Gravity telescope to image exoplanets

Peer-Reviewed Publication

STANFORD UNIVERSITY

 

IMAGE: AN EXAMPLE OF A RECONSTRUCTION OF EARTH, USING THE RING OF LIGHT AROUND THE SUN, PROJECTED BY THE SOLAR GRAVITATIONAL LENS. THE ALGORITHM THAT ENABLES THIS RECONSTRUCTION CAN BE APPLIED TO EXOPLANETS FOR SUPERIOR IMAGING. view more 

CREDIT: ALEXANDER MADUROWICZ

In the time since the first exoplanet was discovered in 1992, astronomers have detected more than 5,000 planets orbiting other stars. But when astronomers detect a new exoplanet, we don’t learn a lot about it: we know that it exists and a few features about it but the rest is a mystery.

To sidestep the physical limitations of telescopes, Stanford University astrophysicists have been working on a new conceptual imaging technique that would be 1,000 times more precise than the strongest imaging technology currently in use. By taking advantage of gravity’s warping effect on space-time, called lensing, scientists could potentially manipulate this phenomenon to create imaging far more advanced than any present today.

In a paper published on May 2 in The Astrophysical Journal, the researchers describe a way to manipulate solar gravitational lensing to view planets outside our solar system. By positioning a telescope, the sun, and exoplanet in a line with the sun in the middle, scientists could use the gravitational field of the sun to magnify light from the exoplanet as it passes by. As opposed to a magnifying glass which has a curved surface that bends light, a gravitational lens has a curved space-time that enables imaging far away objects.

“We want to take pictures of planets that are orbiting other stars that are as good as the pictures we can make of planets in our own solar system,” said Bruce Macintosh, a physics professor at in the School of Humanities and Sciences at Stanford and deputy director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC). “With this technology, we hope to take a picture of a planet 100 light-years away that has the same impact as Apollo 8’s picture of Earth.”

The catch, at present, is that their proposed technique would require more advanced space travel than is currently available. Still, the promise of this concept and what it could reveal about other planets, makes it worth continued consideration and development, said the researchers.

The perks of light bending

Gravitational lensing wasn’t experimentally observed until 1919 during a solar eclipse. With the moon obstructing the light from the sun, scientists were able to see stars near the sun offset from their known positions. This was unequivocal proof that gravity could bend light and the first observational evidence that Einstein’s theory of relativity was correct. Later, in 1979, Von Eshleman, a Stanford professor, published a detailed account of how astronomers and spacecraft could exploit the solar gravitational lens. (Meanwhile, astronomers including many at Stanford’s KIPAC now routinely use the powerful gravity of the most massive galaxies to study the early evolution of the universe.)

But it wasn’t until 2020 that the imaging technique was explored in detail in order to observe planets. Slava Turyshev of California Institute of Technology’s Jet Propulsion Laboratory described a technique where a space-based telescope could use rockets to scan around the rays of light from a planet to reconstruct a clear picture, but the technique would require a lot of fuel and time.

Building on Turyshev’s work, Alexander Madurowicz, a PhD student at KIPAC, invented a new method that can reconstruct a planet’s surface from a single image taken looking directly at the sun. By capturing the ring of light around the sun formed by the exoplanet, the algorithm Madurowicz designed can undistort the light from the ring by reversing the bending from the gravitational lens, which turns the ring back into a round planet.

Madurowicz demonstrated his work by using images of the rotating Earth taken by the satellite DSCOVR that sits between Earth and the sun. Then, he used a computer model to see what Earth would look like peering through the warping effects of the sun’s gravity. By applying his algorithm to the observations, Madurowicz was able to recover the images of Earth and prove that his calculations were correct.

In order to capture an exoplanet image through the solar gravitational lens, a telescope would have to be placed at least 14 times farther away from the sun than Pluto, past the edge of our solar system, and further than humans have ever sent a spacecraft. But, the distance is a tiny fraction of the light-years between the sun and an exoplanet.

“By unbending the light bent by the sun, an image can be created far beyond that of an ordinary telescope,” Madurowicz said. “So, the scientific potential is an untapped mystery because it’s opening this new observing capability that doesn’t yet exist.”

Sights set beyond the solar system

Currently, to image an exoplanet at the resolution the scientists describe, we would need a telescope 20 times wider than the Earth. By using the sun’s gravity like a telescope, scientists can exploit this as a massive natural lens. A Hubble-sized telescope in combination with the solar gravitational lens would be sufficient to image exoplanets with enough power to capture fine details on the surface.

“The solar gravitational lens opens up an entirely new window for observation,” said Madurowicz. “This will allow investigation of the detailed dynamics of the planet atmospheres, as well as the distributions of clouds and surface features, which we have no way to investigate now.”

Madurowicz and Macintosh both say that it will be a minimum of 50 years before this technology could be deployed, likely longer. In order for this to be adopted, we will need faster spacecraft because, with current technology, it could take 100 years to travel to the lens. Using solar sails or the sun as a gravitational slingshot, the time could be as short as 20 or 40 years. Despite the timeline’s uncertainty, the possibility to see whether some exoplanets have continents or oceans, Macintosh said, drives them. The presence of either is a strong indicator that there may be life on a distant planet.

“This is one of the last steps in discovering whether there’s life on other planets,” Macintosh said. “By taking a picture of another planet, you could look at it and possibly see green swatches that are forests and blue blotches that are oceans – with that, it would be hard to argue that it doesn’t have life.”

Macintosh is also a member of Stanford Bio-X. The research was sponsored by the NASA grant NNX15AD95G, which relies on the Nexus for Exoplanet System Science (NExSS) coordination network.

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JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4357/ac5e9d 

ARTICLE TITLE

Integral field spectroscopy with the solar gravitational lens

ARTICLE PUBLICATION DATE

2-May-2022

Experiments measure freezing point of extraterrestrial oceans to aid search for life

Peer-Reviewed Publication

UNIVERSITY OF WASHINGTON

 

IMAGE: THE LEFT PANEL’S GRAY AND BLUE LAYERS SHOW THE DEEP, ICE-COVERED OCEAN ON EUROPA, A MOON OF JUPITER THAT COULD HOST EXTRATERRESTRIAL LIFE. THIS OCEAN IS THOUGHT TO BE MUCH DEEPER THAN OCEANS ON EARTH. NEW RESEARCH HINTS AT WHERE LIQUID WATER MIGHT BE FOUND IN THESE ENVIRONMENTS. view more 

CREDIT: IMAGE BY NASA/JPL-CALTECH, WITH MODIFICATIONS BY BAPTISTE JOURNAUX

Researchers from the University of Washington and the University of California, Berkeley have conducted experiments that measured the physical limits for the existence of liquid water in icy extraterrestrial worlds.  This blend of geoscience and engineering was done to aid in the search for extraterrestrial life and the upcoming robotic exploration of oceans on moons of other planets.

The results were recently published in Cell Reports Physical Sciences. 

“The more a liquid is stable, the more promising it is for habitability,” said co-corresponding author Baptiste Journaux, an acting assistant professor of Earth and space sciences at the UW.   “Our results show that the cold, salty, high-pressure liquids found in the deep ocean of other planets’ moons can remain liquid to much cooler temperature than they would at lower pressures. This extends the range of possible habitats on icy moons, and will allow us to pinpoint where we should look for biosignatures, or signs of life.”

Jupiter and Saturn’s icy moons — including Europa, Ganymede and Titan — are leading candidates within our solar system for hosting extraterrestrial life. These ice-encrusted moons are thought to harbor enormous liquid oceans, up to several dozen times the volume of oceans on Earth.

“Despite its designation as the ‘blue marble,’ Earth is remarkably dry when compared to these worlds,“ Journaux said.

The oceans on these moons may contain various types of salts and are expected to range from about 100 miles deep, on Europa, to more than 400 miles deep, on Titan.

“We know that water supports life, but the major part of the oceans on these moons are likely below zero degrees Celsius and at pressures higher than anything experienced on Earth,” Journaux said. “We needed to know how cold an ocean can get before entirely freezing, including in its deepest abyss.”

The study focused on eutectics, or the lowest temperature that a salty solution can remain liquid before entirely freezing. Salt and water are one example — salty water remains liquid below the freezing temperature of pure water, one of the reasons people sprinkle salt on roads in winter to avoid the formation of ice.

The experiments used UC Berkeley equipment originally designed for the future cryopreservation of organs for medical applications and for food storage. For this research, however, the authors used it to simulate the conditions thought to exist on other planets’ moons.

Journaux, a planetary scientist and expert on the physics of water and minerals, worked with UC Berkeley engineers to test solutions of five different salts at pressures up to 3,000 times atmospheric pressure, or 300 megapascals — about three times the pressure in Earth’s deepest ocean trench.

“Knowing the lowest temperature possible for salty water to remain a liquid at high pressures is integral to understanding how extraterrestrial life could exist and thrive in the deep oceans of these icy ocean worlds,” said co-corresponding author Matthew Powell-Palm, who did the work as a postdoctoral researcher at UC Berkeley, also co-founder and CEO of the cryopreservation company BioChoric, Inc.

Journaux recently started working with NASA’s Dragonfly mission team, which will send a rotorcraft in 2027 to Saturn’s largest moon, Titan. NASA also is leading the Europa Clipper mission in 2024 to explore Europa, one of the many moons orbiting Jupiter. Meanwhile, the European Space Agency in 2023 will send its JUICE spacecraft, or Jupiter Icy Moons Explorer, to explore three of Jupiter’s largest moons: Ganymede, Callisto and Europa.

“The new data obtained from this study may help further researchers’ understanding of the complex geological processes observed in these icy ocean worlds,” Journaux said.

Other authors are Boris Rubinsky, Brooke Chang, Anthony Consiglio, Drew Lilley and Ravi Prasher, all at UC Berkeley. The study was funded by the National Science Foundation and NASA. 

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For more information, contact Journaux at bjournau@uw.edu or Powell-Palm at mpowellp@berkeley.edu.    

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JOURNAL

Cell Reports

DOI

10.1016/j.xcrp.2022.100856 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

On the pressure dependence of salty aqueous eutectics

Stevia Tasteful 2022 World Congress will be held next June – Lisbon will host the 10th World convention of the World Stevia Organization

Stevia Tasteful 2022 hybrid meeting grants you an innovative educational experience, and boosts your knowledge of stevia "The Green Gold".

Meeting Announcement

MITOCHONDRIA-MICROBIOTA TASK FORCE

 

IMAGE: WSO TASTING AWARDS FOR PRODUCT AND EXTRACT CATEGORIES; 3 AWARDS ARE AVAILABLE view more 

CREDIT: WORLD STEVIA ORGANIZATION

The World Stevia organization will host its 10th World Convention on Stevia “Stevia Tasteful 2022: The Subtle Balance” on June 2-3 online and in Lisbon, Portugal, at the Radisson Blu Hotel.

Led by Prof. Gerd Birkenmeier, University of Leipzig, Germany, the conference will bring together worldwide professional researchers and industrials to discuss, share and critique the latest advances in Stevia application. The conference looks to critically examine emerging trends and contemporary best practices of the natural sweetener stevia. It will discuss not only the health effects of stevia, but also the impact of formulation on Stevia taste and after-taste, present new innovations to reduce Stevia after taste in products, and show the latest marketing tools used to present Stevia and persuade consumers to use it.

 

Stevia Tasteful 2022 Topics & Speakers:

Gerd Birkenmeier, President of the World Stevia Organization, University of Leipzig, Germany, will introduce the meeting with a strategic talk “Stevia Tasteful 2022: Today and Tomorrow”.

• Stevia & Health Effects 2022 – Recent Advances & Perspectives

This session will be dedicated to expose the impact of Stevia on health, especially on microbiota, with the following talks:

Sidd Purkayastha, Vice President, Head of Global Scientific & Regulatory Affairs at PureCircle/Ingregion Inc., USA – Metabolism and Effect of Steviol Glycosides and Steviol on Human Gut Microbiome

Karley Mahalak, United States Department of Agriculture, Eastern Regional Research Center, USA – Impact of Steviol Glycosides and Erythritol on the Human and Cebus apella Gut Microbiome

Other health effects will be demonstrated:

John T. McLaughlin, University of Manchester, United Kingdom – Effects of the Daily Consumption of Stevia on Glucose Homeostasis, Body Weight, and Energy Intake of Healthy Adults

Armine Isoyan, Orbeli Institute of Physiology NAS RA, Armenia – Stevia rebaudiana Has the Potential to Improve Functional Recovery of Injured Peripheral Nerved in Diabetic Rats

Vasil Pirgozliev, Harper Adams University, UK – Feeding Stevia (Stevia rebaudiana) to Poultry: Effect on Dietary Energy and Nutrient Availability, Production and Health

• Stevia 2022 – Characterization & Optimization

Gertrud Morlock, Justus Liebig University Giessen, Germany – NanoGIT+active and Super-Hyphenations - Detecting the Essentials of Food

Maria Margarida Ribeiro, Polytechnic Institute of Castelo Branco, Portugal – What can Molecular and Biochemical Markers Tell Us About Stevia rebaudiana Genotypes' Collection?

Yuming Sun, Chinese Academy of Sciences, China – Improve Steviol Glycosides Productivity by Optimizing Nitrogen Fertilization Strategy

Marta Libik-Konieczny, Polish Academy of Sciences, Poland – Steviol Glycosides Profile in Stevia rebaudiana Bertoni Hairy Roots Cultured under Oxidative Stress-Inducing Conditions

Xiaoyang Xu, Chinese Academy of Sciences, China – The Chromosome-Level Stevia Genome Provides Insights into Steviol Glycoside Biosynthesis

• Stevia in Food Industry – Innovations & Technology

Lucy Dahlgren, Founder of the company Bayn Europe, Stockholm – The Importance of Developing a Commercially Viable Solution - An Innovative Business Model to Accelerate Stevia Market Entry and Business Revenue

Maria Rosa Zorzenon, State University of Maringá, Brazil – Spray Drying Encapsulation of Stevia Extract with Maltodextrin and Evaluation of the Properties of Produced Powders

Muhammad Farhan Jahangir Chughtai, Khwaja Fareed University of Engineering & Information Technology, Pakistan – An Insight on the Future Therapeutic Application of Stevia Rebaudiana as Emerging Sweetener: A Way Forward for Sweetener Industry

Sungeun Cho, Auburn University, USA – Consumer Acceptability and Sensory Characterization of Steviol Glycosides (Rebaudioside A, D, and M)

Xiao Hua, Jiangnan University, China – Recovery of Steviol Glycosides from Industrial Stevia By-Product, Preparation and Practical Application of Stevia in Milk Tea

Rajnibhas Sukeaw Samakradhamrongthai, Prince of Songkla University, Thailand – Stevia in Food Product Development: Formulation and Evaluation

Christos Stamatis, CEO of Stevia Hellas Cooperative, Greece – Stevia from Field to the Table - Case of Greece

• Stevia Breeding & Cultivation – 2022

Buhara Yücesan, Bolu Abant Izzet Baysal University, Turkey – Stevia Breeding & Cultivation in 2022

Gabriele Gusmini, Founder of the Plant Pathways Company, Inc., USA – Breeding and Agricultural Supply Chain Expertise for a Fresh Look at Stevia Leaf Production and Processing

Todd Wehner, North Carolina State University, USA – Optimum Experiment Size for Stevia Trials

Probir Kumar Pal, CSIR - Institute of Himalayan Bioresource Technology, India – Recent Agronomic Development on Stevia towards attaining Higher Productivity

 

Take a better look at the program and meet the speakers.

You can also share your most recent research related to the above sessions through a short oral/ poster presentation. Submit your abstract.

Tasting Awards – Stevia Products & Extracts 2022

Wait there is more! At the end of the conference, the attendees will be invited to taste and judge some Stevia Finished Products and Stevia Extracts in order to discern the Stevia Tasteful Awards 2022.

Two categories will be awarded:

• Stevia Tasteful Award - Finished Product Category
• Stevia Tasteful Award - Extract Category

To participate, follow this link.

The World Stevia Organization wishes to make some comments about stevia and its strategic role in our food and lifestyle. It envisions a world where Stevia is a "healthier" alternative that can replace free sugar and artificial sweeteners in our drinks and food. 

For more information visit https://www.wso-site.com/

Contact us at wso@wso-site.com

Researchers discover new species of salamander from Gulf Coastal plains hotspot

Discovery sheds light on a region that is understudied, but species-rich

Peer-Reviewed Publication

GEORGE WASHINGTON UNIVERSITY

 

IMAGE: D. PASCAGOULA FROM FRANKLIN CREEK, MOBILE CO., ALABAMA view more 

CREDIT: DAVE BEAMER

WASHINGTON (May 3, 2022) — There are approximately 750 species of salamander known to science, a third of which reside in North America. Now, a team of researchers led by R. Alexander Pyron, the Robert F. Griggs Associate Professor of Biology at the George Washington University, has discovered a new species of swamp-dwelling dusky salamander from the Gulf Coastal Plain of southeastern Mississippi and southwestern Alabama. 

The discovery increases knowledge of the biodiversity in the southeastern United States Coastal Plain, a candidate region meeting the global criteria for a biodiversity hotspot. According to the researchers, the region has been studied intensively for hundreds of years, but nonetheless still contains abundant undescribed diversity.

“This discovery shows us how much more there is to learn even in our own backyards,” Pyron said. “The famed naturalist E.O. Wilson called this region ‘America’s Amazon,’ where ivory-billed woodpeckers and red wolves once lived. We are losing biodiversity at a dramatic rate, while still discovering how much was originally there. Salamanders are among the most imperiled animals globally, and we’ve yet to understand their true biodiversity.”

The researchers determined that the new species of salamander, known as Desmognathus pascagoula, is similar to another recently discovered species known as Desmognathus valentinei. However, certain morphological, genetic and geographic aspects of the new species differ. The researchers sequenced the genomes from D. valentinei and D. pascagoula specimens, revealing genetic variations in 881 different genes. They also compared the body structure of D. pascagoula with D. valentinei and Desmognathus conanti, another species that occurs in the area, using collections from the Smithsonian’s National Museum of Natural History. They found subtle but significant differences: D. pascagoula has a longer, more slender body and a narrower head and nostrils.

CAPTION

D. valentinei from West Creek, Harrison Co., Mississippi

CREDIT

Jason A. Colston

CAPTION

D. conanti from Pigeon Creek in Clarke Co., Alabama

CREDIT

Jason A. Colston

“Many of these dusky salamanders are cryptic, meaning they can’t easily be told apart with the naked eye, which is one reason they went undiscovered for so long,” Pyron said. “Only with genome sequencing can we see how different they really are. Then, precise measurements of preserved specimens reveal tiny differences in things like the width of the head, which are otherwise imperceptible.”

According to the researchers, additional work will be needed to provide insight both into the biology of D. pascagoula, as well as its former and current geographical extent. Pyron encourages other researchers in the field or citizen scientists searching for the species to focus on images of the lateral surfaces of the body and head, such that “portholes,” postocular stripes, and snouts are clearly visible. Future research may also reveal the presence of other undescribed species of Desmognathus in the Coastal Plain of the southeastern U.S.

The study, “A new, narrowly endemic species of swamp-dwelling dusky salamander (Plethodontidae: Desmognathus) from the Gulf Coastal Plain of Mississippi and Alabama” was published May 3, 2022, in the journal Zootaxa. The research team also included Kyle O’Connell of GW, Jennifer Lamb of St. Cloud State University, and David Beamer of Nash Community College.

The National Science Foundation (DEB-1655737, DEB-1656111 and DGE-0947944) supported this research.

CAPTION

Cowart Branch, Greene Co., Mississippi

CREDIT

Alex Pyron

-GW-

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JOURNAL

Zootaxa

DOI

10.11646/zootaxa.5133.1.3 

ARTICLE TITLE

A new, narrowly endemic species of swamp-dwelling dusky salamander (Plethodontidae: Desmognathus) from the Gulf Coastal Plain of Mississippi and Alabama

ARTICLE PUBLICATION DATE

3-May-2022

Beetle iridescence a deceptive form of warning coloration, study finds

Peer-Reviewed Publication

UNIVERSITY OF BRISTOL

 

IMAGE: JEWEL BEETLE (STERNOCERA SP.) IRIDESCENCE CAN PROTECT PREY VIA CAMOUFLAGE AND BY ACTING AS A FORM OF DECEPTIVE WARNING COLORATION view more 

CREDIT: DR. KARIN KJERNSMO

A new study published today in Animal Behaviour shows for the first time that brilliant iridescence and gloss found in some animals can have a protective function by working as a form of deceptive warning colouration, and that it is the key feature of iridescence, its changing colours, that is important for this effect.

This striking form of structural coloration in which the hue and intensity of colours will vary depending on the angle of view, has also evolved independently in everything from birds such as magpies and starlings, to many insects such as rose chafers, rosemary beetles and in the demoiselle.

By looking at its biological functions, a team of researchers at Bristol University’s CamoLab investigated why this vivid metallic coloration has evolved so may times in the animal kingdom, and what makes this striking form of animal coloration such a successful anti-predator strategy. The team had previously discovered that iridescence can act as a highly efficient form of camouflage, but whether such striking forms of structural coloration could also protect prey post-detection, and if so, what optical properties were important for this effect, remained unknown until now.

Lead author Dr. Karin Kjernsmo of the University of Bristol’s School of Biological Sciences said: “One of the challenges when studying the functions of such highly reflective structural colouration has been to separate the effects of the changeability of colours, the hallmark of iridescence, from the effects of simply having multiple colours at the same time, and also to separate the effects of gloss from the effects of iridescence.”

They tested if and how iridescence could provide a survival benefit to prey post-detection by presenting both iridescent and non-iridescent, as well as glossy and matte versions of the two, to birds that had no previous experience with such prey, and then looked at the birds’ willingness to attack the prey. They found that iridescence significantly reduced the attack-willingness of the birds, and that gloss also had an independent effect.

“Here we have, for the first time, effectively managed to test for each of these two effects on their own, and shown that both iridescence and gloss can protect prey even post-detection, providing yet another adaptive explanation for the evolution and widespread existence of iridescence” Dr. Kjernsmo added.

The study was funded by the Biotechnology & Biological Sciences Research Council (BBSRC).

Paper

Beetle iridescence induces an avoidance response in naïve avian predators by Karin Kjernsmo et al in Animal Behaviour.

  

CAPTION

Jewel beetle (Sternocera sp.) iridescence can protect prey via camouflage and by acting as a form of deceptive warning coloration

CREDIT

Dr. Karin Kjernsmo

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JOURNAL

Animal Behaviour

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Beetle iridescence induces an avoidance response in naïve avian predator’

ARTICLE PUBLICATION DATE

3-May-2022

Repairing tendons with silk proteins

Peer-Reviewed Publication

TERASAKI INSTITUTE FOR BIOMEDICAL INNOVATION

 

IMAGE: SILK FIBROIN FROM SILKWORM COCOONS ARE USED IN SCAFFOLDS FOR OPTIMIZED REGENERATIVE TISSUES FOR TENDON REPAIR. view more 

CREDIT: TERASAKI INSTITUTE FOR BIOMEDICAL INNOVATION (TIBI)

(LOS ANGELES) – Just mentioning a ruptured Achilles tendon would make anyone wince. Tendon injuries are well known for their lengthy, difficult and often incomplete healing processes. Sudden or repetitive motion, experienced by athletes and factory workers, for example, increases the risk of tears or ruptures in the tendons; thirty percent of all people will have a tendon injury, with the risk being highest in women. What’s more, those who suffer from these injuries are more prone to further injuries at the site or never recover fully.

Tendons are bands of fibrous connective tissue that attach muscles to bones. They are soft tissues connected to stiff bones; this creates a complex interface with a very specific structure. Following injury, this structure is disrupted, and the connective tissue changes from a linear to a kinked formation. Excess scarring can also occur, changing the tendon’s mechanical properties and its ability to bear loads.

During the body’s natural healing processes, tendon and other cells are recruited to reconstruct the tendon’s original matrix of aligned connective tissue fibers. But this reconstruction can take weeks to months and the resultant tendon is often imperfect. This results in weakness, chronic pain and decreased quality of life.

Possible treatments for tendon injuries include tendon tissue grafts from patients or donors, but these pose risks such as infections, transplant rejection or necrosis. Synthetic transplants have been attempted, but mechanical, biocompatibility and biodegradation issues have hampered these efforts.

Another approach is to use mesenchymal stem cells (MSCs), specialized cells that play a pivotal role in tissue regeneration. At the wound site, they can differentiate into various cells types and produce signaling molecules which regulate immune response, cellular migration, and new blood vessel formation; this enables tissue regeneration.

However, treatment methods using systemic infusion, direct injection or genetic modification of MSCs present their own difficulties: infusion lacks targeting specificity to the injury site, direct injection requires prohibitively high cell numbers, and genetic modification is inefficient and produces cells that are difficult to isolate.

Yet another approach has been to construct biomaterial frameworks, or scaffolds, on which to introduce MSCs and growth factors in order to generate new tendon tissue. A collaborative team from the Terasaki Institute for Biomedical Innovation (TIBI) has utilized this approach to develop a method which has yielded significant improvements in MSC tendon regeneration.

The team first turned to silk fibroin, a silk protein produced by the Bombyx mori silkworm. In addition to its use in beautiful silk fabrics, silk fibroin is used in optical and electrical devices, and in several biomedical applications, from suture materials to bioengineered ligaments, bone and even corneal tissue. Because of its superior strength, durability, biocompatibility and bio-degradative qualities, silk fibroin is ideal for use in scaffolds for tendons.

In order to improve the scaffold’s ability for tissue regeneration, the team next paired silk fibroin with GelMA, a gelatin-based, water-retaining gel, due to GelMA’s biocompatibility, controllable degradation, stiffness and ability to promote cell attachment and growth.

“The synergistic effects of GelMA’s capacity for supporting regenerative tissue formation and the structural advantages of silk fibroin make our composite material well suited for tendon repair,” said HanJun Kim, Ph.D., D.V.M, TIBI’s team leader on the project.  

They prepared mixtures with varying ratios of silk fibroin and GelMA (SG) and fabricated them into thin nanofiber sheets. They then tested the sheets for fiber structure and stretchiness and chose an optimum formulation with the best mechanical properties. They also observed that the silk fibroin imparted an increased porosity to the material; this enhances tendon repair.

The optimized SG sheets were seeded with MSCs and subjected to various tests to measure MSC compatibility and differentiation, growth factor production, and genetic activity triggering matrix formation.

The MSCs on the SG sheets showed an increase in cell viability and proliferation over those on silk fibroin sheets without GelMA (SF). Genetic analysis showed that relevant gene activity in SG MSCs was significantly increased, in contrast to those on SF sheets, which was decreased.

Staining tests revealed that the MSCs on the SG sheets showed a more than 80% attachment rate and had an elongated shape characteristic of cells attached to a surface, as opposed to a 60% attachment rate, with spherically-shaped cells observed on SF and GelMA only surfaces.

Further tests on a growth factor secreted by MSCs seeded onto nanofiber sheets showed that the growth factors produced by the MSCs on the SG sheets were best able to repair injured tendon tissue cultivated in a culture dish.

Experiments were also conducted on live rats with injured Achilles tendons. MSC-seeded nanofiber sheets were implanted onto the injury site and the SG sheets promoted the most accelerated healing, with reduced injury sites and the formation of well-aligned, densely packed tendon fibers and remodeled muscle components.

“Tissue remodeling for tendon repair is especially difficult to achieve,” said Ali Khademhosseini, Ph.D., TIBI’s Director and CEO. “The work done here significantly advances that achievement.”

 

Authors are: Yumeng Xue, HanJun Kim, Junmin Lee, Yaowen Liu, Tyler Hoffman, Yi Chen, Xingwu Zhou, Wujin Sun, Shiming Zhang, Hyun-Jong Cho, JiYong Lee, WonHyoung Ryu, Chang Moon Lee, Samad Ahadian, Mehmet R. Dokmeci, Bo Lei, KangJu Lee, and Ali Khademhosseini.

This work was supported by the National Institutes of Health (EB021857, EB022403 and R01EB021857).

 

PRESS CONTACT

 

Stewart Han, shan@terasaki.org, +1 818-836-4393

Terasaki Institute for Biomedical Innovation

 

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The Terasaki Institute for Biomedical Innovation (terasaki.org) is a non-profit research organization that invents and fosters practical solutions that restore or enhance the health of individuals.  Research at the Terasaki Institute leverages scientific advancements that enable an understanding of what makes each person unique, from the macroscale of human tissues down to the microscale of genes, to create technological solutions for some of the most pressing medical problems of our time.  We use innovative technology platforms to study human disease on the level of individual patients by incorporating advanced computational and tissue-engineering methods.  Findings yielded by these studies are translated by our research teams into tailored diagnostic and therapeutic approaches encompassing personalized materials, cells and implants with unique potential and broad applicability to a variety of diseases, disorders, and injuries. 

The Institute is made possible through an endowment from the late Dr. Paul I Terasaki, a pioneer in the field of organ transplant technology.

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JOURNAL

Small

DOI

10.1002/smll.202107714 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Lab-produced tissue samples

ARTICLE TITLE

Co-electrospun silk fibroin and gelatin methacryloyl sheet seeded with mesenchymal stem cells for tendon regeneration