Posted on

Inexpensive 3D Printed Membrane Feeder Aids in Malaria Studies

[Image: National Geographic]

According to the Centers for Disease Control, in 2016 roughly 445,000 people around the world died of malaria, a serious disease caused by a parasite that often infects a certain type of mosquito, which in turn feeds on humans. 91% of these deaths were estimated to have taken place in the WHO African region, and most of these deaths were of young children, who are among the most vulnerable in areas of high transmission as they have not developed an immunity to the disease yet.

Malaria is one of the world’s most severe public health problems, and a lot of work has gone into using 3D printing to help diagnose and even cure the disease.

A group of researchers from Imperial College London is studying how malaria is transmitted, which requires mosquito test subjects to be infected with Plasmodium gametocytes – the blood stage parasites that actually cause malaria. In a Standard Membrane Feeding Assay (SMFA) test, an artificial membrane feeding apparatus, which simulates the host’s skin and body temperature, is used to get the mosquitoes to eat reconstituted blood containing the gametocytes. These feeders warm infected blood using glass chambers or electric heating elements, both of which are hard to acquire and expensive to boot.

The team recently published a paper, titled “An inexpensive open source 3D-printed membrane feeder for human malaria transmission studies,” that presents their creation and testing of an inexpensive, 3D printed membrane feeder.

“Presented here is a simple two-piece water-jacketed membrane feeder designed to hold a volume of 500 µl,” the paper reads. “Using the files presented here, the feeder can be 3D-printed directly and inexpensively by stereolithography by any equipped lab or commercial 3D-printing provider. Alternatively, by using a CAD package the size of the feeder can be up- or downscaled to hold more or less volume respectively.”

a) The membrane feeder was designed in two parts, a top chamber that connects to a circulating water bath and a bottom chamber holding a water reservoir and the RBC/gametocyte/serum sample on the underside. b) Both pieces are glued together into a single, watertight unit.

The researchers created the two-part membrane feeder design using the free, open source CAD modeling program Art of Illusion, then had Shapeways 3D print the parts out USP VI medical-grade “Fine Detail Plastic” acrylic resin (VisiJet M3 Crystal). Then, they conducted three independent SMFAs, using the Plasmodium falciparum laboratory strain NF54, in order to compare the performance of their 3D printed membrane feeder to that of a commercial glass feeder.

Comparative P. falciparum SMFAs with a commercial glass feeder and 3D-printed feeder.

According to the study, “Exflagellation rates as well as oocyst counts indicate that there is no significant difference between the two, within the statistical power given by triplicate SMFAs used as standard by the research community.”

The researchers believe that by making the design files for their 3D printed membrane feeder open source, more laboratories will be able to perform these SMFAs, and can even customize the design if necessary.

“The 3D-printed feeder design enables researchers to inexpensively produce their own SMFA feeders as an alternative to expensive and fragile glass feeders that require specialist manufacturing,” the study concludes. “This new 3D-printed feeder can be used in a wide range of applications in addition to standard SMFAs, as it is not limited to the species used here. Application might include the assessment of vector competence for malaria, the epidemiological assessment of the infectious reservoir for malaria, clinical drug trials, and transmission-blocking studies.”

Co-authors of the paper include Kathrin Witmer, Ellie Sherrard-Smith, Ursula Straschil, Mark Tunnicliff, Jake Baum, and Michael Delves. The design files for the 3D printable membrane feeder can be found in the paper.

Discuss this story and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below.

Posted on

Custom 3D Printed CT-Bone Graft Implants Coming to Japan and Europe

We first heard of innovative CT-Bone technology three years ago, when Dutch company Xilloc reached an agreement with Tokyo-based Next21 K.K., the creator of CT-Bone, to bring 3D printable bone into hospitals in Europe. Back in 2001, Next 21 K.K. collaborated with the University of Tokyo and RIKEN on developmental research into the technology, which uses 3D printing to make synthetic bone grafts out of calcium-deficient HA material.

Now, after receiving an approval for manufacturing and marketing medical devices from the country’s Ministry of Health, Labor and Welfare (MHLW), the company is announcing formal approval for a new technology to 3D print synthetic bone grafts, which can both fuse and be assimilated into a patient’s existing bone.

There are currently four different types of existing bone grafts for patients with different kinds of bone defects and deformities: Autograft and Allograft (the most common), Synthetic Bone graft, and Xenograft. Custom synthetic graft materials are shaped from a heated and sintered block of material with machine tools, and is hard for natural bone tissue to absorb, which could lead to inflammation.

Autograft, which is the foremost transplant method in Japan, requires an additional surgery in order to remove a piece of bone from the patient’s leg or hip, so patients have to go through a second invasive procedure and deal with the potential risks, like damage and infection, from extended exposure. Allograft from a bone bank is the most common in the US and Europe, but as it’s harvested from cadavers, there are potential infectious and ethical conundrums to consider. Additionally, it can be hard to find a cadaver bone that’s the appropriate size and shape to match a patient’s original bone.

But, 3D printing makes it possible to reproduce the shape of the original bone with 0.1 mm accuracy, and CT-Bone also uses a curing treatment method to help with recrystallization. This the technology, as Next21 K.K. puts it, “most suitable for molding biomaterial like a bone graft.”

CT-Bone does not use a sintering process to increase mechanical strength like other synthetic bones or 3D printed ceramics do, so it actually becomes physiologically activated; this helps the material in the custom implant fuse and assimilate to the patient’s existing bone much more quickly.

While most typical bone implants are made from material like titanium or PEEK, or even cut and re-positioned bone from the patient, CT-bone is a 3D printable, calcium phosphate implant that’s actually converted into real bone by the patient’s own body.

After a CT-scan, Next21 K.K.’s biomedical engineers work with the surgeons to create a patient-specific implant (PSI), which can incorporate porosity and match the patient’s anatomy perfectly, which helps facilitate bony ingrowth and good bone-to-implant contact. It only takes a few months post-implantation for CT-Bone to unify with the patient’s existing bone.

Thanks to a subsidy from the New Energy and Industrial Technology Development Organization (NEDO), the company completed a pre-clinical study for CT-Bone, titled “Computed tomographic evaluation of novel custom-made artificial bones, “CT-bone”, applied for maxillofacial reconstruction” and performed with support from the National Institute of Biomedical Innovation, Health and Nutrition (NIBIOHN). Co-authors include Yuki Kanno from the University of Tokyo, Takashi Nakatsuka with Saitama Medical School, Hideto Saijo, Yuko Fujihara, and Hikita Atsuhiko from the university, Ung-il Chung with the university’s Graduate Schools of Engineering and Medicine, and Tsuyoshi Takato and Kazuto Hoshi with the university.

The abstract reads, “We fabricated custom-made artificial bones using three-dimensionally layered manufacturing (3D printing) process, and have applied them to patients with facial deformities. We termed this novel artificial bone the “CT-bone”. The aim of the present study was to evaluate the middle-and long-term safety and effectiveness of the CT-bones after transplantation.”

CT-Bone grafts were implanted into 23 sites on 20 patients with facial bone deformities and then evaluated through the use of CT scans post-op, minimally for one year and then maximally for seven years and three months after transplantation.

According to the paper, “No serious systemic events due to the CT-bone graft were found during the observation period (1 year postoperatively). In 4 sites of 4 patients, the CT-bones were removed due to local infection of the surgical wounds at 1-5 years postoperatively. Compatibility of the shapes between the CT-bone and the recipient bone was confirmed to be good during the operation in all of the 20 cases, implying that the CT-bones could be easily installed onto the recipient sites. During the CT evaluation (<7 years and 3 months), no apparent chronological change was seen in the shape of the CT-bones. Sufficient bone union was confirmed in 19 sites. The inner CT values of the CT-bones increased in all the sites. The longer the postoperative period, greater increases in the CT values of the CT-bones tended to be observed.”

Next21 K.K. plans to commercialize CT-bone in the Japanese market, and initiate export to other Asian countries. Having already reached a license agreement with Xilloc for local manufacturing and sales of CT-Bone in the EU, the company will also expand sales to Europe.

Discuss this story and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the comments below. 

[Images provided by Next21 K.K.]

Posted on

Desktop 3D Printing and Functional Replacement Parts

3D printing is seeing increasing use in the manufacture of components for bikes, and sometimes even the bikes themselves. Bikes with 3D printed parts don’t just look cool, either – they perform just as well as, and sometimes even better than, regular bikes.

Open source advocate and 3D printing educator at Michigan Tech Dr. Joshua Pearce recently published an Ultimaker blog post about how to use your desktop 3D printer to create functional, inexpensive replacement parts for complex machines that require mechanical integrity – like bicycles.

Dr. Pearce’s team partnered up with the research group of John Gershenson. Dr. Pearce, Gershenson, Nagendra Tanikella, and Ben Savonen completed a study on the use of open source 3D printers for making components for the popular Black Mamba bicycle.

Dr. Pearce wrote, “Specifically, we chose to start tests with pedals that fail often and have clear standards namely the CEN (European Committee for Standardization) standards for racing bicycles for 1) static strength, 2) impact, and 3) dynamic durability.”

First, the teams used parametric open source FreeCAD to design a custom CAD model of a replacement pedal; the model and STL files are available for download from Youmagine. The pedal was made using the most common 3D printing material – biodegradable, inexpensive PLA.

Static strength test

The pedal was first subjected to a 1,500 N vertical downward force under the CEN static strength test, which found no fractures. Then, the pedal was tested to a 3,000 N compression load applied pedal uniformly – this is actually twice the required amount, which meant that the pedal well exceeded the standard, and, as Dr. Pearce put it, was able to “clear the first hurdle!”

A mass of 15 kg was dropped onto the pedal from 400 mm up, 60 mm from the mounting face, for the CEN bicycle pedal impact resistance test. While the test resulted in a minor dent, there weren’t any fractures – another test passed.

In order to simulate a real-world bicycle, with a person on the pedals, the CEN developed its dynamic durability test for bike pedals. For this test, the research groups had to spin the spindle at 100 rev/min for 100,000 revolutions; at the same time, the pedal also had a mass of 65 kg suspended only by a string. Just like with the static strength test, the pedal’s dynamic durability was designed to exceed the CEN standard under normal conditions.

Impact resistance

Rather than using a rig, the team attached the 3D printed pedal to a bicycle for direct testing, and went 200,000 revolutions with a person’s 75 kg weight being carried solely by the pedals. Again, this was twice the CEN standard, and passed again – I’m sensing a theme here.

Dr. Pearce wrote, “Our humble 3D printed pedal is now good enough for European [racing] bikes…but wait it is actually better!”

The 3D printed pedals are nearly a third of the moss of the Black Mamba stock pedals, which is performance-enhancing as well as cost-effective…if raw PLA pellets or recycled materials, like ABS, nylon, or PET, are used, that is.

Dr. Pearce also provided some easy, DIY guidelines to achieve lab-worthy results for the 3D printed pedals, so you won’t have to redo any bike part experiments.

First, look into expertise already available through a study that researched the parts you were interested in, such as this one regarding the viability of distributed manufacturing of 3D printed PLA bike pedals. Then, determine the material’s mechanical requirements – check out this study for a handy open access list of most of the commonly available tensile strengths of the more common 3D printing materials.

Sub-optimal layers

Print the component in the right material, and with required infills, to achieve your application’s desired mechanical properties. Then, make sure to check out the print’s exterior for any sub-optimal layers from under-extrusion – if the part is under-extruded, fix your 3D printer and try it again.

Finally, weigh the part to make sure there isn’t any under-extrusion inside that you’re not able to see; Dr. Pearce explained that a digital food scale has “acceptable precision and accuracy” for most prints done on extrusion-based 3D printers.

“This mass is compared to the theoretical value using the densities from this table for the material and the volume of the object,” Dr. Pearce said.

The previously mentioned study with the list of tensile strengths was able to find a linear relationship between a 3D printed part’s ideal mass and the maximum stress able to be undertaken by samples. You can just check the study to see how far off from the ideal your part is, and then determine if it needs to be reprinted before figuring out the high probability of your needed properties.

According to mechanical studies completed on many extrusion 3D printers, open source machines produce stronger prints than proprietary systems, mostly thanks to the setting limitations of the latter.

“But be aware that there is a range and the properties of your parts will depend a lot on your machine and the settings you use,” Dr. Pearce warns. “In general printing at the high end of the extruder temperature range for your material will result in a higher strength.”

Just use that weighing technique, and compare your part’s mass to the ideal, to find out where it will most likely lie on the strength range.

You can read Dr. Pearce’s full rundown at Ultimaker.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below. 

 

 

Posted on

3D Printing News Briefs: June 29, 2018

In today’s 3D Printing News Briefs (the last one this month, how is the summer going by so quickly?!), a few companies are announcing special honors and recognitions, and then we’re sharing stories stories about some interesting new 3D printing projects, and finally wrapping things up before the weekend with some business news. Renishaw’s Director of R&D has been honored by the Royal Academy of Engineering, while MakerBot earned an important designation for its 3D printing certification program for educators and Renovis Surgical Technologies received FDA approval for its new 3D printed implant. Festo is introducing three new bionic robots, one of which is partially 3D printed, and CINTEC is using 3D printing for its restoration of a famous government house. GE wants to use blockchains for 3D printing protection, and ExOne announced a global cost realignment.

Royal Academy of Engineering Honors Renishaw’s Chris Sutcliffe

Earlier this week, the Royal Academy of Engineering (RAE) awarded a Silver Medal to Professor Chris Sutcliffe, the Director of Research and Development of the Additive Manufacturing Products Division (AMPD) for global metrology company Renishaw. This award is given to recognize outstanding personal contributions to British engineering, and is given to no more than four people a year. The Silver Medal Sutcliffe received was in recognition of his part in driving the development of metal 3D printed implants in both human and veterinary surgery, and also celebrates his successful commercialization of 3D printed products with several companies, including Renishaw, and the University of Liverpool.

“Throughout my career I’ve worked hard to commercialise additive manufacturing technology. As well as AM’s benefit to the aerospace and automotive sectors, commercialisation of AM and associated technologies has been lifechanging for those with musculoskeletal diseases,” said Sutcliffe. “The award celebrates the successes of the engineers I have worked with to achieve this and I am grateful to receive the award to recognise our work.”

MakerBot’s Certification Program for Educators Gets Important Designation

One of the leaders in 3D printing for education is definitely MakerBot, which has sent its 3D printers to classrooms all over the world. Just a few months ago, the company launched a comprehensive, first of its kind 3D printing certification program, which trains educators to become 3D printing experts and create custom curriculum for STEAM classrooms. An independent review of the program showed that it meets the International Society for Technology in Education (ISTE) standards, and it has earned the prestigious ISTE Seal of Alignment from the accreditation body. In addition, a survey conducted over the last three years of over 2,000 MakerBot educators shows that the percentage of teachers reporting that MakerBot’s 3D printers met their classroom needs has doubled in just two years.

“This data shows that MakerBot isn’t just growing its user base in schools. We’re measurably improving teachers’ experiences using 3D printing,” said MakerBot CEO Nadav Goshen. “Much of this impressive teacher satisfaction is thanks to the effort we’ve put into solving real classroom problems—like the availability of 3D printing curriculum with Thingiverse Education, clear best practices with the MakerBot Educators Guidebook, and now training with the new MakerBot Certification program.”

Earlier this week, MakerBot exhibited its educator solutions at the ISTE Conference in Chicago.

FDA Grants Clearance for 3D Printed Interbody Spinal Fusion System 

California-headquartered Renovis Surgical Technologies, Inc. announced that it has received 510(k) clearance from the FDA for its Tesera SA Hyperlordotic ALIF Interbody Spinal Fusion System. All Tesera implants are 3D printed, and use a proprietary, patent-pending design to create a porous, roughened surface structure, which maximizes biologic fixation, strength, and stability to allow for bone attachment and in-growth to the implant.

The SA implant, made with Renovis’s trabecular technology and featuring a four-screw design and locking cover plate, is a titanium stand-alone anterior lumbar interbody fusion system. They are available in 7˚, 12˚, 17˚, 22˚ and 28˚ lordotic angles, with various heights and footprints for proper lordosis and intervertebral height restoration, and come with advanced instrumentation that’s designed to decrease operative steps during surgery.

Festo Introduces Partially 3D Printed Bionic Robot

German company Festo, the robotics research of which we’ve covered before, has introduced its Bionic Learning Network’s latest project – three bionic robots inspired by a flic-flac spider, a flying fox, and a cuttlefish. The latter of these biomimetic robots, the BionicFinWave, is a partially 3D printed robotic fish that can autonomously maneuver its way through acrylic water-filled tubing. The project has applications in soft robotics, and could one day be developed for tasks like underwater data acquisition, inspection, and measurement.

The 15 oz robot propels itself forward and backward through the tubing using undulation forces from its longitudinal fins, while also communicating with and transmitting data to the outside world with a radio. The BionicFinWave’s lateral fins, molded from silicone, can move independently of each other and generate different wave patterns, and water-resistant pressure and ultrasound sensors help the robot register its depth and distance to the tube walls. Due to its ability to realize complex geometry, 3D printing was used to create the robot’s piston rod, joints, and crankshafts out of plastic, along with its other body elements.


Cintec Using 3D Printing on Restoration Work of the Red House

Cintec North America, a leader in the field of structural masonry retrofit strengthening, preservation, and repair, completes structural analysis and design services for projects all around the world, including the Egyptian Pyramids, Buckingham Palace, Canada’s Library of Parliament, and the White House. Now, the company is using 3D printing in its $1 million restoration project on the historic Red House, which is also known as the seat of Parliament for the Republic of Trinidad and Tobago and was built between 1844 and 1892.

After sustaining damage from a fire, the Red House, featuring signature red paint and Beaux-Arts style architecture, was refurbished in 1904. In 2007, Cintec North America was asked to advise on the required repairs to the Red House, and was given permission to install its Reinforcing Anchor System. This landmark restoration project – the first where Cintec used 3D printing for sacrificial parts – denotes an historic moment in structural engineering, because one of the reinforcement anchors inserted into the structure, measuring 120 ft, is thought to be the longest in the world.

GE Files Patent to Use Blockchains For 3D Printing Protection

According to a patent filing recently released by the US Patent and Trademark Office (USPTO), industry giant GE wants to use a blockchain to verify the 3D printed parts in its supply chain and protect itself from fakes. If a replacement part for an industrial asset is 3D printed, anyone can reproduce it, so end users can’t verify its authenticity, and if it was made with the right manufacturing media, device, and build file. In its filing, GE, which joined the Blockchain in Transport Alliance (BiTA) consortium in March, outlined a method for setting up a database that can validate, verify, and track the manufacturing process, by integrating blockchains into 3D printing.

“It would therefore be desirable to provide systems and methods for implementing a historical data record of an additive manufacturing process with verification and validation capabilities that may be integrated into additive manufacturing devices,” GE stated in the patent filing.

ExOne to Undergo Global Cost Realignment

3D printer and printed products provider ExOne has announced a global cost realignment program, in order to achieve positive earnings and cash flow in 2019. In addition to maximizing efficiency through aligning its capital resources, ExOne’s new program will be immediately reducing the company’s consulting projects and headcount – any initial employee reductions will take place principally in consulting and select personnel. The program, which has already begun, will focus first on global operations, with an emphasis on working capital initiatives, production overhead, and general and administrative spending. This program will continue over the next several quarters.

“With the essential goal of significantly improving our cash flows in 2019, we have conducted a review of our cost structure and working capital practices. We are evaluating each position and expense within our organization, with the desire to improve productivity. As a result, we made the difficult decision to eliminate certain positions within ExOne, reduce our spending on outside consultants and further rely on some of our recently instituted and more efficient processes,” explained S. Kent Rockwell, ExOne’s Chairman and CEO. “Additional cost analyses and changes to business practices to improve working capital utilization will be ongoing over the next several quarters and are expected to result in additional cost reductions and improved cash positions. All the while, we remain focused on our research and development goals and long-term revenue growth goals, which will not be impacted by these changes, as we continue to lead the market adoption of our binder jetting technology.”

Discuss these stories, and other 3D printing topics, at 3DPrintBoard.com or share your thoughts in the Facebook comments below.