What can an insect hear? Surprisingly, quite a lot. Though small and simple, their hearing systems are highly efficient. For example, with a membrane only 2 millimeters across, the desert locust can decompose frequencies comparable to human capability. By understanding how insects perceive sound and using 3D-printing technology to create custom materials, it is possible to develop miniature, bio-inspired microphones.
The displacement of the wax moth Acroia grisella membrane, which is one of the key sources of inspiration for designing miniature, bio-inspired microphones. Credit: Andrew Reid
Andrew Reid of the University of Strathclyde in the U.K. will present his work creating such microphones, which can autonomously collect acoustic data with little power consumption. His presentation, “Unnatural hearing — 3D printing functional polymers as a path to bio-inspired microphone design,” will take place Wednesday, May 10 , at 10:05 a.m. Eastern U.S. in the Northwestern/Ohio State room, as part of the 184th Meeting of the Acoustical Society of America running May 8-12 at the Chicago Marriott Downtown Magnificent Mile Hotel.
“Insect ears are ideal templates for lowering energy and data transmission costs, reducing the size of the sensors, and removing data processing,” said Reid.
Reid’s team takes inspiration from insect ears in multiple ways. On the chemical and structural level, the researchers use 3D-printing technology to fabricate custom materials that mimic insect membranes. These synthetic membranes are highly sensitive and efficient acoustic sensors. Without 3D printing, traditional, silicon-based attempts at bio-inspired microphones lack the flexibility and customization required.
“In images, our microphone looks like any other microphone. The mechanical element is a simple diaphragm, perhaps in a slightly unusual ellipsoid or rectangular shape,” Reid said. “The interesting bits are happening on the microscale, with small variations in thickness and porosity, and on the nanoscale, with variations in material properties such as the compliance and density of the material.”
More than just the material, the entire data collection process is inspired by biological systems. Unlike traditional microphones that collect a range of information, these microphones are designed to detect a specific signal. This streamlined process is similar to how nerve endings detect and transmit signals. The specialization of the sensor enables it to quickly discern triggers without consuming a lot of energy or requiring supervision.
The bio-inspired sensors, with their small size, autonomous function, and low energy consumption, are ideal for applications that are hazardous or hard to reach, including locations embedded in a structure or within the human body.
Bio-inspired 3D-printing techniques can be applied to solve many other challenges, including working on blood-brain barrier organoids or ultrasound structural monitoring.
A Rutgers [Rutgers State University of New Jersey, US] scientist has developed a formulation of low-fat chocolate that can be printed on a 3D printer in pretty much any shape a person can conceive, including a heart.
The work heralds what the researcher hopes will be a new line of “functional foods” – edibles specially designed with health benefits. The aim is to develop healthier kinds of chocolate easily accessible to consumers.
Reporting in the scientific journal, Food Hydrocolloids, a Rutgers-led team of scientists described the successful creation and printing of a mixture producing low-fat chocolate — substituting fatty cocoa butter with a lower-fat, water-in-oil emulsion.
“Everybody likes to eat chocolate, but we are also concerned with our health,” said Qingrong Huang, a professor in the Department of Food Science at the Rutgers School of Environmental and Biological Sciences. “To address this, we have created a chocolate that is not only low-fat, but that can also be printed with a 3D printer. It’s our first ‘functional’ chocolate.”
Huang, an author of the study, said he already is working on manipulating sugar content in the new chocolate formulation for low-sugar and sugar-free varieties.
Researchers create emulsions by breaking down two immiscible liquids into minute droplets. In emulsions, the two liquids will usually quickly separate – as is the case with oil and vinegar – unless they are held together by a third, stabilizing ingredient known as an emulsifier. (An egg is the emulsifier in a vinaigrette.)
Chocolate candy is generally made with cocoa butter, cocoa powder and powdered sugar and combined with any one of a variety of different emulsifiers.
For the study, the scientific team experimented with different ratios of the ingredients for a standard chocolate recipe to find the best balance between liquid and solid for 3D printing. Seeking to lower the level of fat in the mixture, researchers created a water-in-cocoa butter emulsion held together by gum arabic, an extract from the acacia tree that is commonly used in the food industry, to replace the cocoa butter. The researchers mixed the emulsion with golden syrup to enhance the flavor and added that combination to the other ingredients.
As delightful as it is to eat, Huang said, chocolate is a material rich with aspects for food scientists to explore.
Employing advanced techniques examining the molecular structure and physical properties of chocolate, researchers investigated the printed chocolate’s physical characteristics. They were seeking the proper level of viscosity for printing and looking for the optimal texture and smoothness “for a good mouthfeel,” Huang said. Experimenting with many different water-oil ratios, they varied the percentages of all the main ingredients before settling on one mixture.
In 3D printing, a printer is used to create a physical object from a digital model by laying down layers of material in quick succession. The 3D printer, and the shapes it produces, can be programmed by an app on a cellphone, Huang said.
Ultimately, Huang said he plans to design functional foods containing healthy added ingredients – substances he has spent more than two decades studying, such as extracts from orange peel, tea, red pepper, onion, Rosemary, turmeric, blueberry and ginger – that consumers can print and eat.
“3D food printing technology enables the development of customized edible products with tailored taste, shape and texture as well as optimal nutrition based on consumer needs,” Huang said.
Other researchers on the study included Siqi You and Xuanxuan Lu of the Department of Food Science and Engineering at Jinan University in Guangzhou, China.
Hopefully this will limit the number of head injuries suffered by soldiers.
Some years ago I was at dinner with friends when one of them, a doctor at the local hospital, told me that the Canadian military, which was in Afghanistan at the time, was dealing with a high number of head injury cases, in part due to the soldiers’ own protective gear.
For example, the protective helmet meant you were less likely to receive a catastrophic injury to your cranium (e.g., metal cracking through bone) but your head would be shaken and that isn’t good for anyone’s brain.
Rice University researchers have received $1.3 million from the Office of Naval Research through the Defense Research University Instrumentation Program to create the world’s first printable military “smart helmet” using industrial-grade 3D printers.
Led by principal investigator Paul Cherukuri, executive director of Rice’s Institute of Biosciences and Bioengineering, the Smart Helmet program aims to modernize standard-issue military helmets by 3D-printing a nanomaterial-enhanced exoskeleton with embedded sensors to actively protect the brain against kinetic or directed-energy effects.
Rice will utilize Carbon Inc.’s L1 printer to develop a strong-but-light military-grade helmet that incorporates advances in materials, image processing, artificial intelligence, haptic feedback and energy storage. The printer enables rapid prototyping that in turn simplifies the process of incorporating the sensors, cameras, batteries and wiring harnesses the program requires, Cherukuri said.
“Current helmets have evolved little since the last century and are still heavy, bulky, passive devices,” he said. “Because of advances in sensors and additive manufacturing, we’re now reimagining the helmet as a 3D-printed, AI-enabled, ‘always-on’ wearable that detects threats near or far and is capable of launching countermeasures to protect soldiers, sailors, airmen and Marines. Essentially, we’re building J.A.R.V.I.S.”
The Smart Helmet program will use technology drawn from projects like the FlatCam, a system developed by co-investigator and electrical and computer engineer Ashok Veeraraghavan and his colleagues that incorporates sophisticated image processing to eliminate the need for bulky lenses, as well as Cherukuri’s Teslaphoresis, a kind of tractor beam for nanomaterials that could help create physical and electromagnetic shields inside the helmets.
“A smart helmet task force has been assembled from some of the finest minds at Rice to tackle the challenge of creating a self-contained, intelligent system that protects the warfighter at all times,” Cherukuri said. The task force includes the labs of materials scientist Pulickel Ajayan, civil and environmental engineer and Rice Provost Reginald DesRoches, mechanical engineer Marcia O’Malley, chemist James Tour and Veeraraghavan.
While the location of the L1 has yet to be determined, a Carbon M2 printer will be located at the Oshman Engineering Design Kitchen (OEDK), where it will be available for projects other than the helmet. Rice undergraduates who design and build their mandated capstone projects at the OEDK are taking part in the helmet project, working alongside graduate students and postdoctoral researchers to develop the heads-up display.
“We’ve got a lot of innovative tech in university labs that has never seen the light of day,” Cherukuri said. “We’re simply developing that technology into a device that gives the men and women protecting our country a real chance at coming home safe and sound. This is for them.”
Two Singapore-designed artefacts are now orbiting around the Earth on the International Space Station (ISS), as part of Moon Gallery.
These artworks were successfully launched into space recently as part of a test flight by the Moon Gallery and will come back to Earth after 10 months.
Currently consisting of 64 artworks made by artists all around the world, the Moon gallery will eventually consist of 100 artworks, which will then be placed on the moon by 2025. Out of these 64 art pieces on the ISS, only two are Singaporean artworks.
The Moon Gallery Foundation is developing an art gallery to be sent to the Moon, contributing to the establishment of the first lunar outpost and permanent museum on Earth’s only natural satellite. The international initiative will see one hundred artworks from artists around the world integrated into a 10 cm x 10 cm x 1 cm grid tray, which will fly to the Moon by 2025. The Moon Gallery aims to expand humanity’s cultural dialog beyond Earth. The gallery will meet the cosmos for the first time in low Earth orbit in 2022 in a test flight.
The test flight is in collaboration with Nanoracks, a private in-space service provider. The gallery is set to fly to the International Space Station (ISS) aboard the NG-17 rocket as part of a Northrop Grumman Cygnus resupply mission in February of 2022. The art projects featured in the gallery will reach the final frontier of human habitat in space, and mark the historical meeting point of the Moon Gallery and the cosmos. Reaching low Earth orbit on the way to the Moon is a pivotal first step in extending our cultural dialog to space.
On its return flight, the Moon Gallery will become a part of the NanoLab technical payload, a module for space research experiments. The character of the gallery will offer a diverse range of materials and behaviors for camera observations and performance tests with NanoLab.
In return, Moon Gallery artists will get a chance to learn about the performance of their artworks in space. The result of these observations will serve as a solid basis for the subsequent Moon Gallery missions and a source of a valuable learning experience for future space artists. The test flight to the ISS is a precursor mission, contributing to the understanding of future possibilities for art in space and strengthening collaboration between the art and space sectors.
Our every perception, analysis, and thought reflect the influences from our surroundings and the Universe in a world of collaboration, communication and interaction, making it possible to explore the real, the imagined and the unknown. The ‘Structure and Reflectance’ cube, a marriage of Art and Technology, is one of the hundred artworks selected by the Moon Gallery, with a unifying message of an integrated world, making it a quintessential signature of humankind on the Moon.
Ms Lakshmi Mohanbabu, a Singaporean architect and designer, is the first and only local artist to have her artwork selected for the Moon Gallery. Coined the ‘Structure and Reflectance’ cube, Lakshmi’s art is a marriage of Art and Technology and is one of the hundred artworks selected by the Moon Gallery. The cube signifies a unifying message of an integrated world, making it a quintessential signature of humankind on the Moon.
The early-stage prototyping and design iterations of the ‘Structure and Reflectance’ cube were performed with Additive Manufacturing, otherwise known as 3D printing, at Nanyang Technological University, Singapore’s (NTU Singapore)Singapore Centre for 3D Printing (SC3DP). This was part of a collaborative project supported by the National Additive Manufacturing Innovation Cluster (NAMIC), a national programme office which accelerates the adoption and commercialisation of additive manufacturing technologies. Previously, the NTU Singapore team at SC3DP produced a few iterations of Moon-Cube using metal 3D printing in various materials such as Inconel and Stainless Steel to evaluate the best suited material.
The newest iteration of the cube comprises crystals—ingrained in the cube via additive manufacturing technology— revealed to the naked eye by the microscopic differences in their surface roughness, which reflect light along different directions.
“Additive Manufacturing is suitable for enabling this level of control over the crystal structure of solids. More specifically, the work was created using ‘laser powder bed fusion technology’ a metal additive manufacturing process which allows us to control the surface roughness through varying the laser parameter,” said Dr Matteo Seita, Nanyang Assistant Professor, NTU Singapore, is the Principal Investigator overseeing the project for the current cube design.
Dr Seita shared the meaning behind the materials used, “Like people, materials have a complex ‘structure’ resulting from their history—the sequence of processes that have shaped their constituent parts—which underpins their differences. Masked by an exterior façade, this structure often reveals little of the underlying quality in materials or people. The cube is a material representation of a human’s complex structure embodied in a block of metal consisting of two crystals with distinct reflectivity and complementary shape.”
Ms Lakshmi added, “The optical contrast on the cube surface from the crystals generates an intricate geometry which signifies the duality of man: the complexity of hidden thought and expressed emotion. This duality is reflected by the surface of the Moon where one side remains in plain sight, while the other has remained hidden to humankind for centuries; until space travel finally allowed humanity to gaze upon it. The bright portion of the visible side of the Moon is dependent on the Moon’s position relative to the Earth and the Sun. Thus, what we see is a function of our viewpoint.”
The hidden structure of materials, people, and the Moon are visualized as reflections of light through art and science in this cube. Expressed in the Structure & Reflectance cube is the concept of human’s duality—represented by two crystals with different reflectance—which appears to the observer as a function of their perspective.
Dr Ho Chaw Sing, Co-Founder and Managing Director of NAMIC said, “Space is humanity’s next frontier. Being the only Singaporean – among a selected few from the global community – Lakshmi’s 3D printed cube presents a unique perspective through the fusion of art and technology. We are proud to have played a small role supporting her in this ‘moon-shot’ initiative.”
Lakshmi views each artwork as a portrayal of humanity’s quests to discover the secrets of the Universe and—fused into a single cube—embody the unity of humankind, which transcends our differences in culture, religion, and social status.
The first cube face, the Primary, is divided into two triangles and depicts the two faces of the Moon, one visible to us from the earth and the other hidden from our view.
The second cube face, the Windmill, has two spiralling windmill forms, one clockwise and the other counter-clockwise, representing our existence, energy, and time.
The third cube face, the Dromenon, is a labyrinth form of nested squares, which represents the layers that we—as space explorers—are unravelling to discover the enigma of the Universe.
The fourth cube face, the Nautilus, reflects the spiralling form of our DNA that makes each of us unique, a shape reflected in the form of our galaxy.
Not having heard of the Moon Gallery or the Moon Gallery Foundation, I did a little research. There’s a LinkedIn profile for the Moon Gallery Foundation (both the foundation and the gallery are located in Holland [Netherlands]),
Moon Gallery is where art and space meet. We aim to set up the first permanent museum on the Moon and develop a culture for future interplanetary society.
Moon Gallery will launch 100 artefacts to the Moon within the compact format of 10 x 10 x 1cm plate on a lunar lander exterior panelling no later than 2025. We suggest bringing this collection of ideas as the seeds of a new culture. We believe that culture makes a distinction between mere survival and life. Moon Gallery is a symbolic gesture that has a real inﬂuence – a way to reboot culture, rethink our values for better living on Earth planet.
The Moon Gallery has its own website, where I found more information about events, artists, and partners such as Nanoracks,
Nanoracks is dedicated to using our unique expertise to solve key problems both in space and on the Earth – all while lowering the barriers to entry of space exploration. Nanoracks’s main office is in Houston, Texas. The business development office is in Washington, D.C., and additional offices are located in Abu Dhabi, United Arab Emirates (UAE) and Turin, Italy. Nanoracks provides tools, hardware and services that allow other companies, organizations and governments to conduct research and other projects in space. Some of Nanoracks customers include Student Spaceflight Experiments Program (SSEP), the European Space Agency (ESA), the German Space Agency (DLR), NASA, Planet Labs, Space Florida, Virgin Galactic, Adidas, Aerospace Corporation, National Reconnaissance Office (NRO), UAE Space Agency, Mohammed bin Rashid Space Centre (MBRSC), and the Beijing Institute of Technology.
Vaccine patch sounds a lot friendlier than ‘needle’ and in the hoopla about vaccine hesitation I have to wonder if the fact that some people don’t like or are deeply fearful of needles is being overlooked.
Perhaps this or some other vaccine patch* will be ready for use in time for the next pandemic. From a September 24, 2021 news item on ScienceDaily,
Scientists at Stanford University and the University of North Carolina [UNC] at Chapel Hill have created a 3D-printed vaccine patch that provides greater protection than a typical vaccine shot.
The trick is applying the vaccine patch directly to the skin, which is full of immune cells that vaccines target.
The resulting immune response from the vaccine patch was 10 times greater than vaccine delivered into an arm muscle with a needle jab, according to a study conducted in animals and published by the team of scientists in the Proceedings of the National Academy of Sciences [PNAS].
Considered a breakthrough are the 3D-printed microneedles lined up on a polymer patch and barely long enough to reach the skin to deliver vaccine.
“In developing this technology, we hope to set the foundation for even more rapid global development of vaccines, at lower doses, in a pain- and anxiety-free manner,” said lead study author and entrepreneur in 3D print technology Joseph M. DeSimone, professor of translational medicine and chemical engineering at Stanford University and professor emeritus at UNC-Chapel Hill.
The ease and effectiveness of a vaccine patch sets the course for a new way to deliver vaccines that’s painless, less invasive than a shot with a needle and can be self-administered.
Study results show the vaccine patch generated a significant T-cell and antigen-specific antibody response that was 50 times greater than a subcutaneous injection delivered under the skin
That heightened immune response could lead to dose sparing, with a microneedle vaccine patch using a smaller dose to generate a similar immune response as a vaccine delivered with a needle and syringe.
While microneedle patches have been studied for decades, the work by Carolina and Stanford overcomes some past challenges: through 3D printing, the microneedles can be easily customized to develop various vaccine patches for flu, measles, hepatitis or COVID-19 vaccines.
Advantages of the vaccine patch
The COVID-19 pandemic has been a stark reminder of the difference made with timely vaccination. But getting a vaccine typically requires a visit to a clinic or hospital.
There a health care provider obtains a vaccine from a refrigerator or freezer, fills a syringe with the liquid vaccine formulation and injects it into the arm.
Although this process seems simple, there are issues that can hinder mass vaccination – from cold storage of vaccines to needing trained professionals who can give the shots.
Meanwhile vaccine patches, which incorporate vaccine-coated microneedles that dissolve into the skin, could be shipped anywhere in the world without special handling and people can apply the patch themselves.
Moreover, the ease of using a vaccine patch may lead to higher vaccination rates.
How the patches are made
It’s generally a challenge to adapt microneedles to different vaccine types, said lead study author Shaomin Tian, researcher in the Department of Microbiology and Immunology in the UNC School of Medicine.
“These issues, coupled with manufacturing challenges, have arguably held back the field of microneedles for vaccine delivery,” she said.
Most microneedle vaccines are fabricated with master templates to make molds. However, the molding of microneedles is not very versatile, and drawbacks include reduced needle sharpness during replication.
“Our approach allows us to directly 3D print the microneedles which gives us lots of design latitude for making the best microneedles from a performance and cost point-of-view,” Tian said.
The microneedle patches were 3D printed at the University of North Carolina at Chapel Hill using a CLIP prototype 3D printer that DeSimone invented and is produced by CARBON, a Silicon-Valley company he co-founded.
The team of microbiologists and chemical engineers are continuing to innovate by formulating RNA vaccines, like the Pfizer and Moderna COVID-19 vaccines, into microneedle patches for future testing.
“One of the biggest lessons we’ve learned during the pandemic is that innovation in science and technology can make or break a global response,” DeSimone said. “Thankfully we have biotech and health care workers pushing the envelope for us all.”
Additional study authors include Cassie Caudill, Jillian L. Perry, Kimon lliadis, Addis T. Tessema and Beverly S. Mecham of UNC-Chapel Hill and Brian J. Lee of Stanford.
I’m not sure how I feel about a t-shirt, regardless of size, made of living biological material but these researchers seem uniformly enthusiastic. From a May 3, 2021 news item on phys.org (Note: A link has been removed),
Living materials, which are made by housing biological cells within a non-living matrix, have gained popularity in recent years as scientists recognize that often the most robust materials are those that mimic nature.
For the first time, an international team of researchers from the University of Rochester [located in New York state, US] and Delft University of Technology in the Netherlands used 3D printers and a novel bioprinting technique to print algae into living, photosynthetic materials that are tough and resilient. The material has a variety of applications in the energy, medical, and fashion sectors. The research is published in the journal Advanced Functional Materials.
“Three-dimensional printing is a powerful technology for fabrication of living functional materials that have a huge potential in a wide range of environmental and human-based applications.” says Srikkanth Balasubramanian, a postdoctoral research associate at Delft and the first author of the paper. “We provide the first example of an engineered photosynthetic material that is physically robust enough to be deployed in real-life applications.”
HOW TO BUILD NEW MATERIALS: LIVING AND NONLIVING COMPONENTS
To create the photosynthetic materials, the researchers began with a non-living bacterial cellulose–an organic compound that is produced and excreted by bacteria. Bacterial cellulose has many unique mechanical properties, including its flexibility, toughness, strength, and ability to retain its shape, even when twisted, crushed, or otherwise physically distorted.
The bacterial cellulose is like the paper in a printer, while living microalgae acts as the ink. The researchers used a 3D printer to deposit living algae onto the bacterial cellulose.
The combination of living (microalgae) and nonliving (bacterial cellulose) components resulted in a unique material that has the photosynthetic quality of the algae and the robustness of the bacterial cellulose; the material is tough and resilient while also eco-friendly, biodegradable, and simple and scalable to produce. The plant-like nature of the material means it can use photosynthesis to “feed” itself over periods of many weeks, and it is also able to be regenerated–a small sample of the material can be grown on-site to make more materials.
ARTIFICIAL LEAVES, PHOTOSYNTHETIC SKINS, AND BIO-GARMENTS
The unique characteristics of the material make it an ideal candidate for a variety of applications, including new products such as artificial leaves, photosynthetic skins, or photosynthetic bio-garments.
Artificial leaves are materials that mimic actual leaves in that they use sunlight to convert water and carbon dioxide–a major driver of climate change–into oxygen and energy, much like leaves during photosynthesis. The leaves store energy in chemical form as sugars, which can then be converted into fuels. Artificial leaves therefore offer a way to produce sustainable energy in places where plants don’t grow well, including outer space colonies. The artificial leaves produced by the researchers at Delft and Rochester are additionally made from eco-friendly materials, in contrast to most artificial leaf technologies currently in production, which are produced using toxic chemical methods.
“For artificial leaves, our materials are like taking the ‘best parts’ of plants–the leaves–which can create sustainable energy, without needing to use resources to produce parts of plants–the stems and the roots–that need resources but don’t produce energy,” says Anne S. Meyer, an associate professor of biology at Rochester. “We are making a material that is only focused on the sustainable production of energy.”
Another application of the material would be photosynthetic skins, which could be used for skin grafts, Meyer says. “The oxygen generated would help to kick-start healing of the damaged area, or it might be able to carry out light-activated wound healing.”
Besides offering sustainable energy and medical treatments, the materials could also change the fashion sector. Bio-garments made from algae would address some of the negative environmental effects of the current textile industry in that they would be high-quality fabrics that would be sustainability produced and completely biodegradable. They would also work to purify the air by removing carbon dioxide through photosynthesis and would not need to be washed as often as conventional garments, reducing water usage.
“Our living materials are promising because they can survive for several days with no water or nutrients access, and the material itself can be used as a seed to grow new living materials,” says Marie-Eve Aubin-Tam, an associate professor of bionanoscience at Delft. “This opens the door to applications in remote areas, even in space, where the material can be seeded on site.”
Graphene excels at removing contaminants from water, but it’s not yet a commercially viable use of the wonder material.
That could be changing.
In a recent study, University at Buffalo [UB] engineers report a new process of 3D printing graphene aerogels that they say overcomes two key hurdles — scalability and creating a version of the material that’s stable enough for repeated use — for water treatment.
“The goal is to safely remove contaminants from water without releasing any problematic chemical residue,” says study co-author Nirupam Aich, PhD, assistant professor of environmental engineering at the UB School of Engineering and Applied Sciences. “The aerogels we’ve created hold their structure when put in water treatment systems, and they can be applied in diverse water treatment applications.”
An aerogel is a light, highly porous solid formed by replacement of liquid in a gel with a gas so that the resulting solid is the same size as the original. They are similar in structural configuration to Styrofoam: very porous and lightweight, yet strong and resilient.
Graphene is a nanomaterial formed by elemental carbon and is composed of a single flat sheet of carbon atoms arranged in a repeating hexagonal lattice.
To create the right consistency of the graphene-based ink, the researchers looked to nature. They added to it two bio-inspired polymers — polydopamine (a synthetic material, often referred to as PDA, that is similar to the adhesive secretions of mussels), and bovine serum albumin (a protein derived from cows).
In tests, the reconfigured aerogel removed certain heavy metals, such as lead and chromium, that plague drinking water systems nationwide. It also removed organic dyes, such as cationic methylene blue and anionic Evans blue, as well as organic solvents like hexane, heptane and toluene.
To demonstrate the aerogel’s reuse potential, the researchers ran organic solvents through it 10 times. Each time, it removed 100% of the solvents. The researchers also reported the aerogel’s ability to capture methylene blue decreased by 2-20% after the third cycle.
The aerogels can also be scaled up in size, Aich says, because unlike nanosheets, aerogels can be printed in larger sizes. This eliminates a previous problem inherent in large-scale production, and makes the process available for use in large facilities, such as in wastewater treatment plants, he says. He adds the aerogels can be removed from water and reused in other locations, and that they don’t leave any kind of residue in the water.
Aich is part of a collaboration between UB and the University of Pittsburgh, led by UB chemistry professor Diana Aga, PhD, to find methods and tools to degrade per- and polyfluoroalkyl substances (PFAS), toxic materials so difficult to break down that they are known as “forever chemicals.” Aich notes the similarities to his work with 3D aerogels, and he hopes results from the two projects can be brought together to create more effective methods of removing waterborne contaminants.
“We can use these aerogels not only to contain graphene particles but also nanometal particles which can act as catalysts,” Aich says. “The future goal is to have nanometal particles embedded in the walls and the surface of these aerogels and they would be able to degrade or destroy not only biological contaminants, but also chemical contaminants.”
Aich, Chi, and Masud [Arvid Masud, PhD] hold a pending patent for the graphene aerogel described in the study, and they are looking for industrial partners to commercialize this process.
Imagine if surgeons could transplant healthy neurons into patients living with neurodegenerative diseases or brain and spinal cord injuries. And imagine if they could “grow” these neurons in the laboratory from a patient’s own cells using a synthetic, highly bioactive material that is suitable for 3D printing.
By discovering a new printable biomaterial that can mimic properties of brain tissue, Northwestern University researchers are now closer to developing a platform capable of treating these conditions using regenerative medicine.
A key ingredient to the discovery is the ability to control the self-assembly processes of molecules within the material, enabling the researchers to modify the structure and functions of the systems from the nanoscale to the scale of visible features. The laboratory of Samuel I. Stupp published a 2018 paper in the journal Science which showed that materials can be designed with highly dynamic molecules programmed to migrate over long distances and self-organize to form larger, “superstructured” bundles of nanofibers.
Now, a research group led by Stupp has demonstrated that these superstructures can enhance neuron growth, an important finding that could have implications for cell transplantation strategies for neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease, as well as spinal cord injury.
“This is the first example where we’ve been able to take the phenomenon of molecular reshuffling we reported in 2018 and harness it for an application in regenerative medicine,” said Stupp, the lead author on the study and the director of Northwestern’s Simpson Querrey Institute. “We can also use constructs of the new biomaterial to help discover therapies and understand pathologies.
Walking molecules and 3D printing
The new material is created by mixing two liquids that quickly become rigid as a result of interactions known in chemistry as host-guest complexes that mimic key-lock interactions among proteins, and also as the result of the concentration of these interactions in micron-scale regions through a long scale migration of “walking molecules.”
The agile molecules cover a distance thousands of times larger than themselves in order to band together into large superstructures. At the microscopic scale, this migration causes a transformation in structure from what looks like an uncooked chunk of ramen noodles into ropelike bundles.
“Typical biomaterials used in medicine like polymer hydrogels don’t have the capabilities to allow molecules to self-assemble and move around within these assemblies,” said Tristan Clemons, a research associate in the Stupp lab and co-first author of the paper with Alexandra Edelbrock, a former graduate student in the group. “This phenomenon is unique to the systems we have developed here.”
Furthermore, as the dynamic molecules move to form superstructures, large pores open that allow cells to penetrate and interact with bioactive signals that can be integrated into the biomaterials.
Interestingly, the mechanical forces of 3D printing disrupt the host-guest interactions in the superstructures and cause the material to flow, but it can rapidly solidify into any macroscopic shape because the interactions are restored spontaneously by self-assembly. This also enables the 3D printing of structures with distinct layers that harbor different types of neural cells in order to study their interactions.
Signaling neuronal growth
The superstructure and bioactive properties of the material could have vast implications for tissue regeneration. Neurons are stimulated by a protein in the central nervous system known as brain-derived neurotrophic factor (BDNF), which helps neurons survive by promoting synaptic connections and allowing neurons to be more plastic. BDNF could be a valuable therapy for patients with neurodegenerative diseases and injuries in the spinal cord but these proteins degrade quickly in the body and are expensive to produce.
One of the molecules in the new material integrates a mimic of this protein that activates its receptor known as Trkb, and the team found that neurons actively penetrate the large pores and populate the new biomaterial when the mimetic signal is present. This could also create an environment in which neurons differentiated from patient-derived stem cells mature before transplantation.
Now that the team has applied a proof of concept to neurons, Stupp believes he could now break into other areas of regenerative medicine by applying different chemical sequences to the material. Simple chemical changes in the biomaterials would allow them to provide signals for a wide range of tissues.
“Cartilage and heart tissue are very difficult to regenerate after injury or heart attacks, and the platform could be used to prepare these tissues in vitro from patient-derived cells,” Stupp said. “These tissues could then be transplanted to help restore lost functions. Beyond these interventions, the materials could be used to build organoids to discover therapies or even directly implanted into tissues for regeneration since they are biodegradable.”
When the team combined the twisting patterns with a specialised concrete mix enhanced with steel fibres, the resulting material was stronger than traditionally-made concrete.
Lead researcher Dr Jonathan Tran said 3D printing and additive manufacturing opened up opportunities in construction for boosting both efficiency and creativity.
“3D concrete printing technology has real potential to revolutionise the construction industry, and our aim is to bring that transformation closer,” said Tran, a senior lecturer in structured materials and design at RMIT.
“Our study explores how different printing patterns affect the structural integrity of 3D printed concrete, and for the first time reveals the benefits of a bio-inspired approach in 3DCP.
“We know that natural materials like lobster exoskeletons?have evolved into high-performance structures over millions of years, so by mimicking their key advantages we can follow where nature has already innovated.”
3D printing for construction
The automation of concrete construction is set to transform how we build, with construction the next frontier in the automation and data-driven revolution known as industry 4.0.
A 3D concrete printer builds houses or makes structural components by depositing the material layer-by-layer, unlike the traditional approach of casting concrete in a mould.
With the latest technology, a house can be 3D printed in just 24 hours for about half the cost, while construction on the world’s first 3D printed community began in 2019 in Mexico.
The emerging industry is already supporting architectural and engineering innovation, such as a 3D printed office building in Dubai, a nature-mimicking concrete bridge in Madrid and The Netherlands’ sail-shaped “Europe Building”.
The research team in RMIT’s School of Engineering focuses on 3D printing concrete, exploring ways to enhance the finished product through different combinations of printing pattern design, material choices, modelling, design optimisation and reinforcement options.
Patterns for printing
The most conventional pattern used in 3D printing is unidirectional, where layers are laid down on top of each other in parallel lines.
The new study published in a special issue of 3D Printing and Additive Manufacturing investigated the effect of different printing patterns on the strength of steel fibre-enhanced concrete.
Previous research by the RMIT team found that including 1-2% steel fibres in the concrete mix reduces defects and porosity, increasing strength. The fibres also help the concrete harden early without deformation, enabling higher structures to be built.
The team tested the impact of printing the concrete in helicoidal patterns (inspired by the internal structure of lobster shells), cross-ply and quasi-isotropic patterns (similar to those used for laminated composite structures and layer-by-layer deposited composites) and standard unidirectional patterns.
Supporting complex structures
The results showed strength improvement from each of the patterns, compared with unidirectional printing, but Tran said the spiral patterns hold the most promise for supporting complex 3D printed concrete structures.
“As lobster shells are naturally strong and naturally curved, we know this could help us deliver stronger concrete shapes like arches and flowing or twisted structures,” he said.
“This work is in early stages so we need further research to test how the concrete performs on a wider range of parameters, but our initial experimental results show we are on the right track.”
Further studies will be supported through a new large-scale mobile concrete 3D printer recently acquired by RMIT – making it the first research institution in the southern hemisphere to commission a machine of this kind.
The 5×5m robotic printer will be used by the team to research the 3D printing of houses, buildings and large structural components.
The team will also use the machine to explore the potential for 3D printing with concrete made with recycled waste materials such as soft plastic aggregate.
The work is connected to a new project with industry partners Replas and SR Engineering, focusing on sound-dampening walls made from post-consumer recycled soft plastics and concrete, which was recently supported with an Australian Government Innovations Connections grant.
Researchers dipped their new, printed sensors into tuna broth and watched the readings.
It turned out the sensors – printed with high-resolution aerosol jet printers on a flexible polymer film and tuned to test for histamine, an allergen and indicator of spoiled fish and meat – can detect histamine down to 3.41 parts per million.
The U.S. Food and Drug Administration has set histamine guidelines of 50 parts per million in fish, making the sensors more than sensitive enough to track food freshness and safety.
I find using 3D-printing techniques to produce graphene, a 2-d material, intriguing. Apparently, the technique is cheaper and offers an advantage as it allows for greater precision than other techniques (inkjet printing, chemical vapour depostion [CVD], etc.)
Making the sensor technology possible is graphene, a supermaterial that’s a carbon honeycomb just an atom thick and known for its strength, electrical conductivity, flexibility and biocompatibility. Making graphene practical on a disposable food-safety sensor is a low-cost, aerosol-jet-printing technology that’s precise enough to create the high-resolution electrodes necessary for electrochemical sensors to detect small molecules such as histamine.
“This fine resolution is important,” said Jonathan Claussen, an associate professor of mechanical engineering at Iowa State University and one of the leaders of the research project. “The closer we can print these electrode fingers, in general, the higher the sensitivity of these biosensors.”
Claussen and the other project leaders – Carmen Gomes, an associate professor of mechanical engineering at Iowa State; and Mark Hersam, the Walter P. Murphy Professor of Materials Science and Engineering at Northwestern University in Evanston, Illinois – have recently reported their sensor discovery in a paper published online by the journal 2D Materials. (…)
The paper describes how graphene electrodes were aerosol jet printed on a flexible polymer and then converted to histamine sensors by chemically binding histamine antibodies to the graphene. The antibodies specifically bind histamine molecules.
The histamine blocks electron transfer and increases electrical resistance, Gomes said. That change in resistance can be measured and recorded by the sensor.
“This histamine sensor is not only for fish,” Gomes said. “Bacteria in food produce histamine. So it can be a good indicator of the shelf life of food.”
The researchers believe the concept will work to detect other kinds of molecules, too.
“Beyond the histamine case study presented here, the (aerosol jet printing) and functionalization process can likely be generalized to a diverse range of sensing applications including environmental toxin detection, foodborne pathogen detection, wearable health monitoring, and health diagnostics,” they wrote in their research paper.
For example, by switching the antibodies bonded to the printed sensors, they could detect salmonella bacteria, or cancers or animal diseases such as avian influenza, the researchers wrote.
Claussen, Hersam and other collaborators (…) have demonstrated broader application of the technology by modifying the aerosol-jet-printed sensors to detect cytokines, or markers of inflammation. The sensors, as reported in a recent paper published by ACS Applied Materials & Interfaces, can monitor immune system function in cattle and detect deadly and contagious paratuberculosis at early stages.
Claussen, who has been working with printed graphene for years, said the sensors have another characteristic that makes them very useful: They don’t cost a lot of money and can be scaled up for mass production.
“Any food sensor has to be really cheap,” Gomes said. “You have to test a lot of food samples and you can’t add a lot of cost.”
Claussen and Gomes know something about the food industry and how it tests for food safety. Claussen is chief scientific officer and Gomes is chief research officer for NanoSpy Inc., a startup company based in the Iowa State University Research Park that sells biosensors to food processing companies.
They said the company is in the process of licensing this new histamine and cytokine sensor technology.
It, after all, is what they’re looking for in a commercial sensor. “This,” Claussen said, “is a cheap, scalable, biosensor platform.”
Here’s a link to and a citation for the two papers mentioned in the news release,