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Unconventional Superconductor May Unlock New Ways To Build Quantum Computers

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If it looks like a duck, swims like a duck and quacks like a duck, then it probably is a duck.

Scientists on the hunt for an unconventional kind of superconductor have produced the most compelling evidence to date that they’ve found one. In a pair of papers, researchers at the University of Maryland’s (UMD) Quantum Materials Center (QMC) and colleagues have shown that uranium ditelluride (or UTe2 for short) displays many of the hallmarks of a topological superconductor — a material that may unlock new ways to build quantum computers and other futuristic devices.

“Nature can be wicked,” says Johnpierre Paglione, a professor of physics at UMD, the director of QMC and senior author on one of the papers. “There could be other reasons we’re seeing all this wacky stuff, but honestly, in my career, I’ve never seen anything like it.”

All superconductors carry electrical currents without any resistance. It’s kind of their thing. The wiring behind your walls can’t rival this feat, which is one of many reasons that large coils of superconducting wires and not normal copper wires have been used in MRI machines and other scientific equipment for decades.

Topological Superconductor Crystals

Crystals of a promising topological superconductor grown by researchers at the University of Maryland’s Quantum Materials Center. Credit: Sheng Ran/NIST

But superconductors achieve their super-conductance in different ways. Since the early 2000s, scientists have been looking for a special kind of superconductor, one that relies on an intricate choreography of the subatomic particles that actually carry its current.

This choreography has a surprising director: a branch of mathematics called topology. Topology is a way of grouping together shapes that can be gently transformed into one another through pushing and pulling. For example, a ball of dough can be shaped into a loaf of bread or a pizza pie, but you can’t make it into a donut without poking a hole in it. The upshot is that, topologically speaking, a loaf and a pie are identical, while a donut is different. In a topological superconductor, electrons perform a dance around each other while circling something akin to the hole in the center of a donut.

Unfortunately, there’s no good way to slice a superconductor open and zoom in on these electronic dance moves. At the moment, the best way to tell whether or not electrons are boogieing on an abstract donut is to observe how a material behaves in experiments. Until now, no superconductor has been conclusively shown to be topological, but the new papers show that UTe2 looks, swims and quacks like the right kind of topological duck.

One study, by Paglione’s team in collaboration with the group of Aharon Kapitulnik at Stanford University, reveals that not one but two kinds of superconductivity exist simultaneously in UTe2. Using this result, as well as the way light is altered when it bounces off the material (in addition to previously published experimental evidence), they were able to narrow down the types of superconductivity that are present to two options, both of which theorists believe are topological. They published their findings on July 15, 2021, in the journal Science.

In another study, a team led by Steven Anlage, a professor of physics at UMD and a member of QMC, revealed unusual behavior on the surface of the same material. Their findings are consistent with the long-sought-after phenomenon of topologically protected Majorana modes. Majorana modes, exotic particles that behave a bit like half of an electron, are predicted to arise on the surface of topological superconductors. These particles particularly excite scientists because they might be a foundation for robust quantum computers. Anlage and his team reported their results in a paper published May 21, 2021 in the journal Nature Communications.

Superconductors only reveal their special characteristics below a certain temperature, much like water only freezes below zero Celsius. In normal superconductors, electrons pair up into a two-person conga line, following each other through the metal. But in some rare cases, the electron couples perform a circular dance around each other, more akin to a waltz. The topological case is even more special — the circular dance of the electrons contains a vortex, like the eye amidst the swirling winds of a hurricane. Once electrons pair up in this way, the vortex is hard to get rid of, which is what makes a topological superconductor distinct from one with a simple, fair-weather electron dance.

Back in 2018, Paglione’s team, in collaboration with the team of Nicholas Butch, an adjunct associate professor of physics at UMD and a physicist at the National Institute of Standards and Technology (NIST), unexpectedly discovered that UTe2 was a superconductor. Right away, it was clear that it wasn’t your average superconductor. Most notably, it seemed unphased by large magnetic fields, which normally destroy superconductivity by splitting up the electron dance couples. This was the first clue that the electron pairs in UTe2 hold onto each other more tightly than usual, likely because their paired dance is circular. This garnered a lot of interest and further research from others in the field.

“It’s kind of like a perfect storm superconductor,” says Anlage. “It’s combining a lot of different things that no one’s ever seen combined before.”

In the new Science paper, Paglione and his collaborators reported two new measurements that reveal the internal structure of UTe2. The UMD team measured the material’s specific heat, which characterizes how much energy it takes to heat it up by one degree. They measured the specific heat at different starting temperatures and watched it change as the sample became superconducting.

“Normally there’s a big jump in specific heat at the superconducting transition,” says Paglione. “But we see that there’s actually two jumps. So that’s evidence of actually two superconducting transitions, not just one. And that’s highly unusual.”

The two jumps suggested that electrons in UTe2 can pair up to perform either of two distinct dance patterns.

In a second measurement, the Stanford team shone laser light onto a piece of UTe2 and noticed that the light reflecting back was a bit twisted. If they sent in light bobbing up and down, the reflected light bobbed mostly up and down but also a bit left and right. This meant something inside the superconductor was twisting up the light and not untwisting it on its way out.

Kapitulnik’s team at Stanford also found that a magnetic field could coerce UTe2 into twisting light one way or the other. If they applied a magnetic field pointing up as the sample became superconducting, the light coming out would be tilted to the left. If they pointed the magnetic field down, the light tilted to the right. This told that researchers that, for the electrons dancing inside the sample, there was something special about the up and down directions of the crystal.

To sort out what all this meant for the electrons dancing in the superconductor, the researchers enlisted the help of Daniel F. Agterberg, a theorist and professor of physics at the University of Wisconsin-Milwaukee and a co-author of the Science paper. According to the theory, the way uranium and tellurium atoms are arranged inside the UTe2 crystal allows electron couples to team up in eight different dance configurations. Since the specific heat measurement shows that two dances are going on at the same time, Agterberg enumerated all the different ways to pair these eight dances together. The twisted nature of the reflected light and the coercive power of a magnetic field along the up-down axis cut the possibilities down to four. Previous results showing the robustness of UTe2’s superconductivity under large magnetic fields further constrained it to only two of those dance pairs, both of which form a vortex and indicate a stormy, topological dance.

“What’s interesting is that given the constraints of what we’ve seen experimentally, our best theory points to a certainty that the superconducting state is topological,” says Paglione.

If the nature of superconductivity in a material is topological, the resistance will still go to zero in the bulk of the material, but on the surface something unique will happen: Particles, known as Majorana modes, will appear and form a fluid that is not a superconductor. These particles also remain on the surface despite defects in the material or small disruptions from the environment. Researchers have proposed that, thanks to the unique properties of these particles, they might be a good foundation for quantum computers. Encoding a piece of quantum information into several Majoranas that are far apart makes the information virtually immune to local disturbances that, so far, have been the bane of quantum computers.

Anlage’s team wanted to probe the surface of UTe2 more directly to see if they could spot signatures of this Majorana sea. To do that, they sent microwaves towards a chunk UTe2, and measured the microwaves that came out on the other side. They compared the output with and without the sample, which allowed them to test properties of the bulk and the surface simultaneously.

The surface leaves an imprint on the strength of the microwaves, leading to an output that bobs up and down in sync with the input, but slightly subdued. But since the bulk is a superconductor, it offers no resistance to the microwaves and doesn’t change their strength. Instead, it slows them down, causing delays that make the output bob up and down out of sync with the input. By looking at the out-of-sync parts of the response, the researchers determined how many of the electrons inside the material participate in the paired dance at various temperatures. They found that the behavior agreed with the circular dances suggested by Paglione’s team.

Perhaps more importantly, the in-sync part of the microwave response showed that the surface of UTe2 isn’t superconducting. This is unusual, since superconductivity is usually contagious: Putting a regular metal close to a superconductor spreads superconductivity to the metal. But the surface of UTe2 didn’t seem to catch superconductivity from the bulk — just as expected for a topological superconductor — and instead responded to the microwaves in a way that hasn’t been seen before.

“The surface behaves differently from any superconductor we’ve ever looked at,” Anlage says. “And then the question is ‘What’s the interpretation of that anomalous result?’ And one of the interpretations, which would be consistent with all the other data, is that we have this topologically protected surface state that is kind of like a wrapper around the superconductor that you can’t get rid of.”

It might be tempting to conclude that the surface of UTe2 is covered with a sea of Majorana modes and declare victory. However, extraordinary claims require extraordinary evidence. Anlage and his group have tried to come up with every possible alternative explanation for what they were observing and systematically ruled them out, from oxidization on the surface to light hitting the edges of the sample. Still, it is possible a surprising alternative explanation is yet to be discovered.

“In the back of your head you’re always thinking ‘Oh, maybe it was cosmic rays’, or ‘Maybe it was something else,’” says Anlage. “You can never 100% eliminate every other possibility.”

For Paglione’s part, he says the smoking gun will be nothing short of using surface Majorana modes to perform a quantum computation. However, even if the surface of UTe2 truly has a bunch of Majorana modes, there’s currently no straightforward way to isolate and manipulate them. Doing so might be more practical with a thin film of UTe2 instead of the (easier to produce) crystals that were used in these recent experiments.

“We have some proposals to try to make thin films,” Paglione says. “Because it’s uranium and it’s radioactive, it requires some new equipment. The next task would be to actually try to see if we can grow films. And then the next task would be to try to make devices. So that would require several years, but it’s not crazy.”

Whether UTe2 proves to be the long-awaited topological superconductor or just a pigeon that learned to swim and quack like a duck, both Paglione and Anlage are excited to keep finding out what the material has in store.

“It’s pretty clear though that there’s a lot of cool physics in the material,” Anlage says. “Whether or not it’s Majoranas on the surface is certainly a consequential issue, but it’s exploring novel physics which is the most exciting stuff.”

Reference: “Anomalous normal fluid response in a chiral superconductor UTe2” by Seokjin Bae, Hyunsoo Kim, Yun Suk Eo, Sheng Ran, I-lin Liu, Wesley T. Fuhrman, Johnpierre Paglione, Nicholas P. Butch and Steven M. Anlage, 11 May 2021, Nature Communications.
DOI: 10.1038/s41467-021-22906-6

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Researchers reconfigure material topology at microscale

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Encrypted Harvard Shield

The researchers encoded the patterns and designs in the material, making tiny, invisible changes to the geometry of the triangular lattice. Credit: Image courtesy of Shukong Lee / Bolei Deng / Harvard SEAS.

Reconfigurable materials can do amazing things. Flat sheets turn to faceExtruded cube transforms into dozens of different shapes… But there is one thing that a reconfigurable material cannot change yet: its underlying topology. A 100 cell reconfigurable material will always have 100 cells, even if those cells are stretched or compressed.

Now researchers at the Harvard School of Engineering and Applied Sciences. John A. Paulson (SEAS) developed a method for altering the fundamental topology of cellular material at the microscale. Research published in Nature

“The creation of cellular structures that can dynamically change their topology will open up new possibilities in the development of active materials with information encryption, selective particle capture, and customizable mechanical, chemical and acoustic properties,” said Joanna Eisenberg, professor of materials science Amy Smith Berilson. at SEAS, professor of chemistry and chemical biology and senior article author.

Triangle material topology

Hexagon material topology

Researchers have developed a method for altering the fundamental topology of a cellular material at the microscale, paving the way for active materials with tunable mechanical, chemical and acoustic properties. Credit: Images courtesy of Shukong Lee / Bolei Deng / Harvard SEAS.

The researchers used the same physics that binds our hair when it gets wet – capillary force. Capillary force works well on soft, pliable material like our hair, but it fights tough cellular structures that require bending, stretching, or folding, especially around strong, connected knots. Capillary force is also temporary as materials tend to return to their original configuration after drying.

To develop a durable but reversible method for transforming the topology of rigid cellular microstructures, the researchers developed a two-tier dynamic strategy. They started with a rigid polymer honeycomb microstructure with a triangular lattice topology and exposed it to droplets of a volatile solvent chosen to swell and soften the polymer at the molecular level. This made the material temporarily more flexible, and in this flexible state, the capillary forces created by the evaporating liquid brought the edges of the triangles closer together, changing their bonds with each other and turning them into hexagons. Then, as the solvent quickly evaporated, the material dried out and was trapped in its new configuration, regaining its stiffness. The whole process took a matter of seconds.

“When you think about applications, it is very important not to lose the mechanical properties of the material after the transformation process,” said Shukong Lee, a graduate student at Eisenberg’s lab and co-author of the paper. “Here we have shown that we can start with a hard material and end with a hard material while temporarily softening it during the reconfiguration phase.”

Assembly of microstructures

Microstructure assembly video. A liquid acts on the triangular lattice, which swells and softens the polymer. In this flexible state, the capillary forces created by the evaporating liquid brought the edges of the triangles closer together, changing their bonds with each other and turning them into hexagons. Credit: Video courtesy of Shukong Lee / Bolei Deng / Harvard SEAS

The new material topology is so strong that it can withstand heat or immersion in some fluids for days without disassembly. Its reliability actually posed a problem for researchers who hoped to make the conversion reversible.

To go back to the original topology, the researchers developed a method for combining two fluids. The former temporarily enlarges the lattice, which causes the adhering walls of the hexagons to flake off and allows the lattice to return to its original triangular structure. The second, less volatile liquid delays the emergence of capillary forces until the first liquid evaporates and the material regains its rigidity. Thus, structures can be repeatedly assembled and disassembled and held in any intermediate configuration.

Disassembly of microstructures

Video of disassembly of microstructures. The first one temporarily swells the lattice, which peels off the adhered walls. The second, less volatile liquid delays the emergence of capillary forces until the first liquid evaporates and the material regains its rigidity. Credit: Video courtesy of Shukong Lee / Bolei Deng / Harvard SEAS

“To expand our approach to arbitrary lattices, it was important to develop a generalized theoretical model that links cell geometry, material stiffness, and capillary forces,” said Bolei Deng, paper co-author and graduate student at Katya Bertholdi’s laboratory, William and Ami Kuan Danoff Professor of Applied Mechanics. in SEAS.

Guided by this model, the researchers demonstrated programmed reversible topological transformations of various lattice geometries and reacting materials, including the transformation of a lattice of circles into squares.

Researchers have studied various applications for research. For example, the team encoded the patterns and designs in the material, making tiny invisible changes to the geometry of the triangular lattice.

“You can imagine that this will be used to encrypt information in the future, because you cannot see the pattern in the material when it is disassembled,” Lee said.

The researchers also demonstrated very local transformation, assembly and disassembly of sections of the lattice using a tiny liquid droplet. This method can be used to adjust the friction and wetting properties of a material, change its acoustic properties and mechanical elasticity, and even trap gas particles and bubbles.

“Our strategy can be applied to a variety of applications,” said Bertholdi, who is also a co-author of the article. “We can apply this method to a variety of materials, including sensitive materials, with different geometries and different scales, even at the nanoscale, where topology plays a key role in the development of tunable photonic metasurfaces. The design space for that is huge. “

Reference: “Fluid-Induced Topological Transformations of Cellular Microstructures” by Shukong Lee, Bolei Deng, Alison Grintal, Alisha Schneider-Yamamura, Jinliang Kang, Reese S. Martens, Katie T. Zhang, Jiang Li, Xicin Yu, Katya Bertholdi, and Joanna. Eisenberg, April 14, 2021, Nature
DOI: 10.1038 / s41586-021-03404-7

This study was co-authored by Alison Grintal, Alissha Schneider-Yamamura, Jinliang Kang, Reese S. Martens, Katie T. Zhang, Jian Li, and Xiqing Yu.

It was supported by the National Science Foundation under the Material Design for Revolution and Design for Our Future (DMREF) Program # DMR-1922321, Harvard University Materials Research and Engineering Center (MRSEC), award # DMR-18 2011754 and the Department of Energy USA (DOE), Office of Science, Basic Energy Sciences (BES) under number DE-SC0005247.



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Help clean up space junk with the first of its kind Mission Optimizer

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Help clean up space junk with the first of its kind Mission Optimizer

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ClearSpace-1 takes over Vespa

Illustration ClearSpace-1, a planned mission for active garbage collection. Credit: ClearSpace SA.

Less than a year after the UK Space Agency pledged £ 1 million to combat space debris, Fujitsu UK has successfully combined quantum computing and artificial intelligence to support the transformation of its debris removal system.

Fujitsu Prototype – Created in collaboration with Glasgow University, Amazon Web Services and Astroscale UK will improve mission planning so that a single spacecraft can efficiently choose which pieces of space debris to remove in a single mission, much faster than is currently possible.

Removing space debris is key to sustainability in space, reducing or even preventing the risk of legacy spacecraft colliding with new and existing satellites.

What’s more, supporting debris removal missions with Fujitsu technology will help reduce the risk of catastrophic collisions in orbit, which could lead to thousands of other new debris that pose a real threat to operational satellites in orbit.

By carefully deciding what debris and when to collect, Digital Annealer’s quantum proposal optimizes a mission plan to determine the minimum fuel and minimum time needed to safely return a failed spacecraft or satellites to disposal orbit. Finding the optimal route for collecting space debris will significantly save time and money during the mission planning phase, as well as, as a result, increase commercial profitability.

Space debris objects in low Earth orbit

The debris objects shown in the images are artist’s impression based on actual density data. However, debris objects are shown zoomed in to make them visible at the specified scale. Credit: ESA.

With 2350 inoperative satellites Currently in orbit and more than 28,000 debris tracked by space surveillance networks, this technology will help the UK increase its market share in the space sector. It will also further support the UK government’s commitment to a more sustainable future overall.

Dr. Matteo Ceriotti, professor of space engineering, and graduate student Julia Viavattene, who led the project for the University of Glasgow, said: “The University of Glasgow was involved in this project from the very beginning – developing the trajectory. the models needed to efficiently remove space debris as well as to estimate the cost of travel.

“The University has a long history of experience in the design and optimization of space trajectories, which is why we have strived to be at the forefront of any government initiative to enhance the UK’s image in the space sector. With the help of Fujitsu, AWS and Astroscale UK, we have helped overcome the challenges of removing space debris to make future projects easier. ”

Ellen Devereux, digital firing consultant for Fujitsu UK and Ireland, said: “All space debris presents a potential risk of collision with operating systems that many of us take for granted, from weather forecasts to telecommunications.

“With the support of the UK Space Agency, Astroscale UK, AWS and the University of Glasgow, we have developed a solution to optimize the planning of a maintenance ship’s mission before it goes into space. This means that organizations like Astroscale UK can choose to collect more trash faster than ever before.

“This not only makes the process much more cost-effective for organizations that need to move and dispose of garbage, but it also leverages artificial intelligence and quantum computing.

“Over the past six months, we have learned that this technology has tremendous value for optimization in space; not only for garbage collection, but also for in-orbit maintenance and more. We now understand its potential better, and we can’t wait to see how the technology will be applied during the future mission. ”

Jacob Gere, head of space surveillance and tracking at the UK space agency, said: “Monitoring dangerous space objects is vital to protect the services we all rely on, from communications devices to satellite navigation. This project is one of the first examples of the use of quantum computing and artificial intelligence to solve space debris problems, but it is unlikely to be the last.

“The UK is committed to making space sustainable, and Fujitsu, working with Astroscale UK, the University of Glasgow and AWS, has demonstrated the real value of keeping space uncluttered by making it accessible to future generations.”

Stephen Vox, CTO at Astroscale UK, said: “Finding the optimal mission plan manually is time consuming and difficult. Astroscale UK is leading the next pioneering move under the End-of-Life Services by Astroscale (ELSA) program to remove not only one piece of debris, but multiple objects of debris with a single serving satellite known as ELSA-M, which is essentially a more economical way to remove debris from orbit. By teaming up with Fujitsu, AWS and the University of Glasgow, we hope to further optimize this for future missions. ”

The study was carried out under a grant from the UK Space Agency “Expanding Space Surveillance and Tracking Research”. The project, which was developed over six months in accordance with government digital services guidelines, uses fast technologies based on an artificial neural network (ANN). Trajectory design algorithms developed by the University of Glasgow, together with Fujitsu Digital Annealer and Quantum Inspired Optimization Services, to address some of the major optimization problems associated with Active Debris Removal (ADR) mission planning.

Amazon Web Services provided Cloud and AI and ML tools and services to support the project. The Amazon Sagemaker toolbox has been used to rapidly develop ANNs that accurately predict the cost of orbital movements in a fraction of the time required to fully calculate them. Astroscale UK, the world’s first commercial company to embark on a debris removal demonstration mission from lower Earth orbit, offers an end-use case as a typical user of multi-mission optimization.

Fujitsu, which spearheaded the project, is one of seven UK companies to receive more than £ 1 million in space debris tracking from the UK Space Agency. The UK Space Agency and the Department of Defense have announced the next step in their joint initiative to raise UK awareness of events in space.



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Scientists use human protein to deliver RNA molecular drugs to cells

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SEND Technology Restoring Health

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Fully assembled SEND packages

The fully assembled SEND bags are released from the collection cage for gene therapy. Credit: McGovern Institute

A programmable system built from human body components is a step towards safer and more targeted delivery of gene editing and other molecular therapeutics.

Researchers from Massachusetts Institute of TechnologyThe McGovern Institute for Brain Research at MIT, Howard Hughes Medical Institute and the Broad Institute at MIT and Harvard have developed a new way to deliver molecular therapy to cells. A system called SEND can be programmed to encapsulate and deliver various RNA cargo. SEND uses natural proteins in the body that form virus-like particles and bind RNA, and may elicit a smaller immune response than other delivery approaches.

The new delivery platform works effectively in cell models and, with further development, could open up a new class of delivery methods for a wide range of molecular drugs, including gene editing and gene replacement. Existing delivery vehicles for these therapeutic agents may be ineffective and randomly integrate into the genome of cells, and some may stimulate unwanted immune responses. SEND promises to overcome these limitations, which could open up new avenues for the introduction of molecular medicine.


Researchers at MIT, MIT’s McGovern Brain Research Institute, Howard Hughes Medical Institute, and MIT’s Broad Institute and Harvard have developed a new way to deliver molecular therapy to cells. Credit: Created by the McGovern Institute and Opus Design in collaboration with Feng Zhang, Rhiannon Macrae, and the Broad Institute.

“The biomedical community is developing powerful molecular therapeutics, but getting them to cells in an accurate and efficient manner is not an easy task,” said CRISPR pioneer Feng Zhang, senior study author, member of the Broad Institute core institute, researcher at McGovern. Institute, and Professor of Neuroscience James and Patricia Poitras at MIT. “SEND can solve these problems.” Zhang is also a researcher at Howard Hughes Medical Institute and a professor in the Department of Brain, Cognitive Sciences, and Biological Engineering at MIT.

I report The science, the command describes how to SEND (Selective Eendogenous eNcapsidization for cell Delivery) uses molecules produced by human cells. At the center of SEND is a protein called PEG10, which usually binds to its own mRNA and forms a spherical protective capsule around it. In their research, the team developed PEG10 to selectively package and deliver other RNAs. The scientists used SEND to deliver the CRISPR-Cas9 gene editing system to mouse and human cells to edit target genes.

First author Michael Segel, a postdoctoral fellow at Zhang’s lab, and Blake Lash, a second author and graduate student at the lab, said PEG10 is not unique in its ability to carry RNA. “That’s what is so exciting,” Segel said. “This study shows that there are probably other RNA transfer systems in the human body that can also be used for therapeutic purposes. It also raises some really interesting questions about what the natural roles of these proteins might be. “

Inspiration from within

The PEG10 protein exists naturally in the human body and comes from the “retrotransposon” – a virus-like genetic element that was integrated into the genome of human ancestors millions of years ago. Over time, PEG10 was metabolized by the body to become part of the repertoire of proteins essential for life.

Four years ago, researchers showed that another protein derived from the retrotransposon, ARC, forms virus-like structures and is involved in the transfer of RNA between cells. Although these studies have shown that it is possible to create retrotransposon proteins as a delivery platform, scientists have not been able to successfully use these proteins to package and deliver specific RNA shipments into mammalian cells.

SEND Health Recovery Technologies

SEND packages are injected into diseased cells to deliver therapeutic mRNA and restore health. Credit: McGovern Institute

Knowing that some proteins derived from the retrotransposon are capable of binding and packaging molecular loads, Zhang’s team turned to these proteins as possible delivery vehicles. They systematically searched for these proteins in the human genome, looking for those that could form protective capsules. In their initial analysis, the team found 48 human genes encoding proteins that could have this ability. Of these, 19 candidate proteins were present in both mice and humans. In the cell line that the team studied, PEG10 stood out as an efficient shuttle; the cells released significantly more PEG10 particles than any other protein tested. PEG10 particles also predominantly contain their own mRNA, suggesting that PEG10 may be able to package certain RNA molecules.

Development of a modular system

To develop the SEND technology, the team identified molecular sequences or “signals” in PEG10 mRNA that PEG10 recognizes and uses to package its mRNA. The researchers then used these signals to construct both PEG10 and other RNA cargoes so that PEG10 could selectively package those RNAs. The team then adorned the PEG10 capsules with additional proteins called “fusogens” that sit on the surface of cells and help them fuse together.

By creating fusogens on PEG10 capsules, researchers must be able to target the capsule to a specific type of cell, tissue, or organ. As a first step towards this goal, the team used two different fusogens, including one found in the human body, to ensure the delivery of the SEND cargo.

“By mixing and matching the various components in the SEND system, we believe it will provide a modular platform for the development of therapeutic agents for a variety of diseases,” Zhang said.

Progressive gene therapy

SEND is made up of proteins that are naturally produced in the body, which means it cannot trigger an immune response. If demonstrated in further research, the researchers say SEND could open the door to multiple uses of gene therapy with minimal side effects. “SEND technology will augment viral delivery vectors and lipid nanoparticles to further expand the toolbox for gene delivery and therapies into cells,” Lash said.

The team will then test SEND on animals and further develop a system to deliver the cargo to various tissues and cells. They will also continue to explore the natural diversity of these systems in the human body to identify other components that can be added to the SEND platform.

“We are delighted to continue to advance this approach,” Zhang said. “The realization that we can use PEG10 and most likely other proteins to engineer a delivery pathway in the human body to package and deliver new RNA and other potential therapies is a really powerful concept.”

Reference: “The mammalian retrovirus-like protein PEG10 packs its own mRNA and can be pseudotyped to deliver mRNA” Michael Segel, Blake Lash, Jingwei Song, Alim Ladha, Catherine S. Liu, Xin Jin, Sergey L. Mehedov, Rhiannon K. Macrae , Evgeny Kunin and Feng Zhang, August 20, 2021, The science
DOI: 10.1126 / science.abg6155

This work was made possible with the support of the Simons Center for the Social Brain at MIT; Internal Research Program of the National Institutes of Health; National Institutes of Health Grants 1R01-HG009761 and 1DP1-HL141201; Howard Hughes Medical Institute; Open charity; G. Harold and Leila Y. Mathers Charitable Foundation; Edward Mullinkrodt Jr. Foundation; The Poitras Center for Mental Disorders Research at the Massachusetts Institute of Technology; Hock E. Tan and C. Lisa Young, Center for Autism Research, MIT; The Yang Tang Center for Molecular Therapy at the Massachusetts Institute of Technology; Lisa Yang; The Phillips family; R. Metcalfe; and J. and P. Poitras.



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