Researchers in the US and Korea have created nanoparticles with carefully designed “patches” on their surfaces using a new atomic stencilling technique. These patches can be controlled with incredible precision, and could find use in targeted drug delivery, catalysis, microelectronics and tissue engineering.

The first step in the stencilling process is to create a mask on the surface of gold nanoparticles. This mask prevents a “paint” made from grafted-on polymers from attaching to certain areas of the nanoparticles.

“We then use iodide ions as a stencil,” explains Qian Chen, a materials scientist and engineer at the University of Illinois at Urbana-Champaign, US, who led the new research effort. “These adsorb (stick) to the surface of the nanoparticles in specific patterns that depend on the shape and atomic arrangement of the nanoparticles’ facets. That’s how we create the patches – the areas where the polymers selectively bind.” Chen adds that she and her collaborators can then tailor the surface chemistry of these tiny patchy nanoparticles in a very controlled way.

A gap in the field of microfabrication stencilling

The team decided to develop the technique after realizing there was a gap in the field of microfabrication stencilling. While techniques in this area have advanced considerably in recent years, allowing ever-smaller microdevices to be incorporated into ever-faster computer chips, most of them rely on top-down approaches for precisely controlling nanoparticles. By comparison, Chen says, bottom-up methods have been largely unexplored even though they are low-cost, solution-processable, scalable and compatible with complex, curved and three-dimensional surfaces.

Reporting their work in Nature, the researchers say they were inspired by the way proteins naturally self-assemble. “One of the holy grails in the field of nanomaterials is making complex, functional structures from nanoscale building blocks,” explains Chen. “It’s extremely difficult to control the direction and organization of each nanoparticle. Proteins have different surface domains, and thanks to their interactions with each other, they can make all the intricate machines we see in biology. We therefore adopted that strategy by creating patches or distinct domains on the surface of the nanoparticles.”

“Elegant and impressive”

Philip Moriarty, a physicist of the University of Nottingham, UK who was not involved in the project, describes it as “elegant and impressive” work. “Chen and colleagues have essentially introduced an entirely new mode of self-assembly that allows for much greater control of nanoparticle interactions,” he says, “and the ‘atomic stencil’ concept is clever and versatile.”

The team, which includes researchers at the University of Michigan, Pennsylvania State University, Cornell, Brookhaven National Laboratory and Korea’s Chonnam National University as well as Urbana-Champaign, agrees that the potential applications are vast. “Since we can now precisely control the surface properties of these nanoparticles, we can design them to interact with their environment in specific ways,” explains Chen. “That opens the door for more effective drug delivery, where nanoparticles can target specific cells. It could also lead to new types of catalysts, more efficient microelectronic components and even advanced materials with unique optical and mechanical properties.”

She and her colleagues say they now want to extend their approach to different types of nanoparticles and different substrates to find out how versatile it truly is. They will also be developing computational models that can predict the outcome of the stencilling process – something that would allow them to design and synthesize patchy nanoparticles for specific applications on demand.

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Policy drops “paylines” based on peer-review scores and requires geography and other factors to guide approvals

An order for Oman’s first geostationary communications satellite has lifted the global tally for this year to six, matching all of 2024 with a month still to go but still well below the industry’s former double-digit annual pace.

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Learn about the recent eruption of Hayli Gubbi, a volcano in Ethiopia that was previously dormant for nearly 12,000 years. 

Learn about how humans and golden retrievers share genetic traits that make us more likely to experience fear, anxiety, and embarrassment.

Learn more about whooping cough and how a decline in vaccination rates may be contributing to a spike in cases.

Discover how scientists have used iron isotopes to determine the likely origin of the Mars-sized planet named Theia.

Learn how tight clustering helps Madagascar’s hissing cockroaches conserve water during dry spells, offering new insight into how even large insects cope with environmental stress.

Learn more about how AI is helping researchers map the seismic activity around volcanoes. 

The studies may still hold clues to the powers and limits of GLP-1 drugs

World Health Organization supports “spatial repellents” to prevent malaria, but it’s unclear who will pay for them

NASA has revised its commercial crew contract with Boeing, reducing the number of Starliner missions to four, the first of which will carry only cargo.

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Discover how wolves in British Columbia are using crab traps to reel in food.

Learn how newly discovered vertebrae from a 6- to 8-meter shark pushes the origin of mega-predators back by 15 million years.

The $330m Jiangmen Underground Neutrino Observatory (JUNO) has released its first results following the completion of the huge underground facility in August.

JUNO is located in Kaiping City, Guangdong Province, in the south of the country around 150 km west of Hong Kong.

Construction of the facility began in 2015 and was set to be complete some five years later. Yet the project suffered from serious flooding, which delayed construction.

JUNO, which is expected to run for more than 30 years, aims to study the relationship between the three types of neutrino: electron, muon and tau. Although JUNO will be able to detect neutrinos produced by supernovae as well as those from Earth, the observatory will mainly measure the energy spectrum of electron antineutrinos released by the Yangjiang and Taishan nuclear power plants, which both lie 52.5 km away.

To do this, the facility has a 80 m high and 50 m diameter experimental hall located 700 m underground. Its main feature is a 35 m radius spherical neutrino detector, containing 20,000 tonnes of liquid scintillator. When an electron antineutrino occasionally bumps into a proton in the liquid, it triggers a reaction that results in two flashes of light that are detected by the 43,000 photomultiplier tubes that observe the scintillator.

On 18 November, a paper was submitted to the arXiv preprint server concluding that the detector’s key performance indicators fully meet or surpass design expectations.

New measurement 

Neutrinos oscillate from one flavour to another as they travel near the speed of light, rarely interacting with matter. This oscillation is a result of each flavour being a combination of three neutrino mass states.

Yet scientists do not know the absolute masses of the three neutrinos but can measure neutrino oscillation parameters, known as θ₁₂, θ₂₃ and θ₁₃, as well as the square of the mass differences (Δm²) between two different types of neutrinos.

A second JUNO paper submitted on 18 November used data collected between 26 August and 2 November to measure the solar neutrino oscillation parameter θ₁₂ and Δm²₂₁ with a factor of 1.6 better precision than previous experiments.

Those earlier results, which used solar neutrinos instead of reactor antineutrinos, showed a 1.5 “sigma” discrepancy with the Standard Model of particle physics. The new JUNO measurements confirmed this difference, dubbed the solar neutrino tension, but further data will be needed to prove or disprove the finding.

“Achieving such precision within only two months of operation shows that JUNO is performing exactly as designed,” says Yifang Wang from the Institute of High Energy Physics of the Chinese Academy of Sciences, who is JUNO project manager and spokesperson. “With this level of accuracy, JUNO will soon determine the neutrino mass ordering, test the three-flavour oscillation framework, and search for new physics beyond it.”

JUNO, which is an international collaboration of more than 700 scientists from 75 institutions across 17 countries including China, France, Germany, Italy, Russia, Thailand, and the US, is the second neutrino experiment in China, after the Daya Bay Reactor Neutrino Experiment. It successfully measured a key neutrino oscillation parameter called θ₁₃ in 2012 before being closed down in 2020.

JUNO is also one of three next-generation neutrino experiments, the other two being the Hyper-Kamiokande in Japan and the Deep Underground Neutrino Experiment in the US. Both are expected to become operational later this decade.

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New experiments at CERN by an international team have ruled out a potential source of intergalactic magnetic fields. The existence of such fields is invoked to explain why we do not observe secondary gamma rays originating from blazars.

Led by Charles Arrowsmith at the UK’s University of Oxford, the team suggests the absence of gamma rays could be the result of an unexplained phenomenon that took place in the early universe.

A blazar is an extraordinarily bright object with a supermassive black hole at its core. Some of the matter falling into the black hole is accelerated outwards in a pair of opposing jets, creating intense beams of radiation. If a blazar jet points towards Earth, we observe a bright source of light including high-energy teraelectronvolt gamma rays.

During their journey across intergalactic space, these gamma-ray photons will occasionally collide with the background starlight that permeates the universe. These collisions can create cascades of electrons and positrons that can then scatter off photons to create gamma rays in the gigaelectronvolt energy range. These gamma-rays should travel in the direction of the original jet, but this secondary radiation has never been detected.

Deflecting field

Magnetic fields could be the reason for this dearth, as Arrowsmith explains: “The electrons and positrons in the pair cascade would be deflected by an intergalactic magnetic field, so if this is strong enough, we could expect these pairs to be steered away from the line of sight to the blazar, along with the reprocessed gigaelectronvolt gamma rays.” It is not clear, however, that such fields exist – and if they do, what could have created them.

Another explanation for the missing gamma rays involves the extremely sparse plasma that permeates intergalactic space. The beam of electron–positron pairs could interact with this plasma, generating magnetic fields that separate the pairs. Over millions of years of travel, this process could lead to beam–plasma instabilities that reduce the beam’s ability to create gigaelectronvolt gamma rays that are focused on Earth.

Oxford’s Gianluca Gregori  explains, “We created an experimental platform at the HiRadMat facility at CERN to create electron–positron pairs and transport them through a metre-long ambient argon plasma, mimicking the interaction of pair cascades from blazars with the intergalactic medium”. Once the pairs had passed through the plasma, the team measured the degree to which they had been separated.

Tightly focused

Called Fireball, the experiment found that the beams remained far more tightly focused than expected. “When these laboratory results are scaled up to the astrophysical system, they confirm that beam–plasma instabilities are not strong enough to explain the absence of the gigaelectronvolt gamma rays from blazars,” Arrowsmith explains. Unless the pair beam is perfectly collimated, or composed of pairs with exactly equal energies, instabilities were actively suppressed in the plasma.

While the experiment suggests that an intergalactic magnetic field remains the best explanation for the lack of gamma rays, the mystery is far from solved. Gregori explains, “The early universe is believed to be extremely uniform – but magnetic fields require electric currents, which in turn need gradients and inhomogeneities in the primordial plasma.” As a result, confirming the existence of such a field could point to new physics beyond the Standard Model, which may have dominated in the early universe.

More information could come with opening of the Cherenkov Telescope Array Observatory. This will comprise ground-based gamma-ray detectors planned across facilities in Spain and Chile, which will vastly improve on the resolutions of current-generation detectors.

The research is described in PNAS.

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Amazon has unveiled the final production version of Leo Ultra, the company’s highest-performing enterprise terminal for the satellite broadband constellation it aims to bring into service next year.

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Star Wars is back in vogue with President Trump’s executive order to establish the “Golden Dome” missile defense shield. It will feature an ambitious space-based boost-phase interceptor program in addition to terrestrial systems. While admittedly the holy grail of defense against ballistic missiles, the obstacles that plagued its discontinued predecessor, “Brilliant Pebble,” under the Strategic […]

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China conducted a pair of launches last week, adding new spacecraft to its opaque TJS and Shijian satellite series.

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In this episode of Space Minds, Senior Staff Writer Jeff Foust moderates a panel at the Johns Hopkins University Bloomberg Center, the next installment of the Center’s Discovery Series.

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What skills do you use every day in your job?

One thing I can say for sure that I got from working in academia is the ability to quickly read, summarize and internalize information from a bunch of sources. Journalism requires a lot of that. Being able to skim through papers – reading the abstract, reading the conclusion, picking the right bits from the middle and so on – that is a life skill.

In terms of other skills, I’m always considering who’s consuming what I’m doing rather than just thinking about how I’d like to say something. You have to think about how it’s going to be received – what’s the person on the street going to hear? Is this clear enough? If I were hearing this for the first time, would I understand it? Putting yourself in someone else’s shoes – be it the listener, reader or viewer – is a skill I employ every day.

What do you like best and least about your job?

The best thing is the variety. I ended up in this business and not in scientific research because of a desire for a greater breadth of experience. And boy, does this job have it. I get to talk to people around the world about what they’re up to, what they see, what it’s like, and how to understand it. And I think that makes me a much more informed person than I would be had I chosen to remain a scientist.

When I did research – and even when I was a science journalist – I thought “I don’t need to think about what’s going on in that part of the world so much because that’s not my area of expertise.” Now I have to, because I’m in this chair every day. I need to know about lots of stuff, and I like that feeling of being more informed.

I suppose what I like the least about my job is the relentlessness of it. It is a newsy time. It’s the flip side of being well informed, you’re forced to confront lots of bad things – the horrors that are going on in the world, the fact that in a lot of places the bad guys are winning.

What do you know today that you wish you knew when you were starting out in your career?

When I started in science journalism, I wasn’t a journalist – I was a scientist pretending to be one. So I was always trying to show off what I already knew as a sort of badge of legitimacy. I would call some professor on a topic that I wasn’t an expert in yet just to have a chat to get up to speed, and I would spend a bunch of time showing off, rabbiting on about what papers I’d read and what I knew, just to feel like I belonged in the room or on that call. And it’s a waste of time. You have to swallow your ego and embrace the idea that you may sound like you don’t know stuff even if you do. You might sound dumber, but that’s okay – you’ll learn more and faster, and you’ll probably annoy people less.

In journalism in particular, you don’t want to preload the question with all of the things that you already know because then the person you’re speaking to can fill in those blanks – and they’re probably going to talk about things you didn’t know you didn’t know, and take your conversation in a different direction.

It’s one of the interesting things about science in general. If you go into a situation with experts, and are open and comfortable about not knowing it all, you’re showing that you understand that nobody can know everything and that science is a learning process.

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Col. Brian Chatman: The volume is here to stay. The next step is making sure the infrastructure can keep up

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A new German military space policy outlines the ambitions the country has fueled by tens of billions of euros of new spending over the next several years.

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Recent findings reveal that even simple pricing algorithms can make things more expensive.