Category Archives: medicine

‘Nanotraps’ for catching and destroying coronavirus

‘Nanotraps’ are not vaccines although they do call the immune system into play. They represent a different way for dealing with COVID-19. (This work reminds of my June 24, 2020 posting Tiny sponges lure coronavirus away from lung cells where the researchers have a similar approach with what they call ‘nanosponges’.)

An April 27, 2021 news item on Nanowerk makes the announcement,

Researchers at the Pritzker School of Molecular Engineering (PME) at the University of Chicago have designed a completely novel potential treatment for COVID-19: nanoparticles that capture SARS-CoV-2 viruses within the body and then use the body’s own immune system to destroy it.

These “Nanotraps” attract the virus by mimicking the target cells the virus infects. When the virus binds to the Nanotraps, the traps then sequester the virus from other cells and target it for destruction by the immune system.

In theory, these Nanotraps could also be used on variants of the virus, leading to a potential new way to inhibit the virus going forward. Though the therapy remains in early stages of testing, the researchers envision it could be administered via a nasal spray as a treatment for COVID-19.

A scanning electron microscope image of a nanotrap (orange) binding a simulated SARS-CoV-2 virus (dots in green). Scientists at the University of Chicago created these nanoparticles as a potential treatment for COVID-19. Image courtesy Chen and Rosenberg et al.

An April 27, 2021 University of Chicago news release (also on EurekAlert) by Emily Ayshford, which originated the news item, describes the work in more detail,

“Since the pandemic began, our research team has been developing this new way to treat COVID-19,” said Asst. Prof. Jun Huang, whose lab led the research. “We have done rigorous testing to prove that these Nanotraps work, and we are excited about their potential.”

Designing the perfect trap

To design the Nanotrap, the research team – led by postdoctoral scholar Min Chen and graduate student Jill Rosenberg – looked into the mechanism SARS-CoV-2 uses to bind to cells: a spike-like protein on its surface that binds to a human cell’s ACE2 receptor protein.

To create a trap that would bind to the virus in the same way, they designed nanoparticles with a high density of ACE2 proteins on their surface. Similarly, they designed other nanoparticles with neutralizing antibodies on their surfaces. (These antibodies are created inside the body when someone is infected and are designed to latch onto the coronavirus in various ways).

Both ACE2 proteins and neutralizing antibodies have been used in treatments for COVID-19, but by attaching them to nanoparticles, the researchers created an even more robust system for trapping and eliminating the virus.

Made of FDA [US Food and Drug Administration]-approved polymers and phospholipids, the nanoparticles are about 500 nanometers in diameter – much smaller than a cell. That means the Nanotraps can reach more areas inside the body and more effectively trap the virus.

The researchers tested the safety of the system in a mouse model and found no toxicity. They then tested the Nanotraps against a pseudovirus – a less potent model of a virus that doesn’t replicate – in human lung cells in tissue culture plates and found that they completely blocked entry into the cells.

Once the pseudovirus bound itself to the nanoparticle – which in tests took about 10 minutes after injection – the nanoparticles used a molecule that calls the body’s macrophages to engulf and degrade the Nanotrap. Macrophages will generally eat nanoparticles within the body, but the Nanotrap molecule speeds up the process. The nanoparticles were cleared and degraded within 48 hours.

The researchers also tested the nanoparticles with a pseudovirus in an ex vivo lung perfusion system – a pair of donated lungs that is kept alive with a ventilator – and found that they completely blocked infection in the lungs.

They also collaborated with researchers at Argonne National Laboratory to test the Nanotraps with a live virus (rather than a pseudovirus) in an in vitro system. They found that their system inhibited the virus 10 times better than neutralizing antibodies or soluble ACE2 alone.

A potential future treatment for COVID-19 and beyond

Next the researchers hope to further test the system, including more tests with a live virus and on the many virus variants.

“That’s what is so powerful about this Nanotrap,” Rosenberg said. “It’s easily modulated. We can switch out different antibodies or proteins or target different immune cells, based on what we need with new variants.”

The Nanotraps can be stored in a standard freezer and could ultimately be given via an intranasal spray, which would place them directly in the respiratory system and make them most effective.

The researchers say it is also possible to serve as a vaccine by optimizing the Nanotrap formulation, creating an ultimate therapeutic system for the virus.

“This is the starting point,” Huang said. “We want to do something to help the world.”

The research involved collaborators across departments, including chemistry, biology, and medicine.

Here’s a link to and a citation for the paper,

Nanotraps for the containment and clearance of SARS-CoV-2 by Min Chen, Jillian Rosenberg, Xiaolei Cai, Andy Chao Hsuan Lee, Jiuyun Shi, Mindy Nguyen, Thirushan Wignakumar, Vikranth Mirle, Arianna Joy Edobor, John Fung, Jessica Scott Donington, Kumaran Shanmugarajah, Yiliang Lin, Eugene Chang, Glenn Randall, Pablo Penaloza-MacMaster, Bozhi Tian, Maria Lucia Madariaga, Jun Huang. Matter, April 19, 2021, DOI:

This paper appears to be open access.

Protocols for mouse-human chimeric embryos

This work on a type of species boundary-crossing could be very disturbing for some folks. That said, here’s more about the science from a July 2, 2021 news item on,

A year after University at Buffalo [in New York state] scientists demonstrated that it was possible to produce millions of mature human cells in a mouse embryo, they have published a detailed description of the method so that other laboratories can do it, too.

A July 2, 2021 University at Buffalo (UB) news release (also on EurekAlert) by Ellen Goldbaum, which originated the news item, explains why scientists have created these chimeras,

The ability to produce millions of mature human cells in a living organism, called a chimera, which contains the cells of two species, is critical if the ultimate promise of stem cells to treat or cure human disease is to be realized. But to produce those mature cells, human primed stem cells must be converted back into an earlier, less developed naive state so that the human stem cells can co-develop with the inner cell mass in a mouse blastocyst.

The protocol outlining how to do that has now been published in Nature Protocols by the UB scientists. They were invited to publish it because of the significant interest generated by the team’s initial publication describing their breakthrough last May [2020].

“This paper will enable many scientists to use this new platform to study the human disease of their interest,” said Jian Feng, PhD, professor of physiology and biophysics in the Jacobs School of Medicine and Biomedical Sciences at UB and senior author. “Over time, it will transform biomedical research toward a more effective use of the human model system to directly study virtually any inborn condition of an individual. It will stimulate unforeseen discoveries and applications that may fundamentally change our understanding of human biology and medicine.”

The protocol will allow scientists to create animal models that Feng said provide a much more realistic picture of embryonic development than has ever been possible. These more realistic animal models also will have the potential to reveal the mechaniswms behind numerous diseases, especially those that afflict individuals from birth.

Better mouse models

“This step-by-step protocol will benefit the entire field by enabling other scientists to use our methods to generate chimeras to study human diseases that they are experts in,” said Feng. “It will lead to the generation of better mouse models for various human diseases, such as sickle cell anemia, COVID-19 and many others, or various human developmental disorders.” The paper demonstrates how to generate naive human pluripotent stem cells from existing induced pluripotent stem cells that may be derived from patients with various diseases, how to generate mouse-human chimeras using these cells and how to quantify the amount of human cells in the chimeras.

“Using our method, one can now track the development of naive human pluripotent stem cells in mouse-human chimeric embryos in real-time,” said Feng. These stem cells can then be manipulated either genetically or pharmacologically, providing valuable information about human development and disease.

“For example, one can label naive human pluripotent stem cells by inserting green fluorescent protein in a hemoglobin gene to study the development of human red blood cells in mouse-human chimeras,” said Feng.

Another application is to generate humanized mouse models to study many human diseases.

“These mice contain critical human cells, tissues or even organs so that they more accurately reflect the human condition,” said Feng. “With our method, the human cells are made along with the mouse during the development of the mouse embryo. There would be better matching and no rejections, because there are ways for the human cells to be made where there is no competition from their mouse counterparts.”

Organs for transplant in the future

By allowing others to improve and adapt the method to eventually generate chimeras in larger animals, this protocol may also lead to the generation of human organs to address the dire shortage of organs available for transplant, said Feng.

“If naive human pluripotent stem cells are able to generate significant amounts of mature human cells in other larger species, it could be possible to make human tissues or even human organs in chimeric animals,” Feng explained.

This would be possible using blastocyst complementation where, Feng explained, normal pluripotent stem cells from one species can reconstitute an organ for that species in a blastocyst of another species that been genetically modified not to grow that particular organ.

Feng added: “Ultimately, a better understanding of how human cells develop and grow in chimeras may enable the generation of human cells, tissues and organs in a completely artificial system and fundamentally change how we treat many human diseases. Research using chimeras is a bridge that must be crossed to reach that possibility.”

Here’s a link to and a citation for the 2021 article,

Generation of mouse–human chimeric embryos by Boyang Zhang, Hanqin Li, Zhixing Hu, Houbo Jiang, Aimee B. Stablewski, Brandon J. Marzullo, Donald A. Yergeau & Jian Feng. Nature Protocols (2021) DOI: Published 02 July 2021

This article is behind a paywall.

Here’s a link to and citation for the 2020 work, which led to the publication of the protocols,

Transient inhibition of mTOR in human pluripotent stem cells enables robust formation of mouse-human chimeric embryos by Zhixing Hu, Hanqin Li, Houbo Jiang, Yong Ren, Xinyang Yu, Jingxin Qiu, Aimee B. Stablewski, Boyang Zhang, Michael J. Buck, Jian Feng. Science Advances 13 May 2020: Vol. 6, no. 20, eaaz0298 DOI: 10.1126/sciadv.aaz0298

This paper is open access.

Nanosensors use AI to explore the biomolecular world

EPFL scientists have developed AI-powered nanosensors that let researchers track various kinds of biological molecules without disturbing them. Courtesy: École polytechnique fédérale de Lausanne (EPFL)

If you look at the big orange dot (representing the nanosensors?), you’ll see those purplish/fuschia objects resemble musical notes (biological molecules?). I think that brainlike object to the left and in light blue is the artificial intelligence (AI) component. (If anyone wants to correct my guesses or identify the bits I can’t, please feel free to add to the Comments for this blog.)

Getting back to my topic, keep the ‘musical notes’ in mind as you read about some of the latest research from l’École polytechnique fédérale de Lausanne (EPFL) in an April 7, 2021 news item on Nanowerk,

The tiny world of biomolecules is rich in fascinating interactions between a plethora of different agents such as intricate nanomachines (proteins), shape-shifting vessels (lipid complexes), chains of vital information (DNA) and energy fuel (carbohydrates). Yet the ways in which biomolecules meet and interact to define the symphony of life is exceedingly complex.

Scientists at the Bionanophotonic Systems Laboratory in EPFL’s School of Engineering have now developed a new biosensor that can be used to observe all major biomolecule classes of the nanoworld without disturbing them. Their innovative technique uses nanotechnology, metasurfaces, infrared light and artificial intelligence.

To each molecule its own melody

In this nano-sized symphony, perfect orchestration makes physiological wonders such as vision and taste possible, while slight dissonances can amplify into horrendous cacophonies leading to pathologies such as cancer and neurodegeneration.

An April 7, 2021 EPFL press release, which originated the news item, provides more detail,

“Tuning into this tiny world and being able to differentiate between proteins, lipids, nucleic acids and carbohydrates without disturbing their interactions is of fundamental importance for understanding life processes and disease mechanisms,” says Hatice Altug, the head of the Bionanophotonic Systems Laboratory. 

Light, and more specifically infrared light, is at the core of the biosensor developed by Altug’s team. Humans cannot see infrared light, which is beyond the visible light spectrum that ranges from blue to red. However, we can feel it in the form of heat in our bodies, as our molecules vibrate under the infrared light excitation.

Molecules consist of atoms bonded to each other and – depending on the mass of the atoms and the arrangement and stiffness of their bonds – vibrate at specific frequencies. This is similar to the strings on a musical instrument that vibrate at specific frequencies depending on their length. These resonant frequencies are molecule-specific, and they mostly occur in the infrared frequency range of the electromagnetic spectrum. 

“If you imagine audio frequencies instead of infrared frequencies, it’s as if each molecule has its own characteristic melody,” says Aurélian John-Herpin, a doctoral assistant at Altug’s lab and the first author of the publication. “However, tuning into these melodies is very challenging because without amplification, they are mere whispers in a sea of sounds. To make matters worse, their melodies can present very similar motifs making it hard to tell them apart.” 

Metasurfaces and artificial intelligence

The scientists solved these two issues using metasurfaces and AI. Metasurfaces are man-made materials with outstanding light manipulation capabilities at the nano scale, thereby enabling functions beyond what is otherwise seen in nature. Here, their precisely engineered meta-atoms made out of gold nanorods act like amplifiers of light-matter interactions by tapping into the plasmonic excitations resulting from the collective oscillations of free electrons in metals. “In our analogy, these enhanced interactions make the whispered molecule melodies more audible,” says John-Herpin.

AI is a powerful tool that can be fed with more data than humans can handle in the same amount of time and that can quickly develop the ability to recognize complex patterns from the data. John-Herpin explains, “AI can be imagined as a complete beginner musician who listens to the different amplified melodies and develops a perfect ear after just a few minutes and can tell the melodies apart, even when they are played together – like in an orchestra featuring many instruments simultaneously.” 

The first biosensor of its kind

When the scientists’ infrared metasurfaces are augmented with AI, the new sensor can be used to analyze biological assays featuring multiple analytes simultaneously from the major biomolecule classes and resolving their dynamic interactions. 

“We looked in particular at lipid vesicle-based nanoparticles and monitored their breakage through the insertion of a toxin peptide and the subsequent release of vesicle cargos of nucleotides and carbohydrates, as well as the formation of supported lipid bilayer patches on the metasurface,” says Altug.

This pioneering AI-powered, metasurface-based biosensor will open up exciting perspectives for studying and unraveling inherently complex biological processes, such as intercellular communication via exosomesand the interaction of nucleic acids and carbohydrates with proteins in gene regulation and neurodegeneration. 

“We imagine that our technology will have applications in the fields of biology, bioanalytics and pharmacology – from fundamental research and disease diagnostics to drug development,” says Altug. 

Here’s a link to and a citation for the paper,

Infrared Metasurface Augmented by Deep Learning for Monitoring Dynamics between All Major Classes of Biomolecules by Aurelian John‐Herpin, Deepthy Kavungal. Lea von Mücke, Hatice Altug. Advanced Materials Volume 33, Issue 14 April 8, 2021 2006054 DOI: First published: 22 February 2021

This paper is open access.

Gold nanoparticle tattoo changes medical diagnostics?

The tattoos are in fact implantable sensors. Here’s more from an April 6, 2021 news item on ScienceDaily,

The idea of implantable sensors that continuously transmit information on vital values and concentrations of substances or drugs in the body has fascinated physicians and scientists for a long time. Such sensors enable the constant monitoring of disease progression and therapeutic success. However, until now implantable sensors have not been suitable to remain in the body permanently but had to be replaced after a few days or weeks. On the one hand, there is the problem of implant rejection because the body recognizes the sensor as a foreign object. On the other hand, the sensor’s color which indicates concentration changes has been unstable so far and faded over time. Scientists at Johannes Gutenberg University Mainz (JGU) have developed a novel type of implantable sensor which can be operated in the body for several months. The sensor is based on color-stable gold nanoparticles that are modified with receptors for specific molecules. Embedded into an artificial polymeric tissue, the nanogold is implanted under the skin where it reports changes in drug concentrations by changing its color.

An April 6, 2021 Johannes Gutenberg Universitaet Mainz press release (also on EurekAlert), which originated the news item, provides more detail about the proposed tattoo/implantable sensors,

Implant reports information as an “invisible tattoo”

Professor Carsten Sönnichsen’s research group at JGU has been using gold nanoparticles as sensors to detect tiny amounts of proteins in microscopic flow cells for many years. Gold nanoparticles act as small antennas for light: They strongly absorb and scatter it and, therefore, appear colorful. They react to alterations in their surrounding by changing color. Sönnichsen’s team has exploited this concept for implanted medical sensing.

To prevent the tiny particles from swimming away or being degraded by immune cells, they are embedded in a porous hydrogel with a tissue-like consistency. Once implanted under the skin, small blood vessels and cells grow into the pores. The sensor is integrated in the tissue and is not rejected as a foreign body. “Our sensor is like an invisible tattoo, not much bigger than a penny and thinner than one millimeter,” said Professor Carsten Sönnichsen, head of the Nanobiotechnology Group at JGU. Since the gold nanoparticles are infrared, they are not visible to the eye. However, a special kind of measurement device can detect their color noninvasively through the skin.

In their study published in Nano Letters, the JGU researchers implanted their gold nanoparticle sensors under the skin of hairless rats. Color changes in these sensors were monitored following the administration of various doses of an antibiotic. The drug molecules are transported to the sensor via the bloodstream. By binding to specific receptors on the surface of the gold nanoparticles, they induce color change that is dependent on drug concentration. Thanks to the color-stable gold nanoparticles and the tissue-integrating hydrogel, the sensor was found to remain mechanically and optically stable over several months.

Huge potential of gold nanoparticles as long-lasting implantable medical sensors

“We are used to colored objects bleaching over time. Gold nanoparticles, however, do not bleach but keep their color permanently. As they can be easily coated with various different receptors, they are an ideal platform for implantable sensors,” explained Dr. Katharina Kaefer, first author of the study.

The novel concept is generalizable and has the potential to extend the lifetime of implantable sensors. In future, gold nanoparticle-based implantable sensors could be used to observe concentrations of different biomarkers or drugs in the body simultaneously. Such sensors could find application in drug development, medical research, or personalized medicine, such as the management of chronic diseases.

Interdisciplinary team work brought success

Sönnichsen had the idea of using gold nanoparticles as implanted sensors already in 2004 when he started his research in biophysical chemistry as a junior professor in Mainz. However, the project was not realized until ten years later in cooperation with Dr. Thies Schroeder and Dr. Katharina Kaefer, both scientists at JGU. Schroeder was experienced in biological research and laboratory animal science and had already completed several years of research work in the USA. Kaefer was looking for an exciting topic for her doctorate and was particularly interested in the complex and interdisciplinary nature of the project. Initial results led to a stipend awarded to Kaefer by the Max Planck Graduate Center (MPGC) as well as financial support from Stiftung Rheinland-Pfalz für Innovation. “Such a project requires many people with different scientific backgrounds. Step by step we were able to convince more and more people of our idea,” said Sönnichsen happily. Ultimately, it was interdisciplinary teamwork that resulted in the successful development of the first functional implanted sensor with gold nanoparticles.

The researchers have provided an image which illustrates several elements described in the press release,

Caption: Gold nanoparticles embedded in a porous hydrogel can be implanted under the skin and used as medical sensors. The sensor is like an invisible tattoo revealing concentration changes of substances in the blood by color change. Credit: ill./©: Nanobiotechnology Group, JGU Department of Chemistry

Here’s a link to and a citation for the paper,

Implantable Sensors Based on Gold Nanoparticles for Continuous Long-Term Concentration Monitoring in the Body by Katharina Kaefer, Katja Krüger, Felix Schlapp, Hüseyin Uzun, Sirin Celiksoy, Bastian Flietel, Axel Heimann, Thies Schroeder, Oliver Kempski, and Carsten Sönnichsen. Nano Lett. 2021, XXXX, XXX, XXX-XXX DOI: Publication Date:March 30, 2021 © 2021 The Authors. Published by American Chemical Society

This paper is behind a paywall.

A new generation of xenobots made with frog cells

I meant to feature this work last year when it was first announced so I’m delighted a second chance has come around so soon after. From a March 31, 2021 news item on ScienceDaily,

Last year, a team of biologists and computer scientists from Tufts University and the University of Vermont (UVM) created novel, tiny self-healing biological machines from frog cells called “Xenobots” that could move around, push a payload, and even exhibit collective behavior in the presence of a swarm of other Xenobots.

Get ready for Xenobots 2.0.

Here’s a video of the Xenobot 2.0. It’s amazing but, for anyone who has problems with animal experimentation, this may be disturbing,

The next version of Xenobots have been created – they’re faster, live longer, and can now record information. (Source: Doug Blackiston & Emma Lederer)

A March 31, 2021 Tufts University news release by Mike Silver (also on EurekAlert and adapted and published as Scientists Create the Next Generation of Living Robots on the University of Vermont website as a UVM Today story),

The same team has now created life forms that self-assemble a body from single cells, do not require muscle cells to move, and even demonstrate the capability of recordable memory. The new generation Xenobots also move faster, navigate different environments, and have longer lifespans than the first edition, and they still have the ability to work together in groups and heal themselves if damaged. The results of the new research were published today [March 31, 2021] in Science Robotics.

Compared to Xenobots 1.0, in which the millimeter-sized automatons were constructed in a “top down” approach by manual placement of tissue and surgical shaping of frog skin and cardiac cells to produce motion, the next version of Xenobots takes a “bottom up” approach. The biologists at Tufts took stem cells from embryos of the African frog Xenopus laevis (hence the name “Xenobots”) and allowed them to self-assemble and grow into spheroids, where some of the cells after a few days differentiated to produce cilia – tiny hair-like projections that move back and forth or rotate in a specific way. Instead of using manually sculpted cardiac cells whose natural rhythmic contractions allowed the original Xenobots to scuttle around, cilia give the new spheroidal bots “legs” to move them rapidly across a surface. In a frog, or human for that matter, cilia would normally be found on mucous surfaces, like in the lungs, to help push out pathogens and other foreign material. On the Xenobots, they are repurposed to provide rapid locomotion. 

“We are witnessing the remarkable plasticity of cellular collectives, which build a rudimentary new ‘body’ that is quite distinct from their default – in this case, a frog – despite having a completely normal genome,” said Michael Levin, Distinguished Professor of Biology and director of the Allen Discovery Center at Tufts University, and corresponding author of the study. “In a frog embryo, cells cooperate to create a tadpole. Here, removed from that context, we see that cells can re-purpose their genetically encoded hardware, like cilia, for new functions such as locomotion. It is amazing that cells can spontaneously take on new roles and create new body plans and behaviors without long periods of evolutionary selection for those features.”

“In a way, the Xenobots are constructed much like a traditional robot.  Only we use cells and tissues rather than artificial components to build the shape and create predictable behavior.” said senior scientist Doug Blackiston, who co-first authored the study with research technician Emma Lederer. “On the biology end, this approach is helping us understand how cells communicate as they interact with one another during development, and how we might better control those interactions.”

While the Tufts scientists created the physical organisms, scientists at UVM were busy running computer simulations that modeled different shapes of the Xenobots to see if they might exhibit different behaviors, both individually and in groups. Using the Deep Green supercomputer cluster at UVM’s Vermont Advanced Computing Core, the team, led by computer scientists and robotics experts Josh Bongard and Sam Kriegman, simulated the Xenbots under hundreds of thousands of random environmental conditions using an evolutionary algorithm.  These simulations were used to identify Xenobots most able to work together in swarms to gather large piles of debris in a field of particles

“We know the task, but it’s not at all obvious — for people — what a successful design should look like. That’s where the supercomputer comes in and searches over the space of all possible Xenobot swarms to find the swarm that does the job best,” says Bongard. “We want Xenobots to do useful work. Right now we’re giving them simple tasks, but ultimately we’re aiming for a new kind of living tool that could, for example, clean up microplastics in the ocean or contaminants in soil.” 

It turns out, the new Xenobots are much faster and better at tasks such as garbage collection than last year’s model, working together in a swarm to sweep through a petri dish and gather larger piles of iron oxide particles. They can also cover large flat surfaces, or travel through narrow capillary tubes.

These studies also suggest that the in silico [computer] simulations could in the future optimize additional features of biological bots for more complex behaviors. One important feature added in the Xenobot upgrade is the ability to record information.

Now with memory

A central feature of robotics is the ability to record memory and use that information to modify the robot’s actions and behavior. With that in mind, the Tufts scientists engineered the Xenobots with a read/write capability to record one bit of information, using a fluorescent reporter protein called EosFP, which normally glows green. However, when exposed to light at 390nm wavelength, the protein emits red light instead. 

The cells of the frog embryos were injected with messenger RNA coding for the EosFP protein before stem cells were excised to create the Xenobots. The mature Xenobots now have a built-in fluorescent switch which can record exposure to blue light around 390nm.
The researchers tested the memory function by allowing 10 Xenobots to swim around a surface on which one spot is illuminated with a beam of 390nm light. After two hours, they found that three bots emitted red light. The rest remained their original green, effectively recording the “travel experience” of the bots.

This proof of principle of molecular memory could be extended in the future to detect and record not only light but also the presence of radioactive contamination, chemical pollutants, drugs, or a disease condition. Further engineering of the memory function could enable the recording of multiple stimuli (more bits of information) or allow the bots to release compounds or change behavior upon sensation of stimuli. 

“When we bring in more capabilities to the bots, we can use the computer simulations to design them with more complex behaviors and the ability to carry out more elaborate tasks,” said Bongard. “We could potentially design them not only to report conditions in their environment but also to modify and repair conditions in their environment.”

Xenobot, heal thyself

“The biological materials we are using have many features we would like to someday implement in the bots – cells can act like sensors, motors for movement, communication and computation networks, and recording devices to store information,” said Levin. “One thing the Xenobots and future versions of biological bots can do that their metal and plastic counterparts have difficulty doing is constructing their own body plan as the cells grow and mature, and then repairing and restoring themselves if they become damaged. Healing is a natural feature of living organisms, and it is preserved in Xenobot biology.” 

The new Xenobots were remarkably adept at healing and would close the majority of a severe full-length laceration half their thickness within 5 minutes of the injury. All injured bots were able to ultimately heal the wound, restore their shape and continue their work as before. 

Another advantage of a biological robot, Levin adds, is metabolism. Unlike metal and plastic robots, the cells in a biological robot can absorb and break down chemicals and work like tiny factories synthesizing and excreting chemicals and proteins. The whole field of synthetic biology – which has largely focused on reprogramming single celled organisms to produce useful molecules – can now be exploited in these multicellular creatures

Like the original Xenobots, the upgraded bots can survive up to ten days on their embryonic energy stores and run their tasks without additional energy sources, but they can also carry on at full speed for many months if kept in a “soup” of nutrients. 

What the scientists are really after

An engaging description of the biological bots and what we can learn from them is presented in a TED talk by Michael Levin. In his TED Talk, professor Levin describes not only the remarkable potential for tiny biological robots to carry out useful tasks in the environment or potentially in therapeutic applications, but he also points out what may be the most valuable benefit of this research – using the bots to understand how individual cells come together, communicate, and specialize to create a larger organism, as they do in nature to create a frog or human. It’s a new model system that can provide a foundation for regenerative medicine.

Xenobots and their successors may also provide insight into how multicellular organisms arose from ancient single celled organisms, and the origins of information processing, decision making and cognition in biological organisms. 

Recognizing the tremendous future for this technology, Tufts University and the University of Vermont have established the Institute for Computer Designed Organisms (ICDO), to be formally launched in the coming months, which will pull together resources from each university and outside sources to create living robots with increasingly sophisticated capabilities.

The ultimate goal for the Tufts and UVM researchers is not only to explore the full scope of biological robots they can make; it is also to understand the relationship between the ‘hardware’ of the genome and the ‘software’ of cellular communications that go into creating organized tissues, organs and limbs. Then we can gain greater control of that morphogenesis for regenerative medicine, and the treatment of cancer and diseases of aging.

Here’s a link to and a citation for the paper,

A cellular platform for the development of synthetic living machines by Douglas Blackiston, Emma Lederer, Sam Kriegman, Simon Garnier, Joshua Bongard, and Michael Levin. Science Robotics 31 Mar 2021: Vol. 6, Issue 52, eabf1571 DOI: 10.1126/scirobotics.abf1571

This paper is behind a paywall.

Impact of graphene flakes (nanoparticles) on neurons

This research suggests that graphene flakes might have an impact on anxiety-related behaviour. If I read the work correctly, the graphene flakes don’t exacerbate anxiety but, instead, may provide relief.

A March 10, 2021 news item on announces the research into graphene flakes and neurons (rat), Note: Links have been removed,

Effective, specific, with a reversible and non-harmful action: the identikit of the perfect biomaterial seems to correspond to graphene flakes, the subject of a new study carried out by SISSA—International School for Advanced Studies of Trieste, Catalan Institute of Nanoscience and Nanotechnology (ICN2) of Barcelona, and the National Graphene Institute of the University of Manchester, as part of the European Graphene Flagship project. This nanomaterial has demonstrated the ability to interact with the functions of the nervous system in vertebrates in a very specific manner, interrupting the building up of a pathological process that leads to anxiety-related behavior.

“We previously showed that when graphene flakes are delivered to neurons they interfere spontaneously with excitatory synapses by transiently preventing glutamate release from presynaptic terminals,” says Laura Ballerini of SISSA, the leader of the team that carried out the research study “Graphene oxide prevents lateral amygdala dysfunctional synaptic plasticity and reverts long lasting anxiety behavior in rats,” recently published in Biomaterials.

A March 10, 2021 Scuola Internazionale Superiore di Studi Avanzati (SISSA) press release (also on EurekAlert), which originated the news item, provides more detail,

“We investigated whether such a reduction in synaptic activity was sufficient to modify related behaviours, in particular the pathological ones that develop due to a transient and localised hyper-function of excitatory synapses”. This approach would fortify the strategy of selective and transient targeting of synapses to prevent the development of brain pathologies by using the so-called precise medicine treatments.

To test this hypothesis, the team focused on post-traumatic stress disorder (PTSD) and carried out the experiments in two phases, in vivo and in vitro.

“We analysed defensive behaviours caused in rats [emphasis mine] by the presence of a predator, using the exposure to cat odour, to induce an aversive memory” explains Audrey Franceschi Biagioni of SISSA, the first author of the study. “If exposed to the predator odour, the rat has a defensive response, holing up, and this experience is so well-imprinted in the memory, that when the animal is placed in the same context even six days later, the animal remembers the odour of the predator and acts the same protective behaviour. This is a well-known and consolidated model, that we used to reproduce a stress behaviour. Exposure to the predator can modify neuronal connections – a phenomenon that is technically known as plasticity – and increases synaptic activity in a specific area of the amygdala that therefore represented the target of our study to test the effects of the nanomaterial”.

Laura Ballerini adds: “We hypothesised that graphene flakes that we showed to temporarily inhibit excitatory synapses (without causing inflammation, damage to neurons or other side effects) could be injected in the lateral amygdala when the plasticity associated with memory was consolidated. If the nanomaterial was efficient in blocking excitatory synapses, it should inhibit plasticity and decrease the anxiety related response. And this is what happened: the animals that were administered with graphene flakes, after six days, “forgot” the anxiety related responses, rescuing their behaviour”.

The second part of the research was performed in vitro. “In vivo we could observe only behavioural changes and could not evaluate the impact of the graphene flakes on synapses,” explains Giada Cellot, researcher at SISSA and first author of the study together with Audrey Franceschi Biagioni. “In vitro experiments allowed to work on a simplified model, to get insight about the mechanisms through which the graphene flakes can interact with neurons. We used neuronal cultures obtained from the amygdala, the region of the brain where the stress response occurs, and we observed that the effects of nanomaterials were specific for the excitatory synapses and a short exposure to graphene flakes could prevent the pathological plasticity of the synapses”.

Thanks to these findings, graphene flakes have shown their potential as nanotools (biomedical tools composed of nanomaterials) that could act in a specific and reversible way on synaptic activity to interrupt a pathological process and therefore they might be used also to transport drugs or for other applications in the field of precision medicine.

Here’s a link to and a citation for the paper,

Graphene oxide prevents lateral amygdala dysfunctional synaptic plasticity and reverts long lasting anxiety behavior in rats by Audrey Franceschi Biagionia1, Giada Cellot, Elisa Pati, Neus Lozano, Belén Ballesteros, Raffaele Casani, Norberto Cysne Coimbra, Kostas Kostarelos, Laura Ballerini. Biomaterials Volume 271, April 2021, 120749 DOI:

This paper is open access.

Cortical spheroids (like mini-brains) could unlock (larger) brain’s mysteries

A March 19, 2021 Northwestern University news release on EurekAlert announces the creation of a device designed to monitor brain organoids (for anyone unfamiliar with brain organoids there’s more information after the news),

A team of scientists, led by researchers at Northwestern University, Shirley Ryan AbilityLab and the University of Illinois at Chicago (UIC), has developed novel technology promising to increase understanding of how brains develop, and offer answers on repairing brains in the wake of neurotrauma and neurodegenerative diseases.

Their research is the first to combine the most sophisticated 3-D bioelectronic systems with highly advanced 3-D human neural cultures. The goal is to enable precise studies of how human brain circuits develop and repair themselves in vitro. The study is the cover story for the March 19 [March 17, 2021 according to the citation] issue of Science Advances.

The cortical spheroids used in the study, akin to “mini-brains,” were derived from human-induced pluripotent stem cells. Leveraging a 3-D neural interface system that the team developed, scientists were able to create a “mini laboratory in a dish” specifically tailored to study the mini-brains and collect different types of data simultaneously. Scientists incorporated electrodes to record electrical activity. They added tiny heating elements to either keep the brain cultures warm or, in some cases, intentionally overheated the cultures to stress them. They also incorporated tiny probes — such as oxygen sensors and small LED lights — to perform optogenetic experiments. For instance, they introduced genes into the cells that allowed them to control the neural activity using different-colored light pulses.

This platform then enabled scientists to perform complex studies of human tissue without directly involving humans or performing invasive testing. In theory, any person could donate a limited number of their cells (e.g., blood sample, skin biopsy). Scientists can then reprogram these cells to produce a tiny brain spheroid that shares the person’s genetic identity. The authors believe that, by combining this technology with a personalized medicine approach using human stem cell-derived brain cultures, they will be able to glean insights faster and generate better, novel interventions.

“The advances spurred by this research will offer a new frontier in the way we study and understand the brain,” said Shirley Ryan AbilityLab’s Dr. Colin Franz, co-lead author on the paper who led the testing of the cortical spheroids. “Now that the 3-D platform has been developed and validated, we will be able to perform more targeted studies on our patients recovering from neurological injury or battling a neurodegenerative disease.”

Yoonseok Park, postdoctoral fellow at Northwestern University and co-lead author, added, “This is just the beginning of an entirely new class of miniaturized, 3-D bioelectronic systems that we can construct to expand the capacity of the regenerative medicine field. For example, our next generation of device will support the formation of even more complex neural circuits from brain to muscle, and increasingly dynamic tissues like a beating heart.”

Current electrode arrays for tissue cultures are 2-D, flat and unable to match the complex structural designs found throughout nature, such as those found in the human brain. Moreover, even when a system is 3-D, it is extremely challenging to incorporate more than one type of material into a small 3-D structure. With this advance, however, an entire class of 3-D bioelectronics devices has been tailored for the field of regenerative medicine.

“Now, with our small, soft 3-D electronics, the capacity to build devices that mimic the complex biological shapes found in the human body is finally possible, providing a much more holistic understanding of a culture,” said Northwestern’s John Rogers, who led the technology development using technology similar to that found in phones and computers. “We no longer have to compromise function to achieve the optimal form for interfacing with our biology.”

As a next step, scientists will use the devices to better understand neurological disease, test drugs and therapies that have clinical potential, and compare different patient-derived cell models. This understanding will then enable a better grasp of individual differences that may account for the wide variation of outcomes seen in neurological rehabilitation.

“As scientists, our goal is to make laboratory research as clinically relevant as possible,” said Kristen Cotton, research assistant in Dr. Franz’s lab. “This 3-D platform opens the door to new experiments, discovery and scientific advances in regenerative neurorehabilitation medicine that have never been possible.”

Caption: Three dimensional multifunctional neural interfaces for cortical spheroids and engineered assembloids Credit: Northwestern University

As for what brain ogranoids might be, Carl Zimmer in an Aug. 29, 2019 article for the New York Times provides an explanation,

Organoids Are Not Brains. How Are They Making Brain Waves?

Two hundred and fifty miles over Alysson Muotri’s head, a thousand tiny spheres of brain cells were sailing through space.

The clusters, called brain organoids, had been grown a few weeks earlier in the biologist’s lab here at the University of California, San Diego. He and his colleagues altered human skin cells into stem cells, then coaxed them to develop as brain cells do in an embryo.

The organoids grew into balls about the size of a pinhead, each containing hundreds of thousands of cells in a variety of types, each type producing the same chemicals and electrical signals as those cells do in our own brains.

In July, NASA packed the organoids aboard a rocket and sent them to the International Space Station to see how they develop in zero gravity.

Now the organoids were stowed inside a metal box, fed by bags of nutritious broth. “I think they are replicating like crazy at this stage, and so we’re going to have bigger organoids,” Dr. Muotri said in a recent interview in his office overlooking the Pacific.

What, exactly, are they growing into? That’s a question that has scientists and philosophers alike scratching their heads.

On Thursday, Dr. Muotri and his colleagues reported that they  have recorded simple brain waves in these organoids. In mature human brains, such waves are produced by widespread networks of neurons firing in synchrony. Particular wave patterns are linked to particular forms of brain activity, like retrieving memories and dreaming.

As the organoids mature, the researchers also found, the waves change in ways that resemble the changes in the developing brains of premature babies.

“It’s pretty amazing,” said Giorgia Quadrato, a neurobiologist at the University of Southern California who was not involved in the new study. “No one really knew if that was possible.”

But Dr. Quadrato stressed it was important not to read too much into the parallels. What she, Dr. Muotri and other brain organoid experts build are clusters of replicating brain cells, not actual brains.

If you have the time, I recommend reading Zimmer’s article in its entirety. Perhaps not coincidentally, Zimmer has an excerpt titled “Lab-Grown Brain Organoids Aren’t Alive. But They’re Not Not Alive, Either.” published in,

From Life’s Edge: The Search For What It Means To Be Alive by Carl Zimmer, published by Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House, LLC. Copyright © 2021 by Carl Zimmer.

Cleber Trujillo led me to a windowless room banked with refrigerators, incubators, and microscopes. He extended his blue-gloved hands to either side and nearly touched the walls. “This is where we spend half our day,” he said.

In that room Trujillo and a team of graduate students raised a special kind of life. He opened an incubator and picked out a clear plastic box. Raising it above his head, he had me look up at it through its base. Inside the box were six circular wells, each the width of a cookie and filled with what looked like watered-down grape juice. In each well 100 pale globes floated, each the size of a housefly head.

Getting back to the research about monitoring brain organoids, here’s a link to and a citation for the paper about cortical spheroids,

Three-dimensional, multifunctional neural interfaces for cortical spheroids and engineered assembloids by Yoonseok Park, Colin K. Franz, Hanjun Ryu, Haiwen Luan, Kristen Y. Cotton, Jong Uk Kim, Ted S. Chung, Shiwei Zhao, Abraham Vazquez-Guardado, Da Som Yang, Kan Li, Raudel Avila, Jack K. Phillips, Maria J. Quezada, Hokyung Jang, Sung Soo Kwak, Sang Min Won, Kyeongha Kwon, Hyoyoung Jeong, Amay J. Bandodkar, Mengdi Han, Hangbo Zhao, Gabrielle R. Osher, Heling Wang, KunHyuck Lee, Yihui Zhang, Yonggang Huang, John D. Finan and John A. Rogers. Science Advances 17 Mar 2021: Vol. 7, no. 12, eabf9153 DOI: 10.1126/sciadv.abf9153

This paper appears to be open access.

According to a March 22, 2021 posting on the Shirley Riley AbilityLab website, the paper is featured on the front cover of Science Advances (vol. 7 no. 12).

Plug me in: how to power up ingestible and implantable electroncis

From time to time I’ve featured ‘vampire technology’, a name I vastly prefer to energy harvesting or any of its variants. The focus has usually been on implantable electronic devices such as pacemakers and deep brain stimulators.

In this February 16, 2021 Nanowerk Spotlight article, Michael Berger broadens the focus to include other electronic devices,

Imagine edible medical devices that can be safely ingested by patients, perform a test or release a drug, and then transmit feedback to your smartphone; or an ingestible, Jell-O-like pill that monitors the stomach for up to a month.

Devices like these, as well as a wide range of implantable biomedical electronic devices such as pacemakers, neurostimulators, subdermal blood sensors, capsule endoscopes, and drug pumps, can be useful tools for detecting physiological and pathophysiological signals, and providing treatments performed inside the body.

Advances in wireless communication enable medical devices to be untethered when in the human body. Advances in minimally invasive or semi-invasive surgical implantation procedures have enabled biomedical devices to be implanted in locations where clinically important biomarkers and physiological signals can be detected; it has also enabled direct administration of medication or treatment to a target location.

However, one major challenge in the development of these devices is the limited lifetime of their power sources. The energy requirements of biomedical electronic devices are highly dependent on their application and the complexity of the required electrical systems.

Berger’s commentary was occasioned by a review article in Advanced Functional Materials (link and citation to follow at the end of this post). Based on this review, the February 16, 2021 Nanowerk Spotlight article provides insight into the current state of affairs and challenges,

Biomedical electronic devices can be divided into three main categories depending on their application: diagnostic, therapeutic, and closed-loop systems. Each category has a different degree of complexity in the electronic system.

… most biomedical electronic devices are composed of a common set of components, including a power unit, sensors, actuators, a signal processing and control unit, and a data storage unit. Implantable and ingestible devices that require a great deal of data manipulation or large quantities of data logging also need to be wirelessly connected to an external device so that data can be transmitted to an external receiver and signal processing, data storage, and display can be performed more efficiently.

The power unit, which is composed of one or more energy sources – batteries, energy-harvesting, and energy transfer – as well as power management circuits, supplies electrical energy to the whole system.

Implantable medical devices such as cardiac pacemakers, neurostimulators and drug delivery devices are major medical tools to support life activity and provide new therapeutic strategies. Most such devices are powered by lithium batteries whose service life is as low as 10 years. Hence, many patients must undergo a major surgery to check the battery performance and replace the batteries as necessary.

In the last few decades, new battery technology has led to increases in the performance, reliability, and lifetime of batteries. However, challenges remain, especially in terms of volumetric energy density and safety.

Electronic miniaturization allows more functionalities to be added to devices, which increases power requirements. Recently, new material-based battery systems have been developed with higher energy densities.

Different locations and organ systems in the human body have access to different types of energy sources, such as mechanical, chemical, and electromagnetic energies.

Energy transfer technologies can deliver energy from outside the body to implanted or ingested devices. If devices are implanted at the locations where there are no accessible endogenous energies, exogenous energies in the form of ultrasonic or electromagnetic waves can penetrate through the biological barriers and wirelessly deliver the energies to the devices.

Both images embedded in the February 16, 2021 Nanowerk Spotlight article are informative. I’m particularly taken with the timeline which follows the development of batteries, energy harvesting/transfer devices, ingestible electronics, and implantable electronics. The first battery was in 1800 followed by ingestible and implantable electronics in the 1950s.

Berger’s commentary ends on this,

Concluding their review, the authors [in Advanced Functional Materials] note that low energy conversion efficiency and power output are the fundamental bottlenecks of energy harvesting and transfer devices. They suggest that additional studies are needed to improve the power output of energy harvesting and transfer devices so that they can be used to power various biomedical electronics.

Furthermore, durability studies of promising energy harvesters should be performed to evaluate their use in long-term applications. For degradable energy harvesting devices, such as friction-based energy harvesters and galvanic cells, improving the device lifetime is essential for use in real-life applications.

Finally, manufacturing cost is another factor to consider when commercializing novel batteries, energy harvesters, or energy transfer devices as power sources for medical devices.

Here’s a link to and a citation for the paper,

Powering Implantable and Ingestible Electronics by So‐Yoon Yang, Vitor Sencadas, Siheng Sean You, Neil Zi‐Xun Jia, Shriya Sruthi Srinivasan, Hen‐Wei Huang, Abdelsalam Elrefaey Ahmed, Jia Ying Liang, Giovanni Traverso. Advanced Functional Materials DOI: First published: 04 February 2021

This paper is behind a paywall.

It may be possible to receive a full text PDF of the article from the authors. Try here.

There are others but here are two of my posts about ‘vampire energy’,

Harvesting the heart’s kinetic energy to power implants (July 26, 2019)

Vampire nanogenerators: 2017 (October 19, 2017)

Precision targeting of the liver for gene editing

Apparently the magic is in the lipid nanoparticles. A March 1, 2021 news item on Nanowerk announced research into lipid nanoparticles as a means to deliver CRISPR (clustered regularly interspaced short palindromic repeats) to specific organs (Note: A link has been removed),

The genome editing technology CRISPR has emerged as a powerful new tool that can change the way we treat disease. The challenge when altering the genetics of our cells, however, is how to do it safely, effectively, and specifically targeted to the gene, tissue and organ that needs treatment.

Scientists at Tufts University and the Broad Institute of Harvard [University] and MIT [Massachusetts Institute of Technology] have developed unique nanoparticles comprised of lipids — fat molecules — that can package and deliver gene editing machinery specifically to the liver.

In a study published in the Proceedings of the National Academy of Sciences [PNAS] (“Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3”), they have shown that they can use the lipid nanoparticles (LNPs) to efficiently deliver the CRISPR machinery into the liver of mice, resulting in specific genome editing and the reduction of blood cholesterol levels by as much as 57% — a reduction that can last for at least several months with just one shot.

A March 2, 2021 Tufts University news release (also on EurekAlert but published March 1, 2021), which originated the news item, provides greater insight into and technical detail about the research,

The problem of high cholesterol plagues more than 29 million Americans, according to the Centers for Disease Control and Prevention. The condition is complex and can originate from multiple genes as well as nutritional and lifestyle choices, so it is not easy to treat. The Tufts and Broad researchers, however, have modified one gene that could provide a protective effect against elevated cholesterol if it can be shut down by gene editing.

The gene that the researchers focused on codes for the angiopoietin-like 3 enzyme (Angptl3). That enzyme tamps down the activity of other enzymes – lipases – that help break down cholesterol. If researchers can knock out the Angptl3 gene, they can let the lipases do their work and reduce levels of cholesterol in the blood. It turns out that some lucky people have a natural mutation in their Angptl3 gene, leading to consistently low levels of triglycerides and low-density lipoprotein (LDL) cholesterol, commonly called “bad” cholesterol, in their bloodstream without any known clinical downsides.

“If we can replicate that condition by knocking out the angptl3 gene in others, we have a good chance of having a safe and long term solution to high cholesterol,” said Qiaobing Xu, associate professor of biomedical engineering at Tufts’ School of Engineering and corresponding author of the study. “We just have to make sure we deliver the gene editing package specifically to the liver so as not to create unwanted side effects.”

Xu’s team was able to do precisely that in mouse models. After a single injection of lipid nanoparticles packed with mRNA coding for CRISPR-Cas9 and a single-guide RNA targeting Angptl3, they observed a profound reduction in LDL cholesterol by as much as 57% and triglyceride levels by about 29 %, both of which remained at those lowered levels for at least 100 days. The researchers speculate that the effect may last much longer than that, perhaps limited only by the slow turnover of cells in the liver, which can occur over a period of about a year. The reduction of cholesterol and triglycerides is dose dependent, so their levels could be adjusted by injecting fewer or more LNPs in the single shot, the researchers said.

By comparison, an existing, FDA [US Food and Drug Administration]-approved version of CRISPR mRNA-loaded LNPs could only reduce LDL cholesterol by at most 15.7% and triglycerides by 16.3% when it was tested in mice, according to the researchers.

The trick to making a better LNP was in customizing the components – the molecules that come together to form bubbles around the mRNA. The LNPs are made up of long chain lipids that have a charged or polar head that is attracted to water, a carbon chain tail that points toward the middle of the bubble containing the payload, and a chemical linker between them. Also present are polyethylene glycol, and yes, even some cholesterol – which has a normal role in lipid membranes to make them less leaky – to hold their contents better.

The researchers found that the nature and relative ratio of these components appeared to have profound effects on the delivery of mRNA into the liver, so they tested LNPs with many combinations of heads, tails, linkers and ratios among all components for their ability to target liver cells. Because the in vitro potency of an LNP formulation rarely reflects its in vivo performance, they directly evaluated the delivery specificity and efficacy in mice that have a reporter gene in their cells that lights up red when genome editing occurs. Ultimately, they found a CRISPR mRNA-loaded LNP that lit up just the liver in mice, showing that it could specifically and efficiently deliver gene-editing tools into the liver to do their work.

The LNPs were built upon earlier work at Tufts, where Xu and his team developed LNPs with as much as 90% efficiency in delivering mRNA into cells. A unique feature of those nanoparticles was the presence of disulfide bonds between the long lipid chains. Outside the cells, the LNPs form a stable spherical structure that locks in their contents. When they are inside a cell, the environment within breaks the disulfide bonds to disassemble the nanoparticles. The contents are then quickly and efficiently released into the cell. By preventing loss outside the cell, the LNPs can have a much higher yield in delivering their contents.

“CRISPR is one of the most powerful therapeutic tools for the treatment of diseases with a genetic etiology. We have recently seen the first human clinical trail for CRISPR therapy enabled by LNP delivery to be administered systemically to edit genes inside the human body. Our LNP platform developed here holds great potential for clinical translation,” said Min Qiu, post-doctoral researcher in Xu’s lab at Tufts.  “We envision that with this LNP platform in hand, we could now make CRISPR a practical and safe approach to treat a broad spectrum of liver diseases or disorders,” said Zachary Glass, graduate student in the Xu lab. Qiu and Glass are co-first authors of the study.

Here’s a link to and a citation for the paper,

Lipid nanoparticle-mediated codelivery of Cas9 mRNA and single-guide RNA achieves liver-specific in vivo genome editing of Angptl3 by Min Qiu, Zachary Glass, Jinjin Chen, Mary Haas, Xin Jin, Xuewei Zhao, Xuehui Rui, Zhongfeng Ye, Yamin Li, Feng Zhang, and Qiaobing Xu. PNAS March 9, 2021 118 (10) e2020401118 DOI:

This paper appears to be behind a paywall.