Tag Archives: cellulose

International research team creates eco superglue out of cellulose and water

Researchers at the Aalto University, the University of Tokyo, Sichuan University, and the University of British Columbia have developed an eco-friendly, plant-based superglue.

The novel glue is based on plant-sourced cellulose, the same material that paper is made out of. This means that the glue, which “outperforms” its synthetic competition “by a great many measures” can be made from waste plant matter. Unlike superglue, however, the cellulose-based material is strongest in a preferred direction, making it similar to “Peel and Stick” adhesives, the team explains.

Veggie glue

“Reaching a deep understanding on how the cellulose nanoparticles, mixed with water, [forms] such an outstanding adhesive is a result of the work between myself, Dr. Tardy, Luiz Greca, Professor Hirotaka Ejima, Dr Joseph J. Richardson and Professor Junling Guo and it highlights the fantastic collaboration and integration of knowledge towards the development of an extremely appealing, low-cost and safe application,” says Aalto Professor Orlando Rojas, the study’s corresponding author.

The new glue is roughly 70 times stronger (i.e. harder to tear apart) on its principal plane of bond compared to the perpendicular of that plane. In other words, a single drop can hold up to 90kgs of weight or be easily removed with just one or two fingers depending on how you handle it. This level of strength is very surprising for a plant-based glue, the team adds.

It’s even more surprising considering how simple to make this material is. The team created the glue by simply mixing cheap, plant-sourced particles with water. Curing time depends on the evaporation of this water (the team’s current mixture dries in about 2 hours), so it can be sped up by exposing the glue to heat.

The team envisions their glue used in protecting fragile components in machines that can undergo sudden physical shock (such as microelectronics), to fix reusable structural or decorative elements, in packaging, and as a more eco-friendly alternative for general adhesive. The world overall is producing more cellulose than ever, the team explains, making it very cheap — a great time to make eco glue.

“The truly exciting aspect of this is that although our new adhesive can be sourced directly from residual biomass, such as that from the agro-industry or recycled paper,” explains Dr. Blaise Tardy, the paper’s first author.

“It outperforms currently available commercial synthetic products by a great many measures.”

The paper “Exploiting Supramolecular Interactions from Polymeric Colloids for Strong Anisotropic Adhesion between Solid Surfaces” has been published in the journal Advanced Materials.

Sticks and stones will break your bones, then this new cellulose aerogel will heal them

Bone implants are poised to receive an upgrade, as researchers from the University of British Columbia and McMaster University have developed a new foam-like substance for this purpose.

Foam bone cure.

The aerogel derived from plant cellulose.
Image credits Clare Kiernan / UBC.

Most bone implants today are made of hard ceramics. They’re hardy enough for the job, but the material is also very brittle, making it hard to work with. It’s also very tricky getting these implants to conform to the shape of the fractures or holes in the damaged bone — which often leads to the implant failing.

Sponge it

“We created this cellulose nanocrystal aerogel as a more effective alternative to these synthetic materials,” said study author Daniel Osorio, a Ph.D. student in chemical engineering at McMaster.

The team developed a foam-like substance (aerogel) that can be injected into damaged bones to provide scaffolding for the growth of new tissue. It’s formed of nanocrystals obtained from treated plant cellulose which can link up to form a strong but lightweight ‘sponge’ which is strong but also capable to expand or compress in order to fill out a cavity.

In order to test their aerogel, the team worked with two groups of rats. The first received the aerogel implants while the second (control group) received none. Over a three-week period, the first group saw 33% more bone growth and 50% more bone growth by the 12-week mark compared to the control group.

The team says these results show that cellulose nanocrystal aerogels are a viable, even preferable, medium to support bone growth. The implants will break down over time into non-toxic components in the body as bones heal, they add, limiting the need for further invasive procedures and treatments. All in all, even if the material doesn’t remove traditional implants, it is bound to find use as a supportive or novel treatment avenue in lieu of traditional materials.

“We can see this aerogel being used for a number of applications including dental implants and spinal and joint replacement surgeries,” said Grandfield. “And it will be economical because the raw material, the nanocellulose, is already being produced in commercial quantities.”

That being said, we’re still a ways away until the aerogel is ready for use in operating rooms across the world.

“This summer, we will study the mechanisms between the bone and implant that lead to bone growth,” said Grandfield. “We’ll also look at how the implant degrades using advanced microscopes. After that, more biological testing will be required before it is ready for clinical trials.”

The paper “Cross-linked cellulose nanocrystal aerogels as viable bone tissue scaffolds” has been published in the journal Acta Biomaterialia.

Banana.

Banana-sourced cellulose could level up our ice creams

Banana waste could, unexpectedly, hold the secret to better tasting, longer-lasting ice cream.

Banana.

Image via Pexels.

Ice cream, while still in its ‘cream’ form, is definitely one of man’s more fortunate inventions. Nice things don’t tend to last long, however, and ice cream is no exception — on the hot days when you need it most, it’ll readily turn into ice soup.

According to an international team of researchers, that’s because our ice cream lacks one vital ingredient: bananas. Tiny cellulose fibers extracted from banana waste, to be exact.

What?

According to a paper that will be presented today (the 21st of March) at the 255th National Meeting & Exposition of the American Chemical Society (ACS) in New Orleans, adding banana-derived cellulose fibers to our ice cream mix would make the end product thicker, harder to melt, and more palatable.

“As a result, this would allow for a more relaxing and enjoyable experience with the food, especially in warm weather,” says Robin Zuluaga Gallego, lead researcher for the study.

Despite the undeniable popularity that ice cream enjoys today, food scientists have long sought to overcome some of its innate drawbacks — chief among them, its tendency to melt. And they seem to really, really want to make ice-cream reconsider its melty ways, as they’ve gone as far as mixing in wood pulp extracts in an effort to keep it more stable under heat. Other, less wooden ways of going about it, have also popped up, such as a paper published last year by Japanese researchers that developed a melt-resistant ice cream based on polyphenols found in strawberries.

Zuluaga’s team, which brought together researchers from Universidad Pontificia Bolivariana, Colombia and the University of Guelph in Canada, set out to investigate a different approach based on bananas instead of strawberries. Much of this came down to sheer practicality — banana plants are considered waste after the fruits have been collected, whereas strawberries don’t leave much by-product after harvesting.

In particular, the team wanted to see if fibrous material extracted banana fruit stems, or rachis, could be used to slow down melting and extend ice cream‘s shelf life. The researchers first harvested cellulose nanofibrils (CNFs) — particles that are thousands of times smaller than the width of a human hair — from ground-up banana rachis. Then, they mixed various concentrations of CNFs (from zero, used as a control, up to 0.3g/100grams of ice cream) and analyzed how this impacted the end product’s physical properties.

Ice cream mixed with CNFs tended to melt significantly more slowly than traditional compositions, the team reports. They also note than CNFs could extend the shelf life of ice cream products, and decrease their sensitivity to temperature changes as they’re being moved about. No more refrozen ice-cream, yay!

It’s not only producers that will see benefits here. CNFs increased the viscosity of low-fat ice cream — viscosity is what gives the item its texture, it’s what puts the ‘cream’ in ice cream. Paper co-author Velásquez Cock also said that CNFs could help stabilize the fats contained in ice creams, meaning they could potentially replace some of the fats — which would slash calories — without having a noticeable effect on taste, texture, or your overall enjoyment of the product.

Next, the researchers plan to test how different types of fat interact with CNFs in ice cream and other frozen foodstuffs.

The paper “Cellulose nanofibrils in ice cream: an analysis of its influence on the matrix structure” will be presented later today at the 255th National Meeting & Exposition of the American Chemical Society (ACS) in New Orleans. You can watch it live here:

All-new, natural microbeads could be the future of cosmetics

Scientists may have found a replacement for one of society’s notorious pollutants: microbeads.

Microbeads can be a plague upon the environment. Image credits: Oregon State University.

Somewhere on the long list of ways through which we’re harming the planet, microbeads have snuck in as one of the surprising culprits. You wouldn’t think that something as inconspicuous as very small beads of plastic can do such a great deal of damage — but they do. Microplastics are used a lot in the cosmetic industry, especially in scrubs and cleaners. You’ll often find them in products such as toothpaste or facial cleansers. Microbeads don’t really biodegrade, and they tend to be gobbled up by unsuspecting fish. The fish aren’t able to digest or eliminate them, and so they just get stuck inside the fishes’ digestive system, where they can cause massive harm, or even kill the fish. To make things even worse, microbeads also get passed up the food chain, so you’ll find even more of them in predators higher up the food chain.

To put it bluntly, microbeads have got to go.

Illinois became the first US state to ban their usage in 2014, with California soon following suit just a year later. Former President Obama passed a law banning microbeads across the country, but their usage is still permitted in many products. Other countries like Canada are also taking action, but the process is slow and faces massive opposition. This is why researchers are trying to find a substitute.

The problem with replacing microbeads is that they’re cheap and effective at what they do.

“Microbeads used in the cosmetics industry are often made of polyethylene or polypropylene, which are cheap and easy to make,” Dr. Janet Scott said in a statement. Scott is a reader in the Department of Chemistry at the University of Bath and an author on the study. “However these polymers are derived from oil and they take hundreds of years to break down in the environment.”

She and her colleagues have developed biodegradable microbeads, made from cellulose instead of plastic

Cellulose-based microbeads.

Cellulose is a plant fiber which gives trees and other plants their distinctive structure. It doesn’t exhibit many of the properties plastic can boast, but it’s a very robust material which can be used and modified in a number of ways.

For this purpose, Scott dissolved cellulose and then dripped tiny droplets of it onto ethanol, hardening them into small beads. This type of process is also used in the fabrication of spherical caviar. The result they ended up with is tiny cellulose beads, which, just like plastic microbeads, can be used for scrubbing and cleansing to great effect. The difference is that unlike plastic, once these cellulose microbeads hit the sewers, they soon start to decompose in an environmentally friendly way.

Other common substitutes, such as ground walnuts, are irregular in shape and can also be too rough on the skin, whereas this is not the case with the cellulose beads.

To make things even sweeter, Scott says they can be fabricated from leftover materials of the paper industry — which would make the beads not only much cheaper, but also even more eco-friendly.

It remains to be seen whether the industry will take a liking to Scott’s proposed solution. Even if they do, it’ll likely be a few years before the cellulose microbeads can hit the shelves. In the meantime, it’s important to avoid products with microbeads. They may be good for your skin, but they’re bad for the environment.

Journal Reference: James Coombs OBrien, Laura Torrente-Murciano, Davide Mattia, and Janet L. Scott — Continuous Production of Cellulose Microbeads via Membrane Emulsification. DOI: 10.1021/acssuschemeng.7b00662

Scaffolding

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

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

Scaffolding

Image via Pixabay.

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

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

Plantfolding

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Soft, squishy and powerful: The Royal Institute of Technology creates batteries from trees

A team of researchers from the KTH Royal Institute of Technology and Stanford University has developed a method for making elastic, shock-resistant, high-capacity batteries from wood pulp.

A bit like this, only sciencier. Image via 21stcentech.com

The process for creating the material begins with breaking down tree fibers, making them roughly one million times thinner. The nanocellulose is first dissolved, frozen and then freeze-dried so that water is mechanically eliminated without passing through a liquid state. The material then goes through a process in which the molecules are stabilised so that the material does not collapse.

“The result is a material that is both strong, light and soft,” says Max Hamedi, researcher at KTH and Harvard University. “The material resembles foam in a mattress, though it is a little harder, lighter and more porous. You can touch it without it breaking.”

The resulting aerogel is treated with electrically-conductive ink to give it the ability to store energy, the authors report in the publisher paper. “We use a very precise technique, verging on the atomic level, which adds ink that conducts electricity within the aerogel. You can coat the entire surface within.”

Close-up of the soft battery. Image via Max Hamedi and Wallenberg Wood Science Center

Hamedi compares the battery’s structure to that of a pair of human lungs – when unfurled, they can cover huge surfaces, almost as much as a football field. A single cubic decimeter of the battery could cover most of a football pitch. “You can press it as much as you want; While flexible and stretchable electronics already exist, the insensitivity to shock and impact are somewhat new” he says.

Another benefit of the new method is that it can be used to create three-dimensional structures:

“It is possible to make incredible materials from trees and cellulose. One benefit of the new wood-based aerogel material is that it can be used for three-dimensional structures. There are limits to how thin a battery can be, but that becomes less relevant in 3D, ” Hamedi says. “We are no longer restricted to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space. Three-dimensional, porous materials have been regarded as an obstacle to building electrodes. But we have proven that this is not a problem. In fact, this type of structure and material architecture allows flexibility and freedom in the design of batteries,” he added.

Hamedi says the aerogel batteries could be used in electric car bodies, as well as in clothing, providing the garment has a lining.

 

 

Cellulose to carbon electrode

Trees could be used for high tech energy storage devices

When you think of timber technology, the first things that come to mind may be constructing homes, wooden tools and, of course, paper. Oregon State University researchers have found, however, that trees could be employed in a process that produces building blocks for supercapacitors – high tech energy storage devices that are considered paramount for the future’s energy needs and applications.

Cellulose to carbon electrode

Photo: Oregon State University

Scientists found that cellulose , which is the most abundant polymer on Earth found in high concentration in trees, can be heated in a furnace in an anaerobic environment (no oxygen – this process is called pyrolysis) with ammonia present, to produce nitrogen-doped, nanoporous carbon membranes – the electrodes of a supercapacitor. The method is quick, low cost and environmentally benign. The only byproduct is methane, which can be then used as a fuel, either in a fuel cell for less carbon emission, or directly burned alone in a heat engine.

What’s truly remarkable is the simplicity of the thermochemical process. The team involved was really stoked to find that nobody else had reported this fundamental chemical reaction. Wood is extremely cheap and readily available, but few could think of any way to make it into a high tech material.

Supercapacitors are extremely important for filling the world’s energy demands of the future. Like a battery, supercapacitors can store vasts amount of energy, only they can charge and discharge incredibly fast, making them particularly useful  in computers and consumer electronics, such as the flash in a digital camera. Where they truly can fill their potential is in heavy industry applications. A wind farm produces enormous quantities of energy, but this supply tends to be intermittent and unreliable. Using huge supercapacitors, megawatt or gigawatt sized wind turbines could be stabilized and ensure base-load.

We could go on forever about the potential applications of supercapacitors, but what brings them down is cost. The Oregon State University researchers demonstrated how to build a key component for supercapacitors easily, cheaply and fast. If supercapacitor cost can be brought down considerably, as a result of findings such as the high tech tree solution, then society might reap great benefits.

The findings were reported in the journal Nano Letters.