Tag Archives: stem

Researchers successfully reverse aging — in a lab dish

Researchers at the Stanford University School of Medicine have successfully de-aged human cells in a lab dish.

Image via Pixabay.

Carefully exposing human cells to Yamanaka factors, proteins involved in embryonic development that are used to transform adult cells into induced pluripotent stem (or iPS) cells, can reverse cellular aging. The authors report that old human cells in a lab dish treated with these proteins were nearly indistinguishable from fresh cells.

Ageback

“We are very excited about these findings,” said study co-author Thomas Rando, MD, Ph.D., the director of Stanford’s Glenn Center for the Biology of Aging. “My colleagues and I have been pursuing the rejuvenation of tissues since our studies in the early 2000s revealed that systemic factors can make old tissues younger.”

The authors explain that iPS cells produced from adult cells become “youthful” in the process. They wondered whether the process could be stopped mid-way, in order to make the cells more vigorous without causing them to revert back to a stem state. They found that it is possible, but the procedure hinges on carefully controlling the duration of exposure to Yamanaka factors. The team can use their approach to “promote rejuvenation in multiple human cell types,” explains Vittorio Sebastiano, Ph.D. the senior author of the study.

The factors gradually wipe a cell’s genetic material clean of the bits that differentiate them — those that make a skin cell and a blood cell different, for example — and revert them back to a younger state over the course of weeks. Instead, the team only allowed exposure to continue for a few days. They then compared the genetic activity of these cells with untreated cells from both elderly adults and younger participants.

The treated cells showed signs of age reversal after four days of exposure, the team explains, and their patterns of gene expression were similar to those seen in cells from younger participants. Treated cells appeared to be about one-and-a-half to three-and-a-half years younger on average than untreated cells from elderly people. The maximum values were three and a half years for skin cells and seven and a half years for cells lining blood vessels (when comparing methylation levels, a hallmark of cell aging).

“We saw a dramatic rejuvenation across all hallmarks but one in all the cell types tested,” Sebastiano said. “But our last and most important experiment was done on muscle stem cells. Although they are naturally endowed with the ability to self-renew, this capacity wanes with age. We wondered, Can we also rejuvenate stem cells and have a long-term effect?”

The team transplanted treated muscle cells back into old mice, and reported that they regained muscle strength comparable to that of younger mice. The process also helped cells from the cartilage of people (with and without osteoarthritis) reduce the secretion of inflammatory molecules, improve cellular function, and the cells’ ability to divide.

“Although much more work needs to be done, we are hopeful that we may one day have the opportunity to reboot entire tissues,” Sebastiano said. “But first we want to make sure that this is rigorously tested in the lab and found to be safe.”

‘Dish Life’ lets you play as a stem cell researcher on Android, iPhone, or PC

A team of researchers from the University of Cambridge want to make laboratories and the scientific process more familiar to the public in the best way possible: with video games.

Image credits University of Cambridge.

The game is named “Dish Life” and puts the player in the role of a burgeoning stem cell researcher as they navigate the tough (and sometimes hilarious) journey from undergraduate to cutting-edge expert. Dish Life is available for free on the Apple and Android App Stores, as well as on Steam for PC.

But it’s not all empty fun. The game was designed with the help of Cambridge sociologists and stem cell scientists from the University’s Stem Cell Institute to provide a realistic taste of life inside a biotechnology laboratory.

The game of science

“The route to scientific discovery can feel like a mystery to many of us,” said Dr Karen Jent from the ReproSoc group in Cambridge’s Department of Sociology, who led the game’s development. “A lot of people only encounter the process of science through hyperbolic headlines or cinematic tales of the lone genius.”

“We want to use gaming to have a different kind of conversation about science. Science involves teamwork and care as much as reason and logic. We aimed to create an interactive experience reflecting the nurturing of experiments and building of social relationships at the heart of good science.”

Jent explains that her work allowed her to see the interpersonal dynamics that form in stem labs, but also the bond that forms between researchers and the cells they grow. These require near-constant attention and care, she explains, likening them to microscopic kids. These relationships form the foundation of the game: it’s “part Sims, part Tamagotchi,” she explains, with strategy and dilemma thrown in to spice things up.

In Dish Life, players must manage to strike a balance between caring for their (every-hungrier) cells while helping improve their lab’s wellbeing, reputation, and nurturing their own careers through publications and securing promotions. Players need to feed and monitor cell cultures, eventually splitting cultures up when they outgrow their Petri dishes and start converting them into specific cell types. Each success rewards experience points that players can use to unlock new abilities, colleagues, and equipment. However, players also have to keep tabs on the wellbeing of their avatar (the in-game researcher they play) and colleagues by engaging in social life in the lab, and complete quests that include job interviews and to produce new drugs.

The game draws inspiration from a 2016 short film Jent produced with stem cell researchers Dr. Loriana Vitillo and movie director Chloe Thomas (which was also named Dish Life). The film cast children for the role of stem cells and used a paddling pool in lieu of a petri dish. It also featured a number of researchers explaining the quasi-relationship they developed with the cell cultures they cared for through constant monitoring, feeding, even talking aloud to them for months on end.

“It was an ordinary day in the lab, feeding cells, when it occurred to me that we often talk about what we discover but not how we discover, about our real lives,” said Vitillo, game and film co-producer, and Cambridge Stem Cell Institute alumni. “I wanted to tell a different story.”

“With stem cells set to change healthcare, we want to make biotechnology more accessible by showing how this science is really done.”

The game is surprisingly complex and covers a wide range of commentaries on the life of researchers and broader society. Workplace issues such as bullying and maternity cover make an appearance, as do media controversies, government committees, and ethical choices around animal testing and CRISPR. There’s also great depth to the game, with avatars being given access to new issues as they progress in academia.

“Once you run a successful lab, the game opens up questions of medical ethics, environmental impact, the bioeconomy and equality in science,” said Jent explains. “Although those cells will always need feeding.”

The game was designed by Pocket Sized Hands, a Dundee-based games studio. The Cambridge team plans to continue testing the game with groups of stem cell scientists and update gameplay accordingly after release, so you can be sure to always get a realistic taste of life in the lab.

Don’t forget to feed those cells, though

The world’s first ‘living machines’ can move, carry loads, and repair themselves

Researchers at the University of Vermont have repurposed living cells into entirely new life-forms — which they call “xenobots”.

The xenobot designs (top) and real-life counterparts (bottom).
Image credits Douglas Blackiston / Tufts University.

These “living machines” are built from frog embryo cells that have been repurposed, ‘welded’ together into body forms never seen in nature. The millimeter-wide xenobots are also fully-functional: they can move, perform tasks such as carrying objects and healing themselves after sustaining damage.

This is the first time anyone “designs completely biological machines from the ground up,” the team writes in their new study.

It’s alive!

“These are novel living machines,” says Joshua Bongard, a professor in UVM’s Department of Computer Science and Complex Systems Center and co-lead author of the study. “They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.”

“It’s a step toward using computer-designed organisms for intelligent drug delivery.”

The xenobots were designed with the Deep Green supercomputer cluster at UVM using an evolutionary algorithm to create thousands of candidate body forms. The researchers, led by doctoral student Sam Kriegman, the paper’s lead author, would assign the computer certain tasks for the design — such as achieving locomotion in one direction — and the computer would reassemble a few hundred simulated cells into different body shapes to achieve that goal. The software had a basic set of rules regarding what the cells could and couldn’t do and tested each design against these parameters. After a hundred runs of the algorithm, the team selected the most promising of the successful designs and set about building them.

The design of the xenobots.
Image credits Sam Kriegman, Douglas Blackiston, Michael Levin, Josh Bongard, (2020), PNAS.

This task was handled by a team of researchers at Tufts University led by co-lead author Michael Levin, who directs the Center for Regenerative and Developmental Biology at Tufts. First, they gathered and incubated stem cells from embryos of African frogs (Xenopus laevis, hence the name “xenobots”). Finally, these cells were cut and joined together under a microscope in a close approximation of the computer-generated designs.

The team reports that the cells began working together after ‘assembly’. They developed a passive skin-like layer and synchronized the contractions of their (heart) muscle cells to achieve motion. The xenobots were able to move in a coherent fashion up to days or weeks at a time, the team found, powered by embryonic energy stores.

Later tests showed that groups of xenobots would move around in circles, pushing pellets into a central location, spontaneously and collectively. Some of the xenobots were designed with a hole through the center to reduce drag but the team was able to repurpose it so that the bots could carry an object.

It’s still alive… but on its back?

A manufactured quadruped organism, 650-750 microns in diameter.
Image credits Douglas Blackiston / Tufts University.

One of the most fascinating parts of this already-fascinating work, for me, is the resilience of these xenobots.

“The downside of living tissue is that it’s weak and it degrades,” says Bongard. “That’s why we use steel. But organisms have 4.5 billion years of practice at regenerating themselves and going on for decades. We slice [a xenobot] almost in half and it stitches itself back up and keeps going. This is something you can’t do with typical machines.”

“These xenobots are fully biodegradable,” he adds, “when they’re done with their job after seven days, they’re just dead skin cells.”

However, none of the team’s designs was able to turn itself over when flipped on its back. It’s an almost comical little Achilles’ Heel for such capable biomachines.

The manufacturing process of the xenobots.
Image credits Sam Kriegman, Douglas Blackiston, Michael Levin, Josh Bongard, (2020), PNAS.

Still, they have a lot to teach us about how cells communicate and connect, the team writes.

“The big question in biology is to understand the algorithms that determine form and function,” says Levin. “The genome encodes proteins, but transformative applications await our discovery of how that hardware enables cells to cooperate toward making functional anatomies under very different conditions.”

“[Living cells] run on DNA-specified hardware,” he adds, “and these processes are reconfigurable, enabling novel living forms.”

Levin says that being fearful of what complex biological manipulations can bring about is “not unreasonable”, and are very likely going to result in at least some “unintended consequences”, but explains that the current research aims to get a handle on such consequences. The findings are also applicable to other areas of science and technologies were complex systems arise from simple units, he explains, such as the self-driving cars and autonomous systems that will increasingly shape the human experience.

“If humanity is going to survive into the future, we need to better understand how complex properties, somehow, emerge from simple rules,” says Levin. “If you wanted an anthill with two chimneys instead of one, how do you modify the ants? We’d have no idea.”

“I think it’s an absolute necessity for society going forward to get a better handle on systems where the outcome is very complex. A first step towards doing that is to explore: how do living systems decide what an overall behavior should be and how do we manipulate the pieces to get the behaviors we want?”

The paper “A scalable pipeline for designing reconfigurable organisms” has been published in the journal PNAS.

Researchers map the genetic mechanisms that makes hydras ‘immortal’

Researchers are especially interested in hydra’s ability to regenerate its nervous system, which could new therapeutics for treating trauma or degenerative disease in humans.

Image credits Stefan Siebert / UC Davis.

The tiny freshwater invertebrate known as the hydra, while definitely less scary than its mythological counterpart, regenerates damaged cells and tissues. This ability is so poignant that, were you to cut a hydra in half, it would regrow its body and nervous system in a matter of days.

Trying to understand exactly how it does this, researchers at the University of California have traced the evolution of the hydra’s cells throughout its life, finding three lines of stem cells that differentiate into nerves, muscles, or other tissues.

Life renewed

“The beauty of single-cell sequencing and why this is such a big deal for developmental biologists is that we can actually capture the genes that are expressed as cells differentiate from stem cells into their different cell types,” says Celina Juliano, assistant professor in the UC Davis Department of Molecular and Cellular Biology and lead author of the study.

Juliano’s team sequenced RNA transcripts of 25,000 single hydra cells to follow the genetic trajectory of nearly all of the animal’s differentiated cell types. The study thus creates a high-resolution map of the entire developmental path of the hydra’s cells.

Hydras continuously renew their cells from stem cell populations, the team explains. Based on the analysis of sets of messenger RNA molecules (transcriptomes) retrieved from individual cells and groups of cells (based on shared expressed genes), the team separated these stem cells into three different lineages. They could then build a decision tree showing how each lineage matures into different cell types and tissues. For example, the interstitial stem cell lineage produces nerve cells, gland cells, and the stinging cells in the animal’s tentacles.

“By building a decision tree for the interstitial lineage, we unexpectedly found evidence that the neuron and gland cell differentiation pathway share a common cell state,” said Juliano. “Thus, interstitial stem cells appear to pass through a cell state that has both gland and neuron potential before making a final decision.”

The molecular map also allowed Juliano and colleagues to identify the genes that influence these decision-making processes, which will be the focus of future studies.

The team hopes that their work will allow developmental biologists to understand regulatory gene networks that control the early evolution of the hydra, networks that they say are shared among many animals, including humans. Understanding how the hydra regenerates its entire nervous system could thus help us better understand neurodegenerative diseases in humans.

“All organisms share the same injury response pathway but in some organisms like hydra, it leads to regeneration,” said coauthor and graduate student Abby Primack. “In other organisms, like humans, once our brain is injured, we have difficulty recovering because the brain lacks the kind of regenerative abilities we see in hydra.”

The paper “Stem cell differentiation trajectories in Hydra resolved at single-cell resolution” has been published in the journal Science.

Skin old, new.

Stem-cell-laden skin grafts could heal burn victims 30% faster, if not quicker

It’s the phoenix of skin grafts!

Skin old, new.

Image via Pixabay.

Researchers at the University of Toronto (UoT) are working to give burn victims their skin back. The team has developed a new process by which stem cells are retrieved from the burned skin and used to speed up recovery. Such a treatment option would greatly improve the chances of survival for those involved in fires or industrial accidents, as well as their quality of life to boot.

The team plans to start human trials by early 2019.

Skin to ashes, ashes to skin

“Because we’re using actual skin stem cells, and not from some other part of the body, we believe the quality of the skin will be better,” says Saeid Amini-Nik, a professor in the UoT Faculty of Medicine

“You want skin that stretches normally. In burn patients skin gets scarred and they have trouble moving joints because skin is not elastic.

Current procedures call for the removal and discarding of burned skin as medicinal waste. Collagen dressings are then applied to the site to protect the injury while it’s healing. This can take up to several months, however, during which patients are at high risk of developing (often fatal) infections.

Given the limitations of the current approach, researchers have long been interested in using stem cells to heal burns. Such cells were harvested from samples of organs from themselves or other patients/donors (such as umbilical cords, for example), which comes with its own host of problems:

  • Tissue incompatibility, leading to high rejection rates for the grafts.
  • Difficulties harvesting stem cells from the patients themselves. The cells used in such treatments are most often derived from undamaged portions of a patient’s skin or bone marrow. However, burn victims who need treatment with their own stem cells are usually those who have suffered extensive injuries — usually covering more than half of their bodies. Their extensive burns already pose a significant, potentially fatal risk, and they’re already at a high risk of infection. Surgically removing the skin or marrow needed for the treatment thus poses a real risk to their survival.

The team’s new approach started with them looking for live stem cells in samples of discarded dermis taken from burn victims. It was virtually unheard-of up to now, as it was considered a fool’s errand. The UoT researchers themselves hoped to find even one living cell in such samples — they were astonished to find thousands (even a million in one case) of living, usable cells in the burned tissue.

A preclinical trial involving animal models showed that adding human dermis stem cells to the collagen dressings improved healing speeds by 30%. There were no cases of rejection, and the stem cells naturally created skin to cover the wounds. The team hopes to see higher regrowth rates in the upcoming human trials, as they will be using human cells on people.

Cardiac stem cells.

Cardiac stem cells.
Image credits Gepstein Laboratory.

Amini-nik says the team expects the healing process to happen “very fast, possibly days instead of weeks or months,” which would be grand. Speed is key in healing burns, as each day spent with open wounds that need fresh dressings increases the chance of developing an infection — the baseline risk is already very high, and “sometimes [patients] die of sepsis.

Another major plus is that “using a patient’s own stem cells also won’t raise ethical issues,” the team explains.

“Much faster healing would be a major step forward,” says Amini-Nik. “We also believe this will be better for quality of life: Itching and inability to sweat are big problems for burn patients. We believe if we use the stem cells from the very same organ, we’ll grow better skin. ”

“Our goal is no death, no scar, and no pain,” adds Marc Jeschke, paper co-author. “With this approach we come closer to no death and no scar.”

The paper “Stem cells derived from burned skin – The future of burn care” has been published in the journal EBioMedicine.

Women in STEM.

More gender equal countries have fewer women in STEM, paradoxically

Puzzlingly, women in countries with greater gender equality are less likely to take degrees in science, technology, engineering, and mathematics (STEM). New research delves into this ‘gender equality paradox’.

Women in STEM.

Image credits Eryk Salvaggio.

You’d expect countries which make it harder for women to carve their own path in life to have fewer women involved in STEM fields — however, that is not the case. It’s actually quite the opposite: countries like Algeria or Albania enjoy a greater percentage of women (and of their total female population) amongst their STEM graduates than Finland, Norway, or Sweden.

The STEM of the issue

Researchers from the Leeds Beckett University in the UK and the University of Missouri in the USA wondered what’s up and set out to investigate. Their working hypothesis was that this divide stems from the poorer quality of life in countries with lower equality, which often have little welfare support, making STEM careers (which are generally better-paid jobs) more attractive to women who live there. The teams also looked at what factors motivate boys and girls to choose STEM subjects, including overall ability, whether or not science subjects were a personal academic strength, as well as personal interest or sheer enjoyment of the topic.

The data used in the study was drawn from 475,000 teenagers across 67 countries and regions. Boys and girls had overall similar achievement levels in STEM fields, however, science was more likely to be the best subject for boys. Girls, even in cases where their ability and achievements in science were comparable to or greater than that of boys, were more likely to be better overall in reading comprehension, which is more closely tied to non-STEM subjects. Girls, overall, also tended not to be as interested in science subjects as boys. The authors note that these differences were near-universal across all the countries and regions in their analysis.

So on the one hand, girls generally tend not to care about science as much as boys, and they’re also, generally speaking, likely to be better than boys at non-STEM-related skills. According to first author Gijsbert Stoet from LBU, this already explains some of the gender disparity we see in STEM fields participation.

“The further you get in secondary and then higher education, the more subjects you need to drop until you end with just one. We are inclined to choose what we are best at and also enjoy. This makes sense and matches common school advice.”

“So, even though girls can match boys in terms of how well they do at science and mathematics in school, if those aren’t their best subjects and they are less interested in them, then they’re likely to choose to study something else.”

And it makes sense; with limited resources to invest (both financial and time-wise) in education, we all want to go for something we both like and are good at. According to these findings, girls by-and-large seem to be naturally better at non-STEM-related tasks. I’m not saying they’re not good at STEM-related skills, and the authors aren’t either — it’s just that they’re even better at doing something else.

Where gender equality comes in

Bathroom sign.

Image via provera250.

That explanation, however, only tells part of the story. STEM fields, after all, tend to be the better-paying ones, and that’s certainly a powerful motivator when deciding on a career path. So, based on the criteria I’ve listed above, the team looked at how many girls could be expected to study in STEM fields. They took the number of girls in each country that had the necessary ability in STEM and for whom it was also their best subject and compared to the number of women actually graduating in STEM.

All things considered, they report that every country had a disparity between those two figures, however, more gender equal countries had the widest gaps. In the UK for example, 29% of STEM graduates are female, whereas 48% of girls might be expected to take those subjects based on science ability alone, and 39% could be expected to do so once both ability and interest were factored in.

“Although countries with greater gender equality tend to be those where women are actively encouraged to participate in STEM, they lose more girls from an academic STEM track who might otherwise choose it, based on their personal academic strengths,” says co-author Professor David Geary, UoM.

“Broader economic factors appear to contribute to the higher participation of women in STEM in countries with low gender equality and the lower participation in gender-equal countries.”

Using the UNESCO overall life satisfaction (OLS) figures as a stand-in for economic opportunity and hardship, the researchers found that in more gender equal countries, overall life satisfaction was higher. The team reports that STEM careers are generally more secure and well-paid than their competition. However, in countries where any choice of career feels relatively safe (i.e. richer countries, which tend to be more gender equal) women may put more emphasis on non-economic factors, such as personal preference, over economic factors, such as pay. Sex differences in academic strength and interests would thus factor in much more in women’s college and career choices in a more gender-equal country, Geary adds.

The findings could help guide efforts of getting more women into STEM, where their presence has remained broadly stable for decades despite efforts to increase participation.

“It’s important to take into account that girls are choosing not to study STEM for what they feel are valid reasons, so campaigns that target all girls may be a waste of energy and resources,” adds Professor Stoet.

“If governments want to increase women’s participation in STEM, a more effective strategy might be to target the girls who are clearly being ‘lost’ from the STEM pathway: those for whom science and maths are their best subjects and who enjoy it but still don’t choose it. If we can understand their motivations, then interventions can be designed to help them change their minds.”

The paper “The Gender-Equality Paradox in Science, Technology, Engineering, and Mathematics Education” has been published in the journal Psychological Science.

Red blood cells.

Immortal cells could usher in the age of plentiful, artificial blood for transfusions

Immortalized cell lines could one day be used to create an endless supply of blood for medical uses. A new paper reports the first successful use of such an immortalized line to synthesize blood.

Red blood cells.

Image credits Gerd Altmann.

Blood is really important if you plan on staying alive. But it does have an annoying habit of flowing out and away from pokes and scratches in your body, or during surgery and other medical procedures — so doctors need to have a steady supply on hand at all times to replenish the losses.

Trouble is, doctors today rely on donors to keep stocks of blood up, and there are way more patients than donors. Not only that, they also need to match the blood type of the patient with the donor and make sure they have the right volume of blood. So overall, it can get pretty nerve-racking for doctors to make sure they have enough healthy blood of the right type available when they need it.

Blood on tap

But the life of doctors (and probably vampires) is about to get a whole lot better as a group of scientists at the University of Bristol, along with colleagues from the NHS Blood and Transplant, developed a method that should allow us to produce a virtually endless supply of high-quality artificial blood.

The breakthrough would allow for a steady supply of red blood cells to be produced, which could then be used to create artificial blood for transfusions. There are a number of techniques available today to do just that, but they’re very limited in the amount of cells they can produce. For example, certain types of stem cells can be used to produce red blood cells, but the generating sample dies off after producing about 50.000 cells — but a typical bag of blood contains somewhere around 1 million such cells.

The solution, the team says, is immortalizing the generating cell line, so they will never die off and keep making red blood cells. One such cell line has been pioneered by UoB researchers, and they named it the BEL-A (Bristol Erythroid Line Adult). The secret to their success is that they immortalized the stem cells in their premature stage. The cells can then be mobilized to divide and produce red blood cells. It’s the first known line of cells which can continuously produce red blood cells and also generate additional lines successfully.

“Cultured red blood cells provide such an alternative and have potential advantages over donor blood, such as a reduced risk of infectious disease transmission, and as the cells are all nascent, the volume and number of transfusions administered to patients requiring regular transfusions (sickle cell disease, thalassaemia myelodysplasia, certain cancers) could be reduced, ameliorating the consequences of organ damage from iron overload” the paper reads.

Their use could allow a constant supply of blood even in hospitals situated in remote and isolated areas, making a huge difference in life-or-death scenarios where doctors won’t have to wait on a shipment of blood to arrive. Another huge implication of the BEL-A cells is that they could finally decouple the patients from donors, meaning people with rare blood types won’t lack for blood due to a shortage in donors with the same blood type.

The researchers say that in addition to its role in supplying blood, BEL-A cells can also prove to be a powerful tool in further research. Right now, the technique is awaiting clinical trials.

The paper “An immortalized adult human erythroid line facilitates sustainable and scalable generation of functional red cells” has been published in the journal Nature Communications.

 

Scaffolding

If stem cells don’t grow as you want them to, just add a dash of parsley-husk scaffolding

University of Wisconsin-Madison researchers are investigating de-cellularized plant husks as potential 3D scaffolds which, when seeded with human stem cells, could lead to a new class of biomedical implants and tailored tissues.

Scaffolding

Image via Pixabay.

We may like to call ourselves the superior being or top of the food chain and all that, but as far as design elegance and functionality is concerned, the things nature comes up with make us look like amateurs. Luckily, we’re not above emulating/copying/appropriating these designs, meaning that structures created by plants and animals have long and liberally been used to advance science and technology.

Joining this noblest of scientific traditions, UWM scientists have turned to de-celled husks of plants such as parsley, vanilla, or orchids to create 3D scaffolds which can be seeded with human stem cells and optimized for growth in lab cultures. This approach would provide an inexpensive, easily scalable and green technology for creating tiny structures which can be used to repair bits of our bodies using stem cells.

Plantfolding

The technology draws on the natural qualities of plant structures — strength, porosity, low weight, all coupled with large surface-to-volume ratios — to overcome several of the limitations current scaffolding methods, such as 3D printing or injection molding, face in creating efficient feedstock structures for biomedical applications.

“Nature provides us with a tremendous reservoir of structures in plants,” explains Gianluca Fontana, lead author of the new study and a UW-Madison postdoctoral fellow. “You can pick the structure you want.”

“Plants are really special materials as they have a very high surface area to volume ratio, and their pore structure is uniquely well-designed for fluid transport,” says William Murphy, professor of biomedical engineering and co-director of the UW-Madison Stem Cell and Regenerative Medicine Center, who coordinated the team’s efforts.

The team worked together with Madison’s Olbrich Botanical Gardens’ staff and curator John Wirth to identify which species of plants could be used for the tiny scaffolds. In addition to parsley and orchids, the garden’s staff also found that bamboo, elephant ear plants, and wasabi have structures that would be useful in bioengineering for their shape or other properties. Bulrush was also found to hold promise following examinations of plants in the UW Arboretum.

Human fibroblast cells growing on decellularized parsley.
Image credits Gianluca Fontana / UW-Madison.

Plants form such good scaffolds because their cellular walls are rich in cellulose — probably the most abundant polymer on Earth, as plants use it to form a rough equivalent of our skeleton. The UWM team found that if they strip away all the plant’s cells and chemically treat the left-over cellulose, human stem cells such as fibroblasts are very eager to take up residence in the husks.

Even better, the team observed that stem cells seeded into the scaffolds tended to align to the scaffold’s structure. So it should be possible to use these plant husks to control the structure and alignment of developing human tissues, Murphy says, a critical achievement for muscle or nerve tissues — which don’t work unless correctly aligned and patterned. Since there’s a huge variety of plants — with unique cellulose structures — in nature, we can simply find one that suits our need and use that to tailor the tissues we want.

“Stem cells are sensitive to topography. It influences how cells grow and how well they grow,” Fontana added.

“The vast diversity in the plant kingdom provides virtually any size and shape of interest,” notes Murphy. “It really seemed obvious. Plants are extraordinarily good at cultivating new tissues and organs, and there are thousands of different plant species readily available. They represent a tremendous feedstock of new materials for tissue engineering applications.”

Another big plus for the plantfolds is how easy they are to produce and work with, being “quite pliable […] easily cut, fashioned, rolled or stacked to form a range of different sizes and shapes,” according to Murphy. They’re also easy and cheap to mass produce as well as renewable on account of being, you know, plants.

So far, these scaffolds seem to hold a huge potential. They’ve yet to be tested in living organisms, but there are plans to do so in the future.

The scaffolds have yet to be tested in an animal model, but plans are underway to conduct such studies in the near future.

“Toxicity is unlikely, but there is potential for immune responses if these plant scaffolds are implanted into a mammal,” says Murphy.

“Significant immune responses are less likely in our approach because the plant cells are removed from the scaffolds.”

The full paper “Biomanufacturing Seamless Tubular and Hollow Collagen Scaffolds with Unique Design Features and Biomechanical Properties” has been published in the journal Advanced Healthcare Materials.

This is Isis Wenger, a computer scientist whose photo was used for a recruitment campaign by the engineering company she works for. A lot of people went nuts on facebook calling BS because they couldn't believe Isis was a real computer scientist. Credit: U-C Boulder.

Women scientists with feminine traits less likely to be judged as scientists

This is Isis Wenger, a computer scientist whose photo was used for a recruitment campaign by the engineering company she works for. A lot of people went nuts on facebook calling BS because they couldn't believe Isis was a real computer scientist. Credit: U-C Boulder.

This is Isis Wenger, a computer scientist whose photo was used for a recruitment campaign by the engineering company she works for. A lot of people went nuts on facebook calling BS because they couldn’t believe Isis was a real computer scientist. Credit: U-C Boulder.

Researchers at University of Colorado Boulder showed volunteers pictures of men and women, then asked them to judge each person how masculine or feminine they looked. Unbeknownst to the participants, all of the men and women featured in the photos were working scientists, but those women who were rated high for “feminine” traits like long hair or fine skin were generally assumed to be non-scientists.

“What we find is that for photos of men, there is no impact of gendered appearance,” said Sarah Banchefsky, a postdoctoral researcher in social psychology and lead author of the paper.

Can a woman without a lab coat still be a scientist?

Depending on how you look at the findings, these can be either surprising or obvious. Anyone who has taken a university course in engineering or hard physical sciences knows there’s a disproportionate amount of men attending classes. Since there are few women looking for a career in STEM, let alone attractive ones, it’s no wonder that participants were inclined to judge the women scientists with feminine traits featured in the photos as more likely to work as early childhood educators — a field 80 percent occupied by women.

“There are some accounts of women in STEM fields who not only feel like they can’t wear makeup or a dress, but also can’t talk about wanting to have kids,” Banchefsky said

The main conclusion of the study is that “people use variation in women’s feminine appearance as a cue to her career,” something that doesn’t necessarily happen for men. But is this a cultural bias or sexism? The authors of the study conclude “this work empirically validates claims made by some women in STEM that their belonging or aptitude in their career has been doubted simply due to their feminine appearance, and it contributes to research suggesting that appearance is more valued, scrutinized, and consequential for women than men.” They call this a new form of gender bias, but personally I feel this is just classical stereotype enforcement — one that starts at a very fragile age, as I’ll explain later.

The study does, however, start a very interesting discussion that’s worth debating. Feminity and women come together like a hand in a glove, just like masculinity and men for that matter. That’s common sense. But we have a problem when people almost unanimously agree that women have to be unfeminine to have a career in STEM. It does nothing but further exacerbate the gender gap because most woman will turn their back on a field where their can’t express their femininity.

A study from 2013 followed the science aspirations and career choice of 10–14-year-old children. After surveying 9,000 children and interviewing 92 children and 78 parents, the researchers conclude that a career in science is “largely ‘unthinkable’ for these girls because they do not fit with either their constructions of desirable/intelligible femininity nor with their sense of themselves as learners/students.”

“We argue that an underpinning construction of science careers as ‘clever’/‘brainy’, ‘not nurturing’ and ‘geeky’ sits in opposition to the girls’ self-identifications as ‘normal’, ‘girly’, ‘caring’ and ‘active’. Moreover, we suggest that this lack of fit is exacerbated by social inequalities, which render science aspirations potentially less thinkable for working-class girls in particular,” the researchers of 2013 study wrote.

The following quote from one of the participants is most telling.

“I [a mother] said so how do you feel about science? And she [a daughter] said it’s really interesting, I love it, but don’t only geeks do it? [Int: Oh did she?] I now and this is why I wanted to get away a bit from her thinking that science is only for people I don’t know who…because she’s got this impression that only people who don’t have a life do science, which is terrible.”

Bernadette Park, professor of social psychology and neuroscience, says the recent U-C Boulder study highlights a troubling implications for the future of science in America.

“These feminine-looking women have ‘heard’ verbally or nonverbally that they don’t look like scientists, that they don’t belong in these male-dominated, highly prestigious fields,” Park said. “The message that your appearance matters and that it is relevant to your career choice likely leads other women — as undergraduates, as high-school students and even as young girls — to conclude they just don’t fit with science.”

I also feel this is a big problem, one with no obvious solution in sight. I also think, however, that society as a whole is coming to terms with the fact that there’s nothing stopping women from going into STEM if this is something they really want to do. If in the 1970s, men were 1.6 to 1.7 times as likely as women to later earn a STEM Ph.D., by the 1990s the gender gap had closed and both sexes are as likely to complete their education, according to a study featured previously on ZME Science.

But there’s still so much work ahead before we can eliminate sexism and racial bias from the academia.

Credit: “Double Jeopardy: Gender Bias Against Women of Color in Science

Sexism and racism in STEM: women scientists of color mistaken for janitors

A new report highlights the reprehensible state of women working in STEM fields—science, technology, engineering, and mathematics— where they’re not only under represented, but also under constant pressure to over perform. The report also stresses how sexism and racism is “still a thing” in labs, universities and technology companies. In fact, there’s seems to be an entrenched thinking that women don’t have any place in a scientific institution, how else could you explain that almost half of Black and Latina women working as scientists have been mistaken for a janitor or an administrator of their offices?

Credit:  “Double Jeopardy: Gender Bias Against Women of Color in Science

Credit: “Double Jeopardy: Gender Bias Against Women of Color in Science

As one Latina statistician told researchers, “I always amuse my friends with my janitor stories, but it has happened not only at weird hours.” She calmly informed someone that she had the key to the office, not the janitor’s closet.

The report, called  “Double Jeopardy: Gender Bias Against Women of Color in Science,” was released by the Center for WorkLife Law at the University of California, which surveyed 500 female scientists and conducted in-depth interviews with 60 more.

Everybody knows there’s a wide STEM gender gap, with women out numbered three to one. The problem starts as early as grade school. Young girls are rarely encouraged to pursue math and science, which is problematic considering studies show a lack of belief in intellectual growth can actually inhibit it. In addition, there exists an unconscious bias that science and math are typically “male” fields while humanities and arts are primarily “female” fields, and these stereotypes further inhibit girls’ likelihood of cultivating an interest in math and science. This is conventional thinking of course. It’s true, but only half the story. What isn’t mentioned is the hostile and discouraging environment that many women face in male-dominated classrooms, offices, and labs. Of the 60 scientists interviewed in the report, 100 percent reported that they had experienced gender discrimination during their careers. STEM women are also under constant fire to prove themselves; 75 percent of the African-American women scientists surveyed reported having to prove their intelligence over and over again.

These are the four distinct and pervasive patterns of discrimination across STEM careers:

1. Prove It Again: Women often have to provide more evidence of being competent to be treated as equally capable as men. Even then, one study found that when a man and a woman had equal math skills, 90 percent of the time, employers would choose to hire the man.

2. The Tightrope: Women find themselves walking a fine line between being seen as “too feminine to be competent” and “too masculine to be likable.” Half of all the women interviewed said they experienced backlash for being assertive. Latina women in STEM fields are especially likely to say that their coworkers accuse them of being “angry.”

3. The Maternal Wall: Women working in STEM fields face the assumption from their colleagues that their commitment to their work will fade if they have kids. On the other hand, many women without kids report being expected to work longer hours because they aren’t raising children.

4. Tug of War: Women who experience gender bias early in their careers are more likely to distance themselves from women. The researchers call this the “queen bee” effect.

Sarah Mirk, a writer for Bitchmedia thinks the lack of women—and especially women of color—in labs, computer-science jobs, and math careers across the country is symptomatic of deep racism and sexism in our culture. “In order to help the number of female scientists grow, we need to get to a point where none of them are routinely mistaken for janitors,” she goes on to say. I think we all can agree to that.

 

 

gender gap in STEM

STEM gender gap needs rethinking: men and women just as likely to earn PHD

Many scholars who still seek to explain why more women leave  the science, technology, engineering and mathematics (STEM) pipeline than men are stuck in old times. If in the 1970s, men were 1.6 to 1.7 times as likely as women to later earn a STEM Ph.D., by the 1990s the gender gap had closed and both sexes are as likely to complete their education. Efforts to bridge the gap and promote gender diversity have thus been fruitful. There’s still gender gap in STEM among those who first enroll in college, with roughly three times as many men than women.

gender gap in STEM

Credit: XKCD

The “leaky pipeline” metaphor is often used to illustrate how students on a bachelor’s-to-Ph.D. trail stray off this particular path. It’s believed that more women than men “leak” from the pipeline, but a Northwestern University analysis suggests otherwise. The researchers used data from two large nationally representative research samples to reconstruct a 30-year portrait of how bachelor’s-to-Ph.D. persistence rates for men and women have changed in the United States since the 1970s. The graph below illustrates their findings. Decades ago there was a considerable leak gap, but presently this gap is considerably smaller. Particularly, the gender persistence gap completely closed in pSTEM fields (physical science, technology, engineering and mathematics), where women are the least represented.

gender gap STEM graph

Image: Frontiers in Psychology

Yes, more men earn STEM PhDs then women, but this difference can no longer be explained by lack of persistence. The findings appeared in the journal Frontiers in Psychology.

“Our analysis shows that women are overcoming any potential gender biases that may exist in graduate school or undergraduate mentoring about pursing graduate school,” said David Miller, an advanced doctoral student in psychology at Northwestern and lead author of the study. “In fact, the percentage of women among pSTEM degree earners is now higher at the Ph.D. level than at the bachelor’s, 27 percent versus 25 percent.”

As such, the widely used leaky pipeline metaphor is a dated description of gender differences in postsecondary STEM education. Past research has also found that there’s no difference in persistence past the PhD level. For instance, in physical science and engineering fields, male and female Ph.D. holders are equally likely to earn assistant professorships and academic tenure, according to Miller.  The leaky pipeline metaphor is still relevant in life science and economics, however, where more women leak from the Ph.D.-to-assistant-professor pipeline than men.

stem gender gap

Image: Frontiers in Psychology.

The findings should prove particularly useful to those in charge of diverting academic resources. Efforts targeted at bridging a leak gap in most fields would be ineffective and ill placed. Resources would thus be more valued when used to increase women representation in STEM. For instance, women’s representation among pSTEM bachelor’s degrees has been decreasing during the past decade, and this could use “plugging”.

While the researchers are encouraged that gender gaps in doctoral persistence have closed, they stressed that accurately assessing and changing gender biases in science should remain an important goal for educators and policy makers.

BORED_classroom

Active learning greatly outperforms passive lecturing in classrooms

BORED_classroomMost University professors still rely on passive lectures to get their subject across. A meta-study which analyzed 225 studies found that active teaching – lectures that actively engage students and make the learning experience two-way – improves grades and significantly reduces fail rates. The findings add to an already body of literature that suggests the current dominant teaching model is underperforming and obsolete.

Revising the way education is being transferred

“It’s no longer necessary to prove that active-learning methods are better than traditional lectures,” says Rory Waterman, a chemistry professor at the University of Vermont who is an advocate for active-learning methods and a coorganizer of the Cottrell Scholars Collaborative New Faculty Workshop. “The field can instead focus on which active-learning methods are most effective and how they can be best implemented.”

Scott Freeman, a biology lecturer and education researcher at the University of Washington, Seattle, and colleagues combed through a myriad of studies looking for data that would tell them what kind of impact active learning has. In their paper, the researchers define active learning  as any method that engages students in the process of learning as opposed to passively listening to a lecture. This includes anything from so-called ‘clickers’ – an audience response device which allows lecture attendees to participate in the lecture actively – to the common, yet proven study groups, big or small. The findings suggests that active learning outperforms passive lecturing on all levels – be it chemistry or physics, small or large groups.

On average, score cards improved by one-third of a letter grade. While this might not seem like much, the importance of active learning becomes striking when we look at how it improves student retention rates. Students in traditional lectures are 55% more likely to receive a grade of D or F or to withdraw from a class than are students being taught with active-learning approaches. This tremendous improvement, the researchers write, costs only 10% of the lecture’s time. So just by engaging students for even five minutes during a lecture, a professor can significantly improve his class’ scores and overall learning – statistically speaking, at least.

Susan Singer, director of the Division of Undergraduate Education at the National Science Foundation, believes active learning is most important in science disciplines, where student retention rates are usually lower than other fields.

The study warns, however, that it’s not enough to implement active learning in your class – you have to do it right, too.

“You can goof it up if you don’t do it right,” Freeman explains. He’s witnessed “clicker abuse” in some classes. “There’s a literature on how to use clickers effectively. People have never read any of those papers. They’re just doing it off the cuff. For a scientist or engineer who’s trained to respect evidence and act on it, it’s just horrifying.”

Eventually, Freeman hopes, the study might help educators who still rely on traditional teaching methods to revise their course and migrate to a more engaged method.

“Universities are still over-reliant on lecture-based teaching,” Waterman says, “so helping faculty identify the minimum or first steps they need to take in their classrooms to see these incredible gains in student performance has always seemed to me to be the most practical way to advance student-centered learning.”