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May 27, 2015 | By:  Sedeer el-Showk
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Fish Skin Band-Aids: a natural way to speed wound healing

In this guest post, Mae Staples looks at how fish skin may hold the key to improved wound healing.


Have a cut on your hand? You're apt to reach for the box of Band-Aids or roll of gauze in the medicine cabinet. But what about some fish skin protein to cover that wound? It may sound like a remedy straight out of The Little Mermaid, but, in fact, researchers in China have recently discovered that collagen obtained from Tilapia fish significantly speeds up wound healing in rats.

Even before Zhou et al. dove into the sea of wound healing, the use of collagen for promoting skin regeneration was well known. Collagen is one of the main structural proteins in connective tissues in the human body. Pig and cow collagen proteins have been used to promote wound healing successfully in the past, but the risk of introducing disease agents from these mammalian species inhibits broader applications in the medical field. And that's where fish skin swims in. Diseases and bacteria that affect fish are different from most human pathogens, and fish skin is also a cheap, readily available material for bandage production.

In considering the versatility of fish skin collagen, the researchers noted that the protein had excellent thermo-stability and tensile strength. This allows the bandage to adhere to the skin and adjust to body movements. Additionally, Tilapia collagen has been shown to promote the in vitro growth of keratinocytes, one of the two types of cells that are integral to skin wound healing and immune response. The second cell type is known as dermal fibroblasts. Migration of these cells to the wound site helps increase epithelial cell division, and dermal fibroblasts also secrete cytokine signals to promote wound healing.


Zhou et al. began their experiment by extracting collagen from Tilapia skin with chemical purification methods. They then spun the protein into a nanofiber matrix, referred to as a collagen "sponge". Through structure analysis and gene sequencing, the researchers noted that the collagen had a high denaturation temperature and thus retained its unique triple helix shape even under environmental fluctuations. This data is promising for medical applications of the collagen based Band-Aids, as human skin can vary in temperature. A material that can adapt to different skin conditions and still stay in place is integral to bandage design.

Having established that the collagen matrix could stay put on the skin, Zhou et al. focused their attention on the immune response promoted by the foreign protein. In past studies, bovine collagen has caused hypersensitivity when applied to human skin, as well as increased antibody levels in some patients. The immune properties of Tilapia collagen had never been tested prior to this study.

The spleen is one of the largest immune organs in the human body and also contains B and T lymphocytes. These specialized immune cells recognize foreign antigens, or "invaders", and mediate a swift cellular response. Because of these immune properties, the researchers used spleen cell cultures from rats to test the immune response to Tilapia collagen. Their in vitro techniques showed that no noticeable immune response was invoked. The B and T lymphocytes remained at normal levels even with the addition of the collagen sponge.

With fish skin offering promising results in cell cultures, Zhou et al. next turned to live animal experiments. They wanted to see if a different immune response was produced in living organisms, as the bandages would be used on humans in a medical context. This allowed the researchers to study the degradation of the collagen sponge in live tissues to ensure no harmful small molecules innervated the wound as it healed.

IgG and IgM are two major antibodies in humoral immunity, or immunity mediated by macromolecules rather than cells. Collagen sponge was implanted into rat wounds, and levels of these antibodies were measured after twenty-eight days. No increase of the antibodies was observed. This signaled a high level of compatibility between the Tilapia bandage and the mammalian immune system. The ratio of CD4+ and CD8+ lymphocytes was also evaluated. Both categories of lymphocytes are important for antigen recognition and the elimination of infected cells. CD4+ lymphocytes also participate in signal transduction pathways in initiating other parts of the immune response. The ratio of these lymphocytes is a common clinical measure of coordinated cellular immunity. Rats injected with the Tilapia collagen showed a ratio similar to that of control groups without any fish skin bandages. Thus, both humoral and cellular mediated immunity remained at constant levels with collagen sponge additions. Importantly, rats with fish skin bandages also exhibited much faster wound healing than those treated with traditional bandage methods.

While fish skin bandages are a possibility for wound healing in the future, the researchers note that more work must be done before Tilapia collagen appears in your local drug store. Namely, tests on larger mammals must be carried out before human trials are feasible. The researchers are also looking to chemically alter the protein fibers in order to introduce antibacterial properties that safeguard against possible skin infection.


Mae Staples is a recent graduate of Colgate University with a degree in Molecular Biology. She is interested in microbiology and biomedical research, and enjoys exploring the wonderful world of microbes through her scientific endeavors.


1) Zhou T, Wang N, Xue Y, et al. Development of Biomimetic Tilapia Collagen Nanofibers for Skin Regeneration through Inducing Keratinocytes Differentiation and Collagen Synthesis of Dermal Fibroblasts. ACS Appl. Mater. Interfaces 7: 3253-3262 (2015).

2) Pereira RF, Barrias CC, Granja PL, et al. Advanced biofabrication strategies for skin regeneration and repair. Nanomedicine 8(4): 603-621 (2013).

3) Kumar PS, Raj NM, Praveen G, et al. In vitro and in vivo evaluation of microporous chitosan hydrogel/nanofibrin composite bandage for skin tissue regeneration. Tissue Engineering Part A 19(3-4): 380-392 (2012).

4) Turley, Andrew. "Fish skin dressing helps heal wounds." Chemistry World. 18 Feb. 2015. Web.

Image credits
The Tilapia is free of copyright (Source: Dutch Fish Marketing Board). The keratinocyte image by ZEISS microscopy on Flickr Commons is distributed under a CC-BY-NC-ND license.

March 19, 2014 | By:  Kyle Hill
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Do “Smart Pills” Really Make You Smart?

So-called "smart drugs" offer the promise of immediate and tangible cognitive benefits, but how effective are they really? In this guest post, Camilla d'Angelo takes a look at cognitive enhancers and asks whether, by focusing on quick fixes rather than adopting a healthy lifestyle, we are undermining our well being.

When it comes to coping with exam stress or meeting that looming deadline, the prospect of a "smart drug" that could help you focus, learn and think faster is very seductive. At least this is what current trends on university campuses suggest. Just as you might drink a cup of coffee to help you stay alert, an increasing number of students and academics are turning to prescription drugs to boost academic performance.

So-called "smart drugs" are being used off-label for their apparent cognitive enhancing effects. Cognition is the way in which we acquire, process and store information, so the drugs are promising better memorization and attention in normal, healthy people.

Popular smart drugs on the market include methylphenidate (commonly known as Ritalin) and amphetamine (Adderall), stimulants normally used to treat attention deficit hyperactivity disorder or ADHD. In recent years, another drug called modafinil has emerged as the new favourite amongst college students. Primarily used to treat excessive sleepiness associated with the sleep disorder narcolepsy, modafinil increases alertness and energy.

If smart drugs are the synthetic cognitive enhancers, sleep, nutrition and exercise are the "natural" ones. But the appeal of drugs like Ritalin and modafinil lies in their purported ability to enhance brain function beyond the norm. Indeed, at school or in the workplace, a pill that enhanced the ability to acquire and retain information would be particularly useful when it came to revising and learning lecture material. But despite their increasing popularity, do prescription stimulants actually enhance cognition in healthy users?

There is evidence to suggest that modafinil, methylphenidate, and amphetamine enhance cognitive processes such as learning and working least on certain laboratory tasks. One study found that modafinil improved cognitive task performance in sleep-deprived doctors. Even in non-sleep deprived healthy volunteers, modafinil improved planning and accuracy on certain cognitive tasks. Similarly, methylphenidate and amphetamine also enhanced performance of healthy subjects in certain cognitive tasks.

So maybe smart drugs really do make you smarter. Unfortunately, it's not actually that simple.

Despite some positive findings, a lot of studies find no effects of enhancers in healthy subjects. For instance, although some studies suggest moderate enhancing effects in well-rested subjects, modafinil mostly shows enhancing effects in cases of sleep deprivation. A recent study by Martha Farah and colleagues found that Adderall (mixed amphetamine salts) had only small effects on cognition but users believed that their performance was enhanced when compared to placebo.

In addition, the cognitive enhancing effects of stimulant drugs often depend on baseline performance. So whilst stimulants enhance performance in people with low baseline cognitive abilities, they often impair performance in those who are already at optimum. Indeed, in a study by Randall et al., modafinil only enhanced cognitive performance in subjects with a lower (although still above-average) IQ.

Clearly, the hype surrounding drugs like modafinil and methylphenidate is unfounded. These drugs are beneficial in treating cognitive dysfunction in patients with Alzheimer's, ADHD or schizophrenia, but it's unlikely that today's enhancers offer significant cognitive benefits to healthy users. In fact, taking a smart pill is probably no more effective than exercising or getting a good night's sleep.

Sleep itself is an underrated cognition enhancer. It is involved in enhancing long-term memories as well as creativity. For instance, it is well established that during sleep memories are consolidated-a process that "fixes" newly formed memories and determines how they are shaped. Indeed, not only does lack of sleep make most of us moody and low on energy, cutting back on those precious hours also greatly impairs cognitive performance. Exercise and eating well also enhance aspects of cognition. It turns out that both drugs and "natural" enhancers produce similar physiological changes in the brain, including increased blood flow and neuronal growth in structures such as the hippocampus. Thus, cognition enhancers should be welcomed but not at the expense of our health and well being.

So the next time you're tempted to reach for some pills, maybe a good night's sleep is all you really need.


Camilla is a PhD student in Experimental Psychology at the University of Cambridge. She is currently investigating the brain basis of compulsive behaviour, especially related to OCD.

February 24, 2014 | By:  Kyle Hill
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The Invasive Species Wriggling Beneath Your Feet

In this guest post, student Jason Chen explains how some of the most invasive species can be wriggling out of sight, right beneath our feet.

When people envision invasive species, they tend to think about those that have devastating impacts in their new homes. They eat or outcompete natives into extinction, degrade the environment, and make human life miserable. These are the invaders that make the news. Fire ants, rats, Dutch elm disease, and kudzu are some of the most well-known species that have been introduced by humans around the world.

Earthworms are the last animal most people would expect to be invasive in North America. They definitely don't look like they're very good at being nefarious: they sort of ooze along burrows in the soil, eating leaf litter, and only make their existence known to the outside world when they crawl out of their burrows to escape being drowned (after which many of them dry into a disgusting crust on the sidewalk when the sun comes back out). Earthworms don't have the gluttonous reputation of the brown tree snakes of Guam, which have eliminated multiple endemic species of birds from the island. Nor do they have the noxiousness of the brown marmorated stink bug, now infamous in eastern North America for its population booms and pungent defensive odor, or the destructive beauty of the purple loosestrife, which blankets wetlands in tall spikes of attractive magenta flowers. If anything, they've been praised as the farmer's friend since Charles Darwin, who wrote an entire book extolling the humble worm for speeding up the decomposition of organic matter and making tunnels that aerate the soil.

However, that same ability to alter soil architecture that is so valuable to gardeners and farmers is also dangerous for habitats in which worms should not be present. Even worse, people don't seem to realize that the earthworms tunneling through their flower beds and lawns are most likely introductions that arrived as early as the early 17th century. Today, roughly 45 European and Asian species, including the well-known nightcrawler (Lumbricus terrestris), of baitshop fame, and the redworm (Eisenia fetida), frequently used in vermicomposting, have joined the hundred-odd native worm species that survived the last ice age, along with exotic species from less well-known groups such as Amynthas, Octolasion, and Aporrectodea. They have embedded themselves so deeply in their new home that many of us have accepted that these earthworms have always been here, busily tilling and enriching the soil for our benefit. Without a second thought, people continue to distribute and release invasive earthworm species in community composting heaps, potted plants, and bait shops, just as early English colonists dumped soil ballast crawling with worms from their ships hundreds of years ago.

What have these introduced earthworms accomplished during the several centuries after they set up house and established themselves on the North American continent? Earthworms are canonical ecosystem engineers: organisms that play such an important role in creating and maintaining their habitats that their activity can decide which other species benefit or lose out in that environment. Just as beavers create ponds and meadows by cutting trees and building dams, worms of different species can influence natural processes in soils. Native earthworms probably shape different kinds of soils differently from each other and from non-native worms. In the Great Lakes region, which has no native earthworms, invasive earthworms have been found to affect nitrogen levels in stream water by directly excreting ammonium waste into the soil, possibly contributing to nitrogen pollution in the dead zone of the Gulf of Mexico. Introduced earthworms also compete for resources with native species, including soil microarthropods, native earthworms, and millipedes.

Even worse, they can act as agents for the establishment of a host other non-native plants, which can in turn aid the establishment of other species: taking ‘ecosystem engineering' to its ultimate conclusion by building a new community of species within the old, in a process aptly termed ‘invasional meltdown'. Nightcrawlers have been found to facilitate the survival of seedlings of at least one non-native shrub, the European buckthorn, by eliminating competing plants on forest floors. The interaction also works the other way around: Buckthorn leaf litter is more nutritious than the leaves of native trees and shrubs, such that removing buckthorn bushes in an area can actually decrease nightcrawler numbers in an area. Essentially, nightcrawlers and buckthorns are engaged in a mutualism that aids the spread of both partners into native habitats. Other invasive plants, including garlic mustard (Alliaria petiolata), Japanese barberry (Berberis thunbergii), and Japanese stiltgrass (Microstegium vimineum) also seem to benefit by associating with earthworms.

Unfortunately, it is probably too late to do anything about the unfolding earthworm invasion. All biologists can do now is to monitor the spread of the worms across the continent and document its effects on native ecosystems. If there's anything we should take away from all this, it's that we humans urgently need to address our vast ignorance of the far-reaching consequences of events that happen beneath our feet, even when most of us don't even realize how complex . Several attempts to educate the public about this quiet conquest have indeed been established, and in the course of writing this I ran into excellent information websites about invasive earthworms by the University of Minnesota, the University of Alberta, and various state agencies. Whether these programs work is another question: The University of Alberta researchers evaluating the effectiveness of their public outreach, which included appearances on radio programs, magazine articles, and television clips, found that they reached less than 5% of Alberta anglers, their target audience. The program's impact was dismal: The percentage of anglers they surveyed that knew that earthworms were non-native in Alberta barely changed before and after implementing the program, and even worse, nearly half said they would not change how they disposed of extra bait worms, "with many commenting that they did not believe earthworms could be harmful."


Jason is an undergraduate at the University of Pittsburgh, studying ecology & evolution and classics. He likes to do things all normal undergraduates do these days: eating, doing homework, watching TV, and raising giant caterpillars in his room.

Image credits:

  • The European nightcrawler, Lumbricus terrestris. Image by Michael Linnenbach, made available under the Creative Commons Attribution-Share Alike 3.0 Unported license.
  • Japanese stiltgrass, Microstegium vimineum. Image by Siddharth Patil, made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication

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