Category: 7. Science

By Dean Murray

The interior of Mars is filled with vast and mysterious rocks that smashed into the planet, new research shows.

Rocky material up to 2.5 miles (4 kilometers) across remains scattered in giant lumps below the Red Planet’s surface.

The study by Imperial College London and NASA reveals what appear to be fragments from the aftermath of massive impacts on Mars that occurred 4.5 billion years ago.

The discovery was made thanks to NASA’s now-retired InSight lander, which detected the entities deep below the planet’s surface before the mission’s end in 2022.

NASA’s Jet Propulsion Laboratory said: “The ancient impacts released enough energy to melt continent-size swaths of the early crust and mantle into vast magma oceans, simultaneously injecting the impactor fragments and Martian debris deep into the planet’s interior.”

The findings, reported in a study published by the journal Science, offer clues about Mars’ interior and its ancient past.

The paper’s lead author, Constantinos Charalambous of Imperial College London, said: “We’ve never seen the inside of a planet in such fine detail and clarity before.

“What we’re seeing is a mantle studded with ancient fragments. Their survival to this day tells us Mars’ mantle has evolved sluggishly over billions of years.

“On Earth, features like these may well have been largely erased.”

InSight, which was managed by NASA’s Jet Propulsion Laboratory in Southern California, placed the first seismometer on Mars’ surface in 2018. The extremely sensitive instrument recorded 1,319 marsquakes before the lander’s end of mission in 2022.

NASA add: “There’s no way to tell exactly what struck Mars: The early solar system was filled with a range of different rocky objects that could have done so, including some so large they were effectively protoplanets.

“They offer a record preserved only on worlds like Mars, whose lack of tectonic plates has kept its interior from being churned up the way Earth’s is through a process known as convection.”

Few cosmic visitors have captured the fascination of astronomers quite like the interstellar comet 3I/ATLAS. Hurtling through our solar system from the depths of interstellar space, this icy wanderer is only the third known object of its kind, and where it came from remains a mystery.

Since its discovery on July 1, 2025, by the Deep Random Survey remote telescope in Chile, part of the ATLAS (Asteroid Terrestrial-impact Last Alert System) project, scientists have raced to point telescopes toward the visitor as experts and the public are eager for a closer look. Even NASA’s Hubble Space Telescope and the James Webb Space Telescope recently caught glimpses of this icy comet as it continues moving toward our sun.

When it comes to interactions between animals and microbes in the ancient past, focus has primarily been on humans and our closest ancestors rather than extinct animals, such as mammoths.

A new study led by Benjamin Guinet from the Swedish Museum of Natural History has analysed microbial DNA from no fewer than 483 mammoth remains. These remains span over one million years and were uncovered from seven sites located in Canada and Russia.

Using a variety of different genetic techniques, Guinet and his team identified 310 microbes from a range of different mammoth tissues, from teeth to tibia. 

While most of these microbes are thought to have been derived from the surrounding environment after death, there are six that have been identified as ‘host-associated’, meaning they lived symbiotically inside (or on) their hosts.

The dataset assembled by Guinet and his team includes 440 newly sequenced and unpublished samples from a 1.1-million-year-old steppe mammoth found near the Adycha River in northeastern Russia, deep in the wilderness of Siberia. In 2021, scientists successfully recovered DNA from a molar of this particular mammoth. This proved to be the oldest DNA ever sequenced from animal remains, making the so-called ‘Adycha Mammoth’ particularly famous.

From this same molar and as part of this latest study, Guinet and his team recovered genomic evidence of a host-associated microbe known as Erysipelothrix, which, again, was the oldest of its kind ever found. 

Erysipelothrix is a type of bacteria that has previously been isolated from dogs, pigs, cattle and humans and is thought to be involved in endocarditis – a potentially fatal infection of the inner lining of the heart.

Evidence of Erysipelothrix-like bacteria was also discovered in woolly mammoth bones from a different time period and site. The presence of Erysipelothrix in both species of mammoths suggests this bacteria has a long-term association with the group and may have had some influence on mammoth evolution.

The study found genomic evidence of five more types of host-associated bacteria, including Pasteurella and Streptococcus.

Some of the Pasteurella DNA isolated from two Late Pleistocene mammoth samples was very similar to a strain of bacteria identified as causing fatal septicaemia in six African elephants in Zimbabwe in 2020. 

And of two distinct types of Streptococcus identified from six woolly mammoth teeth, one was found to be distantly related to a strain of Streptococcus responsible for tooth decay in humans.

Despite its somewhat bad reputation, bacteria isn’t inherently ‘harmful’. In fact, many of the types identified in this study, including Erysipelothrix, Pasteurella and Streptococcus, can be harmless or even beneficial and only cause disease under certain conditions.

Pasteurella, for example, is involved in the production of succinic acid – a naturally occurring acid that plays a crucial role in metabolism and energy production.

Not only has this latest study assembled a giant database that will form the basis of further studies into the microbiomes of mammoths, it has also shown that it’s possible to detect host-associated bacteria in the remains of extinct animals. 

This new area of research has the potential to change what we thought we knew about the long-term health of extinct animals and how their microbiomes may have shaped their evolutionary trajectories.

Top image: mammoth tusk. Credit: Love Dalén

More amazing wildlife stories from around the world

With the power to rewrite the genetic code underlying countless diseases, CRISPR holds immense promise to revolutionize medicine. But until scientists can deliver its gene-editing machinery safely and efficiently into relevant cells and tissues, that promise will remain out of reach.

Now, Northwestern University chemists have unveiled a new type of nanostructure that dramatically improves CRISPR delivery and potentially extends its scope of utility.

Called lipid nanoparticle spherical nucleic acids (LNP-SNAs), these tiny structures carry the full set of CRISPR editing tools – Cas9 enzymes, guide RNA and a DNA repair template – wrapped in a dense, protective shell of DNA. Not only does this DNA coating shield its cargo, but it also dictates which organs and tissues the LNP-SNAs travel to and makes it easier for them to enter cells.

In lab tests across various human and animal cell types, the LNP-SNAs entered cells up to three times more effectively than the standard lipid particle delivery systems used for COVID-19 vaccines, caused far less toxicity and boosted gene-editing efficiency threefold. The new nanostructures also improved the success rate of precise DNA repairs by more than 60% compared to current methods.

The study will be published on Sept. 5 in the Proceedings of the National Academy of Sciences.

The study paves the way for safer, more reliable genetic medicines and underscores the importance of how a nanomaterial’s structure – rather than its ingredients alone – can determine its potency. This principle underlies structural nanomedicine, an emerging field pioneered by Northwestern’s Chad A. Mirkin and his colleagues and pursued by hundreds of researchers around the world.

“CRISPR is an incredibly powerful tool that could correct defects in genes to decrease susceptibility to disease and even eliminate disease itself,” said Mirkin, who led the new study. “But it’s difficult to get CRISPR into the cells and tissues that matter. Reaching and entering the right cells – and the right places within those cells – requires a minor miracle. By using SNAs to deliver the machinery required for gene editing, we aimed to maximize CRISPR’s efficiency and expand the number of cell and tissue types that we can deliver it to.”

A nanotechnology and nanomedicine pioneer, Mirkin is the George B. Rathmann Professor of Chemistry at Northwestern’s Weinberg College of Arts and Sciences; professor of chemical and biological engineering, biomedical engineering and materials science and engineering at the McCormick School of Engineering; professor of medicine at the Feinberg School of Medicine; executive director of the International Institute for Nanotechnology; and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

CRISPR needs a ride

When CRISPR machinery reaches its target inside a cell, it can disable genes, fix mutations, add new functions and more. But CRISPR machinery cannot enter cells by itself. It always needs a delivery vehicle. 

Currently, scientists typically use viral vectors and lipid nanoparticles (LNPs) to perform this function. Naturally good at sneaking into cells, viruses are efficient, but they can cause the human body to mount an immune response, leading to painful or even dangerous side effects. LNPs, on the other hand, are safer but inefficient. They tend to get stuck in endosomes, or compartments within the cell, where they cannot release their cargo.

Only a fraction of the CRISPR machinery actually makes it into the cell and even a smaller fraction makes it all the way into the nucleus. Another strategy is to remove cells from the body, inject the CRISPR components and then put the cells back in. As you can imagine, that’s extremely inefficient and impractical.”

Chad A. Mirkin, Northwestern University

A DNA-wrapped taxi

To overcome this barrier, Mirkin’s team turned to SNAs, which are globular – rather than linear – forms of DNA and RNA previously invented in Mirkin’s lab at Northwestern. The spherical genetic material surrounds a nanoparticle core, which can be packed with cargo. Roughly 50 nanometers in diameter, the tiny structures possess a proven ability to enter cells for targeted delivery. Seven SNA-based therapies are already in human clinical trials, including a Phase 2 clinical trial for Merkel cell carcinoma being developed by Flashpoint Therapeutics, a clinical-stage biotechnology startup.

In the new study, Mirkin’s team started with an LNP core carrying the CRISPR machinery inside. Then, they decorated the particle’s surface with a dense layer of short strands of DNA. Because the DNA can interact with a cell’s surface receptors, cells easily absorb SNAs. The DNA also can be engineered with sequences that target specific cell types, making delivery more selective.

“Simple changes to the particle’s structure can dramatically change how well a cell takes it up,” Mirkin said. “The SNA architecture is recognized by almost all cell types, so cells actively take up the SNAs and rapidly internalize them.”

Boosted performance across the board

After successfully synthesizing LNP-SNAs with CRISPR cargo, Mirkin and his team added them to cellular cultures, which included skin cells, white blood cells, human bone marrow stem cells and human kidney cells. 

Then, the team observed and measured several key factors: how efficiently the cells internalized the particles, whether the particles were toxic to cells and if the particles successfully delivered a gene. They also analyzed the cells’ DNA to determine if CRISPR had made the desired gene edits. In every category, the system demonstrated its ability to successfully deliver CRISPR machinery and enable complex genetic modifications.

Next, Mirkin plans to further validate the system in multiple in vivo disease models. Because the platform is modular, researchers can adapt it for a wide range of systems and therapeutic applications. Northwestern biotechnology spin-out Flashpoint Therapeutics is commercializing the technology with the goal of rapidly moving it toward clinical trials.

“CRISPR could change the whole field of medicine,” Mirkin said. “But how we design the delivery vehicle is just as important as the genetic tools themselves. By marrying two powerful biotechnologies – CRISPR and SNAs – we have created a strategy that could unlock CRISPR’s full therapeutic potential.”

The study, “A general genome editing strategy using CRISPR lipid nanoparticle spherical nucleic acids,” was supported by the Air Force Office of Scientific Research (award number FA9550-22-1-0300), the National Science Foundation (award number DMR-2428112) and Edgar H. Bachrach through the Bachrach Foundation.

Date:

September 2, 2025

Source:

NASA

Summary:

NASA’s SPHEREx joined Webb and Hubble in studying interstellar comet 3I/ATLAS, gathering data on its size, chemistry, and physical traits. While harmless to Earth, the comet provides scientists a rare opportunity to learn more about solar system wanderers.

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By improving astronomers’ understanding of spotty stars, the new model — called StarryStarryProcess — can help discover more about planetary atmospheres and potential habitability using data from telescopes like NASA’s upcoming Pandora mission.

“Many of the models researchers use to analyze data from exoplanets, or worlds beyond our solar system, assume that stars are uniformly bright disks,” said Sabina Sagynbayeva, a graduate student at Stony Brook University in New York. “But we know just by looking at our own Sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located, and how bright or dark they are.”

A paper describing StarryStarryProcess, led by Sagynbayeva, published on August 25, in The Astrophysical Journal.

NASA’s TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler Space Telescope were designed to identify planets using transits, dips in stellar brightness caused when a planet passes in front of its star.

These measurements reveal how the star’s light varies with time during each transit, and astronomers can arrange them in a plot astronomers call a light curve. Typically, a transit light curve traces a smooth sweep down as the planet starts passing in front of the star’s face. It reaches a minimum brightness when the world is fully in front of the star and then rises smoothly as the planet exits and the transit ends.

By measuring the time between transits, scientists can determine how far the planet lies from its star and estimate its surface temperature. The amount of missing light from the star during a transit can reveal the planet’s size, which can hint at its composition.

Every now and then, though, a planet’s light curve appears more complicated, with smaller dips and peaks added to the main arc. Scientists think these represent dark surface features akin to sunspots seen on our own Sun — star spots.

The Sun’s total number of sunspots varies as it goes through its 11-year solar cycle. Scientists use them to determine and predict the progress of that cycle as well as outbreaks of solar activity that could affect us here on Earth.

Similarly, star spots are cool, dark, temporary patches on a stellar surface whose sizes and numbers change over time. Their variability impacts what astronomers can learn about transiting planets.

Scientists have previously analyzed transit light curves from exoplanets and their host stars to look at the smaller dips and peaks. This helps determine the host star’s properties, such as its overall level of spottiness, inclination angle of the planet’s orbit, the tilt of the star’s spin compared to our line of sight, and other factors. Sagynbayeva’s model uses light curves that include not only transit information, but also the rotation of the star itself to provide even more detailed information about these stellar properties.

“Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop,” said co-author Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore. “For example, at cool enough temperatures, stars can have water vapor in their atmospheres. If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we better be very sure that we’re not confusing the two.”

To test their model, Sagynbayeva and her team looked at transits from a planet called TOI 3884 b, located around 141 light-years away in the northern constellation Virgo.

Discovered by TESS in 2022, astronomers think the planet is a gas giant about five times bigger than Earth and 32 times its mass.

The StarryStarryProcess analysis suggests that the planet’s cool, dim star — called TOI 3384 — has concentrations of spots at its north pole, which also tips toward Earth so that the planet passes over the pole from our perspective.

Currently, the only available data sets that can be fit by Sagynbayeva’s model are in visible light, which excludes infrared observations taken by NASA’s James Webb Space Telescope. But NASA’s upcoming Pandora mission will benefit from tools like this one. Pandora, a small satellite developed through NASA’s Astrophysics Pioneers Program, will study the atmospheres of exoplanets and the activity of their host stars with long-duration multiwavelength observations. The Pandora mission’s goal is to determine how the properties of a star’s light differs when it passes through a planet’s atmosphere so scientists can better measure those atmospheres using Webb and other missions.

“The TESS satellite has discovered thousands of planets since it launched in 2018,” said Allison Youngblood, TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets. The more we understand the individual parts of a planetary system, the better we understand the whole — and our own.”

A tiny digital radio receiver space-based system, based on a compact single-board computer about the size of a credit card, could help astronomers unravel the mysteries of the Cosmic Dawn, the time when the first stars and galaxies formed in the universe. Scientists believe this mysterious period holds the key to understanding the universe as we see it today, making it an irresistible frontier for discovery.

However, very little is known about this period due to a lack of precise observations. Christened PRATUSH (Probing ReionizATion of the Universe using Signal from Hydrogen), the first space payload of its kind in a lunar orbit has been conceptualised by a team from Raman Research Institute (RRI). PRATUSH can detect a faint radio signal emitted from hydrogen atoms, carrying imprints of several events during the Cosmic Dawn.

Capturing this signal is like hearing a whisper in a stadium full of noise, as it’s buried under interference millions of times stronger than the signal itself. On Earth, this whisper from the past is drowned out by radio noise and interference, such as FM transmissions. Therefore, PRATUSH envisions a lunar far-side mission, expected to be the most radio-quiet place in the inner solar system, free from Earth’s interference and ionospheric distortion.

The PRATUSH team has built a laboratory model of their radiometer to demonstrate its suitability for detecting the faint cosmological signal. This research has been published in Experimental Astronomy, a peer-reviewed journal. The radio signals are captured by the antenna, amplified by the analog receiver, and turned into digital data by a receiver.

An advanced powerful chip called Field Programmable Gate Array processes this data, converting it into fine fingerprints representing the sky’s brightness at different radio frequencies. Considering the stringent requirements of space payloads and the focus on low-mass, high-capability payloads, PRATUSH demonstrates how a compact controller can handle precision radio measurements.

The single-board computer (SBC) acts as the master conductor of PRATUSH’s radiometer, coordinating the antenna, receiver, and chip that processes streams of cosmic radio data. Besides recording and storing this information, SBC performs crucial calibrations, capturing high-speed data streams and carrying out preliminary data processing.

“SBCs, as scaled-down versions of desktops or laptops, deliver an appealing balance of size, performance, and efficiency to manage data through software instructions,” said Girish BS, a senior scientist at RRI. Performance tests confirm that this minimalist strategy is highly effective. With newly implemented software enhancements and next-generation space-grade devices, the system is on track for even greater performance, ensuring data integrity.

Rocket emissions and re-entry pollutants threaten to delay ozone recovery, but coordinated action and cleaner propulsion could prevent long-term damage.

The sharp increase in global rocket launches may hinder the recovery of the ozone layer, warns Sandro Vattioni. Although the risk is being underestimated, he notes that it could be reduced through proactive and coordinated measures.

In recent years, the expansion of satellite constellations in low Earth orbit has transformed the night sky, fueled by the rapid growth of the space industry. This progress creates major opportunities but also raises environmental challenges. Pollutants released during rocket launches and from burning debris during re-entry accumulate in the middle atmosphere, where they can damage the ozone layer — Earth’s shield against harmful ultraviolet radiation. Scientists are only beginning to fully assess the scale of this threat.

Investigations into how rocket emissions affect ozone began more than three decades ago, but for many years the impact was considered minimal. As the frequency of launches continues to rise, this view is shifting. In 2019, only 97 orbital launches were recorded worldwide, but by 2024 the figure had climbed to 258, with projections pointing to continued rapid growth.

A long-underestimated concern

Unlike ground-level pollutants, emissions from rockets and re-entering satellites can persist in the middle and upper atmosphere up to 100 times longer, since removal processes such as precipitation do not occur at those altitudes. While most launches take place in the Northern Hemisphere, atmospheric circulation eventually distributes the pollutants globally.

To investigate long-term effects, researchers from ETH Zurich and the Physical Meteorological Observatory in Davos (PMOD/WRC), in collaboration with Laura Revell’s international team at the University of Canterbury, used a chemistry–climate model to simulate how future emissions might impact the ozone layer by 2030.

In a high-growth scenario with 2,040 annual launches by 2030 — roughly eight times the 2024 total — the model predicts that global average ozone thickness would decrease by nearly 0.3%. Seasonal losses could reach as much as 4% over Antarctica, where the ozone hole continues to reappear each spring.

While these reductions may appear small, the context is critical. The ozone layer is still recovering from earlier depletion caused by long-lived chlorofluorocarbons (CFCs), which were banned under the 1989 Montreal Protocol. Even today, global ozone thickness remains about 2% below pre-industrial levels, and full recovery is not expected until around 2066. The study suggests that unchecked rocket emissions — which currently remain unregulated — could push this timeline back by several years or even decades, depending on how quickly the space industry expands.

With rockets, too, the choice of fuel matters

The main contributors to ozone depletion from rocket emissions are gaseous chlorine and soot particles. Chlorine catalytically destroys ozone molecules, while soot particles warm the middle atmosphere, accelerating ozone-depleting chemical reactions.

While most rocket propellants emit soot, chlorine emissions primarily come from solid rocket motors. Currently, the only propulsion systems that have a negligible effect on the ozone layer are those which use cryogenic fuels such as liquid oxygen and hydrogen. However, due to the technological complexity of handling cryogenic fuels, only about 6% of rocket launches currently use this technology.

Re-entry effects are still uncertain

We would like to mention that our study only considered emissions released from rockets during ascent into space. But this is only part of the picture. Most satellites in low Earth orbit re-enter the atmosphere at the end of their operational life, burning up in the process.

This process generates additional pollutants, including various metal particles and nitrogen oxides, due to the intense heat generated upon re-entry. While nitrogen oxides are known to deplete ozone catalytically, metal particles may contribute to forming polar stratospheric clouds or serve as reaction surfaces themselves, both of which can intensify ozone loss.

These re-entry effects are still poorly understood and not yet incorporated into most atmospheric models. From our point of view, it is clear that with increasing satellite constellations, re-entry emissions will become more frequent, and the total impact on the ozone layer is likely to be even higher than current estimates. Science is called upon to fill these gaps in our understanding.

Needed: Foresight and coordinated action

But that alone will not be enough. The good news: We believe a launch industry that avoids ozone-damaging effects is entirely possible: Monitoring rocket emissions, minimizing the usage of chlorine and soot-producing fuels, promoting alternative propulsion systems, and implementing the necessary and appropriate regulations are all key to ensuring that the ozone layer continues its recovery. This will take coordinated efforts between scientists, policymakers, and industry.

The Montreal Protocol successfully demonstrated that even planetary-scale environmental threats can be addressed through global cooperation. As we enter a new era of space activity, the same kind of foresight and international coordination will be needed to avoid harmful effects on the ozone layer – one of the Earth’s most vital natural shields.

Reference: “Near-future rocket launches could slow ozone recovery” by Laura E. Revell, Michele T. Bannister, Tyler F. M. Brown, Timofei Sukhodolov, Sandro Vattioni, John Dykema, David J. Frame, John Cater, Gabriel Chiodo and Eugene Rozanov, 9 June 2025, npj Climate and Atmospheric Science.
DOI: 10.1038/s41612-025-01098-6

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Northwestern scientists developed DNA-wrapped nanoparticles that triple CRISPR efficiency, paving the way for more effective gene editing therapies

Northwestern University researchers have unveiled a major breakthrough in CRISPR technology, demonstrating that DNA-wrapped nanoparticles can deliver gene editing tools with three times the efficiency of current methods. The discovery marks a step forward in making gene editing therapies safer, faster, and more accessible.

The study will be published in the Proceedings of the National Academy of Sciences on September 5th.

Lipid nanoparticle spherical nucleic acids: An exciting discovery

Lipid nanoparticle spherical nucleic acids (LNP-SNAs) are tiny structures that carry the complete set of CRISPR editing tools – Cas9 enzymes, guide RNA, and a DNA repair template – wrapped in a dense, protective shell of DNA. The DNA coating not only guides LNP-SNAs to specific organs and tissues but also facilitates their entry into cells.

The scientists conducted lab tests on various human and animal cell types. They found that the new CRISPR delivery system, involving DNA-wrapped nanoparticles, entered cells up to three times more effectively than the standard lipid particle delivery systems used for COVID-19 vaccines. This impressive efficiency, coupled with significantly reduced toxicity, and a threefold boost in gene editing efficiency, is a cause for excitement and anticipation in the scientific community. 

“CRISPR is a potent tool that could correct defects in genes to decrease susceptibility to disease and even eliminate disease itself,” said nanotechnology and nanomedicine pioneer Chad A. Mirkin, who led the new study. “But it’s difficult to get CRISPR into the cells and tissues that matter. Reaching and entering the right cells — and the right places within those cells — requires a minor miracle. By using SNAs to deliver the machinery required for gene editing, we aimed to maximize CRISPR’s efficiency and expand the number of cell and tissue types that we can deliver it to.”

The study highlights the importance of how a nanomaterial’s structure can determine its potency. It underlies the emerging field of structural nanomedicine, pioneered by Northwestern’s Chad A. Mirkin and his colleagues.

CRISPR’s biggest hurdle: Inefficient delivery into cells and nuclei

While CRISPR can disable genes, repair mutations, and add new functions once inside a cell, it cannot enter on its own and instead relies on delivery vehicles such as viral vectors or lipid nanoparticles (LNPs). 

While viruses are efficient, they can trigger an immune response in the human body, leading to painful or even dangerous side effects. In contrast, lipid nanoparticles are safer but less efficient, often becoming trapped in endosomes or cellular compartments. The new CRISPR delivery system, involving DNA-wrapped nanoparticles, offers a safer alternative, providing reassurance and confidence in its potential for gene editing therapies.

“Only a fraction of the CRISPR machinery actually makes it into the cell, and even a smaller fraction makes it all the way into the nucleus,” Mirkin said. “Another strategy is to remove cells from the body, inject the CRISPR components, and then put the cells back in. As you can imagine, that’s extremely inefficient and impractical.”

DNA-wrapped support for CRISPR

To overcome CRISPR delivery problems, Mirkin’s team turned to SNAs, which are globular, instead of linear, forms of DNA and RNA previously invented in Mirkin’s lab at Northwestern.

The spherical genetic material surrounds a nanoparticle core, which can be packed with cargo. Roughly 50 nanometers in diameter, the tiny structures possess a proven ability to enter cells for targeted delivery. Seven SNA-based therapies are already in human clinical trials, including a Phase 2 clinical trial for Merkel cell carcinoma being developed by Flashpoint Therapeutics, a clinical-stage biotechnology startup.

In the new study, Mirkin’s team began with an LNP core that carried the CRISPR machinery inside. The team then decorated the particle’s surface with a dense layer of short strands of DNA, as DNA can interact with a cell’s surface receptors, and cells readily absorb SNAs. The DNA can also be engineered to make delivery more selective.

“Simple changes to the particle’s structure can dramatically change how well a cell takes it up,” Mirkin said. “The SNA architecture is recognized by almost all cell types, so cells actively take up the SNAs and rapidly internalize them.”

Three-fold improved performance

After successfully synthesizing LNP-SNAs with CRISPR cargo, Mirkin and his team added them to cellular cultures, which included skin cells, white blood cells, human bone marrow stem cells, and human kidney cells. 

The team observed and measured several key factors:

• How efficiently the cells internalised the particles
• Whether the particles were toxic to cells
• If the particles successfully deliver a gene

They also analysed the cells’ DNA to determine if CRISPR had made the desired gene edits, finding that across every factor, the system successfully delivered CRISPR machinery and enabled complex genetic modifications.

In the future, Mirkin plans further to validate the system in multiple in vivo disease models. Because the platform is modular, researchers can adapt it for a wide range of systems and therapeutic applications.

“CRISPR could change the whole field of medicine,” Mirkin said. “But how we design the delivery vehicle is just as important as the genetic tools themselves. By marrying two powerful biotechnologies — CRISPR and SNAs — we have created a strategy that could unlock CRISPR’s full therapeutic potential.”