Associate professor Chenguang Lou from the Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, together with Professor Hanbin Mao from Kent State University, is the parent of a special artificial hybrid molecule that could lead to the creation of artificial life forms. They have now published a review in the journal Cell Reports Physical Science on the state of research in the field behind their creation. The field is called “hybrid peptide-DNA nanostructures,” and it is an emerging field, less than ten years old.

Lou’s vision is to create viral vaccines (modified and weakened versions of a virus) and artificial life forms that can be used for diagnosing and treating diseases.

“In nature, most organisms have natural enemies, but some do not. For example, some disease-causing viruses have no natural enemy. It would be a logical step to create an artificial life form that could become an enemy to them,” he says.

Similarly, he envisions such artificial life forms can act as vaccines against viral infection and can be used as nanorobots or nanomachines loaded with medication or diagnostic elements and sent into a patient’s body.

“An artificial viral vaccine may be about 10 years away. An artificial cell, on the other hand, is on the horizon because it consists of many elements that need to be controlled before we can start building with them. But with the knowledge we have, there is, in principle, no hindrance to produce artificial cellular organisms in the future,” he says.

What are the building blocks that Lou and his colleagues in this field will use to create viral vaccines and artificial life? DNA and peptides are some of the most important biomolecules in nature, making DNA technology and peptide technology the two most powerful molecular tools in the nanotechnological toolkit today. DNA technology provides precise control over programming, from the atomic level to the macro level, but it can only provide limited chemical functions since it only has four bases: A, C, G, and T. Peptide technology, on the other hand, can provide sufficient chemical functions on a large scale, as there are 20 amino acids to work with. Nature uses both DNA and peptides to build various protein factories found in cells, allowing them to evolve into organisms.

Recently, Hanbin Mao and Chenguang Lou have succeeded in linking designed three-stranded DNA structures with three-stranded peptide structures, thus creating an artificial hybrid molecule that combines the strengths of both. This work was published in Nature Communications in 2022.

Elsewhere in the world, other researchers are also working on connecting DNA and peptides because this connection forms a strong foundation for the development of more advanced biological entities and life forms.

At Oxford University, researchers have succeeded in building a nanomachine made of DNA and peptides that can drill through a cell membrane, creating an artificial membrane channel through which small molecules can pass. (Spruijt et al., Nat. Nanotechnol. 2018, 13, 739-745)

At Arizona State University, Nicholas Stephanopoulos and colleagues have enabled DNA and peptides to self-assemble into 2D and 3D structures. (Buchberger et al., J. Am. Chem. Soc. 2020, 142, 1406-1416)

At Northwest University, researchers have shown that microfibers can form in conjunction with DNA and peptides self-assembling. DNA and peptides operate at the nano level, so when considering the size differences, microfibers are huge. (Freeman et al., Science, 2018, 362, 808-813)

At Ben-Gurion University of the Negev, scientists have used hybrid molecules to create an onion-like spherical structure containing cancer medication, which holds promise to be used in the body to target cancerous tumors. (Chotera et al., Chem. Eur. J., 2018, 24, 10128-10135)

“In my view, the overall value of all these efforts is that they can be used to improve society’s ability to diagnose and treat sick people. Looking forward, I will not be surprised that one day we can arbitrarily create hybrid nanomachines, viral vaccines and even artificial life forms from these building blocks to help the society to combat those difficult-to-cure diseases. It would be a revolution in healthcare,” says Chenguang Lou.

Pulsars are the left-over corpses of stars that spectacularly exploded in a supernova. The explosions leave behind a tiny, dead star with a diameter of just some 20 kilometres, rotating extremely fast and endowed with an enormous magnetic field. “These dead stars are almost entirely made up of neutrons and are incredibly dense: a teaspoon of their material has a mass of more than five billion tonnes, or about 900 times the mass of the Great Pyramid of Giza,” explains H.E.S.S. scientist Emma de Oña Wilhelmi, a co-author of the publication working at DESY.

Pulsars emit rotating beams of electromagnetic radiation, somewhat like cosmic lighthouses. If their beam sweeps across our solar system, we see flashes of radiation at regular time intervals. These flashes, also called pulses of radiation, can be searched for in different energy bands of the electromagnetic spectrum. Scientists think that the source of this radiation are fast electrons produced and accelerated in the pulsar’s magnetosphere, while traveling towards its periphery. The magnetosphere is made up of plasma and electromagnetic fields that surround and co-rotate with the star. “On their outward journey, the electrons acquire energy and release it in the form of the observed radiation beams,” says Bronek Rudak from the Nicolaus Copernicus Astronomical Center (CAMK PAN) in Poland, also a co-author.

The Vela pulsar, located in the Southern sky in the constellation Vela (sail of the ship), is the brightest pulsar in the radio band of the electromagnetic spectrum and the brightest persistent source of cosmic gamma rays in the giga-electronvolts (GeV) range. It rotates about eleven times per second. However, above a few GeV, its radiation ends abruptly, presumably because the electrons reach the end of the pulsar’s magnetosphere and escape from it.

But this is not the end of the story: using deep observations with H.E.S.S., a new radiation component at even higher energies has now been discovered, with energies of up to tens of tera-electronvolts (TeV). “That is about 200 times more energetic than all radiation ever detected before from this object,” says co-author Christo Venter from the North-West University in South Africa. This very high-energy component appears at the same phase intervals as the one observed in the GeV range. However, to attain these energies, the electrons might have to travel even farther than the magnetosphere, yet the rotational emission pattern needs to remain intact.

“This result challenges our previous knowledge of pulsars and requires a rethinking of how these natural accelerators work,” says Arache Djannati-Atai from the Astroparticle & Cosmology (APC) laboratory in France, who led the research. “The traditional scheme according to which particles are accelerated along magnetic field lines within or slightly outside the magnetosphere cannot sufficiently explain our observations. Perhaps we are witnessing the acceleration of particles through the so-called magnetic reconnection process beyond the light cylinder, which still somehow preserves the rotational pattern? But even this scenario faces difficulties to explain how such extreme radiation is produced.”

Whatever the explanation, next to its other superlatives, the Vela pulsar now officially holds the record as the pulsar with the highest-energy gamma rays discovered to date. “This discovery opens a new observation window for detection of other pulsars in the tens of teraelectronvolt range with current and upcoming more sensitive gamma-ray telescopes, hence paving the way for a better understanding of the extreme acceleration processes in highly magnetised astrophysical objects,” says Djannati-Atai.

Excitons are a key part of many technologies, including solar panels, photodetectors and sensors, as well as light-emitting diodes found in televisions and digital display screens. In most cases, the exciton pairs are bound by electrical, or electrostatic, forces, also known as Coulomb interactions. Now, in a new study in Nature Physics, Caltech researchers report detecting excitons that are not bound via Coulomb forces but rather by magnetism. This is the first experiment to detect how these so-called Hubbard excitons, named after the late physicist John Hubbard, form in real-time.

“Using an advanced spectroscopic probe, we were able to observe in real time the generation and decay of magnetically bound excitons, the Hubbard excitons,” says study lead author Omar Mehio (PhD ’23), a recent graduate student at Caltech who worked with David Hsieh, the Donald A. Glaser Professor of Physics at Caltech. Mehio is now a postdoctoral fellow at the Kavli Institute at Cornell.

“In most insulators, oppositely charged electrons and holes interact with one another just as an electron and a proton bind to form a hydrogen atom,” Mehio explains. “However, in a special class of materials known as Mott insulators, the photo-excited electrons and holes instead bind through magnetic interactions.”

The results could have applications in the development of new exciton-related technologies, or excitonics, in which the excitons would be manipulated through their magnetic properties. “Hubbard excitons and their magnetic binding mechanism demonstrate a drastic departure from the paradigms of traditional excitonics, creating the opportunity to develop a whole ecosystem of novel technologies that are fundamentally unavailable in conventional excitonic systems,” Mehio says. “Having excitons and magnetism strongly intertwined in a single material could lead to new technologies that harness both properties.”

To create the Hubbard excitons, the researchers applied light to a type of insulating material known as an antiferromagnetic Mott insulator. These are magnetic materials in which the electron spins are aligned in a repeating, stable pattern. The light excites the electrons, which jump to other atoms, leaving holes behind.

“In these materials, when an electron or hole moves through the lattice, they leave in their wake a string of magnetic excitations,” Mehio says. “Imagine you tie one end of an elastic rope around your friend, and the other end around yourself. If your friend runs away from you, you will feel the rope pull you in that direction and you will begin to follow. This scenario is analogous to what happens between a photo-excited electron and the hole it leaves behind in a Mott insulator. With Hubbard excitons, the string of magnetic excitations between the pair serves the same role as the rope connecting you to your friend.”

To demonstrate the existence of the Hubbard excitons, the researchers used a method called ultrafast time-domain terahertz spectroscopy, which allowed them to look for the very short-lived signatures of the excitons at very low-energy scales. “Excitons are unstable because the electrons want to go back into the holes,” Hsieh explains. “We have a way of probing the short time window before this recombination occurs, and that allowed us to see that a fluid of Hubbard excitons is transiently stabilized.”

According to the researchers, Pennsylvania’s ruffed grouse populations have declined by up to 70% since the early 1960s, with birds in the southern part of the state particularly affected by West Nile virus, which is spread by mosquitoes, and by habitat fragmentation due to development.

“By all typical metrics, the ruffed grouse is in a state of rapid decline,” said Julian Avery, associate research professor of wildlife conservation at Penn State and co-author of the paper. “Yet, until now, no one had used genetic tools to investigate the effects of this decline at a deeper level. By applying whole-genome sequencing, we have found that the bird is genetically better off than we suspected, which means that habitat protection and other management interventions can work to protect this species.”

Leilton Luna, postdoctoral researcher at Penn State and corresponding author of the paper, explained that when an organism’s population size drops too low because of disease or habitat loss, inbreeding can occur, which can lead to a decline in genetic diversity over time.

“Populations with low genetic diversity have a harder time evolving in response to changing environmental conditions and are at greater risk of extinction,” Luna said. “In the case of the Pennsylvania ruffed grouse, due to the sharp population decline, it certainly doesn’t have the same healthy genetic conditions as it did in the past. Even so, the current levels of genetic diversity and connectivity give us great hope for the preservation of this species.”

As an initial step, the team produced the first high-quality reference genome for ruffed grouse. A reference genome, Luna said, is a representative example of a particular organism’s genes.

“This reference genome serves as a standardized genetic baseline, facilitating accurate comparisons of genome-wide diversity between individuals and populations,” Luna said. “Additionally, this genomic resource will enable us to investigate important questions, such as whether specific genetic components, like adapted genes, contribute to varying population responses to West Nile virus in different ruffed grouse populations.”

To investigate the population health of the ruffed grouse in Pennsylvania, the research team sequenced 54 individual bird genomes within habitats that were both fragmented by development and intact. The researchers examined the sequence data for evidence of gene flow, which indicates that genetic material is readily exchanged among migrating populations.

“We compared each individual to every other individual that we sampled,” Luna said. “By doing this, we were able to tell if the birds all belong to a single geographic population or to different populations, as well as how environmental factors such as habitat fragmentation and terrain elevation shape the effective dispersal of birds and, therefore, the exchange of genes.”

He said the team’s DNA analysis provided weak evidence of population subdivision across the state, although the researchers identified reduced genetic connectivity in the south, where the bird’s habitat is fragmented by human development.

“This tells us that the population may not be doing as bad as we expected,” Luna said. “It also helped us to inform wildlife managers which areas would most benefit from the development of habitat corridors. However, it is just a snapshot of the population at this particular moment. In the future, we hope to analyze the DNA of museum specimens so we can compare the genetic diversity and connectivity of today’s populations with those from before West Nile virus was present and before the habitat was so fragmented.”

Surprisingly, the team said, it also stumbled onto the presence of two genetic “anomalies,” called chromosomal inversions. These occur when a segment of DNA breaks off and then reattaches in reverse order.

“We found chromosomal inversions within some of the individuals we sampled, and these were found in individuals from across the Commonwealth,” said co-author David Toews, assistant professor of biology at Penn State.

“The data are very clear,” he said. “There are these two large chunks of the ruffed grouse genome that are highly differentiated from the rest of the genome, and they are not associated with any obvious geographic pattern among the birds. It adds a fun ruffle to the story.”

Toews noted that chromosomal inversions previously were found in other bird species and were expressed via different plumage patterns or more aggressive behaviors, for example. He said the team does not yet know how the inversions might affect the ruffed grouse. It’s a topic the team plans to further investigate.

In the meantime, Toews said, the chromosomal inversions have important implications for conservation.

“On the surface, all ruffed grouse look fairly similar, but they actually have deep genetic differences,” he said. “In the context of conservation, it may be important to think beyond the species overall to consider protecting individuals with these genetic variations.”

Avery noted that Penn State has a long history of working with state agencies — such as the Pennsylvania Game Commission, Pennsylvania Fish and Boat Commission and Pennsylvania Department of Conservation and Natural Resources — to collect and analyze scientific data that can help inform conservation strategies. He said the team’s findings suggest that certain management interventions may help the bird to maintain healthy populations. These include:

• Creating and maintaining habitats that functionally connect forested regions and populations
• Evaluating the impact of hunting to ensure harvest is not contributing to the decline of more vulnerable populations
• Implementing periodic genetic monitoring to track changes and assess whether habitat interventions lead to positive genetic changes

“Not only do ruffed grouse play an important role in the ecosystem, but they are also really interesting,” Avery said. “The males make this drumming sound in the spring to attract mates. You can physically feel the bass when they’re drumming in the woods. They also pair the drumming with a flashy display of ornamental feathers and a spread tail, similar to the over-the-top performance of a male peacock. To top it off, during the fall, ruffed grouse grow these fascinating extensions of their toe scales that may help to increase surface area during the winter months. They’re just beautiful and bizarre, and they deserve our conservation attention.”

Other authors on the paper include Lisa Williams, wildlife biologist; Kenneth Duren, game bird section supervisor; and Reina Tyl, wildlife biologist, all at the Pennsylvania Game Commission.

The Pennsylvania Game Commission supported this research.

Known as MXene and MBene compounds, these substances are only a few atoms thick, making them two-dimensional. Because of their large surface area, the materials have the potential to absorb carbon dioxide molecules from the atmosphere, which could help reduce the harmful effects of climate change by safely sequestering carbon dioxide.

In a paper published Oct. 4 in the journal Chem, UC Riverside professor Mihri Ozkan and her co-authors explain the potential of MXenes and MBenes in carbon capture technologies.

“In this review, we conducted an exhaustive analysis and proposed strategies for the widespread implementation of these materials in large-scale applications,” said Ozkan, a climate action professor in UCR’s Electrical and Computer Engineering Department at the Bourns College of Engineering.

“Their unique properties make them excellent candidates for capturing carbon dioxide.”

According to Ozkan, these two-dimensional materials can be engineered to selectively capture carbondioxide. One of their key advantages is their high selectivity towards carbon dioxide, which can be attributed to a process called interlayer distance engineering. Additionally, the materials are mechanically stable and maintain their structural integrity even after multiple cycles of carbon capture and release.

graphic As human-caused carbon dioxide emissions continue to increase, developing carbon-capture technologies has become a top priority. It is projected that the planet’s temperature could rise by 1.5°C above pre-industrial levels within the next decade, leading to more frequent severe weather events, worsening drought, crop failures, increased levels of human migration, and political instability. These negative impacts highlight the urgent need for action to curb carbon emissions and mitigate the effects of climate change.

Scientists at Drexel University in Philadelphia, Pa., discovered MXenes and MBenes in the early 2010s. MXene is an inorganic compound made up of atomically thin layers of transition metal carbides, nitrides or carbonitrides. On the other hand, MBenes are dimensional transition metal borides made from boron. These compounds are produced through chemical etching techniques and have crystalline lattices with repeating orthorhombic and hexagonal structures.

Ozkan explained that these materials can be used in conjunction with existing technologies, such as those developed by the Swiss company Climework AS. These systems extract carbon dioxide directly from the atmosphere and sequester it for safe and long-term storage.

Before these compounds can be used in carbon capture devices, several technical issues need to be resolved, according to Ozkan. First and foremost, scientists must address the bottlenecks associated with synthesis-related challenges in large-volume production. Other obstacles to large-scale manufacturing include non-uniform mixing, temperature gradients, and problems with heat transfer, among others.

Still, these hurdles can be overcome.

A top-down approach is ideal for large-scale MXene synthesis by scaling up wet etching methods or developing new ones, according to Ozkan.

The paper’s co-authors are UCR’s Kathrine A.M. Quiros, Jordyn M. Watkins, Talyah M. Nelson, Navindra D. Singh, Mahbub Chowdhury, Thrayesh Namboodiri, Kamal R. Talluri, and Emma Yuan.