STL file of a parabolic mirror

3D printed objects don’t come off the print bed perfectly smooth; on the contrary, many 3D printing technologies leave a decent amount of surface roughness, which is unacceptable for applications involving optics. These applications may include mirrors, lenses, and solar panels, just to name a few. It would be easy to write off 3D printing as a method of producing these optics, but there are ways around the issue, as Stanford University researchers Nina Vaidya and Olav Solgaard demonstrate in a new paper entitled “3D printed optics with nanometer scale surface roughness.” You can access the full publication here.

3D printing is, in fact, an appealing option for 3D printing optics, as it allows for fast and cheap production of geometries that other methods of fabrication are not capable of. The rough surfaces of 3D printed objects, however, create scattering, which reduces optical performance. The Stanford researchers developed a UV curable polymer mixture that they applied to the surface of 3D printed parts, which reduces the surface roughness to a few nanometers as opposed to tens of microns.

3D printed parabolic mirrors at different stages of the fabrication process: As printed (a), after smoothing (b), and the completed mirror after smoothing and Al deposition (c)

“We tried a number of smoothing techniques, including flame polishing, acetone vapor polishing, spraying of polymer coatings, and mechanical polishing,” the researchers explain. “None of these methods create the nanometer scale smooth surfaces required for optical applications. To meet this surface roughness criterion, we coated the printed optics with a UV curable polymer mixture consisting of methacrylates, acrylates, and urethane based polymers. This gel resulted in smooth and tough films that adhered well to the printed surfaces. When compared to a heat cure, a UV cure minimizes shrinkage of the polymer, which maximizes surface smoothness and conformal coverage.”

Solar concentrator lens array: The input side is arranged as a tileable array of hexagons that along the length of the concentrators gradually morph into squares on the output side. The smaller squares at the output allow smaller solar cells to be used to convert the concentrated power. The molds were filled with graded-index polymers to complete the concentrator array. Figures a–d show the process flow from as-printed part to the completed concentrator array

The process takes several steps:

• Rinse the 3D printed part with water and detergent, blow dry and leave in low temperature oven
• Place the part in a vacuum to de-gas for a few hours
• Coat a thin layer of UV curable polymer mixture on the surface of the part with a fine brush
• Place in vacuum chamber to get rid of any air trapped in the printed material, in the gel layer, or in between the printed surface and the gel so that the gel can fill in any pores or depressions to make smooth surfaces
• If needed for conformal coverage, use gravity or spinning to remove excess gel. Let gel flow under gravity by placing the optics flat on a stand. Spin at around 1400 rpm for 3–5 min while the gel is still un-cured. Brush off excess gel at the edge of the frame/support
• UV cure the finished gel surface for a couple of minutes, with the exact time depending on the size of the part

The researchers tested their technique with both flat and parabolic mirrors, solar concentrator arrays, and immersion lenses used in microscopy of biological samples. Consistently, they were able to reduce the surface roughness to less than three nanometers after the smoothing process.

“Imaging with 3D printed parabolic mirrors were comparable to a diamond turned metal mirror and nearly diffraction-limited spot sizes were measured with modest incidence apertures,” the researchers state. “Solar concentrator hexagonal arrays were made using 3D printing and they demonstrated 5 suns concentration across an acceptance angle of 40°. PDMS immersion lenses were made with nanometer smooth surfaces released from 3D printed molds.”

3D printing has been used before to manufacture optical components, typically using highly specialized equipment to get the kind of surface needed. Vaidya and Solgaard tested multiple 3D printing technologies and found that SLA and wax printers were the most effective for creating optical components, as long as the smoothing solution was applied afterwards. Their method enabled them to produce optics that were low-cost, customizable, lightweight, low on material waste and easy to fabricate.

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When I think about clamps, if I do at all, it’s in terms of holding wood steady in a scene shop while making sets for a play, or keeping two large objects that have been glued together tight while the glue dries. But there are many different purposes and applications for clamps, including in the medical field, demonstrated by the 3D printed cardioplegia clamps designed for King’s College Hospital Foundation Trust two years ago.

Recently, a collaborative group of researchers from the University of Otago and the Auckland University of Technology in New Zealand and the University of Leipzig in Germany published a paper, titled “Utilization of 3D printing technology to facilitate and standardize soft tissue testing,” in the Scientific Reports journal that detailed their work in creating 3D printed clamps and fixtures that can help mount soft tissues for testing purposes.

The abstract reads, “This report will describe our experience using 3D printed clamps to mount soft tissues from different anatomical regions. The feasibility and potential limitations of the technology will be discussed. Tissues were sourced in a fresh condition, including human skin, ligaments and tendons. Standardized clamps and fixtures were 3D printed and used to mount specimens. In quasi-static tensile tests combined with digital image correlation and fatigue trials we characterized the applicability of the clamping technique. Scanning electron microscopy was utilized to evaluate the specimens to assess the integrity of the extracellular matrix following the mechanical tests. 3D printed clamps showed no signs of clamping-related failure during the quasi-static tests, and intact extracellular matrix was found in the clamping area, at the transition clamping area and the central area from where the strain data was obtained. In the fatigue tests, material slippage was low, allowing for cyclic tests beyond 10⁵ cycles. Comparison to other clamping techniques yields that 3D printed clamps ease and expedite specimen handling, are highly adaptable to specimen geometries and ideal for high-standardization and high-throughput experiments in soft tissue biomechanics.

Soft tissues have several special characteristics, such as being diverse, directionally dependent (anistropic), and viscoelastic (exhibiting both viscous and elastic characteristics when undergoing deformation). The power of these qualities is increased by things like post-mortem delay, water content alterations, and traumatic pathology, all of which can cause issues when it comes to standardized mechanical tests of the tissue under strain.

Fixtures and clamps have been used to help with issues like material slippage, but are limited when working with soft tissue due to reasons like, as the paper lists, “avulsion at the clamping site or the risk of temperature-induced changes in the mechanical behavior.”

Over the last few years, the team developed a technique called partial plastination that uses ceramic-reinforced polyurethane resin at the clamp mounting sites to help with slippage. But it takes a long time to prepare this method, which also requires special (read expensive and hard to come by) equipment like casting fixtures and vacuum pumps, and errors can come up during the clamping due to how difficult it can be to position soft tissues in a test that involves the effects of gravity.

“As a consequence, we aimed to explore alternative techniques which may facilitate tissue clamping, and aid in standardizing the clamping of soft tissues for biomechanical testing in a less time-consuming manner,” the researchers explained in their paper. “3D printing has meanwhile become broadly available, and such professional extrusion solutions can be utilized for customizing and printing fixtures and adjustments for biomechanical testing using commercially-available filaments. Furthermore, it can be utilized to provide affordable add-ons to existing testing devices all over the world, going beyond just soft-tissue biomechanics. The possibility of sharing existing digital models enables a broad availability and exchange of research and knowledge. 3D printing may also be used for clamping mechanisms, and variations in clamping design appear to be eased by the rapid-prototyping approach with the ubiquitously-available software.”

Standardization in material testing and test setup. Focus of this study will be the boxes highlighted in red.

During a quick Internet search, I found models of 3D printable clamps on Thingiverse, Instructables, and 3D Hubs, though none were for medical purposes. The research team’s clamping systems were designed using Creo 4.0 3D CAD software, and printed on an Ultimaker 3 Extended in commercially available ABS, PLA, nylon, and TPU filaments.

In their paper, the research team described their experience mounting human soft tissues, from three different anatomical regions with differing properties, using 3D printed clamps, and also compared this new way of clamping to their previous partial plastination method.

Co-authors of the paper are Mario Scholze, Aqeeda Singh, Pamela F. Lozano, Benjamin Ondruschka, Maziar Ramezani, Michael Werner, and Niels Hammer.

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The work of Daniel A Tillman, Professor in Educational Technology, College of Education at the University of Texas at El Paso centers around educating children and technology. Professor Tillman has been writing about using 3D printing and other digital fabrication tools in the classroom since 2009. He writes about how fablabs, AR, 3D printers and music can help kids learn math. 3D Printing has often been touted as a resource for educators and children alike. Most of the people talking about education and 3D printing have a vested interest in presenting it as a panacea. We continually here that this or that amazing 3D printing project is going to help kids and see lots of happy kids with 3D printers. But, can 3D printing actually help kids learn? What are actual findings? Is 3D printing amazing for education, allways, for everyone? At 3DPrint.com we were curious to see if a more nuanced view was possible and so we searched for someone who had considerable research in the classroom with various technologies including 3D printing. We found Professor Tillman’s work on the pedagogical value of digital fabrication, letting kids make musical instruments to learn math and using makerspaces in education and turned to him for that nuance through an interview.

In workshops I’ve organized I’ve used 3D printed parts and files to illustrate the “why” for math as well as how it combines the screen and the real. Is that something you feel 3D printing can do?

3D printing is a great way to introduce students to design and engineering, and if they pursue those interests they will certainly encounter the “why” for math–but if a kid sees a 3D printer in action and isn’t interested, because they are instead focused on music or sports or painting etc then the 3D printing is just like a microwave to them, a useful tool perhaps but not likely to convince them they need math if their goal is to become a guitarist.

I’ve always felt that when giving workshops that kids can really grasp concepts better if they can hold the 3d print. Do you think that this is something that could benefit a lot of kids?

I’ve met many kids and teachers that find 3D printing to be fascinating and instructional, and other kids and teachers that weren’t too impressed–so yes, it can help a lot of kids, maybe even the majority of kids, but it is not a one-size-fits-all solution for getting all kids excited about math or convincing them math is helpful.

Things such as diagrams or maps of battles are often complex to read. Wouldn’t a 3D print be better?

Perhaps, but the logistical challenges with bringing 3D printers into classrooms and providing accompanying professional development are much more challenging then for example using videos or virtual manipulatives or computer models, which is why the current educational model is more focused on teachers using multimedia.

How did you use mobile makerspaces to stimulate learning? 

Mobile makerspaces are a great complement to having a room-based makerspace, and they are also a great way to jumpstart creation of a room-based makerspace if there isn’t one in a school already.

Do you think schools should have makerspaces?

I think schools should have a makerspace-mentality wherein every learning space is a potential opportunity for kids to learn by making cool stuff.

How can 3D printing help kids to become more interested in STEM?

3D printing is a great way to introduce kids to advanced design and engineering tools, and show them the rapid prototyping process.
​

You’ve done research into music’s role in math education, how does that work?

Regarding music, I focus mostly on activities with musical instrument design, choreography-design, and music composition as contexts for mathematical problem-solving tasks.

Do you think that iterative experimentation with engineering and 3D printing will better prepare kids for the modern world?

Definitely, I think we should be teaching all students about the engineering design process just like we teach them about science and history.

How can we prepare kids for a world ten twenty years into the future when we don’t know what that world will be like?

One of the things we know won’t change is that productive people will always seek worthwhile projects, so I think the best thing we can do to prepare kids for the future is to help them have opportunties to learn where their talents and interests intersect with the problems and demands that the world will present.

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

What’s an alligator without a tail? Still an alligator, and potentially dangerous, but a lot more stubby – which is how Mr. Stubbs the alligator got his name. 10 years ago, Mr. Stubbs was found in the wild missing his tail, and while rescuers are unsure how he lost it, they assume it was due to a fight with another gator. He wouldn’t survive long in the wild, being unable to swim or get to food as quickly as competitors, so he was taken to Phoenix Herpetological Society. However, he still struggled without a tail, so scientists at Midwestern University, upon hearing of his problem, decided to make him a prosthetic.

In 2013, the scientists built a silicon prosthetic tail, but Mr. Stubbs outgrew it. Since he had doubled in size, the scientists didn’t want to risk getting close enough to take a plaster cast of his tail stump, so they decided to 3D scan him instead.

“We contacted the 3D-scanning and -printing company Stax3D to find out what they could do to help us,” explained Dr. Justin Georgi, associate professor of anatomy at Midwestern University. “They used an Artec3D scanner to create a high-resolution, digital model of the tail. We [were able to] manipulate that model to produce any alteration to the tail we needed. We fixed imperfections, made it exactly the correct length and size, [and] adjusted the front end so it matched Mr. Stubbs’ stump with a perfect custom fit.”

The team 3D printed the model and used it to make a silicone cast. That cast was then used to make multiple prosthetic tails for Mr. Stubbs. Why didn’t they just 3D print a wearable prosthetic? While 3D printing has been used to create numerous prosthetics for animals, an alligator tail is especially large, and the team would have needed a large-scale 3D printer to print the prosthetic all in one piece. There are certainly 3D printers that could handle the job, but it would have been a time-consuming print, especially since they wanted to make multiple prosthetics. It would be easier to make one 3D print, use it to make a mold, and quickly cast several pieces.

There’s also the fact that the team used silicone to make the tail. Silicone 3D printing only became possible two years ago, and silicone 3D printers still aren’t that common. Other animal prosthetics have been made from more common 3D printing materials like PLA or nylon – the latter lends itself well to the purpose in particular, thanks to its flexibility and toughness. Silicone made the most sense for an alligator tail, however.

With his new tails, Mr. Stubbs can swim and quickly get to food.

“[He is] doing very well,” Dr. Georgi said. “Whenever he is wearing one of his tails, he continues to show improvement. We are now in the process of building a new tail for him, based on what we have learned from the recent experiments. We expect that as his growth slows with age, and we build him a tail that he can grow into, he should soon have one that will benefit him for many years, not just the next two or three.”

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You’ve likely needed to use lithium-ion batteries for at least one device at some point. They can be a pain to replace when they run out of juice, and though they typically last a long time, they don’t last forever. But a group of researchers at Carnegie Mellon University and Missouri University of Science and Technology have developed a method of 3D printing lithium-ion batteries which greatly improves their capacity and charge-discharge rates. The results are published in a paper entitled “3D printed hierarchically-porous microlattice electrode materials for exceptionally high specific capacity and areal capacity lithium ion batteries,” which you can access here.

It has already been possible to 3D print porous electrodes for lithium-ion batteries, but the design of the 3D printed electrodes is limited to just a few possible architectures. The capacity of lithium-ion batteries can be greatly improved by creating pores and channels at the microscale in the electrodes. The internal geometry that has produced the best porous electrodes through 3D printing is called interdigitated geometry, which involves metal prongs interlocked like clasped fingers, with lithium moving back and forth between both sides. This geometry is not optimal, however.

The research team, led by Carnegie Mellon Associate Professor of Mechanical Engineering Rahul Panat, has developed a new method of 3D printing lithium-ion battery electrodes. Their method creates a 3D microlattice structure with controlled porosity.

“In the case of lithium-ion batteries, the electrodes with porous architectures can lead to higher charge capacities,” said Panat. “This is because such architectures allow the lithium to penetrate through the electrode volume leading to very high electrode utilization, and thereby higher energy storage capacity. In normal batteries, 30-50% of the total electrode volume is unutilized. Our method overcomes this issue by using 3-D printing where we create a microlattice electrode architecture that allows the efficient transport of lithium through the entire electrode, which also increases the battery charging rates.”

Panat and fellow author Mohammad Sadeq Saleh have been studying the 3D printing of microlattice structures for some time now, and used a method of Aerosol Jet 3D printing that they developed themselves to create the porous microlattice architectures for the battery electrodes. The microlattice structure (Ag) used for the batteries’ electrodes improved battery performance in several ways, including a fourfold increase in specific capacity and a twofold increase in areal capacity when compared to a solid block (Ag) electrode. The electrodes were also incredibly robust, retaining their 3D lattice structures after 40 electrochemical cycles. The batteries can, therefore, have high capacity for the same weight or the same capacity for a greatly reduced weight, which is important for transportation applications.

Before this, 3D printed batteries were created using extrusion-based 3D printing, which could create interdigitated structures but was not capable of fabricating the complex geometries that the research team’s Aerosol Jet method can manage. With their method, individual droplets can be quickly assembled one by one into 3D structures.

“Because these droplets are separated from each other, we can create these new complex geometries,” said Panat. “If this was a single stream of material, as is in the case of extrusion printing, we wouldn’t be able to make them. This is a new thing. I don’t believe anybody until now has used 3-D printing to create these kinds of complex structures.”

This method has many implications for consumer electronics, medical devices, and aerospace. The researchers believe that the technology will be able to be translated to industrial applications in two to three years.

Authors of the paper include Panat, Saleh, Jie Li and Jonghyun Park.

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[Images: Rahul Panat]

Italian 3D printer company Wasproject is rather different than most firms. It has a stated goal of saving the world through 3D printing. Developing and selling 3D printers are to them just a way through which they can develop ever larger printers that solve ever bigger problems. The company wants to build buildings and entire villages using 3D printing. Today they showed us how to build a lovely structure in Milan.

The Trabeculae Pavilion can be seen at the Politecnico di Milano, Piazza Leonardo da Vinci in Milan. The entire structure covers an area of 36 m² and weighs 335 Kilos. Measuring 7,5m x  6,0m  x 3,6m the pavilion is a bioinspired lightweight structure that took 4352 hours to print. Thats a 180 days. In total it took five Wasp printers (four DeltaWASP 4070 and one 60100) to continuously produce the structure twentyfour seven out of 352 parts. The material is a mysterious biopolymer made by FILOALFA. 

“The design is based on a computational process that finds inspiration in Nature, specifically in the materialization logics of the trabeculae, the internal cells that form the bone microstructure. From this investigation, custom algorithms have been developed to support the creation of a cellular load-responsive structure with continuous variations in sizing, topology, orientation and section, in order to maximize material efficiency.”

Trabecular bone is at the moment being 3D Printed and other companies are looking at how to get things to mimic or adhere to trabecular bones. To then take the same development and supersize it is efficient as well as fun.

“The last decades have witnessed an exponential growth in the demand of raw materials due to the rapid urbanization and industrialization of emerging economies. This research looks at biological models and at the opportunities offered by the new additive production technologies in order to find sustainable solutions to the exploitation of materials. Our objective is to explore a new model of construction: advanced, efficient and sustainable” declare Roberto Naboni, Architect and currently Assistant Professor at University of Southern Denmark (SDU).

The Pavilion

At first glance this kind of structure may seem to be more art than architecture. Pretty? Sure but useful? Probably not. Actually by looking at lightweighting buildings Wasproject is looking at how to print them the quickest. A structure such as this one could be cladded quite easily in order to become a more functional building. If we look at Wasproject’s methods and goals these are much closer to where we need to be when wanting to 3D print houses. Many other architects and 3D printing house teams are simply using old methods and old thinking to make buildings with 3D printing. There is little value add there. Through truly innovative rethinking of the structure and the idea of structure we can come to more efficient buildings in the future. Bioinspired lightweight structures such as this one could be combined with “sail-like” shells to create quick to print structures that use comparatively little material. Since every kilo that has to be schlepped to the building site is one more, on agregate this will save a lot of material and cost. If these new structures are then as functional than the old then we will have actually made progress.

While 3D bioprinting is not yet able to fabricate full human organs just yet, it can be used to manufacture several different kinds of human tissue, such as heart and bile duct. One of the main barriers of forming viable tissues for clinical and scientific use is the development of vasculature for engineered tissue constructs, mainly due to generating branching channels in hydrogel constructs that can later produce vessel-like structures after being seeded with endothelial cells.

But thanks to 3D bioprinting, it’s now possible to 3D print complex structures on multiple length scales within a single construct. This enables the generation of branching, interconnected vessel systems of small, vein-like microvessels and larger macrovessels, which couldn’t be done with former tissue engineering methods. However, the best sacrificial material for fabricating branching vascular conduits in constructs based in hydrogel has yet to be determined.

A team of researchers from the University of Toronto recently published a paper, titled “Generating vascular channels within hydrogel constructs using an economical open-source 3D bioprinter and thermoreversible gels,” in the Bioprinting journal. Co-authors of the paper include Ross EB Fitzsimmons, Mark S. Aquilino, Jasmine Quigley, Oleg Chebotarev, Farhang Tarlan, and Craig A. Simmons.

The abstract reads, “The advent of 3D bioprinting offers new opportunities to create complex vascular structures within engineered tissues. However, the most suitable sacrificial material for producing branching vascular conduits within hydrogel-based constructs has not yet been resolved. Here, we assess two leading contenders, gelatin and Pluronic F-127, for a number of characteristics relevant to their use as sacrificial materials (printed filament diameter and its variability, toxicity, rheological properties, and compressive moduli). To aid in our assessment and help accelerate the adoption of 3D bioprinting by the biomedical field, we custom-built an inexpensive (< $3000 CAD) 3D bioprinter. This open-source 3D printer was designed to be fabricated in a modular manner with 3D printed/laser-cut components and off-the-shelf electronics to allow for easy assembly, iterative improvements, and customization by future adopters of the design. We found Pluronic F-127 to produce filaments with higher spatial resolution, greater uniformity, and greater elastic modulus than gelatin filaments, and with low toxicity despite being a surfactant, making it particularly suitable for engineering smaller vascular conduits. Notably, the addition of hyaluronan to gelatin increased its viscosity to achieve filament resolutions and print uniformity approaching that with Pluronic F-127. Gelatin-hyaluronan was also more resistant to plastic deformation than Pluronic F-127, and therefore may be advantageous in situations in which the sacrificial material provides structural support. We expect that this work to establish an economical 3D bioprinter and assess sacrificial materials will assist the ongoing development of vascularized tissues and will help accelerate the widespread adoption 3D bioprinting to create engineered tissues.”

3D Bioprinter Hardware.

Existing 3D bioprinters have different technical advantages and deposition methods, which influence their prices and available applications. Extrusion-based 3D printers are good for tissue engineering, but the cost is usually too high for the field to experience significant growth.

For this experiment, the researchers chose to create their own open source 3D bioprinter, which costs roughly $3,000 and can be used for lower resolution applications, such as 3D printing perfusable microvessels in tissue constructs.

Printer operational overview.

Both the chosen method and material have to meet a certain number of requirements to successfully 3D print complex branching vessel systems within hydrogel constructs. First, sacrificial materials, which need to be non-toxic and maintain a uniform filament diameter during printing, have to be deposited in the desired vascular design during printing, then flushed away once the construct is done.

In addition, the 3D printer needs to have enough resolution to print all the channels – even those that will act as the small artery vessels of ~0.5–1 mm. It also needs to be able to deposit at least two materials, though more is better when it comes to creating heterogeneous tissues with different regions of varying cell and hydrogel composition.

The team investigated formulations of gelatin and PF127 due to their potential advantages as sacrificial materials in hydrogel-based tissue constructs. Gelatin, which has been used in several biomedical applications, is a thermoreversible (the property of certain substances to be reversed when exposed to heat) biopolymer of several hydrolyzed collagen segments, and can be 3D printed at ~37 °C, which is a temperature compatible with cells.

PF127 is a surfactant, meaning that it could have potential cytotoxic effects on embedded cells. But, it has inverse thermal gelation, which means it can be 3D printed at an ambient temperature, and then removed at ~4 °C to create void vascular channels.

According to the paper, “By using our custom-built printer in order to assess the printability of these materials and assessing mechanical properties, we aimed to establish which may be the best option for creating branching vascular channels within engineered tissues.”

The team’s modular 3D bioprinter includes extruding systems, 3D printed out of ABS on a MakerBot 3D printer, which were designed specifically to hold commercially-available, sterile 10 mL syringes, instead of custom-made reservoirs that would need to be specially made and repeatedly sterilized. An open-source Duet v0.6 controller board controls the system, and the print heads are isolated from the XYZ movements executed by the lower part of the chassis.

Fabricating perfusable channels.

For testing purposes, water droplets were 3D printed in a defined pattern with each extruder system, and the average distance between the droplets’ centers in the X and Y directions were measured; then, the mean distances were compared to the pre-defined CAD model distances.

“In conclusion, we found that PF127 is generally superior to gelatin as a sacrificial material for creating vascularized tissues by merit of its filament uniformity during printing and its greater compressive modulus,” the paper concluded.

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Hospital-acquired infections are a growing problem everywhere. The CDC calls them a “major, yet preventable threat to patient safety,” and the key to preventing them lies in keeping bacteria from spreading in a setting where bacteria is rampant. As 3D printing becomes more and more prevalent in the medical field, it is vital to make sure that 3D printed implants and tools do not play a role in spreading disease. Certain companies have been working on creating antibacterial 3D printing filament, and a group of researchers has conducted a study on bioactive filaments with antimicrobial and antifungal properties. You can access the paper, entitled Bioactive Potential of 3D-Printed Oleo-Gum-Resin Disks: B. papyrifera , C.myrrha , and S. benzoin Loading Nanooxides—TiO2 , P25, Cu2O, and MoO3, here.

The researchers point out that bacteria have managed to develop resistance to many antibiotics, but that there are many natural antibiotics to which resistance has not yet been developed. They extracted oleo-gum-resins from benzoin, myrrha, and olibanum plants and combined some of them with 10% of metal nano oxide particles. 3D printer filament was created from the resins and metals, then 3D printed into disks which were subject to a number of tests.

“Due to their intrinsic properties, disks containing resins in pure state mostly prevent surface-associated growth; meanwhile, disks loaded with 10% oxides prevent planktonic growth of microorganisms in the susceptibility assay,” the researchers explain. “The microscopy analysis showed that part of nanoparticles was encapsulated by the biopolymeric matrix of resins, in most cases remaining disorderly dispersed over the surface of resins. Thermal analysis shows that plant resins have peculiar characteristics, with a thermal behavior similar to commercial available semicrystalline polymers, although their structure consists of a mix of organic compoundsThe disks 3D printed from the natural materials, in most cases, inhibited the growth of the clinical pathogens being studied, and when nano oxide particles were added, the materials were even more effective.

Whats more these materials behaved just like some polymers do. The resins,

showed thermal behavior inherent to semicrystalline polymers such as polyester and polyurea; at some point, the molecules disposed in amorphous matrix obtain enough freedom of motion to spontaneously rearrange themselves into crystalline forms. This transition from amor-phous solid to crystalline solid was evidenced by distinct exothermic peaks, as the temperature increases to 500∘C samples, eventually reaching its melting point.

In short this is a promising study. Polymeric behavior from these Oleo-Gum-Resin may make it easy to process them just as many other 3D printing materials. Furthermore, as 3D printing is being increasingly used to create things such as surgical instruments, surgical guides and implants, special consideration should be given to the materials that are used to 3D print these tools. Of course, all surgical instruments and implants are made to be sterile before being used, but what if they could be made from materials that actively prevented infection? There’s a big difference between tools that are free of pathogens and those that actively repel pathogens. Surgeries could be made safer and recoveries quicker, without the complications and extended hospital stays that happen when infections are acquired. 3D printing surgical tools from these materials will not eliminate all hospital-acquired infections; there are a number of causes for these diseases that go beyond surgeries themselves and threaten anyone who has to stay in a hospital. But if the use of these materials could cut down even a little bit on surgical complications, that would be progress.

Authors of the paper include Diogo José Horst, Sergio Mazurek Tebcerhani, Evaldo Toniolo Kubaski, and Rogério de Almeida Vieira.

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