideas to support biotechnology and modeling for healthcare. It makes sense that nursing programs would, minimally, utilize 3D printers to enrich their institutional simulation laboratory and to manufacture specialty materials for training students in a cost-efficient manner. Opportunities to collaborate with other academic departments and community partners in the development and production of timely and effective solutions to pressing healthcare needs enriches student learning, nursing programs, and their graduates. Faculty buy-in and purposeful integration throughout the curriculum are vital variables associated with the successful implementation of 3D printing in a nursing program. Additional benefits include opportunities for publications, presentation of papers, and interprofessional collaboration.


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