Tag Archives: 3D printing

A cheaper way to make artificial organs

Leave a reply

In the quest to develop artificial organs, the University of British Columbia (UBC) is the not the first research institution that comes to my mind. It seems I may need to reevaluate now that UBC (Okanagan) has announced some work on bio-inks and artificial organs in a Sept. 12, 2017 news  release (also on EurekAlert) by Patty Wellborn,,

A new bio-ink that may support a more efficient and inexpensive fabrication of human tissues and organs has been created by researchers at UBC’s Okanagan campus.

Keekyoung Kim, an assistant professor at UBC Okanagan’s School of Engineering, says this development can accelerate advances in regenerative medicine.

Using techniques like 3D printing, scientists are creating bio-material products that function alongside living cells. These products are made using a number of biomaterials including gelatin methacrylate (GelMA), a hydrogel that can serve as a building block in bio-printing. This type of bio-material—called bio-ink—are made of living cells, but can be printed and molded into specific organ or tissue shapes.

The UBC team analyzed the physical and biological properties of three different GelMA hydrogels—porcine skin, cold-water fish skin and cold-soluble gelatin. They found that hydrogel made from cold-soluble gelatin (gelatin which dissolves without heat) was by far the best performer and a strong candidate for future 3D organ printing.

“A big drawback of conventional hydrogel is its thermal instability. Even small changes in temperature cause significant changes in its viscosity or thickness,” says Kim. “This makes it problematic for many room temperature bio-fabrication systems, which are compatible with only a narrow range of hydrogel viscosities and which must generate products that are as uniform as possible if they are to function properly.”

Kim’s team created two new hydrogels—one from fish skin, and one from cold-soluble gelatin—and compared their properties to those of porcine skin GelMA. Although fish skin GelMA had some benefits, cold-soluble GelMA was the top overall performer. Not only could it form healthy tissue scaffolds, allowing cells to successfully grow and adhere to it, but it was also thermally stable at room temperature.

The UBC team also demonstrated that cold-soluble GelMA produces consistently uniform droplets at temperatures, thus making it an excellent choice for use in 3D bio-printing.

“We hope this new bio-ink will help researchers create improved artificial organs and lead to the development of better drugs, tissue engineering and regenerative therapies,” Kim says. “The next step is to investigate whether or not cold-soluble GelMA-based tissue scaffolds are can be used long-term both in the laboratory and in real-world transplants.”

Three times cheaper than porcine skin gelatin, cold-soluble gelatin is used primarily in culinary applications.

Here’s a link to and a citation for the paper,

Comparative study of gelatin methacrylate hydrogels from different sources for biofabrication applications by Zongjie Wang, Zhenlin Tian, Fredric Menard, and Keekyoung Kim. Biofabrication, Volume 9, Number 4 Special issue on Bioinks https://doi.org/10.1088/1758-5090/aa83cf Published 21 August 2017

© 2017 IOP Publishing Ltd

This paper is behind a paywall.

4D printing, what is that?

Leave a reply

According to an April 12, 2017 news item on ScienceDaily, shapeshifting in response to environmental stimuli is the fourth dimension (I have a link to a posting about 4D printing with another fourth dimension),

A team of researchers from Georgia Institute of Technology and two other institutions has developed a new 3-D printing method to create objects that can permanently transform into a range of different shapes in response to heat.

The team, which included researchers from the Singapore University of Technology and Design (SUTD) and Xi’an Jiaotong University in China, created the objects by printing layers of shape memory polymers with each layer designed to respond differently when exposed to heat.

“This new approach significantly simplifies and increases the potential of 4-D printing by incorporating the mechanical programming post-processing step directly into the 3-D printing process,” said Jerry Qi, a professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech. “This allows high-resolution 3-D printed components to be designed by computer simulation, 3-D printed, and then directly and rapidly transformed into new permanent configurations by simply heating.”

The research was reported April 12 [2017] in the journal Science Advances, a publication of the American Association for the Advancement of Science. The work is funded by the U.S. Air Force Office of Scientific Research, the U.S. National Science Foundation and the Singapore National Research Foundation through the SUTD DManD Centre.

…

An April 12, 2017 Singapore University of Technology and Design (SUTD) press release on EurekAlert provides more detail,

4D printing is an emerging technology that allows a 3D-printed component to transform its structure by exposing it to heat, light, humidity, or other environmental stimuli. This technology extends the shape creation process beyond 3D printing, resulting in additional design flexibility that can lead to new types of products which can adjust its functionality in response to the environment, in a pre-programmed manner. However, 4D printing generally involves complex and time-consuming post-processing steps to mechanically programme the component. Furthermore, the materials are often limited to soft polymers, which limit their applicability in structural scenarios.

A group of researchers from the SUTD, Georgia Institute of Technology, Xi’an Jiaotong University and Zhejiang University has introduced an approach that significantly simplifies and increases the potential of 4D printing by incorporating the mechanical programming post-processing step directly into the 3D printing process. This allows high-resolution 3D-printed components to be designed by computer simulation, 3D printed, and then directly and rapidly transformed into new permanent configurations by using heat. This approach can help save printing time and materials used by up to 90%, while completely eliminating the time-consuming mechanical programming process from the design and manufacturing workflow.

“Our approach involves printing composite materials where at room temperature one material is soft but can be programmed to contain internal stress, and the other material is stiff,” said Dr. Zhen Ding of SUTD. “We use computational simulations to design composite components where the stiff material has a shape and size that prevents the release of the programmed internal stress from the soft material after 3D printing. Upon heating, the stiff material softens and allows the soft material to release its stress. This results in a change – often dramatic – in the product shape.” This new shape is fixed when the product is cooled, with good mechanical stiffness. The research demonstrated many interesting shape changing parts, including a lattice that can expand by almost 8 times when heated.

This new shape becomes permanent and the composite material will not return to its original 3D-printed shape, upon further heating or cooling. “This is because of the shape memory effect,” said Prof. H. Jerry Qi of Georgia Tech. “In the two-material composite design, the stiff material exhibits shape memory, which helps lock the transformed shape into a permanent one. Additionally, the printed structure also exhibits the shape memory effect, i.e. it can then be programmed into further arbitrary shapes that can always be recovered to its new permanent shape, but not its 3D-printed shape.”

Said SUTD’s Prof. Martin Dunn, “The key advance of this work, is a 4D printing method that is dramatically simplified and allows the creation of high-resolution complex 3D reprogrammable products; it promises to enable myriad applications across biomedical devices, 3D electronics, and consumer products. It even opens the door to a new paradigm in product design, where components are designed from the onset to inhabit multiple configurations during service.”

Here’s a video,


Uploaded on Apr 17, 2017

A research team led by the Singapore University of Technology and Design’s (SUTD) Associate Provost of Research, Professor Martin Dunn, has come up with a new and simplified 4D printing method that uses a 3D printer to rapidly create 3D objects, which can permanently transform into a range of different shapes in response to heat.

Here’s a link to and a citation for the paper,

Direct 4D printing via active composite materials by Zhen Ding, Chao Yuan, Xirui Peng, Tiejun Wang, H. Jerry Qi, and Martin L. Dunn. Science Advances  12 Apr 2017: Vol. 3, no. 4, e1602890 DOI: 10.1126/sciadv.1602890

This paper is open access.

Here is a link to a post about another 4th dimension, time,

4D printing: a hydrogel orchid (Jan. 28, 2016)

Hollywood and neurosurgery

Leave a reply

Usually a story about Hollywood and science (in this case, neurosurgery) is focused on how scientifically accurate the portrayal is. This time the situation has been reversed and science has borrowed from Hollywood. From an April 25, 2017 Johns Hopkins University School of Medicine news release (also on EurekAlert), Note: A link has been removed,

A team of computer engineers and neurosurgeons, with an assist from Hollywood special effects experts, reports successful early tests of a novel, lifelike 3D simulator designed to teach surgeons to perform a delicate, minimally invasive brain operation.

A report on the simulator that guides trainees through an endoscopic third ventriculostomy (ETV) was published in the Journal of Neurosurgery: Pediatrics on April 25 [2017]. The procedure uses endoscopes, which are small, computer-guided tubes and instruments, to treat certain forms of hydrocephalus, a condition marked by an excessive accumulation of cerebrospinal fluid and pressure on the brain. ETV is a minimally invasive procedure that short-circuits the fluid back into normal channels in the brain, eliminating the need for implantation of a shunt, a lifelong device with the associated complications of a foreign body.

“For surgeons, the ability to practice a procedure is essential for accurate and safe performance of the procedure. Surgical simulation is akin to a golfer taking a practice swing,” says Alan R. Cohen, M.D., professor of neurosurgery at the Johns Hopkins University School of Medicine and a senior author of the report. “With surgical simulation, we can practice the operation before performing it live.”

While cadavers are the traditional choice for such surgical training, Cohen says they are scarce, expensive, nonreusable, and most importantly, unable to precisely simulate the experience of operating on the problem at hand, which Cohen says requires a special type of hand-eye coordination he dubs “Nintendo Neurosurgery.”

In an effort to create a more reliable, realistic and cost-effective way for surgeons to practice ETV, the research team worked with 3D printing and special effects professionals to create a lifelike, anatomically correct, full-size head and brain with the touch and feel of human skull and brain tissue.

The fusion of 3D printing and special effects resulted in a full-scale reproduction of a 14-year-old child’s head, modeled after a real patient with hydrocephalus, one of the most common problems seen in the field of pediatric neurosurgery. Special features include an electronic pump to reproduce flowing cerebrospinal fluid and brain pulsations. One version of the simulator is so realistic that it has facial features, hair, eyelashes and eyebrows.

To test the model, Cohen and his team randomly paired four neurosurgery fellows and 13 medical residents to perform ETV on either the ultra-realistic simulator or a lower-resolution simulator, which had no hair, lashes or brows.

After completing the simulation, fellows and residents each rated the simulator using a five-point scale. On average, both the surgical fellows and the residents rated the simulator more highly (4.88 out of 5) on its effectiveness for ETV training than on its aesthetic features (4.69). The procedures performed by the trainees were also recorded and later watched and graded by two fully trained neurosurgeons in a way that they could not identify who the trainees were or at what stage they were in their training.

The neurosurgeons assessed the trainees’ performance using criteria such as “flow of operation,” “instrument handling” and “time and motion.”

Neurosurgeons consistently rated the fellows higher than residents on all criteria measured, which accurately reflected their advanced training and knowledge, and demonstrated the simulator’s ability to distinguish between novice and expert surgeons.

Cohen says that further tests are needed to determine whether the simulator will actually improve performance in the operating room. “With this unique assortment of investigators, we were able to develop a high-fidelity simulator for minimally invasive neurosurgery that is realistic, reliable, reusable and cost-effective. The models can be designed to be patient-specific, enabling the surgeon to practice the operation before going into the operating room,” says Cohen.

Other authors on this paper include Roberta Rehder from the Johns Hopkins School of Medicine, and Peter Weinstock, Sanjay P. Parbhu, Peter W. Forbes and Christopher Roussin from Boston Children’s Hospital.

Funding for the study was provided by a grant from the Boston Investment Conference. The research team acknowledges the contribution of FracturedFX, an Emmy Award-winning special effects group from Hollywood, California, in the development of the surgical models.

The investigators report no financial stake or interests in the success of the simulator.

Here’s what the model looks like,

Caption: A. Low-fidelity simulated surgical model for ETV. B. High-fidelity model with hair, eyelashes and eyebrows. Credit: Copyright AANS. Used with permission.

An April 25, 2017 Journal of Neurosurgery news release on EurekAlert details the refinements applied to this replica (Note: There is some repetitive material),

….

A neurosurgery residency training program generally lasts seven years–longer than any other medical specialty. Trainees log countless hours observing surgeries performed by experienced neurosurgeons and developing operative skills in practice labs before touching patients. It is challenging to create a realistic surgical experience outside an operating room. Cadaveric specimens and virtual reality programs have been used, but they are costly and do not provide as realistic an experience as desired.

The new training simulation model described in this paper is a full-scale reproduction of the head of an adolescent patient with hydrocephalus. The external appearance of the head is uncannily accurate, as is the internal neuroanatomy.

One failing of 3D models is the stiffness of most sculpting material. This problem was overcome by addition of special-effects materials that reproduce the textures of external skin and internal brain structures. In addition, the operative environment in this training model is amazingly alive, with pulsations of a simulated basilar artery and ventricles as well as movement of cerebrospinal fluid. These advances provide visual and tactile feedback to the trainee that closely resembles that of the surgical experience.

The procedure selected to test the new training model was endoscopic third ventriculostomy (ETV), a minimally invasive surgical procedure increasingly used to treat hydrocephalus. The goal of ETV is to create a hole in the floor of the third ventricle. This provides a new pathway by which excess cerebrospinal fluid can circulate.

During ETV, the surgeon drills a small hole in the skull of the patient and inserts an endoscope into the ventricular system. The endoscope accommodates a lighted miniature video camera to visualize the operative site and specialized surgical instruments suited to perform operative tasks through the endoscope. The video camera sends a direct feed to external monitors in the operating room so that surgeons can clearly see what they are doing.

To evaluate the usefulness of the training simulation model of ETV, the researchers solicited feedback from users (neurosurgical residents and fellows) and their teachers. Trainees were asked to respond to a 14-item questionnaire focused on the external and internal appearances of the model and its tactile feel during simulated surgery (face validity) as well as on how closely the simulated procedure reproduced an actual ETV (content validity). The usefulness of the model in assessing trainees’ performances was then evaluated by two attending neurosurgeons blinded to the identity and training status (post-graduate year of training) of the residents and fellows (construct validity).

The neurosurgical residents and fellows gave high scores to the training model for both face and content validity (mean scores of 4.69 and 4.88, respectively; 5 would be a perfect score). The performance scores given to individual trainees by the attending neurosurgeons clearly distinguished novice surgeons from more experienced surgeons, accurately reflecting the trainees’ post-graduate years of training.

The training model described in this paper is not limited to hydrocephalus or treatment with ETV. The simulated head accommodates replaceable plug-and-play components to provide a fresh operative field for each training session. A variety of diseased or injured brain scenarios could be tested using different plug-and-play components. In addition, the ability to pop in new components between practice sessions greatly reduces training costs compared to other models.

When asked about the paper, the senior author, Alan R. Cohen, MD, at Johns Hopkins Hospital, said, “This unique collaboration of interdisciplinary experts resulted in the creation of an ultra-realistic 3D surgical training model. Simulation has become increasingly important for training in minimally invasive neurosurgery. It also has the potential to revolutionize training for all surgical procedures.

…

Here’s a link to and a citation for the paper,

Creation of a novel simulator for minimally invasive neurosurgery: fusion of 3D printing and special effects by Peter Weinstock, Roberta Rehder, Sanjay P. Parbhu, Peter W. Forbes, Christopher J. Roussin, and Alan R. Cohen. Journal of Neurosurgery: Pediatrics, published online, ahead of print, April 25, 2017; DOI: 10.3171/2017.1.PEDS16568

This paper appears to be open access.

Saving modern art with 3D-printed artwork

Leave a reply

I first wrote about the NanoRestART project in an April 4. 2016 post highlighting work which focuses on a problem unique to modern and contemporary art, the rapid deterioration of the plastics and synthetic materials used to create the art and the lack of conservation techniques for preserving those materials. A Dec. 22, 2016 news item on phys.org provides an update on the project,

Many contemporary artworks are endangered due to their extremely fast degradation processes. NANORESTART—a project developing nanomaterials to protect and restore this cultural heritage—has created a 3-D printed artwork with a view to testing restoration methods.

The 3D printed sculpture was designed by engineer-artist Tom Lomax – a UK-based sculptor and painter specialised in 3D-printed colour sculpture. Drawing inspiration from the aesthetic of early 20th century artworks, the sculpture was made using state-of-the-art 3D printing processes and can be downloaded for free. [I believe the downloadable files are available at the end of the paper in Heritage Science in the section titled: Additional files, just prior to the References {see below for citation and link to the paper}

Fig. 1
Images of the RP artwork “Out of the Cauldron” designed by Tom Lomax produced with the most common RP Technologies: (1) stereolithography (SLA®) (2) polyjet (3) 3D printing (3DP) (4) selective laser sintering (SLS). Before (above) and after (below) photodegradation
Courtesy: Heritage Science

A Dec. 21, 2016 Cordis press release, which originated the news item, provides more information about the artist and his 3D printed sculpture,

‘As an artist I previously had little idea of the conservation threat facing contemporary art – preferring to leave these issues for conservators and focus on the creative process. But while working on this project with UCL [University College of London] I began to realise that artists themselves have a crucial role to play,’ Lomax explains.

The structure has been printed using the most common rapid prototyping (RP) technologies, which are gaining popularity among designers and artists. It will be a key tool for the project team to test how these structures degrade and come up with solutions to better preserve them.

As Caroline Coon, researcher at the UCL Institute for Sustainable Heritage, notes, ‘Art is being transformed by fast-changing new technologies and it is therefore vital to preempt conservation issues, rather than react to them, if we are to preserve our best contemporary works for future generations. This research project will benefit both artists and academics alike – but ultimately it is in the best interests of the public that art and science combine to preserve works.’

The NANORESTART team subjected the artwork to accelerated testing, discovering that many 3D-printing technologies use materials that degrade particularly rapidly. It is particularly true for polymers, whose only-recently achieved cultural heritage status also means that conservation experience is almost inexistent.

Preserving or not: an intricate question for artists

The experiments were part of a UCL paper entitled ‘Preserving Rapid Prototypes: A Review’, published in late November in Heritage Science. In this review, Caroline Coon and her team have critically assessed the most commonly used technologies used to tackle the degradation of materials, noting that ‘to conserve RP artworks it is necessary to have an understanding of the process of creation, the different technologies involved, the materials used as well as their chemical and mechanical properties.’

Besides technical concerns, the paper also voices those of artists, in particular the importance of the original artefact and the debate around the appropriateness of preventing the degradation process of artworks. Whilst digital conservation of these artworks would prevent degradation and allow designs to be printed on-demand, some artists argue that the original artefact is actually the one with artistic value as it references a specific time and place. On the other hand, some artists actually embrace and accept the natural degradation of their art as part of its charm.

With two more years to go before its completion, NANORESTART will undoubtedly bring valuable results, resources and reflexions to both conservators and artists. The nanomaterials it aims to develop will bring the EU at the forefront of a conservation market estimated at some EUR 5 billion per year.

Here`s a link to and a citation for the paper,

Preserving rapid prototypes: a review by Carolien Coon, Boris Pretzel, Tom Lomax, and Matija Strlič. Heritage Science 2016 4:40 DOI: 10.1186/s40494-016-0097-y Published: 22 November 2016

©  The Author(s) 2016

This paper is open access.

Korea Advanced Institute of Science and Technology (KAIST) at summer 2016 World Economic Forum in China

Leave a reply

From the Ideas Lab at the 2016 World Economic Forum at Davos to offering expertise at the 2016 World Economic Forum in Tanjin, China that is taking place from June 26 – 28, 2016.

Here’s more from a June 24, 2016 KAIST news release on EurekAlert,

Scientific and technological breakthroughs are more important than ever as a key agent to drive social, economic, and political changes and advancements in today’s world. The World Economic Forum (WEF), an international organization that provides one of the broadest engagement platforms to address issues of major concern to the global community, will discuss the effects of these breakthroughs at its 10th Annual Meeting of the New Champions, a.k.a., the Summer Davos Forum, in Tianjin, China, June 26-28, 2016.

Three professors from the Korea Advanced Institute of Science and Technology (KAIST) will join the Annual Meeting and offer their expertise in the fields of biotechnology, artificial intelligence, and robotics to explore the conference theme, “The Fourth Industrial Revolution and Its Transformational Impact.” The Fourth Industrial Revolution, a term coined by WEF founder, Klaus Schwab, is characterized by a range of new technologies that fuse the physical, digital, and biological worlds, such as the Internet of Things, cloud computing, and automation.

Distinguished Professor Sang Yup Lee of the Chemical and Biomolecular Engineering Department will speak at the Experts Reception to be held on June 25, 2016 on the topic of “The Summer Davos Forum and Science and Technology in Asia.” On June 27, 2016, he will participate in two separate discussion sessions.

In the first session entitled “What If Drugs Are Printed from the Internet?” Professor Lee will discuss the future of medicine being impacted by advancements in biotechnology and 3D printing technology with Nita A. Farahany, a Duke University professor, under the moderation of Clare Matterson, the Director of Strategy at Wellcome Trust in the United Kingdom. The discussants will note recent developments made in the way patients receive their medicine, for example, downloading drugs directly from the internet and the production of yeast strains to make opioids for pain treatment through systems metabolic engineering, and predicting how these emerging technologies will transform the landscape of the pharmaceutical industry in the years to come.

In the second session, “Lessons for Life,” Professor Lee will talk about how to nurture life-long learning and creativity to support personal and professional growth necessary in an era of the new industrial revolution.

During the Annual Meeting, Professors Jong-Hwan Kim of the Electrical Engineering School and David Hyunchul Shim of the Aerospace Department will host, together with researchers from Carnegie Mellon University and AnthroTronix, an engineering research and development company, a technological exhibition on robotics. Professor Kim, the founder of the internally renowned Robot World Cup, will showcase his humanoid micro-robots that play soccer, displaying their various cutting-edge technologies such as imaging processing, artificial intelligence, walking, and balancing. Professor Shim will present a human-like robotic piloting system, PIBOT, which autonomously operates a simulated flight program, grabbing control sticks and guiding an airplane from take offs to landings.

In addition, the two professors will join Professor Lee, who is also a moderator, to host a KAIST-led session on June 26, 2016, entitled “Science in Depth: From Deep Learning to Autonomous Machines.” Professors Kim and Shim will explore new opportunities and challenges in their fields from machine learning to autonomous robotics including unmanned vehicles and drones.

Since 2011, KAIST has been participating in the World Economic Forum’s two flagship conferences, the January and June Davos Forums, to introduce outstanding talents, share their latest research achievements, and interact with global leaders.

KAIST President Steve Kang said, “It is important for KAIST to be involved in global talks that identify issues critical to humanity and seek answers to solve them, where our skills and knowledge in science and technology could play a meaningful role. The Annual Meeting in China will become another venue to accomplish this.”

I mentioned KAIST and the Ideas Lab at the 2016 Davos meeting in this Nov. 20, 2015 posting and was able to clear up my (and possible other people’s) confusion as to what the Fourth Industrial revolution might be in my Dec. 3, 2015 posting.

Printing in midair

Leave a reply

Dexter Johnson’s May 16, 2016 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) was my first introduction to something wonder-inducing (Note: Links have been removed),

While the growth of 3-D printing has led us to believe we can produce just about any structure with it, the truth is that it still falls somewhat short.

Researchers at Harvard University are looking to realize a more complete range of capabilities for 3-D printing in fabricating both planar and freestanding 3-D structures and do it relatively quickly and on low-cost plastic substrates.

In research published in the journal Proceedings of the National Academy of Sciences (PNAS),  the researchers extruded a silver-nanoparticle ink and annealed it with a laser so quickly that the system let them easily “write” free-standing 3-D structures.

While this may sound humdrum, what really takes one’s breath away with this technique is that it can create 3-D structures seemingly suspended in air without any signs of support as though they were drawn there with a pen.

…

Laser-assisted direct ink writing allowed this delicate 3D butterfly to be printed without any auxiliary support structure (Image courtesy of the Lewis Lab/Harvard University)

Laser-assisted direct ink writing allowed this delicate 3D butterfly to be printed without any auxiliary support structure (Image courtesy of the Lewis Lab/Harvard University)

A May 16, 2016 Harvard University press release (also on EurekAlert) provides more detail about the work,

“Flat” and “rigid” are terms typically used to describe electronic devices. But the increasing demand for flexible, wearable electronics, sensors, antennas and biomedical devices has led a team at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) and Wyss Institute for Biologically Inspired Engineering to innovate an eye-popping new way of printing complex metallic architectures – as though they are seemingly suspended in midair.

…

“I am truly excited by this latest advance from our lab, which allows one to 3D print and anneal flexible metal electrodes and complex architectures ‘on-the-fly,’ ” said Lewis [Jennifer Lewis, the Hansjörg Wyss Professor of Biologically Inspired Engineering at SEAS and Wyss Core Faculty member].

Lewis’ team used an ink composed of silver nanoparticles, sending it through a printing nozzle and then annealing it using a precisely programmed laser that applies just the right amount of energy to drive the ink’s solidification. The printing nozzle moves along x, y, and z axes and is combined with a rotary print stage to enable freeform curvature. In this way, tiny hemispherical shapes, spiral motifs, even a butterfly made of silver wires less than the width of a hair can be printed in free space within seconds. The printed wires exhibit excellent electrical conductivity, almost matching that of bulk silver.

When compared to conventional 3D printing techniques used to fabricate conductive metallic features, laser-assisted direct ink writing is not only superior in its ability to produce curvilinear, complex wire patterns in one step, but also in the sense that localized laser heating enables electrically conductive silver wires to be printed directly on low-cost plastic substrates.

According to the study’s first author, Wyss Institute Postdoctoral Fellow Mark Skylar-Scott, Ph.D., the most challenging aspect of honing the technique was optimizing the nozzle-to-laser separation distance.

“If the laser gets too close to the nozzle during printing, heat is conducted upstream which clogs the nozzle with solidified ink,” said Skylar-Scott. “To address this, we devised a heat transfer model to account for temperature distribution along a given silver wire pattern, allowing us to modulate the printing speed and distance between the nozzle and laser to elegantly control the laser annealing process ‘on the fly.’ ”

The result is that the method can produce not only sweeping curves and spirals but also sharp angular turns and directional changes written into thin air with silver inks, opening up near limitless new potential applications in electronic and biomedical devices that rely on customized metallic architectures.

Seeing is believing, eh?

Here’s a link to and a citation for the paper,

Laser-assisted direct ink writing of planar and 3D metal architectures by Mark A. Skylar-Scott, Suman Gunasekaran, and Jennifer A. Lewis. PNAS [Proceedings of the National Academy of Sciences] 2016 doi: 10.1073/pnas.1525131113

I believe this paper is open access.

A question: I wonder what conditions are necessary before you can 3D print something in midair? Much as I’m dying to try this at home, I’m pretty that’s not possible.

YBC 7289: a 3,800-year-old mathematical text and 3D printing at Yale University

Leave a reply

1,300 years before Pythagoras came up with the theorem associated with his name, a school kid in Babylon formed a disc out of clay and scratched out the theorem when the surface was drying.  According to an April 12, 2016 news item on phys.org the Bablyonians got to the theorem first, (Note: A link has been removed),

Thirty-eight hundred years ago, on the hot river plains of what is now southern Iraq, a Babylonian student did a bit of schoolwork that changed our understanding of ancient mathematics. The student scooped up a palm-sized clump of wet clay, formed a disc about the size and shape of a hamburger, and let it dry down a bit in the sun. On the surface of the moist clay the student drew a diagram that showed the people of the Old Babylonian Period (1,900–1,700 B.C.E.) fully understood the principles of the “Pythagorean Theorem” 1300 years before Greek geometer Pythagoras was born, and were also capable of calculating the square root of two to six decimal places.

Today, thanks to the Internet and new digital scanning methods being employed at Yale, this ancient geometry lesson continues to be used in modern classrooms around the world.

Just when you think it’s all about the theorem, the story which originated in an April 11, 2016 Yale University news release by Patrick Lynch takes a turn,

“This geometry tablet is one of the most-reproduced cultural objects that Yale owns — it’s published in mathematics textbooks the world over,” says Professor Benjamin Foster, curator of the Babylonian Collection, which includes the tablet. It’s also a popular teaching tool in Yale classes. “At the Babylonian Collection we have a very active teaching and learning function, and we regard education as one of the core parts of our mission,” says Foster. “We have graduate and undergraduate groups in our collection classroom every week.”

The tablet, formally known as YBC 7289, “Old Babylonian Period Mathematical Text,” came to Yale in 1909 as part of a much larger collection of cuneiform tablets assembled by J. Pierpont Morgan and donated to Yale. In the ancient Mideast cuneiform writing was created by using a sharp stylus pressed into the surface of a soft clay tablet to produce wedge-like impressions representing pictographic words and numbers. Morgan’s donation of tablets and other artifacts formed the nucleus of the Yale Babylonian Collection, which now incorporates 45,000 items from the ancient Mesopotamian kingdoms.

Discoverying [sic] the tablet’s mathematical significance

The importance of the geometry tablet was first recognized by science historians Otto Neugebauer and Abraham Sachs in their 1945 book “Mathematical Cuneiform Texts.”

“Ironically, mathematicians today are much more fascinated with the Babylonians’ ability to accurately calculate irrational numbers like the square root of two than they are with the geometry demonstrations,” notes associate Babylonian Collection curator Agnete Lassen.

“The Old Babylonian Period produced many tablets that show complex mathematics, but it also produced things you might not expect from a culture this old, such as grammars, dictionaries, and word lists,” says Lassen “One of the two main languages spoken in early Babylonia  was dying out, and people were careful to document and save what they could on cuneiform tablets. It’s ironic that almost 4,000 years ago people were thinking about cultural preservation, [emphasis mine] and actively preserving their learning for future generations.”.

This business about ancient peoples trying to preserve culture and learning for future generations suggests that the efforts in Palmyra, Syria (my April 6, 2016 post about 3D printing parts of Palmyra) are born of an age-old impulse. And then the story takes another turn and becomes a 3D printing story (from the Yale University news release),

Today, however, the tablet is a fragile lump of clay that would not survive routine handling in a classroom. In looking for alternatives that might bring the highlights of the Babylonian Collection to a wider audience, the collection’s curators partnered with Yale’s Institute for the Preservation of Cultural Heritage (IPCH) to bring the objects into the digital world.

Scanning at the IPCH

The IPCH Digitization Lab’s first step was to do reflectance transformation imaging (RTI) on each of fourteen Babylonian Collection objects. RTI is a photographic technique that enables a student or researcher to look at a subject with many different lighting angles. That’s particularly important for something like a cuneiform tablet, where there are complex 3D marks incised into the surface. With RTI you can freely manipulate the lighting, and see subtle surface variations that no ordinary photograph would reveal.

Chelsea Graham of the IPCH Digitization Lab and her colleague Yang Ying Yang of the Yale Computer Graphics Group then did laser scanning of the tablet to create a three-dimensional geometric model that can be freely rotated onscreen. The resulting 3D models can be combined with many other types of digital imaging to give researchers and students a virtual tablet onscreen, and the same data can be use to create a 3D printed facsimile that can be freely used in the classroom without risk to the delicate original.
3D printing digital materials

While virtual models on the computer screen have proved to be a valuable teaching and research resource, even the most accurate 3D model on a computer screen doesn’t convey the tactile  impact, and physicality of the real object. Yale’s Center for Engineering Innovation and Design has collaborated with the IPCH on a number of cultural heritage projects, and the center’s assistant director, Joseph Zinter, has used its 3D printing expertise on a wide range of engineering, basic science, and cultural heritage projects.

“Whether it’s a sculpture, a rare skull, or a microscopic neuron or molecule highly magnified, you can pick up a 3D printed model and hold it, and it’s a very different and important way to understand the data. Holding something in your hand is a distinctive learning experience,” notes Zinter.

Sharing cultural heritage projects in the digital world

Once a cultural artifact has entered the digital world there are practical problems with how to share the information with students and scholars. IPCH postdoctoral fellows Goze Akoglu and Eleni Kotoula are working with Yale computer science faculty member Holly Rushmeier to create an integrated collaborative software platform to support the research and sharing of cultural heritage artifacts like the Babylonian tablet.

“Right now cultural heritage professionals must juggle many kinds of software, running several types of specialized 2D and 3D media viewers as well as conventional word processing and graphics programs. Our vision is to create a single virtual environment that accommodates many kinds of media, as well as supporting communication and annotation within the project,” says Kotoula.

The wide sharing and disseminating of cultural artifacts is one advantage of digitizing objects, notes professor Rushmeier, “but the key thing about digital is the power to study large virtual collections. It’s not about scanning and modeling the individual object. When the scanned object becomes part of a large collection of digital data, then machine learning and search analysis tools can be run over the collection, allowing scholars to ask questions and make comparisons that aren’t possible by other means,” says Rushmeier.

Reflecting on the process that brings state-of-the-art digital tools to one of humanity’s oldest forms of writing, Graham said “It strikes me that this tablet has made a very long journey from classroom to classroom. People sometimes think the digital or 3D-printed models are just a novelty, or just for exhibitions, but you can engage and interact much more with the 3D printed object, or 3D model on the screen. I think the creators of this tablet would have appreciated the efforts to bring this fragile object back to the classroom.”

There is also a video highlighting the work,

3D print the city of Palmyra (Syria)?

Leave a reply

Designated a World Heritage Site by UNESCO (United Nations Educational, Scientific and Cultural Organization), Palmyra dates back to Second Century BCE (before the common era) as UNESCO’s Site of Palmyra webpage indicates,

An oasis in the Syrian desert, north-east of Damascus, Palmyra contains the monumental ruins of a great city that was one of the most important cultural centres of the ancient world. From the 1st to the 2nd century, the art and architecture of Palmyra, standing at the crossroads of several civilizations, married Graeco-Roman techniques with local traditions and Persian influences.

First mentioned in the archives of Mari in the 2nd millennium BC, Palmyra was an established caravan oasis when it came under Roman control in the mid-first century AD as part of the Roman province of Syria.  It grew steadily in importance as a city on the trade route linking Persia, India and China with the Roman Empire, marking the crossroads of several civilisations in the ancient world. A grand, colonnaded street of 1100 metres’ length forms the monumental axis of the city, which together with secondary colonnaded cross streets links the major public monuments including the Temple of Ba’al, Diocletian’s Camp, the Agora, Theatre, other temples and urban quarters. Architectural ornament including unique examples of funerary sculpture unites the forms of Greco-roman art with indigenous elements and Persian influences in a strongly original style. Outside the city’s walls are remains of a Roman aqueduct and immense necropolises.

Discovery of the ruined city by travellers in the 17th and 18th centuries resulted in its subsequent influence on architectural styles.

Until recently Palmyra was occupied by ISIS or ISIL or IS (depending on what the group is being called today). A March 31, 2016 news item on phys.org presents a perspective on the city and cultural heritage in a time of strife,

The destruction at the ancient city of Palmyra symbolises the suffering of the Syrian people at the hands of the terrorist group known as Islamic State (IS). Palmyra was a largely Roman city located at a desert oasis on a vital crossroad, and “one of the most important cultural centres of the ancient world”. Its remarkable preservation highlighted an intermingling of cultures that today, as then, came to stand for the tolerance and multiculturalism that pre-conflict Syria was renowned for -– tolerance that IS seeks to eradicate.

A March 31, 2016 essay by Emma Cunliffe (University of Oxford) for The Conversation, which originated the news item, expands on the theme,

Early in the conflict, the area was heavily fortified. Roads and embankments were dug through the necropolises and the Roman walls, and the historic citadel defences were upgraded. Yet the terrorists occupied and desecrated the city from May 2015, systematically destroying monuments such as the Temple of Baalshamin, the Temple of Bel, seven tower tombs, a large Lion goddess statue and two Islamic shrines. They ransacked the museum, tortured and executing the former site director Khaled al-Asaad in search of treasure to sell. According to satellite imagery analysis the site was heavily looted throughout it all.

Now the city has been recaptured, the first damage assessments are underway, and Syrian – and international – attention is already turning to restoration. This work will be greatly aided by the Syrians who risked their lives to transport the contents of the Palmyra museum to safety. The last truck pulled out as IS arrived, with bullets whizzing past.

There is a contrasting view as to how much destruction occurred from a March 29, 2016 essay by Paul Rogers (University of Bradford) for The Conversation,

Syrian Army units have taken back the ancient city of Palmyra from Islamic State. The units are now also trying to extend their control to include al-Qaryatain, to the south west of Palmyra, and Sukhnah, to the north east.

There are indications that the damage done to the ancient world heritage site which lies just outside Palmyra has been much less than feared. It may even have been limited to the destruction of two or three individual ruins – certainly important in their own right but just a small part of a huge complex that stretches over scores of hectares.

Written before some of the latest events, Rogers’ perspective is one of military tactics and strategy which contrasts with Cunliffe’s cultural heritage perspective. Like the answers to the classic question ‘Is the glass is half empty or is the glass is half full?’, both are correct, in their way.

Getting back to the cultural heritage aspect, Cunliffe outlines how Syrians and others in the international community are attempting to restore Palmyra, from her March 31, 2016 essay (Note: Links have been removed),

Even as they were displaced, Syrians have worked to keep a detailed memory of the city alive. Syrian artists created artworks depicting the destruction. In a Jordanian camp, refugees made miniature models of the city and other cultural sites, even measuring out the number and position of Palmyra’s columns from photographs.

The international community is also playing its part. Groups like UNOSAT [UNITAR’s Operational Satellite Applications Programme], the UN’s satellite imagery analysts have used satellite imagery to monitor the damage. On the ground, Syrian-founded NGOs like APSA [Association for the Protection Syrian Archaeology] have linked with universities to assess the site. Groups such as NewPalmyra and Palmyra 3D Model are using the latest technology to create open-access 3D computer models from photographs.

Others have gone even further. The Million Image Database Project at the Oxford Institute for Digital Archaeology distributed cameras to volunteers across the Middle East to collect 3D photos of sites. As well as creating 3D models, they will recreate full-scale artefacts, sites, and architectural features using their own cement-based 3D printing techniques. This will start with a recreation of the arch from Palmyra’s Temple of Bel, due to be unveiled in London in April 2016.

Here’s an artistic representation of the destruction,

A depiction of the destruction. Humam Alsalim and Rami Bakhos

A depiction of the destruction. Humam Alsalim and Rami Bakhos

Of course, there are some ethical issues about the restoration being raised, from Cunliffe’s March 31, 2016 essay (Note: Links have been removed),

It wouldn’t be the first time such large-scale restoration has been undertaken. Historic central Warsaw, for example, was destroyed during World War II, and was almost completely reconstructed and is now a World Heritage site. Reconstruction is costly, but might be accomplished more quickly and cheaply using new digital techniques, showing the world that Syria values its cultural heritage.

But many argue that 3D printing fails to capture the authenticity of the original structures, amounting to little more than the Disneyfication of heritage. They also point out that the fighting is still ongoing: 370,000 Syrians are dead, millions are displaced, and perhaps 50%-70% of the nearby town has been destroyed. Given the pressing humanitarian needs, stabilisation alone should be the priority for now.

Rebuilding also fails to redress the loss caused by the extensive looting of the site, focusing only on the dramatically destroyed monuments. Perhaps most importantly, its worth asking whether returning Palmyra exactly to its pre-conflict state denies a major chapter of its history? There needs to be a wide-ranging discussion on the priorities for the immediate future and the nature of any future reconstruction.

While I grasp most of the arguments I’m not sure why 3D printing raises a greater ethical issue, “… many argue that 3D printing fails to capture the authenticity of the original structures, amounting to little more than the Disneyfication of heritage … .” Couldn’t you say that about any form of restoration? Certainly, I was disconcerted when I saw the Sphinx in Cairo in real life where the restoration is quite obvious from angles not usually seen in tourist pictures.

More tangentially, how big is the 3D printer? If memory serves, building materials from ancient times were often large blocks of stone.

Getting back to the point, both Cunliffe’s and Rogers’ essays are worth reading in their entirety if you have the time. And since those essays have been written there has been an update for Associated Press in an April 1, 2016 article by Albert Aji on phys.org. Apparently, the IS retreat included time to plant thousands of mines throughout Palmyra with trees, doors, animals and more being booby-trapped and, now, being detonated by the Syrian army.

One final comment, The booby-trapping reminded me of a scene in the English Patient (movie) when the allies have won the war, the Germans have withdrawn and British and Canadian soldiers have liberated a town in Italy. They celebrate that night and one exuberant Brit soldier climbs a flagpole (I think) and is killed because the Germans had booby-trapped the top of the flagpole. Some years ago, a friend of mine was peacekeeper in Croatia and he said that everything was booby-trapped, flagpoles, mailboxes, cemetery markers, etc. He never said anything much more about but I have the impression it was demoralizing and stressful. I think the discussion about restoration and the artwork produced by Syrians in response to the happenings in Palmyra are an important way to counteract demoralization and stress. Whether money should be spent on restoration or all of it dedicated to pressing humanitarian needs is a question for other people to answer but a society without art and culture is one that is dying so it is heartening to note the vibrancy in Syria.

ETA April 19, 2016: Palmyra’s Arch of Triumph has been successfully replicated and is standing in London, UK according to an April 19, 2016 news item on phys.org. The replica is about 2/3 the size of the original. No reason for the size change is given in the Associated Press article. The arch scheduled to remain in London for a few more days before moving to New York, Dubai, and other destinations before arriving in Palmyra.

Feasibility of printing ear, bone, and muscle structures

Leave a reply

Over ten years ago I attended a show at the Vancouver (Canada) Art Gallery titled ‘Massive Change’ where I saw part of a nose or ear being grown in a petri dish (the work was from an Israeli laboratory) and that was my introduction to tissue engineering. For anyone who’s been following the tissue engineering story, 3D printers have sped up the growth process considerably. More recently, researchers at Wake Forest Baptist Medical Center (North Carolina, US) have announced another step forward for growing organs and body parts, from a Feb. 15, 2016 Wake Forest Baptist Medical Center news release on EurekAlert,

Using a sophisticated, custom-designed 3D printer, regenerative medicine scientists at Wake Forest Baptist Medical Center have proved that it is feasible to print living tissue structures to replace injured or diseased tissue in patients.

Reporting in Nature Biotechnology, the scientists said they printed ear, bone and muscle structures. When implanted in animals, the structures matured into functional tissue and developed a system of blood vessels. Most importantly, these early results indicate that the structures have the right size, strength and function for use in humans.

“This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients,” said Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine (WFIRM) and senior author on the study. “It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation.”

With funding from the Armed Forces Institute of Regenerative Medicine, a federally funded effort to apply regenerative medicine to battlefield injuries, Atala’s team aims to implant bioprinted muscle, cartilage and bone in patients in the future.

Tissue engineering is a science that aims to grow replacement tissues and organs in the laboratory to help solve the shortage of donated tissue available for transplants. The precision of 3D printing makes it a promising method for replicating the body’s complex tissues and organs. However, current printers based on jetting, extrusion and laser-induced forward transfer cannot produce structures with sufficient size or strength to implant in the body.

The Integrated Tissue and Organ Printing System (ITOP), developed over a 10-year period by scientists at the Institute for Regenerative Medicine, overcomes these challenges. The system deposits both bio-degradable, plastic-like materials to form the tissue “shape” and water-based gels that contain the cells. In addition, a strong, temporary outer structure is formed. The printing process does not harm the cells.

A major challenge of tissue engineering is ensuring that implanted structures live long enough to integrate with the body. The Wake Forest Baptist scientists addressed this in two ways. They optimized the water-based “ink” that holds the cells so that it promotes cell health and growth and they printed a lattice of micro-channels throughout the structures. These channels allow nutrients and oxygen from the body to diffuse into the structures and keep them live while they develop a system of blood vessels.

It has been previously shown that tissue structures without ready-made blood vessels must be smaller than 200 microns (0.007 inches) for cells to survive. In these studies, a baby-sized ear structure (1.5 inches) survived and showed signs of vascularization at one and two months after implantation.

“Our results indicate that the bio-ink combination we used, combined with the micro-channels, provides the right environment to keep the cells alive and to support cell and tissue growth,” said Atala.

Another advantage of the ITOP system is its ability to use data from CT and MRI scans to “tailor-make” tissue for patients. For a patient missing an ear, for example, the system could print a matching structure.

Several proof-of-concept experiments demonstrated the capabilities of ITOP. To show that ITOP can generate complex 3D structures, printed, human-sized external ears were implanted under the skin of mice. Two months later, the shape of the implanted ear was well-maintained and cartilage tissue and blood vessels had formed.

To demonstrate the ITOP can generate organized soft tissue structures, printed muscle tissue was implanted in rats. After two weeks, tests confirmed that the muscle was robust enough to maintain its structural characteristics, become vascularized and induce nerve formation.

And, to show that construction of a human-sized bone structure, jaw bone fragments were printed using human stem cells. The fragments were the size and shape needed for facial reconstruction in humans. To study the maturation of bioprinted bone in the body, printed segments of skull bone were implanted in rats. After five months, the bioprinted structures had formed vascularized bone tissue.

Ongoing studies will measure longer-term outcomes.

###

The research was supported, in part, by grants from the Armed Forces Institute of Regenerative Medicine (W81XWH-08-2-0032), the Telemedicine and Advanced Technology Research Center at the U.S. Army Medical Research and Material Command (W81XWH-07-1-0718) and the Defense Threat Reduction Agency (N66001-13-C-2027).

(Sometimes the information about the funding agencies is almost as interesting as the research.) Here’s a link to and a citation for the paper,

A 3D bioprinting system to produce human-scale tissue constructs with structural integrity by Hyun-Wook Kang, Sang Jin Lee, In Kap Ko, Carlos Kengla, James J Yoo, & Anthony Atala. Nature Biotechnology (2016)  doi:10.1038/nbt.3413 Published online 15 February 2016

This paper is behind a paywall.

As you can see, despite being printed, this latest ear is also spending time in a dish,

WakeBaptistEar

Courtesy: Wake Forest Baptist Medical Center