The 23rd edition of the Precision Fair, held at Brabanthallen in 's-Hertogenbosch, has once again positioned itself as the pinnacle event for the high and ultra-precision technology sectors. This year,&nbsp;375 exhibitors&nbsp;and experts from international companies, research institutions, and academia gathered to push the boundaries of precision engineering. The event was enriched with 50 inspirational sessions delivered by industry leaders and innovators, encompassing a diverse range of topics from mechatronic systems to micro processing and motion.The fair not only facilitated a networking arena for professionals but also hosted the prestigious DSPE awards, celebrating significant achievements in the field. Additionally, this year marked the introduction of the International Precision Conference, further highlighting the event’s dedication to fostering global collaboration in pursuing technological advancements.By bringing together the best of industry and academia, the Precision Fair continues to be a critical hub for sharing knowledge and shaping the future of precision technology.Wevolver attended the fair and spoke with a few of the innovative exhibitors.&nbsp;<h2 dir="ltr">Hexagon: Enhancing Engineering Processes&nbsp;</h2>At the Precision Fair, Hexagon showcased its comprehensive approach to streamlining product development and manufacturing processes with advanced hardware and software solutions. Faruk Pehlivan, representing Hexagon, extended an invitation to their upcoming event,<a href="https://events.hexagon.com/Hexagon_LIVE_Eindhoven">&nbsp;Hexagon LIVE Eindhoven</a>, highlighting their commitment to technological innovation.Hexagon's solutions facilitate various stages of product development, from CFD analysis to optimise design functionality to G-code preparation for precise manufacturing execution. The standout at the event was their new MarvellScan, an optical scanning device designed for detailed quality checks and reverse engineering. This scanner is distinguished by its autonomous control, flexible movement capabilities, and wireless functionality, making it ideal for ensuring product quality directly against CAD models and enhancing legacy parts through reverse engineering.These innovations underscore Hexagon's leadership in integrating technology that enhances production efficiency and product reliability, setting a high standard for quality assurance in manufacturing.<a href="https://www.wevolver.com/article/harnessing-manufacturing-intelligence-to-enhance-operational-excellence-in-aerospace">Read more about Hexagon here.&nbsp;</a><h2 dir="ltr">Muon Group: Creating microstructures in glass</h2>Muon Group, through its member LouwersHanique, showcased its cutting-edge technology for creating microstructures in glass at the Precision Fair. Their process involves a two-step method using femtosecond laser technology. Initially, the glass is precisely modified by the laser, which changes its internal structure. This modification is followed by wet chemical etching, selectively removing the altered glass to create intricate 3D microstructures.This technique achieves remarkable precision, allowing for features as small as 1 µm, with tolerances and surface smoothness ideal for specialised industrial applications. Muon Group’s process supports various glass materials like fused silica, sapphire, and borosilicate, catering to a wide range of industries requiring high-precision glass components. Their full suite of capabilities includes not only microfabrication but also complementary services such as optical assembly, CNC milling, and cleanroom packaging, underscoring their comprehensive approach to high-tech glass manufacturing.<h2 dir="ltr">Versatile, agile and efficient: Maxon's SCARA Robotics Innovations at the Precision Fair</h2>Maxon showcased its innovative solutions for SCARA robots at the Precision Fair, featuring a holistic approach that optimises robotic motion and design for enhanced efficiency. Representatives Francis De Wilde and Mark van Zutphen introduced a full setup including a driver and a hollow-axis motor which allows for efficient cable management and increased space-saving on production lines. Their specialised programming facilitates dynamic flipping motions between work areas, improving pick-and-place operations. Maxon's focus on compact design and powerful performance optimises the use of space and resources in industrial settings, with future goals aimed at increasing the versatility and speed of robotic arms.&nbsp;<h2 dir="ltr">New era in precise inspection launched by ZEISS</h2>ZEISS launched the O-INSPECT Duo at the Precision Fair, introducing a large-scale measuring machine capable of inspecting items like circuit boards and batteries with optical, tactile, and microscopic methods. This innovation addresses the challenges of measuring large objects without cutting them, offering rapid and precise analysis. The system utilises ZEISS's established metrology and analysis software, and was showcased with demonstrations at the event, underscoring its potential to streamline quality control processes in manufacturing.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1731678709332-ZEISS-lanceert-nieuwe-O-INSPECT.jpg" style="width: 100%px;" class="fr-fic fr-dib"><h2 dir="ltr">Innovative Duo Wins Prestigious Wim van der Hoek Award at Precision Fair</h2>The Wim van der Hoek Award, also known as the Constructors Award, was presented during the 22nd Precision Fair. For the first time, the award was given to a duo, Marc Slob and Youp Verbakel, for their innovative design of a machine for automatic assembly of shovels and spades. Their project, which originated from Avans University of Applied Sciences, excelled in terms of design freedom, cost considerations, and production reliability, earning them this prestigious accolade in mechanical engineering design.For more details, you can visit the<a href="https://www.dspe.nl/awards/wim-van-der-hoek-award/">&nbsp;DSPE website</a>.<h2 dir="ltr" id="isPasted">Liquid hydrogen-powered retrofit aircraft wins Young Talent Award</h2>On the inaugural day of the fair, student teams from the nation's top three technical universities competed in the Young Talent Pitch Award, presenting their innovative projects to a panel. The entries included diverse technologies ranging from autonomous racing cars and electric motors to hydrogen-fueled aircraft, a rover designed for the South Pole, and an actual rocket. The competition, which judged entries based on their technical feasibility, social impact, and creativity, concluded with Team Aero Delft claiming the top spot, followed by DARE - Stratos V from Delft in second place.Aero Delft is pioneering a transformative approach in aviation with its development of a liquid hydrogen-powered retrofit aircraft. The team is committed to advancing hydrogen propulsion technologies, planning a shift from gaseous to liquid hydrogen to drastically reduce aviation emissions. The jury lauded Aero Delft for their project's technical feasibility and innovative approach, highlighting it as a significant stride towards sustainable aviation. Koen Pijnacker's compelling pitch further solidified their standout status in the competition.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1731678583425-54141210051_2ddebb5594_c.jpg" style="width: 100%px;" class="fr-fic fr-dib"><h2 dir="ltr" id="isPasted">Looking Ahead to 2025 and beyond</h2>The fair not only provided a platform for these technological showcases but also set the stage for future collaborations and innovations. Each presentation underscored the industry's focus on enhancing precision and efficiency, driving the boundaries of what's possible in technology and manufacturing.The next edition will take place on 12th&nbsp;and 13th&nbsp;November 2025.&nbsp;For more details on the event and future plans, visit<a href="https://mikrocentrum.nl/en/precision-technology/overview-precision-fair/">&nbsp;Mikrocentrum's Precision Fair</a>.

The 23rd Precision Fair showcased innovations like Hexagon's MarvellScan and Maxon's SCARA robots, with Aero Delft winning the Young Talent Pitch for their hydrogen aircraft.


Precision in Practice: Highlights from the 23rd Precision Fair

Imagine how a phone call works: Your voice is converted into electronic signals, shifted up to higher frequencies, transmitted over long distances, and then shifted back down so it can be heard clearly on the other end. The process enabling this shifting of signal frequencies is called frequency mixing, and it is essential for communication technologies like radio and Wi-Fi. Frequency mixers are vital components in many electronic devices and typically operate using frequencies that oscillate billions (GHz, gigahertz) to trillions (THz, terahertz) of times per second.&nbsp;Now imagine a frequency mixer that works at a quadrillion (PHz, petahertz) times per second — up to a million times faster. This frequency range corresponds to the oscillations of the electric and magnetic fields that make up light waves.&nbsp;Petahertz-frequency mixers would allow us to shift signals up to optical frequencies and then back down to more conventional electronic frequencies, enabling the transmission and processing of vastly larger amounts of information at many times higher speeds. This leap in speed isn’t just about doing things faster; it’s about enabling entirely new capabilities.Lightwave electronics (or petahertz electronics) is an emerging field that aims to integrate optical and electronic systems at incredibly high speeds, leveraging the ultrafast oscillations of light fields. The key idea is to harness the electric field of light waves, which oscillate on sub-femtosecond (10-15&nbsp;seconds) timescales, to directly drive electronic processes. This allows for the processing and manipulation of information at speeds far beyond what is possible with current electronic technologies. In combination with other petahertz electronic circuitry, a petahertz electronic mixer would allow us to process and analyze vast amounts of information in real time and transfer larger amounts of data over the air at unprecedented speeds. The MIT team’s demonstration of a lightwave-electronic mixer at petahertz-scale frequencies is a first step toward making communication technology faster, and progresses research toward developing new, miniaturized lightwave electronic circuitry capable of handling optical signals directly at the nanoscale.In the 1970s, scientists began exploring ways to extend electronic frequency mixing into the terahertz range using diodes. While these early efforts showed promise, progress stalled for decades. Recently, however, advances in nanotechnology have reignited this area of research. Researchers discovered that tiny structures like nanometer-length-scale needle tips and plasmonic antennas could function similarly to those early diodes but at much higher frequencies.A recent open-access&nbsp;<a href="https://www.science.org/doi/10.1126/sciadv.adq0642" target="_blank">study published in&nbsp;Science Advances</a> by Matthew Yeung, Lu-Ting Chou, Marco Turchetti, Felix Ritzkowsky, Karl K. Berggren, and Phillip D. Keathley at MIT has demonstrated a significant step forward. They developed an electronic frequency mixer for signal detection that operates beyond 0.350 PHz using tiny nanoantennae. These nanoantennae can mix different frequencies of light, enabling analysis of signals oscillating orders of magnitude faster than the fastest accessible to conventional electronics. Such petahertz electronic devices could enable developments that ultimately revolutionize fields that require precise analysis of extremely fast optical signals, such as spectroscopy and imaging, where capturing femtosecond-scale dynamics is crucial (a femtosecond is one-millionth of one-billionth of a second).The team’s study highlights the use of nanoantenna networks to create a broadband, on-chip electronic optical frequency mixer. This innovative approach allows for the accurate readout of optical wave forms spanning more than one octave of bandwidth. Importantly, this process worked using a commercial turnkey laser that can be purchased off the shelf, rather than a highly customized laser.While optical frequency mixing is possible using nonlinear materials, the process is purely optical (that is, it converts light input to light output at a new frequency). Furthermore, the materials have to be many wavelengths in thickness, limiting the device size to the micrometer scale (a micrometer is one-millionth of a meter). &nbsp;In contrast, the lightwave-electronic method demonstrated by the authors uses a light-driven tunneling mechanism that offers high nonlinearities for frequency mixing and direct electronic output using nanometer-scale devices (a nanometer is one-billionth of a meter).While this study focused on characterizing light pulses of different frequencies, the researchers envision that similar devices will enable one to construct circuits using light waves. This device, with bandwidths spanning multiple octaves, could provide new ways to investigate ultrafast light-matter interactions, accelerating advancements in ultrafast source technologies.&nbsp;This work not only pushes the boundaries of what is possible in optical signal processing but also bridges the gap between the fields of electronics and optics. By connecting these two important areas of research, this study paves the way for new technologies and applications in fields like spectroscopy, imaging, and communications, ultimately advancing our ability to explore and manipulate the ultrafast dynamics of light.The research was initially supported by the U.S. Air Force Office of Scientific Research. Ongoing research into harmonic mixing is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Matthew Yeung acknowledges fellowship support from MathWorks, the U.S. National Science Foundation Graduate Research Fellowship Program, and MPS-Ascend Postdoctoral Research Fellowship. Lu-Ting Chou acknowledges financial support from the China's Ministry of Education for the Overseas Internship Program from the Chinese National Science and Technology Council for the doctoral fellowship program. This work was carried out, in part, through the use of MIT.nano.

The demonstration of a lightwave-electronic mixer at petahertz-scale frquencies is a first step toward making communication technology faster and progresses research toward developing new, miniaturized lightwave electronic circuitry capable of handling optical signals directly at the nanoscale. Image: Sampson Wilcox/Research Laboratory of Electronics

Lightwave electronics aim to integrate optical and electronic systems at incredibly high speeds, leveraging the ultrafast oscillations of light fields.

Nanostructures enable on-chip lightwave-electronic frequency mixer

A view into how nanoscale building blocks can rearrange into different organized structures on command is now possible with an approach that combines an electron microscope, a small sample holder with microscopic channels, and computer simulations, according to a new study by researchers at the University of Michigan and Indiana University.The approach could eventually enable smart materials and coatings that can switch between different optical, mechanical and electronic properties.“One of my favorite examples of this phenomenon in nature is in chameleons,” said <a href="https://che.engin.umich.edu/people/dwyer-tobias/" target="_blank" rel="noreferrer noopener">Tobias Dwyer</a>, U-M doctoral student in chemical engineering and co-first author of the study published in Nature Chemical Engineering. “Chameleons change color by altering the spacing between nanocrystals in their skin. The dream is to design a dynamic and multifunctional system that can be as good as some of the examples that we see in biology.”The imaging technique lets researchers watch how nanoparticles react to changes in their environment in real time, offering an unprecedented window into their assembly behavior.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzI1MzIxMzE4NjkzLWZsb3ctY2VsbC5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 100%px;" class="fr-fic fr-dib">An illustration of an imaging technique that allows researchers to watch how nanoparticles respond to changes in their environment in real time. The blue lines represent the beam of an electron microscope as it impacts gold nanoblocks suspended in liquid in a small sample holder device called a liquid flow cell. Image credit: Ella Maru Studio.In the study, the Indiana team first suspended nanoparticles, a class of materials smaller than the average bacteria cell, in tiny channels of liquid on a microfluidic flow cell. This type of device allowed the researchers to flush different kinds of fluid into the cell on the fly while they viewed the mixture under their electron microscope. The researchers learned that the instrument gave the nanoparticles—which normally are attracted to each other—just enough electrostatic repulsion to push them apart and allow them to assemble into ordered arrangements.The nanoparticles, which are cubes made of gold, either perfectly aligned their faces in a tidy cluster or formed a more messy arrangement. The final arrangement of the material depended on the properties of the liquid the blocks were suspended in, and flushing new liquids into the flow cell caused the nanoblocks to switch between the two arrangements.The experiment was a proof of concept for how to steer nanoparticles into desired structures. Nanoparticles are too small to manually manipulate, but the approach could help engineers learn to reconfigure other nanoparticles by changing their environment.“You might have been able to move the particles into new liquids before, but you wouldn’t have been able to watch how they respond to their new environment in real-time,” said <a href="https://www.chem.indiana.edu/faculty/xingchen-ye/" target="_blank">Xingchen Ye</a>, IU associate professor of chemistry who developed the experimental technique and is the study’s lead corresponding author.“We can use this tool to image many types of nanoscale objects, like chains of molecules, viruses, lipids and composite particles. Pharmaceutical companies could use this technique to learn how viruses interact with cells in different conditions, which could impact drug development.”<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1725321753505-ezgif-6-b9c5db5d11.gif" style="width: 100%px;" class="fr-fic fr-dib">A view through an electron microscope of gold nanoparticles reconfiguring themselves in response to researchers changing the liquid the gold nanoparticles are suspended in—either butanol or a mix of octane and butanol. The black and white image on the left is unedited. At right, the gold nanoparticles are color-coded by their orientation. Initially floating in butanol, they’re arranged in a skewed crystal with more unfilled space in its center. Green and orange particles are mixed with blue particles. After researchers change the liquid to a mixture of butanol and octane, the squares’ faces align more closely together and more of the squares in the center of the crystal turn blue and green, representing a more ordered arrangement. Animation credit: Tobias Dwyer, Glotzer Lab, University of Michigan.An electron microscope isn’t necessary to activate the particles in practical morphable materials, the researchers said. Changes in light and pH could also serve that purpose.But to extend the technique to different kinds of nanoparticles, the researchers will need to know how to change their liquids and microscope settings to arrange the particles. Computer simulations run by the U-M team open the door to that future work by identifying the forces that caused the particles to interact and assemble.“We think we now have a good enough understanding of all the physics at play to predict what would happen if we use particles of a different shape or material,” said&nbsp;<a href="https://che.engin.umich.edu/people/moore-timothy/" target="_blank" rel="noreferrer noopener">Tim Moore</a>, U-M assistant research scientist of chemical engineering and co-first author of the study. He designed the computer simulations together with Dwyer and&nbsp;<a href="https://che.engin.umich.edu/people/glotzer-sharon/" target="_blank" rel="noreferrer noopener">Sharon Glotzer</a>, the Anthony C. Lembke Department Chair of Chemical Engineering at U-M and a corresponding author of the study.“The combination of experiments and simulations is exciting because we now have a platform to design, predict, make and observe in real time new, morphable materials together with our IU partners,” said Glotzer, who is also the John Werner Cahn Distinguished University Professor and Stuart W. Churchill Collegiate Professor of Chemical Engineering.

It’s a step toward smart coatings that change color—or other properties—on the fly.

Morphable materials: Researchers coax nanoparticles to reconfigure themselves

Soft polymers with the combined properties of electrolytes and traditional polymers offer some unique and desirable properties that can be drastically changed on demand. These gels, called metallo-polyelectrolyte complexes (MPECs, pronounced "EM-pecks"), can be stimulated externally by magnetic, electrochemical, and optical stimuli, making them ideal for some energy devices, responsive actuators, and nanofiltration systems. Metal ions within their cores provide the materials with these unique capabilities and form dynamic, "reversible" ionic bonds with polymer chains rather than much harder to break covalent bonds.While scientists had previously identified and, in some cases, synthesized, MPECs that demonstrate unusual material properties, which vary, for example, with the pH of the solution before they form into gels, the exact source of those unusual mechanical properties had remained a mystery. In addition, earlier fabrication techniques often were not easily scaled and suffered from uneven composition.Now, through a combination of extensive laboratory experiments, computational theoretical work, and additive manufacturing, a team of Caltech scientists has developed a complete framework for understanding a class of MPECs from the level of molecular bonds up to that of material properties. As a result, the work, reported in <a href="https://www.nature.com/articles/s41467-024-50860-6#Ack1" target="_blank">a paper</a> in the journal Nature Communications, provides a road map of sorts for designing and tailor-making gels with desired functionality and mechanical properties."Our lab typically works on interesting materials, which respond to external stimuli because of the way we build them into specific micro- or nano-architectures. What's so interesting and exciting about MPECs is that they can be actuated even without that kind of architecture," says <a href="https://www.eas.caltech.edu/people/jrgreer?back_url=%2Fpeople" target="_blank">Julia R. Greer</a>, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; and the Fletcher Jones Foundation Director of the <a href="https://kni.caltech.edu/" target="_blank">Kavli Nanoscience Institute</a> at Caltech. She explains that these materials can exhibit vastly different properties and responses. For example, by choice of metal ion and pH, a sample can be made that bends to the left or to the right depending on how fast a force is applied to it. In another case, a sample can fully dissolve in water or remain solid for several days, with the only difference being the metal's ionic charge."This opens the door for 'training' an entire suite of new materials—both computationally and experimentally—that can enable previously challenging technologies, from self-monitoring autonomous filters to advanced ion-exchange membranes and catalysts, and even artificial muscles," Greer says."We were really focused on making a bridge between the molecular level interactions to the mechanical properties on a global scale, providing insight into phenomena that we can't necessarily see," says Seola Lee, co-lead author of a new paper about the work and a PhD student in mechanical engineering in the Greer lab who is currently a research scientist intern at Meta. "We hope that the guidelines we've demonstrated with will help people tap into the design territory in terms of what they will be able to make with these materials."Central to the changeability of MPECs are the metal ions at their cores and the connections they make to charged polymer chains. Many transition metals are multivalent, meaning they can have more than one possible charge. Valency is determined by an atom's outer shell of electrons. Iron, for example, can be present as Fe2+, a form in which it would likely attach to two polymer chains, or Fe3+, which would be more likely to bind with three chains.The Caltech team determined that the metal ions' valency is one of several levers that can be adjusted to tune the properties of MPECs, with the others being pH of the solution and the solvent used.For their investigation, the group used a process called stereolithography, a type of 3D printing where a light-induced polymerization creates a solid structure layer by layer. Carrying out this printing process with a resin that includes various metal ions, it is possible to print out a stable polymer called polyacrylic acid (PAA) with these metal ions bound to it. Next, they conducted exhaustive thermal and mechanical experiments on those materials to probe the material responses at different length scales. Pierre Walker, co-lead author of the paper and a graduate student in chemical engineering in the lab of&nbsp;<a href="https://cce.caltech.edu/people/zhen-gang-wang?back_url=%2Fpeople" target="_blank">Zhen-Gang Wang</a>, the Dick and Barbara Dickinson Professor of Chemical Engineering, analyzed the data and calculated how to model the details from the molecular level up to the full material scale."A lot of this investigation was kind of like walking around in the dark, where there were many different levers that at the time we had no idea were present," Walker says. "Other papers have looked at one or two effects at most in their study. The fact that we were able to couple all three, and the fact that we are able to not only understand how each of them interacts with each other, but how they then impact the global property really makes it much easier for future users of MPEC gels to navigate the space."In the new paper, the authors describe a few examples of MPECs they were able to design using their new framework. One, a shape-memory polymer, looks like a yellow gummy flower that has bloomed and is lying flat. After heating the flower to 90 degrees Celsius, Lee manually lifted the petals, closing the flower into a bud shape. She then cooled the whole thing to -5 degrees C. When she brought the temperature back to 90 degrees C, the flower bloomed and returned to its original shape. Here, the valency of the metal dictated how well the material "remembered" its original shape. The gel made with aluminum (Al3+) returned to the open flower position much more quickly and completely than either calcium (Ca2+) or sodium (Na+).In a second example, the scientists made a gel strip where one side was fabricated with a high pH and the other with a lower pH. Based on the theoretical modeling, the scientists knew how the two sides should behave when submerged in different solutions. And just as expected, when the bilayer was submerged in water, it buckled to the left; when in an aluminum solution, it buckled to the right."We now have a really robust explanation for if you change some of these small molecular levers, here's what comes out at the global scale," says Seneca Velling, a former graduate student in the Greer group who is now completing his studies in the Origins and Habitability Lab at JPL, which Caltech manages for NASA. "Therefore, if you want a global scale property, you can back it out by thinking about what starting conditions make that global property a reality, which is a really cool way to design a material. You can now explain it top-down or bottom-up."Additional authors of the new paper, titled "<a href="https://www.nature.com/articles/s41467-024-50860-6" target="_blank">Molecular Control via Dynamic Bonding Enables Material Responsiveness in Additively Manufactured Metallo-Polyelectrolytes</a>," are Amylynn Chen (PhD '23), Zane W. Taylor (BS '22), Cyrus J.B.M Fiori, Vatsa Gandhi (PhD '23, and Zhen-Gang Wang. The work was supported by funding from the&nbsp;<a href="https://cast.caltech.edu/" target="_blank">Center for Autonomous Systems and Technologies</a> at Caltech, the Army Research Office's Institute for Collaborative Biotechnologies, and the Schwartz/Reisman Foundation's Schwartz/Reisman Collaborative Science Program. Wang receives funding from the Hong Kong Quantum AI Lab and AIRInnoHK of the Hong Kong government.

Soft polymers with the combined properties of electrolytes and traditional polymers offer some unique and desirable properties that can be drastically changed on demand.

Materials Scientists Develop Road Map for Designing Responsive Gels with Unusual Properties

Not only do we need to cut carbon emissions to curb climate change, but many scientists say we also need to capture excess CO2 from the air to prevent continued climate impacts. Currently, however, carbon removal tends to be costly, and polluters may lack incentives to clean up their emissions.One solution is to create useful products from captured CO2, thus increasing the value of drawing it out of the air. Stanford engineers are proposing a way to do just that.In two recent papers, published in the&nbsp;<a href="https://pubs.acs.org/doi/10.1021/jacs.4c03652" data-extlink="" target="_blank">Journal of the American Chemical Society</a>&nbsp;and <a href="https://onlinelibrary.wiley.com/doi/10.1002/anie.202406761" data-extlink="" target="_blank">Angewandte Chemie</a>, a team of Stanford researchers demonstrated that it’s possible not only to convert carbon dioxide to ethanol but also to do so with very few byproducts. Previous efforts have not been able to design a reaction converting the gas with such high selectivity.The researchers chose to focus on ethanol – the same stuff that’s in alcoholic beverages – because the chemical is useful for many industries such as fuels, polymers, and pharmaceuticals. But right now ethanol is mostly made from crops such as corn harvested from vast acres in regions like the Midwest – the process is both land and resource intensive.The researchers propose a win-win: taking captured carbon dioxide and making ethanol, which would further reduce emissions by replacing more energy-intensive ethanol sources. “If we are able to turn CO2 into valuable chemicals, we close the cycle,” said the lead author of the two papers, Chengshuang Zhou, recent PhD graduate in chemical engineering. “We have the opportunity of not producing more carbon, but instead circulating the carbon that is already out there.”<h2>Creating the catalyst</h2>To test this idea, the researchers needed to combine carbon dioxide with hydrogen. But you can’t just put the two gases in a cylinder and shake them to make ethanol, because the reaction isn’t favorable. So the team needed to find a catalyst that would provide an extra kick, moving the reaction in the desired direction.To do so, they first considered the molecular structure of ethanol. “How do we cut several bonds to reconstruct CO2 so that we can retroactively come up with ways to synthesize ethanol from CO2?” Zhou asked. “This reaction would necessarily involve not only hydrogenation, essentially adding hydrogen to CO2, but also coupling two carbon atoms into one single molecule.”He identified that an ideal catalyst must produce at least two fragments, one deeply hydrogenated like methane (-CH3) and one partially hydrogenated like methanol (-CH2OH), which can then come together to form ethanol. He scoured the scientific literature for elements that can both synthesize methanol and encourage hydrogenation, arriving at ruthenium and indium. “Ruthenium has been well documented to be a great catalyst for the CO2 hydrogenation reaction to produce methane,” he said, while “indium oxide-based catalysts have been documented to catalyze CO2 hydrogenation to methanol.” The perfect match.Using nanoscale design and synthesis, the researchers created a ruthenium-indium oxide (Ru/In2O3) catalyst and put it to the test. In a stainless steel tube, the team flowed carbon dioxide and hydrogen across a small scoop of the powdered catalyst, adding pressure and heat to speed the reaction, and analyzed the gases that came out the other end.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1724891477747-schematic_0.jpg" style="width: 100%px;" class="fr-fic fr-dib">A ruthenium-indium oxide catalyst that selectively converts CO2 and H2 into ethanol. Ruthenium nanoparticles (blue) are promoted by the encapsulation of both indium oxide (green) and functional organic polymers (pink). | Chengshuang ZhouIn their initial run, they produced mostly methanol, a promising first step reported in the&nbsp;Journal of the American Chemical Society&nbsp;that provided clues to the catalyst’s function. Now that they had one of two components, they could tweak the catalyst’s structure to encourage more stability, and thus produce ethanol.After the changes, they ran the experiment again and found that the input gases converted to 70% ethanol and only carbon monoxide as a byproduct, a finding reported in&nbsp;Angewandte Chemie. “That’s the biggest discovery,” said&nbsp;<a href="https://profiles.stanford.edu/matteo-cargnello" data-extlink="" target="_blank">Matteo Cargnello</a>, senior author of the papers and an associate professor of chemical engineering. “There was a way to direct this reaction to make mostly ethanol rather than other products.”This high selectivity of conversion is important because separating out ethanol from a mixture would be more energy intensive, which would somewhat defeat the purpose of the research. “If you can selectively make a simple, single product, that will absolutely reduce emissions,” said Cargnello.<h2>Scaling up to smokestacks</h2>While the team performed the experiment in a small tube, they believe the process could scale to settings like industrial chimneys. Before this work, “there hasn’t been a concise guiding principle” for converting carbon dioxide to ethanol, said Zhou. By demonstrating the potential to produce a high rate of ethanol, he believes the work sets the stage for future efforts to use metals that are more abundant. Ruthenium and indium are scarce metals, and using them for mass production of a catalyst would be costly.That’s Cargnello’s next step. He will work with elements in the first row of transition metals on the periodic table, which are far more common and therefore cheaper to scale. He plans to develop a catalyst that can be widely used in conjunction with various sources of carbon dioxide – including captured from the air or from a smokestack – to turn the gas into ethanol, which can then be bottled and sold.“Our hypothesis is that we can make it work with cheaper metals and then be able to scale it up,” Cargnello said. “Because we certainly want our discovery to not just be an academic discovery, we would like it to be translated into a larger scale process.”Cargnello is also a member of&nbsp;<a href="https://biox.stanford.edu/" data-extlink="" target="_blank">Stanford Bio-X</a>.Additional Stanford co-authors of the papers include graduate students Gennaro Liccardo, Jinwon Oh, and Sindhu Nathan; and postdoctoral researchers Michael Stone, Eric J. McShane, and Baraa Werghi.&nbsp;Other co-authors include researchers at the California Institute of Technology, SLAC National Accelerator Laboratory, and Lawrence Berkeley National Lab.&nbsp;

Researchers demonstrated that it’s possible not only to convert carbon dioxide to ethanol but also to do so with very few byproducts. | iStock/onurdongel

Stanford scientists designed a catalyst that turns carbon dioxide into ethanol, which could incentivize cleaning up emissions.

Turning carbon pollution into ethanol

“Nanomaterials” is a broad term used to describe chemical substances or materials in which a single unit is sized between 1 and 100 nanometers (a nanometer is a billionth of a meter). They include exotic materials such as carbon nanotubes, silver nanoparticles (used as antimicrobials), nanoporous materials, and many types of catalysts used for efficiently driving chemical reactions.Nanomaterials are currently used in a wide range of fields, from medicine to electronics, which means that the ability to determine their exact chemical composition is essential. Nonetheless, this proves challenging, because traditional methods for analyzing nanomaterials tend to be susceptible to low signal-to-noise ratios.For example, one extensively used method is energy-dispersive X-ray spectroscopy (EDX), combined with scanning transmission electron microscopy. This technique provides detailed maps of where different elements are located within a sample, but it often produces noisy data, especially on such small objects, and mixed signals when different materials overlap, making precise chemical analysis difficult.The noisy data are usually “cleaned up” with various techniques, from simple spatial filtering to more sophisticated machine learning approaches like principal component analysis, that separate the signals from the noise, but they too have their drawbacks. For example, they can introduce errors, or struggle to distinguish between chemical signals when they are very similar.Now, three scientists at EPFL, Hui Chen, Duncan Alexander, and Cécile Hébert have developed a machine learning-based method called PSNMF (“non-negative matrix factorization-based pan-sharpening”) that enhances the clarity and accuracy of EDX data, making it easier to identify and quantify different chemical elements in nanomaterials.The team started by leveraging a special characteristic of their data called “Poisson noise”. This type of noise occurs because the detection of X-ray photons is random. When the electron beam hits the sample, it produces X-ray photons, but the number detected varies randomly each time, creating a noisy, grainy pattern known as Poisson noise.To improve the clarity of their data, the researchers combined data from nearby pixels, enhancing the signal-to-noise ratio in the spectrum at the cost of the spatial resolution.They then applied a machine learning method called "non-negative matrix factorization" (NMF) to this clearer dataset. NMF is a mathematical technique that breaks down a large dataset into simpler, smaller parts, ensuring all parts are non-negative, which helps identify patterns in the data. This approach gave them good spectral data at the cost of having blurry images with large pixels.Next, they repeated the NMF process on the original high-resolution dataset to preserve detailed spatial information, but initializing the factorization with the previously identified spectral components. Finally, they combined the results from both steps to produce a high-quality dataset, that has both high spectral fidelity and high spatial resolution.The researchers validated PSNMF using synthetic data, computed thanks to a modelling algorithm developed in the lab. Those data mimicked real-world challenges, such as analyzing mineral samples formed under extreme conditions. The method proved highly effective, accurately identifying and separating different materials, even those in tiny amounts.When applied to actual samples, including a nanomineral and a nanocatalyst, PSNMF successfully separated and quantified overlapping materials. This precise analysis is crucial for understanding and developing new technologies that rely on these complex nanostructures.PSNMF is a significant improvement in nanoscale chemical analysis. By providing accurate results despite noisy data and overlapping signals, this method enhances our ability to study and utilize nanomaterials in various fields, from advanced electronics to medical devices.<hr>ReferencesHui Chen, Duncan T.L. Alexander, Cécile Hébert. Leveraging machine learning for advanced nanoscale X-ray analysis: Unmixing multicomponent signals and enhancing chemical quantification. NanoLetters 06 August 2024. DOI:&nbsp;<a href="https://doi.org/10.1021/acs.nanolett.4c02446" title="DOI URL" target="_blank" rel="noopener">10.1021/acs.nanolett.4c02446</a>

EPFL scientists have developed an AI-based technique to improve chemical analysis of nanomaterials, overcoming challenges of noisy data and mixed signals.

AI enhances chemical analysis at the nanoscale

Manufacturing cars with strong, lightweight aluminum alloys rather than steel could improve fuel efficiency and extend electric vehicle range, but the material’s instability at high temperatures has held the alloys back from widespread adoption.Creating tiny, reinforcing particles of titanium carbide (TiC) directly inside of molten aluminum results in a stronger, more temperature resistant aluminum-based material called a metal matrix nanocomposite.Up to this point, researchers have not understood how these nanoparticles form, or how they interact with other features in the microstructure, hindering production of the material on an industrial scale.University of Michigan researchers have used a unique high-resolution, 3D x-ray technique to provide a first glimpse into how nanoparticles form, where they are located and how they facilitate further solidification of the molten metal. A paper on the work will be published in the September edition of Acta Materialia.“Most metals start their lifetimes in the liquid state. How they convert from liquid to solid will ultimately determine their microstructures, and hence, their properties and applications,” said <a href="https://mse.engin.umich.edu/people/shahani" target="_blank" rel="noreferrer noopener">Ashwin Shahani</a>, an associate professor of materials science and engineering and chemical engineering at U-M and co-corresponding author of the study.“The study enabled us to understand exactly how the nanoparticles interact with secondary phases in casting, which has been a major challenge for the past half-century.”&nbsp;As nanoparticles are less than 100 nanometers, one ten-thousandth of a millimeter, the researchers used a powerful imaging technique called synchrotron-based x-ray nanotomography to visualize metal microstructure nondestructively in 3D—a feat not possible with conventional imaging approaches.To obtain the visualizations, the researchers created an aluminum composite reinforced with titanium carbide (TiC). That involved a flux-assisted reaction in which a mixture of carbon powder and titanium-bearing salt was reacted with an aluminum melt. 3D reconstructions revealed an unexpected diversity of titanium aluminide (Al3Ti) intermetallic structures, including one that formed directly on TiC nanoparticles larger than 200 nm in diameter. In that case, the Al3Ti crystals grew into an unusual orthogonal plate structure. Meanwhile, the TiC nanoparticles smaller than the 200 nanometer threshold split the Al3Ti intermetallic plates during solidification, forming branched structures.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1722783000473-ezgif-6-9087a81780.gif" style="width: 100%px;" class="fr-fic fr-dib">A magnified view of the “orthogonal plates” of Al3Ti that nucleated on a TiC nanoparticle. The structure measures 10 μm along its longest dimension. Credit: Ashwin Shahani, Michigan Engineering.In addition to imaging, the researchers used phase-field simulations to fill in spatiotemporal “gaps” in the experiments and propose a mechanism for microstructure formation.“We now have evidence that the nanoparticles form well before the intermetallics, and not the other way around, which has important implications regarding the nucleation of the nanoparticles in the first place,” said Shahani.With these results in hand, industry partners can now guide TiC and Al3Ti formation when manufacturing aluminum composites on a large scale—adjusting solidification pathways or alloy chemistries to achieve the desired microstructure and its associated properties.“We have known for a long time that nano-sized particles could improve the performance of metal matrix composites, but the materials could not be produced at scale. We now understand the formation mechanisms that will enable our industry partners to optimize the process for lightweighting applications,” said Alan Taub, a Robert H. Lurie Professor of Engineering and director of the Electric Vehicle Center at U-M and co-corresponding author of the study.Taub is also a professor of materials science and engineering, mechanical engineering and macromolecular science and engineering.This research was funded by the National Science Foundation (grant no. 1762657).Synchrotron-based x-ray nanotomography was performed at the National Synchrotron Light Source II at Brookhaven National Laboratory. Further characterization was done at the Michigan Center for Materials Characterization. &nbsp;&nbsp;

The lightweight material could extend EV range or fuel efficiency once its microstructure is understood.

First 3D visualization of an aluminum nanocomposite for the auto industry

The glass bottles we toss in the recycling bin don’t always end up where we expect. Only about 33% of glass is recycled in the United States,&nbsp;<a href="https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/glass-material-specific-data#:~:text=EPA%20combined%20data%20from%20the,recycling%20rate%20of%2031.3%20percent." target="_blank">according to the Environmental Protection Agency</a>, partly due to expenses like sorting bottles by color. Penn State scientists recently found that mass-produced soda-lime silicate glass from post-consumer bottles of different colors can be safely melted together in the recycling process, which could potentially lead to more bottles being recycled.The team reported their findings in the&nbsp;<a href="https://ceramics.onlinelibrary.wiley.com/doi/10.1002/ces2.10217" target="_blank">International Journal of Ceramic Engineering and Science</a>.“This work broadly addresses a widespread misconception that different colored glass bottles can’t all be recycled together,” said Katy Gerace, who conducted the research as a doctoral student in the Department of Materials Science and Engineering at Penn State. She graduated in 2023. “We have confirmed that you can melt all these post-consumer glass bottles together to create new, useful glass products.”Soda-lime silicate bottles, the most recycled type of glass, are turned into cullet — glass that has been crushed into small pieces, or grains – before being remelted. Cullet is most often sorted by color so that manufacturers can achieve specific color and clarity for their products. And the availability of pristine, color-sorted glass cullet limits how much recycled material is used in the manufacturing process, the researchers said.Small-scale manufacturers who are focused on recycling, and not on achieving a specific color bottle could utilize mixed-color cullet, keeping more glass bottles out of landfills and reducing energy costs associated with manufacturing glass, the scientists said.<iframe width="640" height="360" src="https://www.youtube.com/embed/CwEixn1u7v8?&amp;wmode=opaque&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-gtm-yt-inspected-23="true" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>Katy Gerace, graduate student, in the Department of Materials Science and Engineering, shares her research in enabling improved glass recycling technology and modeling tools.&nbsp;Remelting glass cullet requires less energy than raw materials, which translates into less carbon dioxide produced during the melting process. For a 10% increase in recycled content, the scientists said, there is a 3% reduction in energy consumption.“We are exploring how to add value to waste,” said Gerace, who is now a research and development senior engineer at Vitro Architectural Glass. “We are trying to think of this not as waste but as something that potentially could have value.”The work stems from&nbsp;<a href="https://www.psu.edu/news/earth-and-mineral-sciences/story/grant-manufacturing-pa-initiative-improve-glass-recycling/" target="_blank">a partnership between Penn State and Remark Glass</a>, a Philadelphia-based company focused on innovative and creative glass recycling.“As a small business, they are really interested in trying to remove glass from the waste stream and keep it out of landfills,” said John Mauro, the Dorothy Pate Enright Professor of Materials Science and Engineering at Penn State and co-author of the study. “They use only post-consumer glass bottles and so they are very interested in understanding the chemical and material properties of the raw materials that come into their business. They wanted to know if there were any technical reasons for them to be concerned about what they’re doing.”Remark provided glass bottles for the study, and Gerace analyzed the samples for chemical composition and thermal properties to quantify variation across five major color families: clear, blue, amber, forest green and emerald green.In addition to demonstrating that post-consumer bottles of different colors and brands can be remelted without risk of material incompatibility, the researchers also presented various processing methods to control color homogeneity in glass produced exclusively from mixed color cullet from recycled glass bottles.Gerace said the particle size of the cullet and the temperature and time of the remelting process have the biggest impacts on color homogeneity.“You have to keep the glass melted for all the different ions to diffuse and move around to create a consistent color,” she said. “So, you can either really extend the time of the melt and hold it at a high temperature for a long time to wait for everything to kind of equilibrate or you can decrease the particle size of the cullet into more of like a fine powder. Then it becomes a little easier to get a nice consistent color.”This means, for example, that various shades of green bottles could be crushed into cullet and melted to produce a homogenous green glass. However, if a specific shade of green is required, then the bottles would be further separated.“Glass is one of the best materials to recycle, but when you actually go look at the process for how it’s done, it’s very non-trivial,” Gerace said. “And unfortunately, we lose a lot of what we put in our recycling bins to the landfill simply because we don’t have a good way of separating and sorting it. And that’s really unfortunate.”

Used glass bottles are crushed into small pieces called cullet before being remelted and remade. A new study found glass from post-consumer bottles of different colors can be safely melted together in the recycling process, which could potentially lead to more bottles being recycled Credit: Provided by Katy Gerace. All Rights Reserved.

Penn State scientists recently found that mass-produced soda-lime silicate glass from post-consumer bottles of different colors can be safely melted together in the recycling process, which could potentially lead to more bottles being recycled.

Message in a bottle: Combining mixed-color glass an option to boost recycling

Researchers have created a new class of materials called “glassy gels” that are very hard and difficult to break despite containing more than 50% liquid. Coupled with the fact that glassy gels are simple to produce, the material holds promise for a variety of applications.Gels and glassy polymers are classes of materials that have historically been viewed as distinct from one another. Glassy polymers are hard, stiff and often brittle. They’re used to make things like water bottles or airplane windows. Gels – such as contact lenses – contain liquid and are soft and stretchy.“We’ve created a class of materials that we’ve termed glassy gels, which are as hard as glassy polymers, but – if you apply enough force – can stretch up to five times their original length, rather than breaking,” says Michael Dickey, corresponding author of a paper on the work and the Camille and Henry Dreyfus Professor of Chemical and Biomolecular Engineering at North Carolina State University. “What’s more, once the material has been stretched, you can get it to return to its original shape by applying heat. In addition, the surface of the glassy gels is highly adhesive, which is unusual for hard materials.”“A key thing that distinguishes glassy gels is that they are more than 50% liquid, which makes them more efficient conductors of electricity than common plastics that have comparable physical characteristics,” says Meixiang Wang, co-lead author of the paper and a postdoctoral researcher at NC&nbsp;State.“Considering the number of unique properties they possess, we’re optimistic that these materials will be useful,” Wang says.Glassy gels, as the name suggests, are effectively a material that combines some of the most attractive properties of both glassy polymers and gels. To make them, the researchers start with the liquid precursors of glassy polymers and mix them with an ionic liquid. This combined liquid is poured into a mold and exposed to ultraviolet light, which “cures” the material. The mold is then removed, leaving behind the glassy gel.“The ionic liquid is a solvent, like water, but is made entirely of ions,” says Dickey. “Normally when you add a solvent to a polymer, the solvent pushes apart the polymer chains, making the polymer soft and stretchable. That’s why a wet contact lens is pliable, and a dry contact lens isn’t. In glassy gels, the solvent pushes the molecular chains in the polymer apart, which allows it to be stretchable like a gel. However, the ions in the solvent are strongly attracted to the polymer, which prevents the polymer chains from moving. The inability of chains to move is what makes it glassy. The end result is that the material is hard due to the attractive forces, but is still capable of stretching due to the extra spacing.”The researchers found that glassy gels could be made with a variety of different polymers and ionic liquids, though not all classes of polymers can be used to create glassy gels.“Polymers that are charged or polar hold promise for glassy gels, because they’re attracted to the ionic liquid,” Dickey says.In testing, the researchers found that the glassy gels don’t evaporate or dry out, even though they consist of 50-60% liquid.“Maybe the most intriguing characteristic of the glassy gels is how adhesive they are,” says Dickey. “Because while we understand what makes them hard and stretchable, we can only speculate about what makes them so sticky.”The researchers also think glassy gels hold promise for practical applications because they’re easy to make.“Creating glassy gels is a simple process that can be done by curing it in any type of mold or by 3D printing it,” says Dickey. “Most plastics with similar mechanical properties require manufacturers to create polymer as a feedstock and then transport that polymer to another facility where the polymer is melted and formed into the end product.“We’re excited to see how glassy gels can be used and are open to working with collaborators on identifying applications for these materials.”The paper, “<a href="https://www.nature.com/articles/s41586-024-07564-0" data-type="link" data-id="https://www.nature.com/articles/s41586-024-07564-0" target="_blank" rel="noreferrer noopener">Glassy Gels Toughened by Solvent</a>,” is published in the journal&nbsp;Nature. Co-lead author of the paper is Xun Xiao of the University of North Carolina at Chapel Hill. The paper was co-authored by Salma Siddika, a Ph.D. student at NC&nbsp;State; Mohammad Shamsi, a former Ph.D. student at NC&nbsp;State; Ethan Frey, a former undergrad at NC state; Brendan O’Connor, a professor of mechanical and aerospace engineering at NC&nbsp;State; Wubin Bai, a professor of applied physical sciences at UNC; and Wen Qian, a research associate professor of mechanical and materials engineering at the University of Nebraska-Lincoln.A video explaining glassy gels, and demonstrating their properties, can be found at <a href="https://www.youtube.com/watch?v=LV-vgxxbNeY" target="_blank" rel="noreferrer noopener">https://www.youtube.com/watch?v=LV-vgxxbNeY</a><iframe width="640" height="360" src="https://www.youtube.com/embed/LV-vgxxbNeY?&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The work was partially supported by funding from the Coastal Studies Institute.

Researchers have created a new class of materials called “glassy gels” that are very hard and difficult to break despite containing more than 50% liquid. Coupled with the fact that glassy gels are simple to produce, the material holds promise for a variety of applications.

Researchers Create New Class of Materials Called 'Glassy Gels'

There are some things in life you can watch and then never unwatch,” said<a href="https://profiles.stanford.edu/manu-prakash" data-extlink="" target="_blank">&nbsp;Manu Prakash</a>, associate professor of bioengineering at Stanford University, calling up a video of his latest fascination, the single-cell organism Lacrymaria olor, a free-living protist he stumbled upon playing with his paper<a href="https://foldscope.com/" data-extlink="" target="_blank">&nbsp;Foldscope</a>.&nbsp;“It’s … just … it’s mesmerizing.”“From the minute Manu showed it to me, I have just been transfixed by this cell,” said Eliott Flaum, a graduate student in the “curiosity-driven”<a href="https://web.stanford.edu/group/prakash-lab/cgi-bin/labsite/" data-extlink="" target="_blank">&nbsp;Prakash Lab</a>. Prakash and Flaum spent the last seven years studying Lacrymaria olor’s&nbsp;every move and recently published<a href="https://www.science.org/doi/10.1126/science.adk5511" data-extlink="" target="_blank">&nbsp;a paper</a> on their work in Science.“The first time I came back with a fluorescence micrograph, it was just breathtaking,” Flaum said. “That image is in the paper.”Beautiful and mesmerizing,&nbsp;L. olor is actually&nbsp;Science’s latest cover art.The video Prakash queued up reveals why this organism is much more than a pretty picture: a single teardrop-shaped cell swims in a droplet of pond water. In an instant, a long, thin “neck” projects out from the bulbous lower end. And it keeps going. And going. Then, just as quickly, the neck retracts back, as if nothing had happened.In seconds, a cell that was just 40 microns tip-to-tail sprouted a neck that extended 1500 microns or more out into the world. It is the equivalent of a 6-foot human projecting its head more than 200 feet. All from a cell without a nervous system.“It is incredibly complex behavior,” Prakash said with a smile.<iframe width="640" height="360" src="https://www.youtube.com/embed/LZArEEBeMpI?&amp;wmode=opaque&amp;rel=0&amp;enablejsapi=1&amp;origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe>Video courtesy of Prakash Lab/Andrew Myers<h2 id="isPasted">Form is function</h2>L. olor has landed on the cover of&nbsp;Science because Prakash and Flaum have discovered in this behavior a new geometric mechanism previously unknown in biology. And they are the first to explain how such a simple cell can produce such incredible morphodynamics, beautiful folding and unfolding – aka origami – at the scale of a single cell, time and again without fail.It is geometry.&nbsp;L. olor’s behavior is encoded in its cytoskeletal structure, just like human behavior is encoded in neural circuits. “This is the first example of cellular origami,” Prakash said. “We’re thinking of calling it lacrygami.”Specifically, it is a subset of traditional origami known as “curved-crease origami.” It is all based on a structure of thin, helical microtubules – ribs that wrap inside the cell’s membrane. These microtubule ribs are encased in a delicate diaphanous membrane, defining the crease pattern of peaks in a series of mountain-and-valley folds.Prakash and Flaum used transmission electron microscopy and other state-of-the-art investigatory techniques to show there are actually 15 of these stiff, helical microtubule ribbons enshrouding&nbsp;L. olor’s cell membrane – a cytoskeleton. These tubules coil and uncoil, leading to long projection and retraction, nesting back into themselves like the bellows of a compressed helical accordion. The gossamer of membrane tucks away inside the cell in neat, well-defined pleats.“When you store pleats on the helical angle in this way, you can store an&nbsp;infinite amount of material,” Flaum explained. “Biology has figured this out.”<h2>Geometry is destiny</h2>The elegance is in the arithmetic. It is mathematically impossible for this structure to unfold in any other way – and, conversely, only one way it can retract. What is perhaps more striking to Prakash is the robustness of the architecture. In its lifetime,&nbsp;L. olor will perform this projection and retraction 50,000 times without flaw, he said: “L. olor is&nbsp;bound by its geometry to fold and unfold in this particular way.”The key is an under-studied mathematical phenomenon occurring at the precise point where the ribs twist and the folded membrane begins to unfurl. It is a&nbsp;singularity – a point where the structure is folded and unfolded at the same time. It is both and neither – singular.Grabbing a piece of paper, Prakash folds it into a cone shape and then pulls on one corner of the paper to demonstrate how this singularity (called d-cone) travels across the sheet in a neat line. And, by pushing back on the corner how the singularity travels back the exact same path to its original position.“It unfolds and folds at this singularity every time, acting as a controller. This is the first time a geometric controller of behavior has been described in a living cell.” Prakash explained.<h2>Recreational biology</h2>A constant theme running throughout the<a href="https://web.stanford.edu/group/prakash-lab/cgi-bin/labsite/publications/" data-extlink="" target="_blank">&nbsp;Prakash Lab’s</a> work is a profound sense of wonder and playfulness that results in the energetic curiosity necessary to pursue such an idea for such a long time. It is, to put it in Prakash’s terms, old-school science. He also calls it recreational biology.To demonstrate his inspiration, Prakash displayed a family tree of other single-celled organisms that he has chosen to study. True, none can do what&nbsp;L. olor can do, he said. But these intricate geometries come in thousands of forms. Beautiful? Certainly, but each is also hiding wonderful and unwritten rules under their sleeves.“We started with a puzzle,” Prakash explained with all the seriousness a scientist can muster. “Ellie and I asked a very simple question: Where does this material come from? And where does it go? As our playground, we chose Tree of Life. Seven years later, here we are.”As for practical applications, Prakash the engineer is already imagining a new era of deployable microscale “living machines” that could transform everything from space telescopes to miniature surgical robots in the operating room.

A side-by-side comparison of Lacrymaria olor, a remarkable ciliate with its “neck” extended and retracted. Researchers discovered origami-like folds make this morphing possible where microtubules define folding pleats. | Prakash Lab

Combining a deep curiosity and “recreational biology,” Stanford researchers have discovered how a simple cell produces remarkably complex behavior, all without a nervous system. It’s origami, they say.

The first example of cellular origami

MIT physicists and colleagues have created a five-lane superhighway for electrons that could allow ultra-efficient electronics and more.&nbsp;The work,&nbsp;<a href="https://www.science.org/doi/10.1126/science.adk9749" target="_blank">reported in the May 10 issue of&nbsp;Science</a>, is one of several important discoveries by the same team over the past year involving a material that is a unique form of&nbsp;<a href="https://news.mit.edu/topic/graphene" target="_blank">graphene</a>.“This discovery has direct implications for low-power electronic devices because no energy is lost during the propagation of electrons, which is not the case in regular materials where the electrons are scattered,” says Long Ju, an assistant professor in the Department of Physics and corresponding author of the&nbsp;Science paper.The phenomenon is akin to cars traveling down an open turnpike as opposed to those moving through neighborhoods. The neighborhood cars can be stopped or slowed by other drivers making abrupt stops or U-turns that disrupt an otherwise smooth commute.<h2>A new material</h2>The material behind this work, known as rhombohedral pentalayer graphene, was discovered two years ago by physicists led by Ju. “We found a goldmine, and every scoop is revealing something new,” says Ju, who is also affiliated with MIT’s Materials Research Laboratory.In a&nbsp;Nature Nanotechnology paper last October, Ju and colleagues&nbsp;<a href="https://news.mit.edu/2023/mit-physicists-turn-pencil-lead-into-gold-1114" target="_blank">reported the discovery</a> of three important properties arising from rhombohedral graphene. For example, they showed that it could be topological, or allow the unimpeded movement of electrons around the edge of the material but not through the middle. That resulted in a superhighway, but required the application of a large magnetic field some tens of thousands times stronger than the Earth’s magnetic field.In the current work, the team reports creating the superhighway without any magnetic field.Tonghang Han, an MIT graduate student in physics, is a co-first author of the paper. “We are not the first to discover this general phenomenon, but we did so in a very different system. And compared to previous systems, ours is simpler and also supports more electron channels.” Explains Ju, “other materials can only support one lane of traffic on the edge of the material. We suddenly bumped it up to five.”Additional co-first authors of the paper who contributed equally to the work are Zhengguang Lu and Yuxuan Yao. Lu is a postdoc in the Materials Research Laboratory. Yao conducted the work as a visiting undergraduate student from Tsinghua University. Other authors are MIT professor of physics Liang Fu;&nbsp;Jixiang Yang and Junseok Seo, both MIT graduate students in physics; Chiho Yoon and Fan Zhang of the University of Texas at Dallas; and Kenji Watanabe and Takashi Taniguchi of the National Institute for Materials Science in Japan.<h2>How it works</h2>Graphite, the primary component of pencil lead, is composed of many layers of graphene, a single layer of carbon atoms arranged in hexagons resembling a honeycomb structure. Rhombohedral graphene is composed of five layers of graphene stacked in a specific overlapping order.Ju and colleagues isolated rhombohedral graphene thanks to a&nbsp;<a href="https://news.mit.edu/2021/custom-made-s-snom-probes-materials-nanoscale-0713" target="_blank">novel microscope</a> Ju built at MIT in 2021 that&nbsp;can quickly and relatively inexpensively determine a variety of important characteristics of a material at the nanoscale. Pentalayer rhombohedral stacked graphene is only a few billionths of a meter thick.In the current work, the team tinkered with the original system, adding a layer of tungsten disulfide (WS2). “The interaction between the WS2&nbsp;and the pentalayer rhombohedral graphene resulted in this five-lane superhighway that operates at zero magnetic field,” says Ju.<h2>Comparison to superconductivity</h2>The phenomenon that the Ju group discovered in rhombohedral graphene that allows electrons to travel with no resistance at zero magnetic field is known as the quantum anomalous Hall effect. Most people are more familiar with superconductivity, a completely different phenomenon that does the same thing but happens in very different materials.Ju notes that although superconductors were discovered in the 1910s, it took some 100 years of research to coax the system to work at the higher temperatures necessary for applications. “And the world record is still well below room temperature,” he notes.Similarly, the rhombohedral graphene superhighway currently operates at about 2 kelvins, or -456 degrees Fahrenheit. “It will take a lot of effort to elevate the temperature, but as physicists, our job is to provide the insight; a different way for realizing this [phenomenon],” Ju says.<h2>Very exciting</h2>The discoveries involving rhombohedral graphene came as a result of painstaking research that wasn’t guaranteed to work. “We tried many recipes over many months,” says Han, “so it was very exciting when we cooled the system to a very low temperature and [a five-lane superhighway operating at zero magnetic field] just popped out.”Says Ju, “it’s very exciting to be the first to discover a phenomenon in a new system, especially in a material that we uncovered.”This work was supported by a Sloan Fellowship; the U.S. National Science Foundation; the U.S. Office of the Under Secretary of Defense for Research and Engineering; the Japan Society for the Promotion of Science KAKENHI; and the World Premier International Research Initiative of Japan.

Artist’s rendition of a newly discovered superhighway for electrons that can occur in rhombohedral graphene. “We found a goldmine, and every scoop is revealing something new,” says MIT Assistant Professor Long Ju. Image: Sampson Wilcox/Research Laboratory of Electronics

The work could lead to ultra-efficient electronics and more.

Physicists create five-lane superhighway for electrons

Imagine a portable 3D printer you could hold in the palm of your hand. The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation.Researchers from MIT and the University of Texas at Austin took a major step toward making this idea a reality by demonstrating the first chip-based 3D printer. Their proof-of-concept device consists of a single, millimeter-scale photonic chip that emits reconfigurable beams of light into a well of resin that cures into a solid shape when light strikes it.The prototype chip has no moving parts, instead relying on an array of tiny optical antennas to steer a beam of light. The beam projects up into a liquid resin that has been designed to rapidly cure when exposed to the beam’s wavelength of visible light.By combining silicon photonics and photochemistry, the interdisciplinary research team was able to demonstrate a chip that can steer light beams to 3D print arbitrary two-dimensional patterns, including the letters M-I-T. Shapes can be fully formed in a matter of seconds.In the long run, they envision a system where a photonic chip sits at the bottom of a well of resin and emits a 3D hologram of visible light, rapidly curing an entire object in a single step.This type of portable 3D printer could have many applications, such as enabling clinicians to create tailor-made medical device components or allowing engineers to make rapid prototypes at a job site.“This system is completely rethinking what a 3D printer is. It is no longer a big box sitting on a bench in a lab creating objects, but something that is handheld and portable. It is exciting to think about the new applications that could come out of this and how the field of 3D printing could change,” says senior author Jelena Notaros, the Robert J. Shillman Career Development Professor in Electrical Engineering and Computer Science (EECS), and a member of the Research Laboratory of Electronics.Joining Notaros on the paper are Sabrina Corsetti, lead author and EECS graduate student; Milica Notaros PhD ’23; Tal Sneh, an EECS graduate student; Alex Safford, a recent graduate of the University of Texas at Austin; and Zak Page, an assistant professor in the Department of Chemical Engineering at UT Austin. The&nbsp;<a href="https://www.nature.com/articles/s41377-024-01478-2" target="_blank">research appears today</a> in&nbsp;Nature Light Science and Applications.<h2>Printing with a chip</h2>Experts in silicon photonics, the Notaros group previously developed integrated optical-phased-array systems that steer beams of light using a series of microscale antennas fabricated on a chip using semiconductor manufacturing processes. By speeding up or delaying the optical signal on either side of the antenna array, they can move the beam of emitted light in a certain direction.Such systems are key for lidar sensors, which map their surroundings by emitting infrared light beams that bounce off nearby objects. Recently, the group has focused on systems that emit and steer visible light for augmented-reality applications.They wondered if such a device could be used for a chip-based 3D printer.At about the same time they started brainstorming, the Page Group at UT Austin demonstrated specialized resins that can be rapidly cured using wavelengths of visible light for the first time. This was the missing piece that pushed the chip-based 3D printer into reality.“With photocurable resins, it is very hard to get them to cure all the way up at infrared wavelengths, which is where integrated optical-phased-array systems were operating in the past for lidar,” Corsetti says. “Here, we are meeting in the middle between standard photochemistry and silicon photonics by using visible-light-curable resins and visible-light-emitting chips to create this chip-based 3D printer. You have this merging of two technologies into a completely new idea.”Their prototype consists of a single photonic chip containing an array of 160-nanometer-thick optical antennas. (A sheet of paper is about 100,000 nanometers thick.) The entire chip fits onto a U.S. quarter.When powered by an off-chip laser, the antennas emit a steerable beam of visible light into the well of photocurable resin. The chip sits below a clear slide, like those used in microscopes, which contains a shallow indentation that holds the resin. The researchers use electrical signals to nonmechanically steer the light beam, causing the resin to solidify wherever the beam strikes it.<h2>A collaborative approach</h2>But effectively modulating visible-wavelength light, which involves modifying its amplitude and phase, is especially tricky. One common method requires heating the chip, but this is inefficient and takes a large amount of physical space.Instead, the researchers used liquid crystal to fashion compact modulators they integrate onto the chip. The material’s unique optical properties enable the modulators to be extremely efficient and only about 20 microns in length.A single waveguide on the chip holds the light from the off-chip laser. Running along the waveguide are tiny taps which tap off a little bit of light to each of the antennas.The researchers actively tune the modulators using an electric field, which reorients the liquid crystal molecules in a certain direction. In this way, they can precisely control the amplitude and phase of light being routed to the antennas.But forming and steering the beam is only half the battle. Interfacing with a novel photocurable resin was a completely different challenge.The Page Group at UT Austin worked closely with the Notaros Group at MIT, carefully adjusting the chemical combinations and concentrations to zero-in on a formula that provided a long shelf-life and rapid curing.In the end, the group used their prototype to 3D print arbitrary two-dimensional shapes within seconds.Building off this prototype, they want to move toward developing a system like the one they originally conceptualized — a chip that emits a hologram of visible light in a resin well to enable volumetric 3D printing in only one step.“To be able to do that, we need a completely new silicon-photonics chip design. We already laid out a lot of what that final system would look like in this paper. And, now, we are excited to continue working towards this ultimate demonstration,” Jelena Notaros says.

The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation. Credit: Sampson Wilcox, RLE

Smaller than a coin, this optical device could enable rapid prototyping on the go.

Researchers demonstrate the first chip-based 3D printer

In this episode, discuss how big of a problem lead contaminated water still is across the world and how a collaboration between MIT & Nanyang University plans to tackle it with a highly accurate and inexpensive water pollution sensor.

Podcast: Is Your Drinking Water Safe? This Sensor Has The Answer

This article was discussed in our <a href="https://www.wevolver.com/profile/the.next.byte" rel="noopener noreferrer" target="_blank">Next Byte podcast</a>.&nbsp;<iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/076af450-88d2-4524-8ec5-df4c5234a282?dark=false" class="fr-draggable" data-lf-form-tracking-inspected-kn9eq4roawkarlvp="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" data-lf-vimeo-playback-inspected-kn9eq4roawkarlvp="true"></iframe> The full article will continue below.<hr>Engineers at MIT, Nanyang Technological University, and several companies have developed a compact and inexpensive technology for detecting and measuring lead concentrations in water, potentially enabling a significant advance in tackling this persistent global health issue.The World Health Organization estimates that 240 million people worldwide are exposed to drinking water that contains unsafe amounts of toxic lead, which can affect brain development in children, cause birth defects, and produce a variety of neurological, cardiac, and other damaging effects. In the United States alone, an estimated 10 million households still get drinking water delivered through lead pipes.<img src="https://images.wevolver.com/eyJidWNrZXQiOiJ3ZXZvbHZlci1wcm9qZWN0LWltYWdlcyIsImtleSI6ImZyb2FsYS8xNzE1NzM1MzgzNjM4LU1JVC1MZWFkLURldGVjdGlvbi0wMi1wcmVzcy5qcGciLCJlZGl0cyI6eyJyZXNpemUiOnsid2lkdGgiOjk1MCwiZml0IjoiY292ZXIifX19" style="width: 100%px;" class="fr-fic fr-dib">Testing setup of the photonic chip sensor, including microfluidic chamber to transport analyte solutions and optical fibers on the sides to measure the photonic response of the chip. Image: Courtesy of the researchers“It’s an unaddressed public health crisis that leads to over 1 million deaths annually,” says Jia Xu Brian Sia, an MIT postdoc and the senior author of the paper describing the new technology.But testing for lead in water requires expensive, cumbersome equipment and typically requires days to get results. Or, it uses simple test strips that simply reveal a yes-or-no answer about the presence of lead but no information about its concentration. Current EPA regulations require drinking water to contain no more that 15 parts per billion of lead, a concentration so low it is difficult to detect.The new system, which could be ready for commercial deployment within two or three years, could detect lead concentrations as low as 1 part per billion, with high accuracy, using a simple chip-based detector housed in a handheld device. The technology gives nearly instant quantitative measurements and requires just a droplet of water.The findings are described in a <a href="https://www.nature.com/articles/s41467-024-47938-6" target="_blank">paper appearing today</a> in the journal Nature Communications, by Sia, MIT graduate student and lead author Luigi Ranno, Professor Juejun Hu, and 12 others at MIT and other institutions in academia and industry.The team set out to find a simple detection method based on the use of photonic chips, which use light to perform measurements. The challenging part was finding a way to attach to the photonic chip surface certain ring-shaped molecules known as crown ethers, which can capture specific ions such as lead. After years of effort, they were able to achieve that attachment via a chemical process known as Fischer esterification. “That is one of the essential breakthroughs we have made in this technology,” Sia says.In testing the new chip, the researchers showed that it can detect lead in water at concentrations as low as one part per billion. At much higher concentrations, which may be relevant for testing environmental contamination such as mine tailings, the accuracy is within 4 percent.The device works in water with varying levels of acidity, ranging from pH values of 6 to 8, “which covers most environmental samples,” Sia says. They have tested the device with seawater as well as tap water, and verified the accuracy of the measurements.In order to achieve such levels of accuracy, current testing requires a device called an inductive coupled plasma mass spectrometer. “These setups can be big and expensive,” Sia says. The sample processing can take days and requires experienced technical personnel.While the new chip system they developed is “the core part of the innovation,” Ranno says, further work will be needed to develop this into an integrated, handheld device for practical use. “For making an actual product, you would need to package it into a usable form factor,” he explains. This would involve having a small chip-based laser coupled to the photonic chip. “It’s a matter of mechanical design, some optical design, some chemistry, and figuring out the supply chain,” he says. While that takes time, he says, the underlying concepts are straightforward.The system can be adapted to detect other similar contaminants in water, including cadmium, copper, lithium, barium, cesium, and radium, Ranno says. The device could be used with simple cartridges that can be swapped out to detect different elements, each using slightly different crown ethers that can bind to a specific ion.“There’s this problem that people don’t measure their water enough, especially in the developing countries,” Ranno says. “And that’s because they need to collect the water, prepare the sample, and bring it to these huge instruments that are extremely expensive.” Instead, “having this handheld device, something compact that even untrained personnel can just bring to the source for on-site monitoring, at low costs,” could make regular, ongoing widespread testing feasible.Hu, who is the John F. Elliott Professor of Materials Science and Engineering, says, “I’m hoping this will be quickly implemented, so we can benefit human society. This is a good example of a technology coming from a lab innovation where it may actually make a very tangible impact on society, which is of course very fulfilling.”“If this study can be extended to simultaneous detection of multiple metal elements, especially the presently concerning radioactive elements, its potential would be immense,” says Hou Wang, an associate professor of environmental science and engineering at Hunan University in China, who was not associated with this work.Wang adds, “This research has engineered a sensor capable of instantaneously detecting lead concentration in water. This can be utilized in real-time to monitor the lead pollution concentration in wastewater discharged from industries such as battery manufacturing and lead smelting, facilitating the establishment of industrial wastewater monitoring systems. I think the innovative aspects and developmental potential of this research are quite commendable.”Wang Qian, a principal research scientist at the Institute of Materials Research in Singapore, who also was not affiliated with this work, says, “The ability for the pervasive, portable, and quantitative detection of lead has proved to be challenging primarily due to cost concerns. This work demonstrates the potential to do so in a highly integrated form factor and is compatible with large-scale, low-cost manufacturing.”The team included researchers at MIT, at Nanyang Technological University and Temasek Laboratories in Singapore, at the University of Southampton in the U.K., and at companies Fingate Technologies, in Singapore, and Vulcan Photonics, headquartered in Malaysia. The work used facilities at MIT.nano, the Harvard University Center for Nanoscale Systems, NTU’s Center for Micro- and Nano-Electronics, and the Nanyang Nanofabrication Center.

Artist’s impression of the chip surface, showing the on-chip light interferometer used to sense the presence of lead. The lead binding process to the crown ether is shown in the inset. Image: Jia Xu Brian Sia

The chip-scale device could provide sensitive detection of lead levels in drinking water, whose toxicity affects 240 million people worldwide.

Scientists develop an affordable sensor for lead contamination

<section id="isPasted">What do volcanic lava, fire smoke, automobile exhaust fumes, and printer toner have in common? They are all sources of ultrafine particles – particles with a diameter below 100 nanometers, which can pose serious health risks if inhaled. Due to their small size, ultrafine nanoparticles are difficult to detect and measure without expensive and sometimes bulky equipment. To overcome these issues, our researchers have designed a new ultra-sensitive fiber-tip sensor that can detect single particles with diameters down to 50 nanometers in size. In the future, the new sensor will be used in studies to control and evaluate indoor air quality at schools.</section><section tabindex="-1">Nanoparticles are very much part of the everyday world that we call home. For example, in medical testing, devices are available to check for nanoparticles like pathogens and biomarkers for diseases such as cancer.And in drug development, a host of nanoparticles are used to make the drug delivery systems of the future.One class of nanoparticle that is garnering plenty of attention due to its connection with the air that we breathe is the ultrafine particle (UFP), a particle with a diameter below 100 nanometers (nm).Exposure to UFPs – which can be found in smoke, exhaust fumes, and even printer toners – can have serious health risks, especially if these particles are directly inhaled.<section tabindex="-1" id="isPasted">“When UFPs lodge in the lungs, it can pose a severe health risk because once in the lungs, they can absorb toxins that we might breathe in from the air around us. As a result, those toxins then stay in the body,” says <a href="https://www.tue.nl/en/research/researchers/arthur-hendriks" target="_blank">Arthur Hendriks</a>, PhD researcher at the Department of Applied Physics and Science Education. “So, to help prevent this, accurate ways of detecting UFPs are needed so as to monitor indoor air quality.”For example, research on indoor air quality is at the forefront of the <a href="https://www.learnproject-heu.eu/" target="_blank" rel="noreferrer">Horizon Europe project LEARN</a>, which is seeking to control and evaluate indoor air quality at schools and to assess the impact of air quality on children’s health, and part of this requires accurate ways to detect UFPs.<h3>The small-big problem</h3>But detecting UFPs is easier said than done though, and ironically, detection of such small particles relies on the use of large and expensive equipment.“Large and expensive isn’t the answer. We need small, compact, accurate, and cheap devices to make it easier to detect UFPs in factories, hospitals, offices, and schools,” notes Hendriks.</section><section tabindex="-1">So, what is the state-of-the-art now then? “There are sensors based on fiber-optic technologies that can measure liquids and gases with good accuracy. But these sensors not suitable for measuring small particles like UFPs and so their application are limited in that sense,” says Hendriks.&nbsp;‘Lab-on-fiber’ technologies have been used to detect biological cells at the micrometer scale (1000 times larger than the nanometer scale). “But this technology cannot detect single nanoparticles similar in size to UFPs,” says Hendriks.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1714987151109-csm_Hendriks+Nanophotonic-fiber-tip-sensor_5fc4f58556.png" style="width: 100%px;" class="fr-fic fr-dib">SEM image of nanophotonic fiber tip sensor. Source: Arthur Hendriks<h3 id="isPasted">A fiber-tip solution</h3>To meet the demand for a new UFP sensing technology, Hendriks and his TU/e collaborators, which includes Andrea Fiore – professor at the Department of Applied Physics and Science Education, developed a nanophotonic fiber-tip sensor that is sensitive to tiny changes in the environment around the sensor, so much so that it can detect a single nanoparticle the same size as UFPs.“Our sensor design is small and compact, and importantly, it clearly indicates when a detection has occurred,” says Hendriks.The researchers’ sensor work is based on a photonic crystal, a periodic or repeating structure that can reflect light in all directions. “A defect, or error, is then added to the crystal, which is known as a photonic crystal cavity, or PhCC for short,” says Hendriks.A PhCC allows light to be trapped in the crystal for an extended period. Hendriks: “In essence, this is something we call the Q-factor, which is a measure of how well light can be trapped in the defect over time. In our case, the light is confined to a tiny volume, which is below 1 µm3. This is known as the mode volume, and to measure tiny nanoparticles, this needs to be very small.”The researchers were able to place the PhCC on the tip of a fiber using a method developed by Andrea Fiore’s group <a href="https://doi.org/10.1063/5.0021701" target="_blank" rel="noreferrer">back in 2020</a>. When a tiny particle comes close to the PhCC in the crystal, it disturbs the cavity by changing its refractive index. “So, the tiny particle changes the wavelength of the trapped light in the cavity, and we measure this change.”<h2 id="isPasted">CHALLENGES</h2><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1714987186281-csm_Hendriks+Schematic_3e24cc23c3.png" style="width: 100%px;" class="fr-fic fr-dib">The major challenge faced by the researchers was that standard cavities cannot be read out using fibers. A standard cavity on a fiber wouldn’t have worked as light from the fiber will not couple to the cavity.The dream scenario for the researchers was to optimize key factors in the device. First, a high Q-factor was required to allow for more accurate tracking of the wavelength of the cavity. Second, a small mode volume was needed as this allows for the detection of smaller particles. Third, a higher coupling efficiency was a necessity to ensure that light from the fiber can couple to the cavity and back, making it possible to measure the cavity wavelength through the fiber.To solve all these challenges, the researchers used a method developed by researchers at Stanford University to optimize factors such as the Q-factor, mode volume, and coupling efficiency at the same time.<h3 id="isPasted">Unprecedented sensitivity</h3>“Our setup provides unprecedented sensitivity in comparison to previous technologies out there,” points out Hendriks. “Using the sensor, we were able to detect in real-time single UFPs with diameters as low as 50 nanometers. In my opinion, that’s just astounding!”The next step for Hendriks and his colleagues is to suspend the cavities so that the quality factor and the coupling efficiency are even higher, which could result in nanophotonic cavities with best-in-class characteristics, but still readable through the fiber.“Our approach could be used to detect even smaller particles. Or even in other applications like single-photon emitters and nano-optomechanical sensors,” says Hendriks. “And an additional application of the new approach might even be the detection of single biological molecules.”Next up for the UFP sensor will be the European project LEARN, which aims at controlling and evaluating air quality at schools, and it will be done in collaboration with the Microsystems group at TU/e.<hr><h3>Further information</h3>The full paper entitled “Detecting single nanoparticles using fiber-tip nanophotonics” can be read&nbsp;<a href="https://opg.optica.org/optica/fulltext.cfm?uri=optica-11-4-512&id=549037" target="_blank" rel="noreferrer">here</a>.</section></section>

Using an ultrasensitive photonic crystal, TU/e researchers were able to detect single particles down to 50 nanometers in diameter. The new research has just been published in the journal Optica.