Researchers from Germany are exploring democratizing bioprinting with their findings outlined in ‘Nydus One Syringe Extruder (NOSE): A Prusa i3 3D printer conversion for bioprinting applications.’ Recognizing the promise of this new technology and all that surrounds it, the authors focus on the potential for eliminating animal testing in the pharmaceutical industry, along with the ability to offer patient-specific treatment in nearly every area of medicine. But, applications could extend far beyond these.
In this study, the research team studies the performance of a Prusa i3 converted with a Nydus One Syringe Extruder (NOSE), allowing for hydrogel extrusion and ‘tunable deposition precision’ with a syringe holder. Projects like these are possible because of open-source technology, and here, the team was able to alter their low-cost 3D printing hardware to experiment in bioprinting. The combination of NOSE and the Prusa i3 platform in an open source bioprinting package is a potentially powerful one that could democratize bioprinting worldwide. Building on CMU’s FRESH research that has already lead to tissues being made on low-cost printers this is really a potentially groundbreaking moment in bioprinting.
So far bioprinters have been niche and cost 100,000’s or tens of thousands. With FRESH CMU already has demonstrated for three years that low-cost bioprinting for $500 to a $1000 is possible. But, this GPL licensed research combined wit the popular Prusa i3 open source 3D printer could be the thing that makes bioprinting accessible. What this paper does is give you a step by step guide on how to bioprint using a modified Prusa printer and some extra parts. In one fell swoop, hundreds of thousands of Prusa operators could potentially now experiment with bioprinting.
No matter what type of hardware, software, or materials are used though, challenges still abound in bioprinting as researchers must work hard to keep cells alive in the lab. Open sourcing allows for smaller labs to forge ahead in bioprinting also as they can bypass the cost of commercial hardware which could cost hundreds of thousands of dollars. Modifications to the Prusa i3 with the NOSE offer many benefits, to include:
- A RepRap basis and GPL license allowing modifications and opening the door to support in a large 3D printing community.
- Specialized P.I.N.D.A. calibration routine for user-friendliness, and ease in reproducing prints
- Open-source software
- Accessibility and affordability for users
- Validated conversion for use with cell lines, stem cells, and FRESH printing for complex structures
Once parameters are set, the researchers promise an algorithm delivering a ‘collision-free path.’ They must be set carefully and correctly, however, and the team suggests that users practice first by fabricating and experimenting with basic samples. If desired, the printer mainframe can also be replaced with a RebelliX frame.
The research paper also includes information regarding:
- Operation instructions
- One-time setup
- Software requirements and downloads
- Slic3r setup
- Bioprinting routine
- Ink preparation
- Support removal
Costs for converting the Prusa i3 into a comprehensive bioprinter are minimal, and the FRESH method means that users can print complex geometries, using concentrated hydrogels for bioprinting purposes. The researchers did note, however, that the NOSE system was lacking in some areas:
“A completely screw-based extruder assembly would enhance the modifiability for following iterations,” stated the researchers. “Rapid infill motions caused by the high center of mass might increase the material fatigue. One potential solution here could be the placement of the servo closer to the y-carriage. Extra mechanical-endstops would improve the user-friendliness, by automatizing the repositioning of the mechanical press. Additionally, thermal extrusion control or UV-emitting diodes could increase the cross-linking capabilities and thus the range of hydrogels in future.”
The NOSE bioprinting setup exhibited an 81 percent survival rate of HEK293 cells during experimentation and promising 85 percent rate for embryonic stem cells (mESC). Again, however, some major issues did arise as the FRESH microgel proved to be ‘non-ideal’ for cells exposed over 30 minutes.
“Overall these findings open up further optimization of the embedded bioprinting method by creating a physiological environment,” concluded the researchers. “Our bioprinting approach is protected with the GPLv3 license, hence we invite you to reproduce our data and modify our approach.”
Bioprinting may be much more common in research labs around the world today, from microfluidic platforms to scaffolds for bone regeneration and more, but for most scientists, the ultimate goal is that of 3D printing human organs. Impressive strides have already been made, however, with cellularized hearts, human brain tissue, animal brains, and many other spectacular models.
Given that the Prusa i3 is an inexpensive 3D printer capable of high-quality 3D prints this development could potentially democratize bioprinting. If the NOSE nozzle works well then this could make the i3 an affordable bioprinting platform, for some bioprinting applications, for use in the lab and classroom. The Prusa i3 is the predominant FDM system architecture and hundreds of thousands of Prusa and Prusa clones are scattered across the earth. Hundreds of vendors sell and manufacture them. With the NOSE nozzle and the i3 bioprinting could now become affordable for many people worldwide. Sometimes a moment changes everything, sometimes that moment is this one.
Metal 3D printing, although it has gone down in cost, is still quite expensive. This limits access to the technology for small and medium-sized businesses, meaning that many applications go untried. In a paper entitled “Design and Development of a Low-Cost 3D Metal Printer,” a group of researchers discuss how they created a low-cost metal 3D printer that utilizes metal inert gas (MIG) welding and an open source microcontroller to fabricate parts.
The researchers took the design of their 3D printer from a Prusa i3 system and used several off-the-shelf components to build it.
“The components consist in developing 3D metal printer machine are; a pair of bearing holder and motor bracket, motor casing, shaft holder, ball screw, coupling, limit switch, linear bearing, stepper motor, polyurethane cylinder, polytetrafluorethylane (PTFE) plastic cylinder and various fastener,” they explain.
A MIG welding machine was used to supply the material and the energy to melt the material. The movement of the printer and the translation of command from the printer’s server to the host computer was controlled by firmware provided with an Arduino microcontroller. The cost of the entire system was about RM 3496, which translates to roughly $840, much more affordable than a typical metal 3D printer.
“In order to ensure the metal print is connected during operations, the MIG welding was set to switch on and off automatically,” the researchers continue. “The shielding gas was set to flow before the printing process starts. The welding torch was placed under the fixture design perpendicular to the bed to build the surface. The distance between the bed surface and nozzle was adjusted to about 6 mm by leveling the height of the welding torch.”
The MIG welding machine begins building a part layer by layer, from bottom to top. In order to test the system, the researchers performed two experiments in which a cylinder and a rectangle were 3D printed.
“The aim for the first experiment is to find the suitable voltage during 3D printing that produce relatively good bead geometry of 3D printed part,” the researchers state. “At first, the welding was deposited along the custom cylinder design. The parameter used for welding voltage varied from 18.5 V to 22.5 V. The first experiment was done with a constant speed of 50 mm/s and current of 100 A. The final dimensions were taken and compared with the actual CAD data. The second experiment was designed so that capability of the newly developed machine to 3D print a rectangular shape can be analyzed. The aim of the second experiment is to find the suitable value of speed in producing good structure.”
Five samples were 3D printed for the first experiment and their average values were recorded. They found that porosity occurred when voltage was either to high or too low, and that higher voltages reduce the size of the specimen due to the excessive flow of the molten metal. A voltage setting of 20.5V produced a good quality part, but it was not dimensionally accurate. In the second experiment, the researchers attempted to find the best printing speed. A too-slow speed resulted in a rough surface and poor fusion. They found that the speed should not be any higher than 20mm/s, however, so that the liquid had time to solidify. Post-processing was required in all cases to get better surface finish. As you can see the results are far from perfect but at this price point many would be able to try to improve such systems. Given more time and investment this could very well be a viable alternative to some metal parts.
“Nevertheless, the study demonstrated that simple design specimens were successfully fabricated using the MIG welding and 3D printing process,” the researchers conclude. “The microstructure shows that the layer perfectly coincides with each printer layer and the top region of manufactured layer has the lowest hardness compared to the initial layer. However, further research needs to be done in the future to improve the product’s quality and to study the mechanical behavior of the parts produced by this technique.”
Authors of the paper include N.A. Rosli, M.R. Alkahari, F.R. Ramli, S. Maidin, M.N. Sudin, S. Subramoniam and T. Furumoto.
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