Tag Archives: skin

We’re getting a better idea of how moles turn into melanoma, and environment is key

New research is upending what we knew about the link between skin moles and melanoma.

Image via Pxhere.

Moles and melanomas are both types of skin tumors, and they originate from the same cells — the pigment-producing melanocytes. However, moles are harmless, and melanomas are a type of cancer that can easily become deadly if left untreated. The close relationship between them has been investigated in the past, in a bid to understand the emergence of melanomas.

New research at the Huntsman Cancer Institute (HCI) , the University of Utah, and the University of California San Francisco (UCSF) comes to throw a wrench into our current understanding of that link. According to the findings, our current “oncogene-induced senescence” model of the emergence of melanomas isn’t accurate. The research aligns with other recent findings on this topic, and propose a different mechanism for the emergence of skin cancer.

Environmentally-driven

“A number of studies have challenged this model in recent years,” says Judson-Torres. “These studies have provided excellent data to suggest that the oncogene-induced senescence model does not explain mole formation but what they have all lacked is an alternative explanation — which has remained elusive.”

Melanocytes are tasked with producing the pigments in our skin which protect us from harmful solar radiation. Changes (mutations) in one specific gene in the genome of melanocytes, known as BRAF gene mutations, are heavily associated with moles; such mutations are found in over 75% of skin moles. At the same time, BRAF gene mutations are encountered in 50% of melanoma cases.

Our working theory up to now — the oncogene-induced senescence– was that when melanocytes develop the BRAFV600E mutation, it blocks their ability to divide, which turns them into a mole. However, when other mutations develop alongside BRAFV600E, melanocytes can start dividing uncontrollably, thus developing into cancer.

The team investigated mole- and melanoma tissues donated by patients at the UCSF Dermatology clinic in San Francisco or the HCI Dermatology clinic in Salt Lake City. Their analysis revolved around two methods known as transcriptomic profiling and digital holographic cytometry. The first one allows them to determine molecular differences between the cells in moles and those in melanomas. The second one was used to track changes inside individual cells.

“We discovered a new molecular mechanism that explains how moles form, how melanomas form, and why moles sometimes become melanomas,” says Judson-Torres.

The team reports that melanocytes don’t need to have mutations besides BRAFV600E to morph into melanoma. What does play a part, however, are environmental factors, transmitted to the melanocytes through the skin cells around them. Depending on exactly what signals they’re getting from their environment, melanocytes express different genes, making them either stop dividing or divide uncontrollably.

“Origins of melanoma being dependent on environmental signals gives a new outlook in prevention and treatment,” says Judson-Torres. “It also plays a role in trying to combat melanoma by preventing and targeting genetic mutations. We might also be able to combat melanoma by changing the environment.”

The authors hope that their findings will help researchers get a better idea of the biomarkers that can predict the emergence of melanoma at earlier stages than possible today. Furthermore, the results here today can also pave the way to more effective topical medicine that can prevent melanoma, or delay its progress.

The paper “BRAFV600E induces reversible mitotic arrest in human melanocytes via microrna-mediated suppression of AURKB” has been published in the journal eLife.

Foam produced during mating of tropical frogs could improve drug delivery through the skin

After mating, some tropical frogs will secure their eggs in foam that at the same time nurtures and shields growing embryos like a bubble-wrapping. In a new study, researchers found that this lathery substance, which contains proteins with antibacterial properties and is highly durable, could be an excellent medium for delivering drugs through the skin, providing an alternative to irritating synthetic foams and gels.

From the jungle to the lab

Most foams, whether it’s shaving, beer, or saliva foams, collapse within minutes. Some can last for hours. But the foams produced by the mating Túngara frogs (Engystomops pustulosus) can last for over a week — and that’s in harsh tropical environments to boot. Given the highly sensitive nature of a frog’s skin, the compounds in the foam are naturally biocompatible. When researchers became aware of all this, a light bulb instantly lit up.

Sarah Brozio, a former researcher at the University of Strathclyde in Glasgow, has been studying Túngara frogs and their foams in Trinidad since she was a graduate student. She teamed up with microbial biochemist Paul Hoskisson and pharmaceutical engineer Dimitrios Lamprou, who were curious whether the stability and structure of frog foams could support carrying and releasing drugs.

Using foam collected from halfway across the world, the team got busy testing the amphibian concoction in their lab in Scotland, where they employed a battery of tests that probed its composition and stability. In the process, they learned that the foam contains a mixture of proteins that share some properties with pharmaceutical foams without the drawbacks.

Most importantly, the foam derived from the tropical frogs is “stable enough to be manipulated and able to withstand shear forces, suggesting potential for the delivery of drugs over prolonged periods,” the researchers mentioned in a study published this week in Royal Society Open Science.

The researchers brought back frog foam from Trinidad, removed the eggs, let them hatch, then released the tadpoles to the wild. Credit: Paul Hoskisson.

The foam contains densely packed bubbles called vesicles, which seemed sturdy enough to carry drug compounds. To put this theory to the test, the researchers inserted rifamycin, a common antibiotic, into the foam. The antibiotic was slowly but steadily released over the course of a week. That’s an almost perfect time frame since patients typically require an antibiotic regimen lasting five to 14 days.

“This is the first time an amphibian foam has been used for drug delivery,” Hoskisson told Smithsonian Mag, adding that the foams “should give us a really nice, safe delivery vehicle that can be administered to patients without any fear of making them sick, unlike many of the other synthetic delivery vehicles.”

Synthetic foams can only release drugs for 24 hours. What’s more, they can sometimes trigger allergies or irritate a patient’s skin. In this context, the frog foam could be a complete game-changer if it can be produced at a mass scale. Brozio showed that the foam could be produced without having to wait for frogs to copulate. She genetically engineered bacteria to contain frog DNA that produced six key proteins in the foam. Her lab foam was stable for 1-2 weeks, on par with the natural, love-tainted frog foam.

Tests on human skill cells in a petri dish showed that the foam was safe. In the future, the researchers will commence tests on pig skin, then live animals like mice and rabbits. If all goes well, clinical trials may commence that determine if the frog-inspired foam is viable for treating a range of ailments, such as infected wounds and burns. 

New, wearable cortisol sensor can help warn us of incoming burnout or depression

It’s no secret that life can get rough. Those who have to contend with that for too long can start feeling overwhelmed — burned out by the stress. Now, a team of researchers proposes a new approach through which we can quantify how much stress someone is under, and for how long. They hope that the new wearable device can help prevent burnout, and let us know when someone is most in need of support or a good old fashioned break from the stress.

Image via Pixabay.

The new device was designed by a team of engineers at Ecole Polytechnique Fédérale de Lausanne (EPFL) Nanoelectronic Devices Laboratory (Nanolab) and Xsensio, a Swiss-based biotech company. It takes the shape of a wearable sensor that measures the levels of stress hormone cortisol in a person’s sweat. This figure can then be used to gauge the levels of cortisol in the blood.

The sensor is placed directly on the skin and provides continuous readings of this hormone’s levels in their sweat.

Skin-deep stress

“Cortisol can be secreted on impulse — you feel fine and suddenly something happens that puts you under stress, and your body starts producing more of the hormone,” says Adrian Ionescu, head of Nanolab.

“But in people who suffer from stress-related diseases, this circadian rhythm is completely thrown off. If the body makes too much or not enough cortisol, that can seriously damage an individual’s health, potentially leading to obesity, cardiovascular disease, depression or burnout.”

Cortisol is synthesized from cholesterol in our body’s adrenal glands — these sit right on top of your kidneys. How much of it is secreted is in turn controlled by the pituitary gland in our brains through the use of the adrenocorticotropic hormone (ACTH).

It’s easy to read “stress hormone” and immediately assume cortisol is a bad guy, but that’s simply not true. As we’ve seen previously, stress is a completely natural and deeply useful response; the issue with it today is that we’re feeling much more stress than we would in our natural environment. In other words, stress isn’t the issue — too much stress, is.

In our day-to-day, cortisol has some very important functions, including keeping our metabolism, blood sugar, and blood pressure in check. It’s also deeply involved in other cardiovascular functions and the workings of the immune system. In a stressful situation, be it something life-threatening or a simple annoyance, cortisol is flooded into the body to make us ready for our ‘fight or flight’. This mostly means prepping up our brain, muscles, and heart for intense activity and possible injury.

Still, cortisol levels in the blood ebb and flow naturally throughout the day, following our circadian rhythm, to keep us functional or asleep as needed. It generally peaks between 6 am and 8 am to rouse us from sleep and then decreases gradually.

Since cortisol is such a good marker for how stressed we feel and how stressed our body actually is, it’s often used as a gold standard to gauge stress. To do that however you need a blood sample, and those aren’t something you can take just anywhere throughout your day.

That’s why the team designed a wearable sensor to measure how much cortisol an individual excretes through their skin. It contains a transistor and a graphene electrode, which the authors explain has very high sensitivity and can detect even low levels of the hormone. Aptamers, short fragments of single-stranded DNA or RNA that can bind to specific compounds, are tied to this graphene electrode, allowing it to interact with the cortisol molecule. Since the aptamers used naturally contain a negative charge, they will be electrostatically attracted to the cortisol molecule and release a charge as they bind together.

The more such molecules are present, the stronger the overall charge becomes. This allows for an accurate and direct measurement of its levels in sweat. The authors explain that this is the first device intended to continuously monitor cortisol levels throughout the circadian cycle (i.e. throughout the day).

“That’s the key advantage and innovative feature of our device. Because it can be worn, scientists can collect quantitative, objective data on certain stress-related diseases. And they can do so in a non-invasive, precise and instantaneous manner over the full range of cortisol concentrations in human sweat,” adds Ionescu.

They tested the device in the lab and found it reliable and efficient; the next step is to now make it available for healthcare workers or researchers. They’ve set up a bridge project with Prof. Nelly Pitteloud, chief of endocrinology, diabetes, and metabolism at the Lausanne University Hospital (CHUV), where the device will be tested for continuous use in a real-life hospital setting. They intend to run the test using healthy individuals as well as patients with Cushing’s syndrome (who produce too much cortisol), Addison’s disease (too little cortisol), and stress-related obesity.

As far as the psychological ramifications of stress, the team explains that they are still “assessed based only on patients’ perceptions and states of mind, which are often subjective”. A system such as this patch can help us determine quite reliably how much cortisol is running through their system, which can be used to gauge those at risk of depression or burnout. If nothing else, it will help them support their claims with cold-hard figures.

The paper “Extended gate field-effect-transistor for sensing cortisol stress hormone” has been published in the journal Communications Materials.

Scientists zoom in on snake skin to see how they navigate sandy surfaces

Despite having a similar body shape and structure, not all snakes move in the same way. Most, when they move from A to B, slither head-first. But a minority of them (especially desert snakes) do it differently: they slither with their mid-sections first, slithering sideways across the loose sand. Now, researchers know why.

At first glance, you’d think that snakes have a hard time moving around — after all, they have no legs. But here’s the thing: not only do snakes do just fine by slithering, they’re found in almost all environments on Earth, managing to thrive on a variety of surfaces, including sandy environments.

If you’ve ever tried jogging on a beach, you know how hard moving across loose sand is. Now imagine you’re a snake, and your whole body is essentially a sole, how would you even manage moving around?

Researchers have known for a while that snakes in sandy environments tend to move in a different way than others, and they suspected it has something to do with the sand itself. So they set out to investigate it.

“The specialized locomotion of sidewinders evolved independently in different species in different parts of the world, suggesting that sidewinding is a good solution to a problem,” says Jennifer Rieser, assistant professor of physics at Emory University and a first author of the study. “Understanding how and why this example of convergent evolution works may allow us to adapt it for our own needs, such as building robots that can move in challenging environments.”

Rieser’s work joins together biology and soft matter physics (flowable materials, like sand). She studies how animals move around on these surfaces, and how this could help us develop new technologies by adapting what we see in nature (something called biomimicry).

Snakes are particularly interesting because they move in such a peculiar way. Even though snakes “have a relatively simple body plan, they are able to navigate a variety of habitats successfully,” she says. What we’ve learned from snakes has already been applied in several fields. Their long flexible bodies have inspired robots used in surgical procedures or search missions in collapsed buildings, for instance.

The key to the movements of these sidewinder snakes lies in their bellies — in the tiny details of their bellies, to be precise. Rieser and colleagues analyzed three sidewinder snakes (all vipers). They gathered skin the snakes had shed and looked at it with an atomic microscope, zooming in to the atomic level. They also scanned skins shed by non-sidewinders for comparison.

A zoomed-in comparison between holes on a sidewinder snake skin (left) and a non-sidewinder snake skin (right). A mathematical model developed by the researchers shows that the lack of spikes allows sidewinder snakes to move on loose surfaces. Image credits: Tai-De Li.

The regular, non-sidewinder snakes had tiny spikes on their skin, invisible to the human eye. These spikes create friction between the snake and the surface, which acts as a grip allowing them to propel themselves forward headfirst. The sidewinders, however, didn’t have the spikes. Instead, they had tiny holes, because you can’t really create friction or a grip with a surface like sand (that’s also why it’s harder to run on sand than concrete or soil).

“You can think about it like the ridges on corduroy material,” Rieser says. “When you run your fingers along corduroy in the same direction as the ridges there is less friction than when you slide your fingers across the ridges.”

However, some snakes also seemed to have a few spikes, which researchers interpret as a sort of evolutionary “work in progress”. These snakes are younger in their evolutionary history, and haven’t yet had time to fully shed their spikes, the team explains.

“That may explain why the sidewinder rattlesnake still has a few micro spikes left on its belly,” Rieser says. “It has not had as much time to evolve specialized locomotion for a sandy environment as the two African species, that have already lost all of their spikes.”

As for biomimicry, it’s a good lesson: if you want to build a robot that can move on a sand or sand-like surface, you need to pay attention to the texture of its skin.

Journal Reference: Jennifer M. Rieser el al., “Functional consequences of convergently evolved microscopic skin features on snake locomotion,” PNAS (2021). www.pnas.org/cgi/doi/10.1073/pnas.2018264118

Canadian researchers develop hand-held skin printer to treat burn patients

Researchers from the University of Toronto (UoT) Engineering and Sunnybrook Hospital, Canada, have developed a new 3D printer that can create sheets of skin to cover large burns and accelerate the healing process.

A simple schematic detailing the use (a) and general structure of the device (b).
Image credits Richard Y Cheng et al., (2020), Biofab.

Nobody likes to get burned — literally and figuratively. So a team of Canadian researchers has developed a handy new tool to take care of our literal burns. This hand-held 3D printer churns out stripes of biomaterial meant to cover burn wounds, promote healing, and reduce scarring. The bio-ink it uses is based on mesenchymal stromal cells (MSCs), a type of stem cell that differentiates into specialized roles depending on their environment.

Don’t feel the burn

“Previously, we proved that we could deposit cells onto a burn, but there wasn’t any proof that there were any wound-healing benefits — now we’ve demonstrated that,” says Axel Guenther, an Associate Professor of Mechanical Engineering at the UoT and the study’s corresponding author.

The team unveiled their first prototype of the printer in 2018. It was quite the novel gadget at the time, the first of its kind to form tissues on-site, deposit them, and have them set in place in under two minutes.

Since then, the team has redesigned the printer 10 times, in an effort to make it more user-friendly and to tailor it to the requirements of an operating room. The current iteration of the design includes a single-use microfluidic printhead (to ensure the part is always sterile), and a soft wheel that’s used to flatten the material and tailor it to wounds of different shapes and sizes.

The MSCs in the ink are intended to promote regeneration and reduce scarring, the team explains. In broad lines, the authors explain, the method is similar to skin grafting, but it doesn’t require for healthy skin to be transplanted from other areas of the patient’s body — it’s printed on the spot. This is especially useful in the case of large burns, they add.

“With big burns, you don’t have sufficient healthy skin available, which could lead to patient deaths,” says Dr. Marc Jeschke, director of the Ross Tilley Burn Centre and study co-author.

The team tested their printer in collaboration with the Ross Tilley Burn Centre and the Sunnybrook Hospital, successfully using the device to treat full-thickness wounds. Such burn wounds involve the destruction of both layers of the skin and often cover a significant portion of the body. While the results were encouraging, the team wants to further refine their printer and improve its ability to prevent scarring.

“Our main focus moving forward will be on the in-vivo side,” explains study leader Richard Cheng, a teaching assistant at the UoT.

“Once it’s used in an operating room, I think this printer will be a game changer in saving lives. With a device like this, it could change the entirety of how we practice burn and trauma care,” adds Jeschke.

The paper “Handheld instrument for wound-conformal delivery of skin precursor sheets improves healing in full-thickness burns” has been published in the journal Biofabrication.

Scientists create new fiber that’s as flexible as skin, but tougher

Credit: North Carolina State University.

Researchers at the North Carolina State University have devised a new material that combines the elasticity of rubber with the strength of steel. The resulting material can stretch up to seven times its original length before failure while simultaneously being able to undergo a lot of strain. The material can also conduct electricity and regenerate itself, making it a promising candidate for stretchable electronics and soft robotics.

The fiber mimics human tissue which often combines several components to obtain a greater resilience against external loads. For instance, skin is made of a network of collagen bundled fibers which dissipate energy and prevent cuts from spreading. Human muscle absorbs tensile loads in a similar way with the help of the biomolecule titin.

“A good way of explaining the material is to think of rubber bands and metal wires,” said Professor Michael Dickey, lead author of the new study published in Science Advances.  “A rubber band can stretch very far, but it doesn’t take much force to stretch it. A metal wire requires a lot of force to stretch it, but it can’t take much strain – it breaks before you can stretch it very far. Our fibers have the best of both worlds.”

Dickey and colleagues took a gallium metal core and covered it in an elastic polymer sheath. The fiber basically has the strength of the metal core. However, it won’t fail when the metal breaks because the polymer absorbs the strain between the breaking points, transferring the stress back to the metal. This is similar to how human tissue will still hold together broken bones.

You can see the fiber in action in the video below:

“Every time the metal core breaks it dissipates energy, allowing the fiber to continue to absorb energy as it elongates,” Dickey says. “Instead of snapping in two when stretched, it can stretch up to seven times its original length before failure, while causing many additional breaks in the wire along the way.

“To think of it another way, the fiber won’t snap and drop a heavy weight. Instead, by releasing energy repeatedly through internal breaks, the fiber lowers the weight slowly and steadily.”

The galium core is also conductive, making the fiber ideal in electronics and soft robotics, besides applications such as packaging materials or next-generation textiles.

“We used gallium for this proof of concept work, but the fibers could be tuned to alter their mechanical properties, or to retain functionality at higher temperatures, by using different materials in the core and shell.”

“This is only a proof of concept, but it holds a lot of potential. We are interested to see how these fibers could be used in soft robotics or when woven into textiles for various applications.”

bioprinter nozzle.

Mobile bioprinter promises to print new ‘skin’ straight onto any wound

A novel bioprinter aims to make skin grafts a thing of the past — by printing skin directly onto wounds using a patient’s own skin.

Skin.

Image via Max Pixel.

Skin-deep wounds may not sound as dangerous as much as annoying, but make no mistake: they can be debilitating. Chronic, particularly large or non-healing wounds, such as diabetic pressure ulcers, affect millions across the world. They are also very costly, as they require multiple rounds of treatment, and they can be agonizing. If that wasn’t enough, burn injuries behave in largely the same way.

Enter the Skinprinter

Researchers at the Wake Forest Institute for Regenerative Medicine (WFIRM) have developed a mobile bioprinting system that can print skin directly into a wound. The printer (the first of its kind ever developed) is supplied with the patient’s cells, rolled to their bedside, and applies successive layers of (bi-layered) skin to jump-start the healing process.

“The unique aspect of this technology is the mobility of the system and the ability to provide on-site management of extensive wounds by scanning and measuring them in order to deposit the cells directly where they are needed to create skin,” said Sean Murphy, Ph.D., an assistant professor at WFIRM and the study’s lead author.

The team reports that the major building blocks of skin — dermal fibroblasts and epidermal keratinocytes — can easily be isolated from a sample of the patient’s uninjured tissue, and cultured to provide the raw ‘ink’. Fibroblasts are cells that synthesize the extracellular matrix and collagen (basically the skin’s structural supports) while keratinocytes are the predominant cells of the epidermis. Both types of cells play an important role in wound healing.

The ink is made up of these cells and a hydrogel substrate. A certain device embedded into the printer scans the wound, and this data is then crunched to guide the printing process. The printer can deliver a different mix of cells at any point, allowing it to simulate the layered structure of the skin. This helps accelerate the growth and formation of normal skin structure and functions, according to the team. As a proof-of-concept of the system, the team printed skin directly onto pre-clinical models.

bioprinter nozzle.

A close up view of the skin bioprinter nozzle.
Image credits WFIRM.

It’s quite an exciting system. The current go-to method for treating large skin wounds are grafts, but they can often be challenging to stretch over the whole wound. Living human skin also comes in quite a limited supply, as you might imagine. Donors are an option, but those grafts run the risk of being rejected by the host. With the WFIRM bioprinter system, the researchers report seeing new skin forming outward from the center of the wound — this only happened when the patient’s own cells were used, because the tissues were not rejected.

The team says their next step is to conduct clinical, human trials.

“The technology has the potential to eliminate the need for painful skin grafts that cause further disfigurement for patients suffering from large wounds or burns,” said WFIRM Director Anthony Atala, M.D., and a co-author of the paper. “A mobile bioprinter that can provide on-site management of extensive wounds could help to accelerate the delivery of care and decrease costs for patients.”

“If you deliver the patient’s own cells, they do actively contribute to wound healing by organizing up front to start the healing process much faster,” said James Yoo, M.D., Ph. D, who led the research team and co-authored the paper. “While there are other types of wound healing products available to treat wounds and help them close, those products don’t actually contribute directly to the creation of skin.”

The paper “In Situ Bioprinting of Autologous Skin Cells Accelerates Wound Healing of Extensive Excisional Full-Thickness Wounds” has been published in the journal Scientific Reports.

Elephant skin.

Collagen networks and hyaluronic acid literally keep you in shape, new study reports

Our tissues have to handle stress and deformation every day. New research is looking into how it copes so well.

Elephant skin.

Image via Pixabay.

We tend to take our bodies for granted but even the most mundane of actions — walking around, breathing — exerts mechanical stress and subsequent deformation of it. And yet, day after day, our tissues take the brunt of it with grace and even heal themselves without any conscious effort on our part.

Curious to see how it pulls off such a feat, researchers from the Wageningen University & Research (WUR) and the AMOLF Institute found that two components in soft tissue, collagen and hyaluronic acid, work together to underpin how tissues respond to mechanical stress.

Feeling stressed

Pull on your earlobe and it will be soft and flexible. Keep pulling, increase the force you apply, and it will become progressively stiffer. It’s not just your earlobes — skin, muscles, the cartilage in your joints and ribs behave the same way.

They’re designed to work like that. While soft, such tissues are easily traversed by cells — but they also need to provide mechanical protection to underlying structures, meaning it has to be tough too, and hard to break. Finally, it’s vital that such tissue is able to transition between the two states.

Needless to say, that’s quite a list of demands. But, our soft tissues rise to the challenge through the use of collagen, hyaluronic acid, and the interactions between the two, a new study reports. The findings not only help us better understand how our bodies function, but may also point the way towards new, synthetic polymers that mimic these impressive properties.

It’s the particular way in which collagen proteins order themselves in soft tissues that give them their resilience. They arrange in a structure known as a sparse network (meaning the proteins don’t form the maximum possible number of bonds between each other). Previous research has gauged the physical resilience of this sparse network in in-vitro conditions: collagen networks were extracted from samples of animal skin and reformed inside a rheometer, an instrument which measures the response of a material during deformation. Such efforts, the team explains, only capture part of the image, however.

“Real tissues are far more complex: they are composed of different molecules that have different sizes and interact with each other in still unknown ways,” says Simone Dussi, postdoc in the WUR Physical Chemistry and one of the study’s corresponding authors. “Because of this complexity, real tissues are way more adaptive than the networks studied so far, made of only collagen.”

“[The presence of hyaluronic acid] significantly changed the mechanical response of the composite networks and we were eager to understand why.”

The team reports that, unlike collagen, hyaluronic acid — a polymer made of much smaller and more flexible molecules — is electromagnetically charged. Because of this, electrostatic interactions generate stress between its individual blocks which accumulates as the tissue is subjected to deformation. According to the team, this buildup of stress basically opposes the deformation.

Networks with a larger amount of hyaluronic acid are “already stiffer at small deformation[s]”, explains co-author Justin Tauber. They also become stiffer in response to larger deformation than networks poor in the acid, the adds.

“We managed to construct a theoretical model and performed computer simulations that matched the experimental results. The key ingredients were identified: In addition to the network structure and the bending rigidity of the collagen fibres, the elasticity and the internal stress generated by the hyaluronic acid are crucial,” Tauber explains.

“The model allows us to make a step further in understanding how real tissues exploit the balance of all these effects. In addition, our findings can be translated into material science to create novel synthetic polymeric materials with more tunable properties.”

The paper “Stress management in composite biopolymer networks” has been published in the journal Nature.

Macro cat tongue.

Cat’s tongues are surprisingly complex — and better at cleaning than any brush we have

Cat’s scaly tongues are actually very, very good at cleaning fur. So good, in fact, that they could teach our doctors and engineers some tricks, a new study reports.

Macro cat tongue.

Image credits Jennifer Leigh / Wikimedia.

Feline owners out there will know that their pet’s tongue can be really scratchy — especially when they’re grooming. One team of researchers from Georgia Tech wanted to know why. Their research reveals how the rough tongues help cats clean their thick fur and cool down on hot days.

Rough around the middle

“Their tongue could help us apply fluids, or clean carpets, or apply medicine” to hairy areas on our body, says lead researcher Alexis Noel.

The secret behind the feline tongue’s roughness — and its superb cleaning ability — is a layer of tiny hooks that cover the surface. These hooks have groove- or scoop-like structures that help them drive saliva deep into the fur. They’re really effective at it, too. The team says these structures can help inspire new inventions for a wide range of application. Noel himself is already seeking a patent for a 3D-printed, tongue-inspired brush.

Cats, when not busy presenting us with dead presents, spend a lot of time grooming their fur; around a quarter of their waking hours are invested in personal hygiene, the team reports. Given how thick their fur can get, and how hard licking it clean seems to be, this isn’t really surprising at first glance. However, Noel’s curiosity was piqued when she witnessed her cat getting its tongue stuck in a fuzzy blanket. She wondered why her pet’s tongue is covered in those cone-like bumps. Luckily for us all, her lab has a background in animal-inspired engineering — so she set out to find the answer.

The team started by taking computerized tomography (CT) scans of cats’ tongues. This step revealed that the ‘cones’ are, in fact, hooks shaped much like a cat’s claws. They typically lie with their barbs pointing towards the neck (i.e. out of the way), until a certain tongue muscle springs into action. At that point, the spines spring straight up.

What really surprised the team, however, was that these spines (called papillae) contain hollow scoops. The researchers obtained preserved feline tongues (from zoos and taxidermists) to study — bobcats, cougars, snow leopards, lions, and tigers all share this trait, the team explains. Papillae were only slightly longer in lions than in housecats, although the tongues of larger felines hold many more such structures.

Feline Papillae.

Comparison of feline papillae from CT scans.
Image credits Alexis Noel / Georgia Tech.

When dabbed with drops of food dye, these spines absorbed the liquid. Noel’s team estimates that a housecat’s papillae (roughly 300) hold saliva and release it when pressed against fur — and ensure that the animal can thoroughly clean its mane. Lab tests with a machine that the team constructed to mimic the strokes of a cat’s grooming showed that saliva from the tongue’s surface alone simply can’t penetrate as deep.

The team also measured cat fur. Our pets are usually quite fuzzy since their manes try to trap as much air as possible to insulate the animal. When compressed, however, the thickness of fur matches the length of these spines in many types of cat, the paper adds. One exception is Persian cats with their super-long fur that veterinarians caution must be brushed daily to avoid matting.

Finally, these spines aren’t just about staying clean — a thermal camera showed evaporating saliva cooled the cats as they groomed.

The paper “Cats use hollow papillae to wick saliva into fur” has been published in the journal Proceedings of the National Academy of Sciences.

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.

Researchers develop octopus skin-inspired infrared camouflage

Octopods are great at camouflage — they even surpass the ability of chameleons. But how does their camouflage system work?

The secret is chromatophores – skin cells that contain different pigments that are wired to the nervous system and to a radial muscle structure that allows it to change in length and thus change the color saturation of the cell. Each chromatophore is linked to the nervous system by a neuron, making the color change happen in less than a second.

 

They are also able to mimic textures via projections on the skin named papillae and can mirror the environment through iridophores —- reflective cells found in the octopi’s skin tissue.

Scientists have long been trying to develop the perfect camouflage system. Even though they succeeded to make objects invisible to the naked human eye, infrared cameras, that allow us to see temperature variations in colors would still be able to detect them because the electrical components that made visual camouflage possible would heat up, demonstrating their bluff.

So, researchers tried to imitate Mother Nature’s design: the octopod’s chromatophores. By combining special electrodes, wrinkled membranes, and an infrared-reflective coating, Chengyi Xu and colleagues created a synthetic device that mimics cephalopod skin. When applying an electrical current, the membrane expands, reflecting more light of a given wavelength. When the electrical current stops flowing through it, the membrane contracts. You can see below how the membrane reacts to electrical stimuli.

Researchers created a squid-shaped version of the device and analyzed its ability to camouflage. Then, they used an infrared camera to measure the changes in the device’s temperature. Scientists report that altering the reflectance of the device so that its temperature changed by a mere 2°Celsius was sufficient to mask its existence from an infrared camera.

Who knows — maybe in the future we could buy octopus skin clothes and activate them when encountering our exes.

Credit: University of Colorado Boulder.

Self-healing and fully recyclable electronic skin will help robots feel touch

Credit: University of Colorado Boulder.

Credit: University of Colorado Boulder.

Scientists at the University of Colorado Boulder devised an electronic skin, or e-skin, which mimics the mechanical and functional properties of natural human skin. The artificial skin is stretchable and bendable, but also capable of measuring pressure, temperature, and vibration. In the future, this upgrade will enable robots to sense their environment, making human-robot interactions less creepy. E-skin will also be helpful for disabled humans who are forced to wear a prosthesis.

Robo-touch

Electronic skin isn’t a novel concept. For the last decade, scientists all over the world have demonstrated functional artificial skin that possesses the ability to feel and touch objects. However, this is the first time that we’re shown an e-skin that can both heal itself and is fully recyclable.

“This particular device … won’t produce any waste,” said study co-author Jianliang Xiao, an assistant professor of mechanical engineering at the University of Colorado Boulder. “We want to make electronics to be environmentally friendly.”

Xiao and colleagues made their e-skin out of polymer and silver nanoparticles, the latter being responsible for the device’s self-healing properties. If for some reason the e-skin is torn in half, the two sides can come back together in the presence of a rehealing agent and heat pressing, which restores the broken chemical bonds. If the damage is irreparable, the device can be put into a solution that separates and recovers the silver nanoparticles, thereby allowing the material to be recycled for a new e-skin.

“What is unique here is that the chemical bonding of polyimine we use allows the e-skin to be both self-healing and fully recyclable at room temperature,” Xiao said.

Schematic of e-skin and its uses. Credit: University of Colorado Boulder .

Schematic of e-skin and its uses. Credit: University of Colorado Boulder .

Xiao envisions the e-skin being fundamental to improving interactions between human beings and robots. For instance, the scientist imagines babysitting robots equipped with fingers covered in e-skin that can tell what the temperature of the baby is or can measure pressure so the robot doesn’t press too hard.

Similarly, prostheses wrapped in e-skin can enable people who have lost a limb to regain control not only of their dexterity — at least in part — but also sensing ability, as reported in the journal Science Advances.   

But this e-skin isn’t perfect. Unlike our own natural skin, the e-skin isn’t very flexible or stretchable. Worse of all, the device isn’t easily reproducible, which is why Xiao and colleagues are working on a solution that might enable them to scale down the e-skin’s manufacturing.

“We are facing pollution issues every day,” Xiao noted. “It’s important to preserve our environment and make sure that nature can be very safe for ourselves and for our kids.”

Augmented Reality could soon help surgeons ‘see’ through the skin

From Pokemon to saving lives: using augmented reality in the operating room could usher in a new age of surgery.

The surgeon’s vision — elements of the patient’s foot were digitized and then fed into a 3D model. Image credits: Philip Pratt et al. Eur Radiol Exp, 2018 / Microsoft HoloLens (c) Microsoft.

Augmented Reality, the technique popularized last year by Pokemon Go, overlays real-life elements with “augmented” bits — most often, computer-generated information. It’s a world where real life as we know it interacts with holograms.

Now, for the first time, doctors have used augmented reality as an aid for surgery. Specifically, they’ve used Microsoft HoloLens headsets to overlay CT scans, indicating the position of bones and key blood vessels, over each of the patient’s legs. Basically, they were able to ‘see’ through the patient’s skin.

The technology helped with a very delicate procedure: the reconnecting of blood vessels, an essential part of reconstructive surgery.

“We are one of the first groups in the world to use the HoloLens successfully in the operating theatre,” said Dr. Philip Pratt, a Research Fellow in the Department of Surgery & Cancer and lead author of the study, published in European Radiology Experimental.

“Through this initial series of patient cases we have shown that the technology is practical, and that it can provide a benefit to the surgical team. With the HoloLens, you look at the leg and essentially see inside of it. You see the bones, the course of the blood vessels, and can identify exactly where the targets are located.”

So far, the technology has only been used in reconstructive limb surgery, but there’s no reason why it couldn’t be adapted to other types of surgery. Image credits: Philip Pratt et al. Eur Radiol Exp, 2018 / Microsoft HoloLens (c) Microsoft.

Doctors carried out five surgeries using the technology. Prior to the surgery, CT scans mapped the structure of the limb. The elements revealed by the CT scan were then split into bone, muscle, fatty tissue and blood vessels by Dr. Dimitri Amiras, a consultant radiologist at Imperial College Healthcare NHS Trust. Amiras used the data to develop a 3D model of the patients’ legs. The models were fed into the HoloLens, allowing surgeons to see them as they were carrying out the procedure. The surgeons also fine-tuned the model — with a simple hand gesture, they made sure that the model lined up with real life.

The procedure is time-consuming but in the future, algorithms could greatly simplify and reduce the work volume.

“The application of AR technology in the operating theatre has some really exciting possibilities,” said Jon Simmons, a plastic and reconstructive surgeon who led the team. “It could help to simplify and improve the accuracy of some elements of reconstructive procedures.

“While the technology can’t replace the skill and experience of the clinical team, it could potentially help to reduce the time a patient spends under anaesthetic and reduce the margin for error. We hope that it will allow us to provide more tailored surgical solutions for individual patients.”

Right now, the technique has only been used for lower limb reconstructive surgery, but the proof of concept is there. This study shows that the technology is practical, accurate, and safe to use. There’s no reason why a similar approach couldn’t be used in different types of surgery.

Augmented reality does nothing to replace the skill and experience of the operating team, but it does complement and amplify it, significantly reducing the margin for error.

The paper ‘Through the HoloLens looking glass: augmented reality for extremity reconstruction surgery using 3D vascular models with perforating vessels’ by Philip Pratt et al. is published in the journal European Radiology Experimental.

Sunburn selfie.

Extremely high doses of vitamin D help with sunburns, reduce inflammation, heal skin cells

White as milk but still thinking of going to the beach? Make sure to pack your sunscreen. But in the future, vitamin D supplements may be all you need — a double-blinded, placebo-controlled clinical trial showed that extremely high doses of this vitamin taken one hour after getting a sunburn ‘significantly’ reduce skin redness, swelling, and inflammation.

Sunburn selfie.

Image credits Hans Braxmeier.

For the trial, performed at the Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, 20 participants were put under the UV lamp to get a small sunburn on their inner arm. They were randomized to receive either a placebo pill or a 50,000, 100,000, or 200,000 IU (international units) of vitamin D one hour after UV exposure, and sent back home. The team followed up on the participants 24, 48, 72 hours and 1 week after the experiment to see how the burns were faring, collect skin biopsies, and perform further tests.

Vitamin heal’D

Overall, vitamin D seems to have played a big part in helping the skin heal. Those participants who had received the largest dose showed the most pronounced and longest-lasting benefits, such as less skin inflammation and redness 48 hours after the burn. When measuring gene activity in the skin samples, the researchers found that participants with the highest levels of vitamin D in their bloodstream showed a jump in gene activity related to skin barrier repair.

“We found benefits from vitamin D were dose-dependent,” said Kurt Lu, MD, senior author on the study and Assistant Professor of Dermatology at Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center.

“We hypothesize that vitamin D helps promote protective barriers in the skin by rapidly reducing inflammation. What we did not expect was that at a certain dose, vitamin D not only was capable of suppressing inflammation, it was also activating skin repair genes.”

Analysis of the skin samples showed that vitamin D increases levels of an anti-inflammatory enzyme in the skin called arginase-1. This compound is known to promote tissue repair and activate a host of other anti-inflammatory proteins. The team, however, notes that the doses involved in this trial were extremely high. The Food and Drug Administration’s recommended adult daily allowance for vitamin D is 400 IU, between a hundredth and a five-hundredth of the doses the team administered.

“I would not recommend at this moment that people start taking vitamin D after sunburn based on this study alone. But, the results are promising and worthy of further study,” Lu cautioned.

So in the meantime, make sure to pack adequate sunscreen.

The authors hope that their findings will help guide research towards the benefits vitamin D, as they believe “there is a lack of evidence demonstrating that intervention with vitamin D is capable of resolving acute inflammation” despite the fact that vitamin D deficiency is well studied. They’re planning on further expanding on their findings, in an effort to find new treatments for burn patients.

The paper “Oral vitamin D rapidly attenuates inflammation from sunburn: an interventional study” has been published in the Journal of Investigative Dermatology.

Mussel-glue-and-protein balm could spell the end of scars forever

The unassuming mussel could deliver us from scars forever, a new paper from the Pohang University of Science and Technology in South Korea.

Scarred cat.

Image credits George Li.

A sticky substance secreted by the common mussel (family Mytilidae) could spell the end of scarring. A glue based on this substance has been shown to help heal rats’ skins seamlessly, without any scars. If shown effective in human trials, this glue could prevent scarring after accidental injuries or surgery.

Old injuries

Our skin scars because when injured, the wave-like arrangement of collagen fibers that give it strength, like rebar in concrete, break apart. If the injury is severe enough these fibers don’t go back together in an orderly fashion during the healing process — instead, they bunch up together, growing thick bundles of parallel collagen fibers that give scars their distinctive lumpy appearance.

This bunching up can be mitigated through the use of decorin, a protein naturally found in the skin which governs how collagen fibers arrange themselves. Still, decorin has a very complex structure and is really hard to synthesize, so most clinics and hospitals don’t have it available.

But fret not, for Hyung Joon Cha and his colleagues at Pohang University of Science and Technology, South Korea have a solution. They developed a simplified version of decorin which retains its collagen-ordering properties by putting together a section of the protein, a collagen-binding agent, and a glue-like substance secreted by mussels.

This substance is sticky enough to help keep wounds closed and help them heal, while at the same time making sure they don’t scar. The team applied the glue on lab rats with deep 8-millimetre-wide wounds, then covered them with clear plastic film. A control group of rats with similar wounds were dressed in the plastic film without the substance being applied first.

In 11 days, 99% of the wounds in the glue group were closed, compared with only 78% in the control group. By day 28, the treated rats were fully recovered and had no visible scarring, while their counterparts healed with thick, purple scar tissue.

New skin

Human skin.

Image credits Montavius Howard.

Microscope inspection of the tissue confirmed that the collagen fibers in the treated wounds returned to their original weave arrangement. Even better, the new skin grew back hair follicles, blood vessels, and glands — all bits and pieces of skin that don’t regrow in scars.

The team notes that their gel promotes normal collagen fiber development because negative charges on the decorin fragments hold these fibers apart. This gives them wiggle room to weave between each other instead of sticking together.

Still, while the results are encouraging, there’s much work to be done before they can be applied to human use. For starters, rat and human skin might respond differently to the protein. Then there’s the fact that rats tend to have loose skin and heal more quickly while humans have tight skin, making scarring more likely.

The team’s next step is to test their glue on pigs, as their skin resembles ours more closely.

The paper “Natural healing-inspired collagen-targeting surgical protein glue for accelerated scarless skin regeneration” has been published in the journal Biomaterials.

Skin impression of one of the last dinosaurs found in Spain

Researchers from the Universitat Autònoma de Barcelona (UAB) working in collaboration with the Institut Català de Paleontologia Miquel Crusafont (ICP), have discovered an impression fossil preserving a Late Cretaceous dinosaur’s skin texture. This marks the time right before their extinction, making the fossil a unique discovery in Europe.

The dinosaur skin impression found at the site.
Image credits Víctor Fondevilla / UAB.

While performing a geological survey near the village of Vallcebre near Barcelona to study the origins of Late Cretaceous rock sediments (roughly 66 millions of years old), researchers found the impression of a dinosaur’s scales. They suspect the fossil formed when the animal had laid down in the mud, as the area corresponded to the muddy banks of a river during that time. The imprint was covered with sand which lithified into sandstone, preserving the relief of the animal’s original skin.

The Late Cretaceous ended with the extinction of the dinosaurs due to a violent meteorite impact. As such, there are very few places on Earth where intact sandstone deposits can be found from this period, making the find unique. Finding data to characterize these late dinosaurs is very important in understanding how they dealt with the extreme conditions and why they disappeared.

“This is the only registry of dinosaur skin from this period in all of Europe, and it corresponds to one of the most recent specimens, closer to the extinction event, in all of the world,” highlights UAB researcher Victor Fondevilla, main author of the research. “There are very few samples of fossilised skin registered, and the only sites with similar characteristics can be found in United States and Asia.”

“Other dinosaur skin fossils have been found in the Iberian Peninsula, in Portugal and Asturias, but they correspond to other more distant periods,” he adds.

The fossil shows scales in a pattern characteristic to some carnivorous dinosaurs and hadrosaurs: a central polygon-like bump surrounded by fire or six more bumps in the form of a rose. But the scales are too large compared to the typical size found in the dinosaurs roaming the area 66 million years ago.

“The fossil probably belongs to a large herbivore sauropod, maybe a titanosaurus, since we discovered footprints from the same species very close to the rock with the skin fossil,” Fondevilla says.

In fact, two skin impressions were found, one measuring approximately 20 centimeter wide, and the other slightly smaller, measuring only 5 centimeter wide, separated by a 1.5 meter distance and probably made by the same animal.

“The fact that they are impression fossils is evidence that the animal is from the sedimentary rock period, one of the last dinosaurs to live on the planet. When bones are discovered, dating is more complicated because they could have moved from the original sediment during all these millions of years,” Fondevilla adds.

The find will allow scientists to better recreate the dinosaurs before their extinction.

“The sites in Berguedà, Pallars Jussà, Alt Urgell and La Noguera, in Catalonia, have provided proof of five different groups of dinosaurs: titanosaurs, ankylosaurids, theropods, hadrosaurs and rhabdodontids,” explains Àngel Galobart, head of the Mesozoic research group at the ICP and director of the Museum of Conca Dellà in Isona.

“The sites in the Pyrenees are very relevant from a scientific point of view, since they allow us to study the cause of their extinction in a geographic point far away from the impact of the meteorite.”

The full paper “Skin impressions of the last European dinosaurs” has been published in the journal Geological Magazine.

We’ve found the genetic key to making red blood cells

Researchers from Lund University in Sweden and the Center of Regenerative Medicine in Barcelona have identified four sequences of genetic code that can reprogram mice skin cells to produce red blood cells. If this method can be used on human tissues, it would provide a reliable source of blood for transfusions and people with anemia.

Red blood cells are the most common cells in the human body, and are necessary in order to transport oxygen and carbon dioxide.
Image via pixabay

While (almost) each of us has a unique genetic make-up, it’s a different story for our cells. DNA holds the entirety of the body’s genetic information, and all of an individual’s cells contain exactly the same DNA strands nestled in their nucleus.

It’s an all-encompassing instruction manual, and everything that our bodies can do — from growing hair and nails to developing the brains that allow you to read this now — is written down in it. But then, why aren’t all out cells identical?

Well, cells differentiate because each one only has access to certain parts of this database; they’re allowed to read the chapters that explain how to do their particular job. The Lund research group wanted to find out if cells can be coaxed into accessing different chapters of DNA — specifically, the one governing the production of erythrocytes, or red blood cells.

“We have performed this experiment on mice, and the preliminary results indicate that it is also possible to reprogram skin cells from humans into red blood cells,” says Johan Flygare, manager of the research group and in charge of the study.

“One possible application for this technique is to make personalised red blood cells for blood transfusions, but this is still far from becoming a clinical reality.”

The team used a retrovirus to add combinations of over 60 genes into the skin cells’ genome, then culturing them to see the results. One day, the team found that their cultured cells had converted to red blood cells.

“This is the first time anyone has ever succeeded in transforming skin cells into red blood cells, which is incredibly exciting,” says Sandra Capellera, doctoral student and lead author of the study.

The study found that out of 20,000 genes, only four are necessary to reprogram skin cells to start producing red blood cells. But you have to use all four in order for it to work.

“It’s a bit like a treasure chest where you have to turn four separate keys simultaneously in order for the chest to open,” explains Sandra.

The discovery is significant from several points of view. Biologically, it will help us better understand the systems that govern cells and their differentiation, paving the way for future cellular applications. From a more practical standpoint, this finding could provide an answer to the ever-growing need for blood donors, as Johan Flygare explains:

“An aging population means more blood transfusions in the future. There will also be an increasing amount of people coming from other countries with rare blood types, which means that we will not always have blood to offer them.”

There are millions of people in the world suffering from anemia, or insufficient blood cells. Patients with chronic anemia are among the most problematic, as they require regular blood transfusions from various donors. In some rare cases, the patient can develop a negative response to the blood — they become allergic to it. But this method would allow to create blood for a patient starting with their own cells. Their blood, for all intents and purposes.

However, further studies on how the generated blood performs in living organisms are needed before that, the team says.

The full paper, titled “Defining the Minimal Factors Required for Erythropoiesis through Direct Lineage Conversion” has been published online in the journal Cell Reports and can be read here.

Scientists create artificial skin that sprouts new hairs and sweats

Creating artificial skin may sound weird, but it can be extremely useful (or even life saving) for people who suffered from burns or any type of similar accident; it is also useful for testing drugs or cosmetic products. Skin transplants are a growing need, and many teams from across the world hope to one day be able to create artificial skin to fulfill that need. This latest attempt from Japan takes us one step closer to that goal: it can create new hairs and even sweat.

A fluorescent protein was used to highlight the area of artificial skin. Credit: Takashi Tsuji/RIKEN

Led by researchers from the RIKEN Centre for Developmental Biology, the team used gum cells from mice, converting them into a new type of stem cell. They then used these cells to build a 3D layer of skin. The artificial skin replicates all the three major layers of skin – the waterproof epidermis which gives our skin tone, the dermis which contains tough connective tissue, hair follicles, and sweat glands, and the hypodermis which is made of fat and connective tissue.

They then transplanted the skin back to hairless mice, where they started to develop normally and integrated fully with the rest of the body.

“Up until now, artificial skin development has been hampered by the fact that the skin lacked the important organs, such as hair follicles and exocrine glands, which allow the skin to play its important role in regulation,” said Takashi Tsuji, who led the new study.

“With this new technique, we have successfully grown skin that replicates the function of normal tissue. We are coming ever closer to the dream of being able to recreate actual organs in the lab for transplantation, and also believe that tissue grown through this method could be used as an alternative to animal testing of chemicals.”

Previously, other teams have tackled the problem from a different angle. Another group has created an artificial skin which can feel pressure and tell your brain about it, offering a realistic sensation. Perhaps the two can be blended together, and we can soon have artificial skin which can feel pressure and also create hair and sweat. The real deal is getting closer and closer.

Journal Reference: Bioengineering a 3D integumentary organ system from iPS cells using an in vivo transplantation model.

A highly stretchable electroluminescent skin capable of stretching to nearly five times its original size. Credit: Chris Larson

Stretchable artificial skin might make robots more human, and vice-versa

stretchable robot skin

This artificial ‘skin’ can stretch up to 480 percent its original size, and can sense changes in pressure – a haptic feature that could lend both robots and human prostheses a sense of touch. The team behind the innovation reckon these features could improve human-robot interactions.  A robot might change color to fit the mood of the house in a given moment or use all of its surface area as one display. The robot can also use the tech to change shape.

A highly stretchable electroluminescent skin capable of stretching to nearly five times its original size. Credit: Chris Larson

A highly stretchable electroluminescent skin capable of stretching to nearly five times its original size. Credit: Chris Larson

Do these features sound familiar? That’s because the Cornell graduate students in charge of the projects mimicked octopuses, that have flexible skin and contain color changing cells. These animals can camouflage with frightening speed and effectiveness. Not nearly as impressive, the artificial skin developed at Cornell does a pretty good job for a proof of concept.

The students were led by  Robert Shepherd, a Cornell assistant professor of mechanical and aerospace engineering, who challenged them to come up with a new tech that can solve the inherent faults of rigid robotics.

“We can take these pixels that change color and put them on these robots, and now we have the ability to change their color,” Shepherd said. “Why is that important? For one thing, when robots become more and more a part of our lives, the ability for them to have emotional connection with us will be important. So to be able to change their color in response to mood or the tone of the room we believe is going to be important for human-robot interactions.”

The skin consists of a dielectric (insulating) elastomer sheet sandwiched between two  transparent hydrogel electrodes. When stretched, the  hyper-elastic light-emitting capacitor (HLEC), as it was dubbed, changes its luminescence and capacity.

[ALSO READ] The squishy bot revolution: how soft robotics is changing the field

To demonstrate potential applications, HLEC was used in a soft robot. Three six-layer HLEC panels were bound together to form a crawling , with the top four layers making up the lit skin and the bottom two the pneumatic actuators. The HLEC chambers were alternately inflate and deflated, and this pressure propelled the soft robot to a crawl.

According to Shepherd there are two main directions this technology can take. Firstly, robots could become less awkward by changing color and shape. Robot-human interactions could also be improved since a human could use any surface of the robot like a touch-screen. Secondly, the tech could be employed to enhance human sensibility.

“You could have a rubber band that goes around your arm that also displays information,” said Chris Larson, a Cornell graduate student and one of the co-authors of the paper published in the journal Science. “You could be in a meeting and have a rubber band-like device on your arm and could be checking your email. That’s obviously in the future, but that’s the direction we’re looking in.”

Why getting a tattoo hurts — the science behind inking

Your leather jacket and motorcycle aren’t enough for you anymore; they fall woefully short of conveying just how much of a badass you really are. This will not do — everyone must see you in all your glory, the world must know. With a spring in your step, you walk into the best tattoo parlor in town, pick out a design that has a dragon with a skull over explosions and roses and chainswords and… OW! Why do tattoos hurt so much!?

mZQDrA

Well, it’s because tattoos have to get that ink deep enough that it won’t get washed away but not too deep so it remains visible — the ideal location ends up being right next to your skin’s pain receptors. Given that most modern tattoo artists do this with mechanical tools that push a needle into the skin from 80 to 150 times a second, it’s easy to see how tattooing gets its painful reputation. However, people have endured excruciating pain throughout history to adorn their bodies with ink. So why do we do it? How do we do it? And can we make it hurt less? The short answer to the last question is yes. Here’s the longer answer:

Not just ink

Tattooing is a controversial subject — some are all for it, others consider it an art form to be perfected and some think it’s repulsive. To each his own, but the fact remains that throughout history, tattoos have had (and in some cases still have) deep running cultural and social implications. People around the globe have long marked their bodies to express cultural identity and community status; it is one method to connect to one’s ancestors or gods, to mark rites of passage, or even “wear” a permanent amulet.

The term “tattoo” is believed to originate from the Polynesian “tatau”, meaning “to mark,” and Dictionary.com defines it as being “the act or practice of marking the skin with indelible patterns, pictures, legends, etc., by making punctures in it and inserting pigments.” It’s a simple enough process, but the tattoo’s shapes, colors, and position on the body, taken together often hold an incredibly deep meaning throughout time.

In New Guinea, the swirly tattoos on a Tofi woman’s face detail her family lineage, while in Cambodia monks display religious beliefs etched in ink on their chests. The Japanese Yakuza’s spectacular patterns or the US gang member’s sprawling tattoos can show affiliation, rank, or if the wearer has committed murder. The “Iceman” discovered in the Alps in 1991 was covered in tattoos, 85% of which line up with acupuncture points, says Dr. Lars Kurtak, world-renowned tattoo expert and anthropologist with the Repatriation Office of the National Museum of Natural History.

“He appeared to have terrible arthritis. [The tattoos were] so dark, they seemed to be repeated applications and some of them he could not reach on his own,” he notes.

In some cultures, successfully enduring the excruciating pain and the blood loss of tattooing with primitive tools marks the transition from infancy to manhood and is considered deeply sacred rites, notes Joseph Campbell in his book Primitive Mythology: The Masks of God. So in the end, there are as many meanings to tattoos as there have been human cultures throughout history.

How are they made — and why do they hurt?

Early tattooing involved cutting the skin and rubbing ink in the wound or using needles made of bone or wood to push ink into the tissue; Western civilization’s first recorded encounter with the Polynesian practice of tattooing dates from 1769, when naturalist Joseph Banks traveling the world aboard the British Endeavour witnessed the “extensive adorning” of a 12-year-old girl.

“It was done with a large instrument about 2 inches long containing about 30 teeth,” Banks wrote in his journal. “Every stroke […] drew blood.”

Banks also recounts how the girl wailed and writhed but two women held her down, occasionally beating her, for more than an hour until the tattoo was complete.

Thankfully, tattooing changed since then. Modern tattoo artists use clean, precise units to deposit dye by mechanically driving one or several needles soldered together in and out of the skin, usually from 80 to 150 times a second, like this:

https://www.youtube.com/watch?v=FEgeQSyaDqk&feature=youtu.be&t=29s

With each prick of the needle, dye gets injected into the skin, and the body’s immune system responds by deploying white cells called macrophages to deal with the threat. Some of the ink gets lost this way, but most don’t — dead macrophages and the ink they didn’t consume is fixed in skin cells named fibroblasts and remains visible through the thin layers of tissue that cover them.

But we know we can get a scratch and not feel any pain or cut our fingers on paper without so much as a blink. So why is tattooing so notoriously painful? Well, it’s all because of where the pigment needs to go to make a tattoo permanent. Let’s look at your skin’s structure to find out why.

Show me some skin!

The skin is the largest and one of the most complex organs in (on?) the body, serving as the soft outer layer of vertebrates; it’s there to protect and delimitate the juicy, fragile “inside” of the organism from the harsh outside.

There are two distinct parts that make up mammalian skin: the epidermis (this is the outer layer of dead keratinocytes that “flakes” off of to be renewed pretty often) together with the more stable dermis (the layer under it that houses all kinds of glands, hair follicles, blood vessels, lymph vessels and sensory cells) forms the cutis. Directly under the cutis lies the subcutis or subcutaneous tissue, where fatty cells are clumped together to protect you from the cold.

The layer where ink needs to be deposited, the dermis, unfortunately also contains receptor cells that send pain signals to the brain to let us know our body is being hurt; it’s not that bad when you prick your toe on a particularly sharp rock, but when your body is being hurt 80 to 150 times a second, they send out a panicked flurry of signals to the brain, making the experience of getting a tattoo rather unpleasant.

On the bright side, since the dermis doesn’t flake off to be renewed like the epidermis, the dye remains embedded in your skin for life.

The inks or dyes themselves have also evolved over time; as a rule of thumb, tattoo ink is made up of two parts: a pigment and a carrier. The pigment is the substance that gives the ink its color, while the carrier is a solvent that ensures the pigment is evenly mixed, protects against pathogens and aids application. Throughout time, water or alcohol have been the most widely used carriers, while glycerine and denatured alcohols have started being used in modern tattooing.

Pigments have been made from, well, mostly anything colorful; traditional colors were made with materials like simple dirt, pen ink (yay, prisons), soot, even blood. Modern pigments are derived from heavy metals, metal oxides, liquid hydrocarbons, or carbon. But be warned: red dyes, in particular, are known to cause allergies and swelling for a few months after getting a tattoo.

One of the most spectacular (read: insane) pigment recipes I’ve come across hails from ancient Rome and calls for Egyptian pine bark, corroded bronze ground in vinegar, and iron sulfate to be mixed with insect eggs, then soaked in water and leek juice. The concoction would be rubbed energetically on fresh wounds made with needles or blades to create the tattoo. It bugged me.

It really bugged me.

Some tattoos hurt and some tattoos really hurt. Here are some tips

Now, getting a tattoo is going to hurt, there’s no way around that. But there are some areas that are more sensitive to pain than others; as an empirical rule, if you’re extremely ticklish in an area, getting tattooed there is probably going to hurt pretty bad. While keeping in mind that everyone has a different threshold for pain, Tattoos-Hurt.com has put together a chart showing how sensitive different areas of the skin are to pain:

I like how they grade things.
Image via tattoos-hurt

Secondly, a lot of people think that getting a tattoo while hammered or after taking painkillers will make it easier to handle the pain; don’t be one of those people. Alcohol is a blood thinner, meaning you will bleed more and the ink won’t take as easily. Your constant drunken movements will also make the process take longer and the end result will be lackluster. Also try to avoid Tylenol, Advil, coffee, and energy drinks before your tattoo session, as they have similar effects.

Drinking water is a good idea, as well-hydrated skin accepts the ink more readily, so start drinking as much water as you need a day or two before. Taking breaks also helps, but try to take them sparingly, as the skin will begin to swell a lot more during your breaks and constant starting and stopping will interrupt a lot of the tattoo process and adrenaline build-up.

So if you’re looking to get a tattoo, either to celebrate your religion or to show off your lineage, or to simply some cool new artwork on your skin, now you know why it has to hurt and how you can make it hurt less; you can also pass the time being thankful you’re not getting crushed bug eggs rubbed into your wounds. Happy inking!