Tag Archives: nanocellulose

Reading (2 of 2): Is zinc-infused underwear healthier for women?

This first part of this Reading ‘series’, Reading (1 of 2): an artificial intelligence story in British Columbia (Canada) was mostly about how one type of story, in this case,based on a survey, is presented and placed in one or more media outlets. The desired outcome is for more funding by government and for more investors (they tucked in an ad for an upcoming artificial intelligence conference in British Columbia).

This story about zinc-infused underwear for women also uses science to prove its case and it, too, is about raising money. In this case, it’s a Kickstarter campaign to raise money.

If Huha’s (that’s the company name) claims for ‘zinc-infused mineral undies’ are to be believed, the answer is an unequivocal yes. The reality as per the current research on the topic is not quite as conclusive.

The semiotics (symbolism)

Huha features fruit alongside the pictures of their underwear. You’ll see an orange, papaya, and melon in the kickstarter campaign images and on the company website. It seems to be one of those attempts at subliminal communication. Fruit is good for you therefore our underwear is good for you. In fact, our underwear (just like the fruit) has health benefits.

For a deeper dive into the world of semiotics, there’s the ‘be fruitful and multiply’ stricture which is found in more than one religious or cultural orientation and is hard to dismiss once considered.

There is no reason to add fruit to the images other than to suggest benefits from nature and fertility (or fruitfulness). They’re not selling fruit and these ones are not particularly high in zinc. If all you’re looking for is colour, why not vegetables or puppies?

The claims

I don’t have time to review all of the claims but I’ll highlight a few. My biggest problem with the claims is that there are no citations or links to studies, i.e., the research. So, something like this becomes hard to assess,

Most women’s underwear are made with chemical-based, synthetic fibers that lead to yeast and UTI [urinary tract infection] infections, odor, and discomfort. They’ve also been proven to disrupt human hormones, have been linked to cancer, pollute the planet aggressively, and stay in landfills far too long.

There’s more than one path to a UTI and/or odor and/or discomfort but I can see where fabrics that don’t breathe can exacerbate or cause problems of that nature. I have a little more difficulty with the list that follows. I’d like to see the research on underpants disrupting human hormones. Is this strictly a problem for women or could men also be affected? (If you should know, please leave a comment.)

As for ‘linked to cancer’, I’m coming to the conclusion that everything is linked to cancer. Offhand, I’ve been told peanuts, charcoal broiled items (I think it’s the char), and my negative thoughts are all linked to cancer.

One of the last claims in the excerpted section, ‘pollute the planet aggressively’ raises this question.When did underpants become aggressive’?

The final claim seems unexceptional. Our detritus is staying too long in our landfills. Of course, the next question is: how much faster do the Huha underpants degrade in a landfill? That question is not addressed in Kickstarter campaign material.

Talking to someone with more expertise

I contacted Dr. Andrew Maynard, Associate Director at Arizona State University (ASU) School for the Future of Innovation in Society, He has a PhD in physics and longstanding experience in research and evaluation of emerging technologies (for many years he specialized in nanoparticle analysis and aerosol exposure in occupational settings),.

Professor Maynard is a widely recognized expert and public commentator on emerging technologies and their safe and responsible development and use, and has testified before [US] congressional committees on a number of occasions. 

None of this makes him infallible but I trust that he always works with integrity and bases his opinions on the best information at hand. I’ve always found him to be a reliable source of information.

Here’s what he had to say (from an October 25, 2019 email),

I suspect that their claims are pushing things too far – from what I can tell, professionals tend to advise against synthetic underwear because of the potential build up of moisture and bacteria and the lack of breathability, and tend to suggest natural materials – which indicating that natural fibers and good practices should be all most people need. I haven’t seen any evidence for an underwear crisis here, and one concern is that the company is manufacturing a problem which they then claim to solve. That said, I can’t see anything totally egregious in what they are doing. And the zinc presence makes sense in that it prevents bacterial growth/activity within the fabric, thus reducing the chances of odor and infection.

Pharmaceutical grade zinc and research into underwear

I was a little curious about ‘pharmaceutical grade’ zinc as my online searches for a description were unsuccessful. Andrew explained that the term likely means ‘high purity’ zinc suitable for use in medications rather than the zinc found in roofing panels.

After the reference to ‘pharmaceutical grade’ zinc there’s a reference to ‘smartcel sensitive Zinc’. Here’s more from the smartcel sensitive webpage,

smartcel™ sensitive is skin friendly thanks to zinc oxide’s soothing and anti-inflammatory capabilities. This is especially useful for people with sensitive skin or skin conditions such as eczema or neurodermitis. Since zinc is a component of skin building enzymes, it operates directly on the skin. An active exchange between the fiber and the skin occurs when the garment is worn.

Zinc oxide also acts as a shield against harmful UVA and UVB radiation [it’s used in sunscreens], which can damage our skin cells. Depending on the percentage of smartcel™ sensitive used in any garment, it can provide up to 50 SPF.

Further to this, zinc oxide possesses strong antibacterial properties, especially against odour causing bacteria, which helps to make garments stay fresh longer. *

I couldn’t see how zinc helps the pH balance in anyone’s vagina as claimed in the Kickstarter campaign and smartcel, on its ‘sensitive’ webpage, doesn’t make that claim but I found an answer in an April 4, 2017 Q&A (question and answer) interview by Jocelyn Cavallo for Medium,

What women need to know about their vaginal p

Q & A with Dr. Joanna Ellington

A woman’s vagina is a pretty amazing body part. Not only can it be a source of pleasure but it also can help create and bring new life into the world. On top of all that, it has the extraordinary ability to keep itself clean by secreting natural fluids and maintaining a healthy pH to encourage the growth of good bacteria and discourage harmful bacteria from moving in. Despite being so important, many women are never taught the vital role that pH plays in their vaginal health or how to keep it in balance.

We recently interviewed renowned Reproductive Physiologist and inventor of IsoFresh Balancing Vaginal Gel, Dr. Joanna Ellington, to give us the low down on what every woman needs to know about their vaginal pH and how to maintain a healthy level.

What is pH?

Dr. Ellington: PH is a scale of acidity and alkalinity. The measurements range from 0 to 14: a pH lower than 7 is acidic and a pH higher than 7 is considered alkaline.

What is the “perfect” pH level for a woman’s vagina?

Dr. E.: For most women of a reproductive age vaginal pH should be 4.5 or less. For post-menopausal women this can go up to about 5. The vagina will naturally be at a high pH right after sex, during your period, after you have a baby or during ovulation (your fertile time).

Are there diet and environmental factors that affect a women’s vaginal pH level?

Dr. E.: Yes, iron zinc and manganese have been found to be critical for lactobacillus (healthy bacteria) to function. Many women don’t eat well and should supplement these, especially if they are vegetarian. Additionally, many vegetarians have low estrogen because they do not eat the animal fats that help make our sex steroids. Without estrogen, vaginal pH and bacterial imbalance can occur. It is important that women on these diets ensure good fat intake from other sources, and have estrogen and testosterone and iron levels checked each year.

Do clothing and underwear affect vaginal pH?

Dr. E.: Yes, tight clothing and thong underwear [emphasis mine] have been shown in studies to decrease populations of healthy vaginal bacteria and cause pH changes in the vagina. Even if you wear these sometimes, it is important for your vaginal ecosystem that loose clothing or skirts be worn some too.

Yes, Dr. Ellington has the IsoFresh Balancing Vaginal Gel and whether that’s a good product should be researched but all of the information in the excerpt accords with what I’ve heard over the years and fits in nicely with what Andrew said, zinc in underwear could be useful for its antimicrobial properties. Also, note the reference to ‘thong underwear’ as a possible source of difficulty and note that Huha is offering thong and very high cut underwear.

Of course, your underwear may already have zinc in it as this research suggests (thank you, Andrew, for the reference),

Exposure of women to trace elements through the skin by direct contact with underwear clothing by Thao Nguyen & Mahmoud A. Saleh. Journal of Environmental Science and Health, Part A Toxic/Hazardous Substances and Environmental Engineering Volume 52, 2017 – Issue 1 Pages 1-6 DOI: https://doi.org/10.1080/10934529.2016.1221212 Published online: 09 Sep 2016

This paper is behind a paywall but I have access through a membership in the Canadian Academy of Independent Scholars. So, here’s the part I found interesting,

… The main chemical pollutants present in textiles are dyes containing carcinogenic amines, metals, pentachlorophenol, chlorine bleaching, halogen carriers, free formaldehyde, biocides, fire retardants and softeners.[1] Metals are also found in textile products and clothing are used for many purposes: Co [cobalt], Cu [copper], Cr [chromium] and Pb [lead] are used as metal complex dyes, Cr as pigments mordant, Sn as catalyst in synthetic fabrics and as synergists of flame retardants,Ag [silver] as antimicrobials and Ti [titanium] and Zn [zinc] as water repellents and odor preventive agents.[2–5] When present in textile materials, the toxic elements mentioned above represent not only a major environmental problem in the textile industry but also they may impose potential danger to human health by absorption through the skin.[6,7] [emphasis mine] Chronic exposure to low levels of toxic elements has been associated with a number of adverse human health effects.[8–11] Also exposure to high concentration of elements which are considered as essential for humans such as Cu, Co, Fe [iron], Mn [manganese] or Zn among others, can also be harmful.[12] [emphasis mine] Co, Cr, Cu and Ni [nitrogen] are skin sensitizers,[13,14] which may lead to contact dermatitis, also Cr can lead to liver damage, pulmonary congestion and cancer.[15] [emphasis mine] The purpose of the present study was to determine the concentrations of a number of elements in various skin-contact clothes. For risk estimations, the determination of the extractable amounts of heavy metals is of importance, since they reflect their possible impact on human health. [p. 2 PDF]

So, there’s the link to cancer. Maybe.

Are zinc-infused undies a good idea?

It could go either way. (For specifics about the conclusions reached in the study, scroll down to the Ooops! subheading.) I like the idea of using sustainable Eucalyptus-based material (TencelL) for the underwear as I have heard that cotton isn’t sustainably cultivated. As for claims regarding the product’s environmental friendliness, it’s based on wood, specifically, cellulose, which Canadian researchers have been experimenting with at the nanoscale* and they certainly have been touting nanocellulose as environmentally friendly. Tencel’s sustainability page lists a number of environmental certifications from the European Union, Belgium, and the US.

*Somewhere in the Kickstarter campaign material, there’s a reference to nanofibrils and I’m guessing those nanofibrils are Tencel’s wood fibers at the nanoscale. As well, I’m guessing that smartcel’s fabric contains zinc oxide nanoparticles.

Whether or not you need more zinc is something you need to determine for yourself. Finding out if the pH balance in your vagina is within a healthy range might be a good way to start. It would also be nice to know how much zinc is in the underwear and whether it’s being used antimicrobial properties and/or as a source for one of minerals necessary for your health.

How the Kickstarter campaign is going

At the time of this posting, they’ve reached a little over $24,000 with six days left. The goal was $10,000. Sadly, there are no questions in the FAQ (frequently asked questions).

Reading tips

It’s exhausting trying to track down authenticity. In this case, there were health and environmental claims but I do have a few suggestions.

  1. Look at the imagery critically and try to ignore the hyperbole.
  2. How specific are the claims? e.g., How much zinc is there in the underpants?
  3. Who are their experts and how trustworthy are the agencies/companies mentioned?
  4. If research is cited, are the publishers reputable and is the journal reputable?
  5. Does it make sense given your own experience?
  6. What are the consequences if you make a mistake?

Overblown claims and vague intimations of disease are not usually good signs. Conversely, someone with great credential may not be trustworthy which is why I usually try to find more than one source for confirmation. The person behind this campaign and the Huha company is Alexa Suter. She’s based in Vancouver, Canada and seems to have spent most of her time as a writer and social media and video producer with a few forays into sales and real estate. I wonder if she’s modeling herself and her current lifestyle entrepreneurial effort on Gwyneth Paltrow and her lifestyle company, Goop.

Huha underwear may fulfill its claims or it may be just another pair of underwear or it may be unhealthy. As for the environmentally friendly claims, let’s hope that the case. On a personal level, I’m more hopeful about that.

Regardless, the underwear is not cheap. The smallest pledge that will get your underwear (a three-pack) is $65 CAD.

Ooops! ETA: November 8, 2019:

I forgot to include the conclusion the researchers arrived at and some details on how they arrived at those conclusions. First, they tested 120 pairs of underpants in all sorts of colours and made in different parts of the world.

Second, some underpants showed excessive levels of metals. Cotton was the most likely material to show excess although nylon and polyester can also be problematic. To put this into proportion and with reference to zinc, “Zn exceeded the limit in 4% of the tested samples
and was found mostly in samples manufactured in China.” [p. 6 PDF] Finally, dark colours tested for higher levels of metals than light colours.

While it doesn’t mention underpants as such, there’s a November 8, 2019 article ‘Five things everyone with a vagina should know‘ by Paula McGrath for BBC news online. McGrath’s health expert is Dr. Jen Gunter, a physician whose specialties are obstetrics, gynaecology, and pain.

Nanocellulose sensors: 3D printed and biocompatible

I do like to keep up with nanocellulose doings, especially when there’s some Canadian involvement, and an October 8, 2019 news item on Nanowerk alerted me to a newish application for the product,

Physiological parameters in our blood can be determined without painful punctures. Empa researchers are currently working with a Canadian team to develop flexible, biocompatible nanocellulose sensors that can be attached to the skin. The 3D-printed analytic chips made of renewable raw materials will even be biodegradable in future.

The idea of measuring parameters that are relevant for our health via the skin has already taken hold in medical diagnostics. Diabetics, for example, can painlessly determine their blood sugar level with a sensor instead of having to prick their fingers.

An October 8, 2019 Empa (Swiss Federal Laboratories for Materials Science and Technology) press release, which originated the news item, provides more detail,

A transparent foil made of wood

Nanocellulose is an inexpensive, renewable raw material, which can be obtained in form of crystals and fibers, for example from wood. However, the original appearance of a tree no longer has anything to do with the gelatinous substance, which can consist of cellulose nanocrystals and cellulose nanofibers. Other sources of the material are bacteria, algae or residues from agricultural production. Thus, nanocellulose is not only relatively easy and sustainable to obtain. Its mechanical properties also make the “super pudding” an interesting product. For instance, new composite materials based on nanocellulose can be developed that could be used as surface coatings, transparent packaging films or even to produce everyday objects like beverage bottles.

Researchers at Empa’s Cellulose & Wood Materials lab and Woo Soo Kim from the Simon Fraser University [SFU] in Burnaby, Canada, are also focusing on another feature of nanocellulose: biocompatibility. Since the material is obtained from natural resources, it is particularly suitable for biomedical research.

With the aim of producing biocompatible sensors that can measure important metabolic values, the researchers used nanocellulose as an “ink” in 3D printing processes. To make the sensors electrically conductive, the ink was mixed with silver nanowires. The researchers determined the exact ratio of nanocellulose and silver threads so that a three-dimensional network could form.

Just like spaghetti – only a wee bit smaller

It turned out that cellulose nanofibers are better suited than cellulose nanocrystals to produce a cross-linked matrix with the tiny silver wires. “Cellulose nanofibers are flexible similar to cooked spaghetti, but with a diameter of only about 20 nanometers and a length of just a few micrometers,” explains Empa researcher Gilberto Siqueira.

The team finally succeeded in developing sensors that measure medically relevant metabolic parameters such as the concentration of calcium, potassium and ammonium ions. The electrochemical skin sensor sends its results wirelessly to a computer for further data processing. The tiny biochemistry lab on the skin is only half a millimeter thin.

While the tiny biochemistry lab on the skin – which is only half a millimeter thin – is capable of determining ion concentrations specifically and reliably, the researchers are already working on an updated version. “In the future, we want to replace the silver [nano] particles with another conductive material, for example on the basis of carbon compounds,” Siqueira explains. This would make the medical nanocellulose sensor not only biocompatible, but also completely biodegradable.

I like the images from Empa better than the ones from SFU,

Using a 3D printer, the nanocellulose “ink” is applied to a carrier plate. Silver particles provide the electrical conductivity of the material. Image: Empa
Empa researcher Gilberto Siqueira demonstrates the newly printed nanocellulose circuit. After a subsequent drying, the material can be further processed. Image: Empa

SFU produced a news release about this work back in February 2019. Again, I prefer what the Swiss have done because they’re explaining/communicating the science, as well as , communicating benefits. From a February 13, 2019 SFU news release (Note: Links have been removed),

Simon Fraser University and Swiss researchers are developing an eco-friendly, 3D printable solution for producing wireless Internet-of-Things (IoT) sensors that can be used and disposed of without contaminating the environment. Their research has been published as the cover story in the February issue of the journal Advanced Electronic Materials.

SFU professor Woo Soo Kim is leading the research team’s discovery, which uses a wood-derived cellulose material to replace the plastics and polymeric materials currently used in electronics.

Additionally, 3D printing can give flexibility to add or embed functions onto 3D shapes or textiles, creating greater functionality.

“Our eco-friendly, 3D-printed cellulose sensors can wirelessly transmit data during their life, and then can be disposed without concern of environmental contamination,” says Kim, a professor in the School of Mechatronic Systems Engineering. The SFU research is being carried out at PowerTech Labs in Surrey, which houses several state-of-the-art 3D printers used to advance the research.

“This development will help to advance green electronics. For example, the waste from printed circuit boards is a hazardous source of contamination to the environment. If we are able to change the plastics in PCB to cellulose composite materials, recycling of metal components on the board could be collected in a much easier way.”

Kim’s research program spans two international collaborative projects, including the latest focusing on the eco-friendly cellulose material-based chemical sensors with collaborators from the Swiss Federal Laboratories for Materials Science.

He is also collaborating with a team of South Korean researchers from the Daegu Gyeongbuk Institute of Science and Technology’s (DGIST)’s department of Robotics Engineering, and PROTEM Co Inc, a technology-based company, for the development of printable conductive ink materials.

In this second project, researchers have developed a new breakthrough in the embossing process technology, one that can freely imprint fine circuit patterns on flexible polymer substrate, a necessary component of electronic products.

Embossing technology is applied for the mass imprinting of precise patterns at a low unit cost. However, Kim says it can only imprint circuit patterns that are imprinted beforehand on the pattern stamp, and the entire, costly stamp must be changed to put in different patterns.

The team succeeded in developing a precise location control system that can imprint patterns directly resulting in a new process technology. The result will have widespread implications for use in semiconductor processes, wearable devices and the display industry.

This paper was made available online back in December 2018 and then published in print in February 2019. As to why there’d be such large gaps between the paper’s publication dates and the two institution’s news/press releases, it’s a mystery to me. In any event, here’s a link to and a citation for the paper,

3D Printed Disposable Wireless Ion Sensors with Biocompatible Cellulose Composites by Taeil Kim, Chao Bao, Michael Hausmann, Gilberto Siqueira, Tanja Zimmermann, Woo Soo Kim. Advanced Electronic Materials DOI: https://doi.org/10.1002/aelm.201970007 First published online December 19, 2018. First published in print: 08 February 2019 (Adv. Electron. Mater. 2/2109) Volume 5, Issue 2 February 2019 1970007

This paper is behind a paywall.

A nanocomposite biomaterial heart valve from the University of British Columbia (Canada)

I wish the folks at the University of British Columbia (UBC) would include more technical/scientific information in their news releases about research. For those who do like a little more technical information, I included the paper’s abstract at the end of this post.

A March 25, 2019 news item on ScienceDaily trumpets the UBC (Okanagan campus) research,

Researchers at UBC have created the first-ever nanocomposite biomaterial heart-valve developed to reduce or eliminate complications related to heart transplants.

By using a newly developed technique, the researchers were able to build a more durable valve that enables the heart to adapt faster and more seamlessly.

A March 25, 2019 UBC news release (also on EurekAlert) by Patty Wellborn, which originated the news item, gives an accessible description of the ‘new’ valve,

Assistant Professor Hadi Mohammadi runs the Heart Valve Performance Laboratory (HVPL) through UBC Okanagan’s School of Engineering. Lead author on the study, he says the newly developed valve is an example of a transcatheter heart valve, a promising new branch of cardiology. These valves are unique because they can be inserted into a patient through small incisions rather than opening a patient’s chest–a procedure that is generally safer and much less invasive.

“Existing transcatheter heart valves are made of animal tissues, most often the pericardium membrane from a cow’s heart, and have had only moderate success to date,” explains Mohammadi. “The problem is that they face significant implantation risks and can lead to coronary obstruction and acute kidney injury.”

The new valve solves that problem by using naturally derived nanocomposites–a material assembled with a variety of very small components–including gels, vinyl and cellulose. The combination of their new material with the non-invasive nature of transcatheter heart valves makes this new design very promising for use with high-risk patients, according to Mohammadi.

“Not only is the material important but the design and construction of our valve means that it lowers stress on the valve by as much as 40 per cent compared to valves currently available,” says Dylan Goode, a graduate researcher at the HVPL. “It is uniquely manufactured in one continuous form, so it gains strength and flexibility to withstand the circulatory complications that can arise following transplantation.”

Working with researchers from Kelowna General Hospital and Western University, the valve will now undergo vigorous testing to perfect its material composition and design. The testing will include human heart simulators and large animal in-vivo studies. If successful, the valve will then proceed to clinical patient testing.

“This has the potential to become the new standard in heart valve replacement and to provide a safer, longer-term solution for many patients.”

The new design was highlighted in a paper published this month in the Journal of Engineering in Medicine with financial support from the Natural Sciences and Engineering Research Council of Canada [NSERC] .

Here’s a link to and a citation for the paper,

Proposed percutaneous aortic valve prosthesis made of cryogel by Hadi Mohammadi, Dylan Goode, Guy Fradet, Kibret Mequanint. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2019; 095441191983730 DOI: 10.1177/0954411919837302 First Published March 20, 2019

This paper is behind a paywall.

As promised, here’s the abstract,

Transcatheter heart valves are promising for high-risk patients. Generally, their leaflets are made of pericardium stented in a Nitinol basket. Despite their relative success, they are associated with significant complications such as valve migration, implantation risks, stroke, coronary obstruction, myocardial infraction, acute kidney injury (which all are due to the release of detached solid calcific pieces in to the blood stream) and expected issues existing with tissue valves such as leaflet calcification. This study is an attempt to fabricate the first ever polymeric percutaneous valves made of cryogel following the geometry and mechanical properties of porcine aortic valve to address some of the above-mentioned shortcomings. A novel, one-piece, tricuspid percutaneous valve, consisting of leaflets made entirely from the hydrogel, polyvinyl alcohol cryogel reinforced by bacterial cellulose natural nanocomposite, attached to a Nitinol basket was developed and demonstrated. Following the natural geometry of the valve, a novel approach was applied based on the revolution about an axis of a hyperboloid shape. The geometry was modified based on avoiding sharp warpage of leaflets and removal of the central opening orifice area of the valve when valve is fully closed using the finite element analysis. The modified geometry was replaced by a cloud of (control) points and was essentially converted to Bezier surfaces for further adjustment. A cavity mold was then designed and fabricated to form the valve. The fabricated valve was sewn into the Nitinol basket which is covered by Dacron cloth. The models presented in this study merit further development and revisions for both aortic and mitral positions.

So, this new valve partially consists of bacterial cellulose and the design is based on porcine (pig) valves. Cellulose is the most abundant organic material on earth and if it forms part of the nanocomposite, I’d expect to see the word ‘nanocellulose’ mentioned somewhere. What puzzles me is the ‘bacterial cellulose’, a term that is unfamiliar to me. Anyone who cares to clarify the matter for me, please feel free to leave a comment.

Regarding the pig valve, I understand that heart patients who require valves have a choice of a pig valve or a mechanical valve. Apparently, people with porcine valves don’t need to take drugs to counteract rejection amongst other advantages but the valves do have a shorter life span (10 to 15 years) in addition to the other shortcomings mentioned in the abstract.

Assuming I properly understand the abstract, this ‘nanocomposite’ valve could combine the advantages of the mechanical and porcine valves while offering more durability than either one.

Again, should anyone care to increase my understanding of the valves and the advantages of this new one, please do leave a comment.

A fire-retardant coating made of renewable nanocellulose materials

Firefighters everywhere are likely to appreciate the efforts of researchers at Texas A&M University (US) to a develop a non-toxic fire retardant coating. From a February 12, 2019 news item on Nanowerk (Note: A link has been removed),

Texas A&M University researchers are developing a new kind of flame-retardant coating using renewable, nontoxic materials readily found in nature, which could provide even more effective fire protection for several widely used materials.

Dr. Jaime Grunlan, the Linda & Ralph Schmidt ’68 Professor in the J. Mike Walker ’66 Department of Mechanical Engineering at Texas A&M, led the recently published research that is featured on the cover of a recent issue of the journal Advanced Materials Interfaces (“Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films”).

Successful development and implementation of the coating could provide better fire protection to materials including upholstered furniture, textiles and insulation.

“These coatings offer the opportunity to reduce the flammability of the polyurethane foam used in a variety of furniture throughout most people’s homes,” Grunlan noted.

A February 8, 2019 Texas A&M University news release (also on EurekAlert) by Steve Kuhlmann, which originated the news item, describes the work being done in collaboration with a Swedish team in more detail,

The project is a result of an ongoing collaboration between Grunlan and a group of researchers at KTH Royal Institute of Technology in Stockholm, Sweden, led by Lars Wagberg. The group, which specializes in utilizing nanocellulose, provided Grunlan with the ingredients he needed to complement his water-based coating procedure.

In nature, both the cellulose – a component of wood and various sea creatures – and clay – a component in soil and rock formations – act as mechanical reinforcements for the structures in which they are found.

“The uniqueness in this current study lies in the use of two naturally occurring nanomaterials, clay nanoplatelets and cellulose nanofibrils,” Grunlan said. “To the best of our knowledge, these ingredients have never been used to make a heat shielding or flame-retardant coating as a multilayer thin film deposited from water.”

Among the benefits gained from using this method include the coating’s ability to create an excellent oxygen barrier to plastic films – commonly used for food packaging – and better fire protection at a lower cost than other, more toxic ingredients traditionally used flame-retardant treatments.

To test the coatings, Grunlan and his colleagues applied the flexible polyurethane foam – often used in furniture cushions – and exposed it to fire using a butane torch to determine the level of protection the compounds provided.

While uncoated polyurethane foam immediately melts when exposed to flame, the foam treated with the researchers’ coating prevented the fire from damaging any further than surface level, leaving the foam underneath undamaged.

“The nanobrick wall structure of the coating reduces the temperature experienced by the underlying foam, which delays combustion,” Grunlan said. “This coating also serves to promote insulating char formation and reduces the release of fumes that feed a fire.”

With the research completed, Grunlan said the next step for the overall flame-retardant project is to transition the methods into industry for implementation and further development. 

Here’s a link to and a citation for the paper,

Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films by Shuang Qin, Maryam Ghanad Pour, Simone Lazar, Oruç Köklükaya, Joseph Gerringer, Yixuan Song, Lars Wågberg, Jaime C. Grunlan. Advanced Materials Interfaces Volume 6, Issue 2 January 23, 2019 1801424 DOI: https://doi.org/10.1002/admi.201801424 First published online: 16 November 2018

This paper is behind a paywall.

Nanocellulosic 3D-printed ears

It’s been a while since I’ve had a story abut cellulose nanocrystals (CNC) and this one comes from Switzerland’s Empa (Swiss Federal Laboratories for Materials Science and Technology) in a January 15, 2019 news item on Nanowerk (Note: A link has been removed),

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing (ACS Nano, “Dynamics of Cellulose Nanocrystal Alignment during 3D Printing”).

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains: “In viscous state cellulose nanocrystals can easily be shaped together with nother biopolymers into complex 3-dimensional structures using a 3D printer, such as the Bioplotter.”

Once cross-linked, the structures remain stable despite their soft mechanical properties. Hausmann is currently investigating the characteristics of the nanocellulose composite hydrogels in order to further optimize their stability as well as the printing process. The researcher already used X-ray analysis to determine how cellulose is distributed and organized within the printed structures.

At this point in time the printed ear is entirely and solely made of cellulose nanocrystals and a biopolymer. However, the objective is to incorporate both human cells and therapeutics into the base structure in order to produce biomedical implants.

Here’s one of the researchers (Michael Hausmann) showing off their ‘ear’,

A 3D-printed ear: Empa researcher Michael Hausmann uses nanocellulose as the basis for novel implants (Image: Empa)

Doesn’t look like much does, eh? It’s scaffolding or, you could say, a kind of skeleton and a January 15, 2019 Empa press release, which originated the news item, describes it and explains how it will house new cells,

A new project is currently underway, looking into how chondrocytes (cartilage cells) can be integrated into the scaffold to yield artificial cartilage tissue. As soon as the colonization of the hydrogel with cells is established, nanocellulose based composites in the shape of an ear could serve as an implant for children with an inherited auricular malformation as for instance, in microtia, where the external ears are only incompletely developed. A reconstruction of the auricle can esthetically and medically correct the malformation; otherwise the hearing ability can be severely impaired. In the further course of the project, cellulose nanocrystals containing hydrogels will also be used for the replacement of articular cartilage (e.g. knee) in cases of joint wear due to, for example, chronic arthritis.

Once the artificial tissue has been implanted in the body, the biodegradable polymer material is expected to degrade over time. The cellulose itself is not degradable in the body, but biocompatible. However, it is not only its biocompatibility that makes nanocellulose the perfect material for implant scaffolds. “It is also the mechanical performance of cellulose nanocrystals that make them such promising candidates because the tiny but highly stable fibers can extremely well reinforce the produced implant,” said Hausmann.

Moreover, nanocellulose allows the incorporation of various functions by chemical modifications into the viscous hydrogel. Thus, the structure, the mechanical properties and the interactions of the nanocellulose with its environment can be specifically tailored to the desired end product. “For instance, we can incorporate active substances that promote the growth of chondrocytes or that sooth joint inflammation into the hydrogel,” says the Empa researcher.

And last but not least, as raw material cellulose is the most abundant natural polymer on earth. Therefore, the use of cellulose nanocrystals not only benefits from the mere elegance of the novel process but also from the availability of the raw material.

The white nanocellulose ear lies glossy on the glass carrier. Just out of the Bioplotter, it is already robust and dimensionally stable. Hausmann can give the go-ahead for the next steps. 

Here’s a link to and a citation for the paper,

Dynamics of Cellulose Nanocrystal Alignment during 3D Printing by Michael K. Hausmann, Patrick A. Rühs, Gilberto Siqueira, Jörg Läuger, Rafael Libanori, Tanja Zimmermann, and André R. Studart. ACS Nano, 2018, 12 (7), pp 6926–6937 DOI: 10.1021/acsnano.8b02366 Publication Date (Web): July 5, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Cellulose biosensor heralds new bioimaging approach to tissue engineering

I keep an eye on how nanocellulose is being used in various applications and I’m not sure that this cellulose biosensor quite fits the bill as nanocellulose, nonetheless, it’s interesting and that’s enough for me. From a December 12, 2018 Sechenov University (Russia) press release on EurekAlert,

I.M. Sechenov First Moscow State Medical University teamed up together with Irish colleagues to develop a new imaging approach for tissue engineering. The team produced so-called ‘hybrid biosensor’ scaffold materials, which are based on cellulose matrices labeled with pH- and calcium-sensitive fluorescent proteins. These materials enable visualization of the metabolism and other important biomarkers in the engineered artificial tissues by microscopy. The results of the work were published in the Acta Biomaterialia journal.
The success of tissue engineering is based on the use of scaffold matrices – materials that support the viability and direct the growth of cells, tissues, and organoids. Scaffolds are important for basic and applied biomedical research, tissue engineering and regenerative medicine, and are promising for development of new therapeutics. However, the ability ‘to see’ what happens within the scaffolds during the tissue growth poses a significant research challenge

“We developed a new approach allowing visualization of scaffold-grown tissue and cells by using labeling with biosensor fluorescent proteins. Due to the high specificity of labeling and the use of fluorescence microscopy FLIM, we can quantify changes in pH and calcium in the vicinity of cells,” says Dr. Ruslan Dmitriev, Group Leader at the University College Cork and the Institute for Regenerative Medicine (I.M. Sechenov First Moscow State Medical University).
To achieve the specific labeling of cellulose matrices, researchers used well-known cellulose-binding proteins. The use of extracellular pH- and calcium-sensitive biosensors allow for analysis of cell metabolism: indeed, the extracellular acidification is directly associated with the balance of cell energy production pathways and the glycolytic flux (release of lactate). It is also a frequent hallmark of cancer and transformed cell types. On the other hand, calcium plays a key role in the extra- and intracellular signaling affecting cell growth and differentiation.

The approach was tested on different types of cellulose matrices (bacterial and produced from decellularised plant tissues) using 3D culture of human colon cancer cells and stem-cell derived mouse small intestinal organoids. The scaffolds informed on changes in the extracellular acidification and were used together with the analysis of real-time oxygenation of intestinal organoids. The resulting data can be presented in the form of colour maps, corresponding to the areas of cell growth within different microenvironments.

“Our results open new prospects in the imaging of tissue-engineered constructs for regenerative medicine. They enable deeper understanding of tissue metabolism in 3D and are also highly promising for commercialisation,” concludes Dr. Dmitriev.

The researchers have provided an image to illustrate their work,

Caption: A 3D reconstruction of a cellulose matrix stained with a pH-sensitive biosensor. Credit: Dr. R. Dmitriev

Here’s a link to and a citation for the paper,

Cellulose-based scaffolds for fluorescence lifetime imaging-assisted tissue engineering by Neil O’Donnell, Irina A. Okkelman, Peter Timashev, Tatyana I.Gromovykh, Dmitri B. Papkovsky, Ruslan I.Dmitriev. Acta Biomaterialia Volume 80, 15 October 2018, Pages 85-96 DOI: https://doi.org/10.1016/j.actbio.2018.09.034


This paper is behind a paywall.

Two new Canada Excellence Research Chairs (CERC) at the University of British Columbia (Canada) bring bioproducts and precision medicine skills

This is very fresh news. One of these chairs has not yet been listed (at the time of this writing) as a member of the institute that he will be leading. Here’s the big picture news from an
April 17, 2019 University of British Columbia (UBC) news release, Note: Links have been removed,

Two internationally recognized researchers join the University of British Columbia as Canada Excellence Research Chairs, bringing international talent in the fields of forest bioproducts and precision cancer drug design.

Orlando Rojas has accepted the Canada Excellence Research Chair in Forest Bioproducts, while Sriram Subramaniam will hold the Gobind Khorana Canada Excellence Research Chair in Precision Cancer Drug Design—named after late Nobel Prize-winning UBC biochemistry professor Har Gobind Khorana.

“We are delighted to welcome Dr. Rojas and Dr. Subramaniam to UBC,” said UBC President and Vice-Chancellor, Professor Santa J. Ono. “Thanks to the CERC program and the generous support of our partners, including VGH & UBC Hospital Foundation, we have an opportunity to continue to build on UBC’s reputation as a global leader in these vitally important research fields.”

The Canada Excellence Research Chairs (CERC) program was established by the federal government in 2008 to attract top research talent from abroad to Canada. UBC will receive up to $10 million over seven years to support each chair and their research teams. In addition, a philanthropic gift of $18 million made to VGH & UBC Hospital Foundation will support cancer drug design that will be carried out by Subramaniam in close partnership with UBC and the Vancouver Prostate Centre at VGH.

“VGH & UBC Hospital Foundation is honoured to announce an $18 million gift from Aqueduct Foundation on behalf of an anonymous donor that will increase capacity for discovering and testing new life-saving cancer treatments right here in B.C. This funding will specifically support the design of precise, targeted and cost-effective drugs for cancer in work led by Dr. Sriram Subramaniam in close partnership with UBC and the Vancouver Prostate Centre at VGH and other research centres,” says Barbara Grantham, president and CEO of VGH & UBC Hospital Foundation.

Bioproducts

The April 17, 2019 UBC news release, goes on to describe the two new chairs,

Breaking new ground in forest bioproducts

Orlando Rojas comes to UBC from Aalto University [Finland], where he directs with VTT, the Technical Research Centre of Finland, a scientific cluster to advance the Finnish materials bio-economy. A recipient of the Anselme Payen Award—one of the highest international recognitions in the area of cellulose and renewable materials—and an elected member of the American Chemical Society and the Finnish Academy of Science and Letters, Rojas is recognized as a worldwide leader in the area of nanocelluloses.

“I’m thrilled to join an already stellar team of researchers at UBC’s BioProducts Institute,” said Rojas. “My research is aimed at uncovering solutions that can be found in nature to fulfill our material needs by using sustainably, readily available bio-resources. I hope to break new grounds to create positive societal impacts and to better our quality of life.”

As the CERC in Forest Bioproducts, Rojas will establish a world-class research program in genomics, synthetic biology, materials science and engineering. Together with his team and by applying cutting-edge nano- and biotechnologies, he will discover new strategies to isolate and transform biomass components—non-fossil organic materials derived from plants (including wood)—as well as side-streams and residuals from forestry and agriculture, oils and biomolecules. The work will lead to the generation of new bio-based precursors and advanced materials critical to the future bioeconomy. Rojas will be the scientific director of the UBC BioProducts Institute, synergizing a distinguished group of professors and researchers across campus who will conduct multi- and cross-disciplinary research that will position UBC at the forefront in the area.

As climate change continues to be the greatest threat to our world, the need to transition toward a more sustainable bio-based circular economy is critical. Rojas’ research is vital in understanding the role of forest and other plant-based resources in facilitating the transition to renewable materials and bioproducts.

As I noted earlier, Rojas has yet to be added to the UBC BioProducts Institute roster but I did find a listing of his published papers on Google Scholar and noted a number of them are focused on nanocellulose with at least one study on cellulose nanocrystals (CNC),

  • Cellulose nanocrystals: chemistry, self-assembly, and applications [by] Y Habibi, LA Lucia, OJ Rojas Chemical reviews 110 (6), 3479-3500

The University of British Columbia was the site for much of the early work in Canada and internationally on cellulose nanocrystals. After the provincial government lost interest in supporting it, the researchers at FPInnovations (I think it was a university spin-off organization) moved their main headquarters (leaving a smaller group in British Columbia) to the province of Québec where they receive significant support . In turn, FPInnovations spun-off a company, CelluForce which produces CNC from forest products.This news about Roja’s appointment would seem to make for an interesting development in Canada’s nanocellulose story.

Precision medicine with cryo-electron microscopy

Now for the second CERC appointment, from the April 17, 2019 UBC news release,

Putting Canada at the forefront of precision medicine

Sriram Subramaniam is recognized as a global leader in the emerging field of cryo-electron microscopy, or cryo-EM, a technology that has sparked a revolution in imaging of protein complexes. Subramaniam and his team demonstrated that proteins and protein-bound drugs could be visualized at atomic resolution with cryo-EM, paving the way for this technology to be used in accelerating drug discovery.

Subramaniam comes to UBC’s faculty of medicine from the US National Cancer Institute (NCI) at the National Institutes of Health (NIH) where he led a research team that made seminal advances in molecular and cellular imaging using electron microscopy, including work on advancing vaccine design for viruses such as HIV. Subramaniam is also founding director of the National Cryo-EM Program at NCI, NIH.

As the Gobind Khorana Canada Excellence Research Chair in Precision Cancer Drug Design, Subramaniam will establish and direct a laboratory located at UBC, aimed at bringing about transformative discoveries in cancer, neuroscience and infectious disease. Subramaniam is appointed both in the department of urologic sciences and in biochemistry and molecular biology at UBC, and is linked to the precision cancer drug design program at the Vancouver Prostate Centre at VGH.

His research is supported by a philanthropic gift of $18 million made to VGH & UBC Hospital Foundation. He will work in close partnership with the Vancouver Prostate Centre at VGH.

“We would not be able to undertake this path aimed at leveraging advances in imaging technology to improve patient outcomes if it weren’t for the generous support of the donor, the Canadian government, and VGH & UBC Hospital Foundation,” said Subramaniam. “I am proud to be part of a team of outstanding researchers here in Vancouver, and working together to harness the true potential of cryo-EM to accelerate drug design. Our work has the potential to establish VGH, UBC and Canada at the forefront of the emerging era of precision medicine.”

I was not able to find much in the way of additional information about Subramaniam—other than this (from the High Resolution Electron Microscopy Lab Members webpage),

Sriram Subramaniam received his Ph.D. in Physical Chemistry from Stanford University and completed postdoctoral training in the Departments of Chemistry and Biology at M.I.T. [Massachusetts Institute of Technology] He is chief of the Biophysics Section in the Laboratory of Cell Biology at the Center for Cancer Research, National Cancer Institute. He holds a visiting faculty appointment at the Johns Hopkins University School of Medicine.

Welcome to both Orlando J. Rohas and Sriram Subramaniam!

Wooden supercapacitors: a cellulose nanofibril story

A May 24, 2018 news item on Nanowerk announces a technique for making sustainable electrodes (Note: A link has been removed),

Carbon aerogels are ultralight, conductive materials, which are extensively investigated for applications in supercapacitor electrodes in electrical cars and cell phones. Chinese scientists have now found a way to make these electrodes sustainably. The aerogels can be obtained directly from cellulose nanofibrils, the abundant cell-wall material in wood, finds the study reported in the journal Angewandte Chemie (“Wood-Derived Ultrathin Carbon Nanofiber Aerogels”).

A May 24, 2018 Wiley Publications press release, which originated the news item, explains further,

Supercapacitors are capacitors that can take up and release a very large amount of energy in a very short time. Key requirements for supercapacitor electrodes are a large surface area and conductivity, combined with a simple production method. Another growing issue in supercapacitor production–mainly for smartphone and electric car technologies–is sustainability. However, sustainable and economical production of carbon aerogels as supercapacitor electrode materials is possible, propose Shu-Hong Yu and colleagues from the University of Science and Technology of China, Hefei, China.

Carbon aerogels are ultralight conductive materials with a very large surface area. They can be prepared by two production routes: the first and cheapest starts from mostly phenolic components and produces aerogels with improvable conductivity, while the second route is based on graphene- and carbon-nanotube precursors. The latter method delivers high-performance aerogels but is expensive and non-environmentally friendly. In their search for different precursors, Yu and colleagues have found an abundant, far less expensive, and sustainable source: wood pulp.

Well, not really wood pulp, but its major ingredient, nanocellulose. Plant cell walls are stabilized by fibrous nanocellulose, and this extractable material has very recently stimulated substantial research and technological development. It forms a highly porous, but very stable transparent network, and, with the help of a recent technique–oxidation with a radical scavenger called TEMPO–it forms a microporous hydrogel of highly oriented cellulose nanofibrils with a uniform width and length. As organic aerogels are produced from hydrogels by drying and pyrolysis, the authors attempted pyrolysis of supercritically or freeze-dried nanofibrillated cellulose hydrogel.

As it turns out, the method was not as straightforward as expected because ice crystal formation and insufficient dehydration hampered carbonization, according to the authors. Here, a trick helped. The scientists pyrolyzed the dried gel in the presence of the organic acid catalyst para-toluenesulfonic acid. The catalyst lowered the decomposition temperature and yielded a “mechanically stable and porous three-dimensional nanofibrous network” featuring a “large specific surface area and high electrical conductivity,” the authors reported.

The authors also demonstrated that their wood-derived carbon aerogel worked well as a binder-free electrode for supercapacitor applications. The material displayed electrochemical properties comparable to commercial electrodes. The method is an interesting and innovative way in which to fabricate sustainable materials suitable for use in high-performance electronic devices.

This is the first time I’ve seen work on wood-based nanocellulose from China. Cellulose according to its Wikipedia entry is: ” … the most abundant organic polymer on Earth.” For example, there’s more cellulose in cotton than there is wood. So, I find it interesting that in a country not known for its forests, nanocellulose (in this project anyway) is being derived from wood.

Here’s a link to and a citation for the paper,

Wood‐Derived Ultrathin Carbon Nanofiber Aerogels by Si‐Cheng Li, Bi‐Cheng Hu, Dr. Yan‐Wei Ding, Prof. Hai‐Wei Liang, Chao Li, Dr. Zi‐You Yu, Dr. Zhen‐Yu Wu, Prof. Wen‐Shuai Chen, Prof. Shu‐Hong Yu. Angewandt Chemie First published: 23 April 2018 DOI: https://doi.org/10.1002/anie.201802753

This paper is behind a paywall.

Canadian research into nanomaterial workplace exposure in the air and on surfaces

An August 30, 2018 news item on Nanowerk announces the report,

The monitoring of air contamination by engineered nanomaterials (ENM) is a complex process with many uncertainties and limitations owing to the presence of particles of nanometric size that are not ENMs, the lack of validated instruments for breathing zone measurements and the many indicators to be considered.

In addition, some organizations, France’s Institut national de recherche et de sécurité (INRS) and Québec’s Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) among them, stress the need to also sample surfaces for ENM deposits.

In other words, to get a better picture of the risks of worker exposure, we need to fine-tune the existing methods of sampling and characterizing ENMs and develop new one. Accordingly, the main goal of this project was to develop innovative methodological approaches for detailed qualitative as well as quantitative characterization of workplace exposure to ENMs.

A PDF of the 88-page report is available in English or in French.

An August 30, 2018 (?) abstract of the IRSST report titled An Assessment of Methods of Sampling and Characterizing Engineered Nanomaterials in the Air and on Surfaces in the Workplace (2nd edition) by Maximilien Debia, Gilles L’Espérance, Cyril Catto, Philippe Plamondon, André Dufresne, Claude Ostiguy, which originated the news item, outlines what you can expect from the report,

This research project has two complementary parts: a laboratory investigation and a fieldwork component. The laboratory investigation involved generating titanium dioxide (TiO2) nanoparticles under controlled laboratory conditions and studying different sampling and analysis devices. The fieldwork comprised a series of nine interventions adapted to different workplaces and designed to test a variety of sampling devices and analytical procedures and to measure ENM exposure levels among Québec workers.

The methods for characterizing aerosols and surface deposits that were investigated include: i) measurement by direct-reading instruments (DRI), such as condensation particle counters (CPC), optical particle counters (OPC), laser photometers, aerodynamic diameter spectrometers and electric mobility spectrometer; ii) transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM) with a variety of sampling devices, including the Mini Particle Sampler® (MPS); iii) measurement of elemental carbon (EC); iv) inductively coupled plasma mass spectrometry (ICP-MS) and (v) Raman spectroscopy.

The workplace investigations covered a variety of industries (e.g., electronics, manufacturing, printing, construction, energy, research and development) and included producers as well as users or integrators of ENMs. In the workplaces investigated, we found nanometals or metal oxides (TiO2, SiO2, zinc oxides, lithium iron phosphate, titanate, copper oxides), nanoclays, nanocellulose and carbonaceous materials, including carbon nanofibers (CNF) and carbon nanotubes (CNT)—single-walled (SWCNT) as well as multiwalled (MWCNT).

The project helped to advance our knowledge of workplace assessments of ENMs by documenting specific tasks and industrial processes (e.g., printing and varnishing) as well as certain as yet little investigated ENMs (nanocellulose, for example).

Based on our investigations, we propose a strategy for more accurate assessment of ENM exposure using methods that require a minimum of preanalytical handling. The recommended strategy is a systematic two-step assessment of workplaces that produce and use ENMs. The first step involves testing with different DRIs (such as a CPC and a laser photometer) as well as sample collection and subsequent microscopic analysis (MPS + TEM/STEM) to clearly identify the work tasks that generate ENMs. The second step, once work exposure is confirmed, is specific quantification of the ENMs detected. The following findings are particularly helpful for detailed characterization of ENM exposure:

  1. The first conclusive tests of a technique using ICP-MS to quantify the metal oxide content of samples collected in the workplace
  2. The possibility of combining different sampling methods recommended by the National Institute for Occupational Safety and Health (NIOSH) to measure elemental carbon as an indicator of NTC/NFC, as well as demonstration of the limitation of this method stemming from observed interference with the black carbon particles required to synthesis carbon materials (for example, Raman spectroscopy showed that less than 6% of the particles deposited on the electron microscopy grid at one site were SWCNTs)
  3. The clear advantages of using an MPS (instead of the standard 37-mm cassettes used as sampling media for electron microscopy), which allows quantification of materials
  4. The major impact of sampling time: a long sampling time overloads electron microscopy grids and can lead to overestimation of average particle agglomerate size and underestimation of particle concentrations
  5. The feasibility and utility of surface sampling, either with sampling pumps or passively by diffusion onto the electron microscopy grids, to assess ENM dispersion in the workplace

These original findings suggest promising avenues for assessing ENM exposure, while also showing their limitations. Improvements to our sampling and analysis methods give us a better understanding of ENM exposure and help in adapting and implementing control measures that can minimize occupational exposure.

You can download the full report in either or both English and French from the ‘Nanomaterials – A Guide to Good Practices Facilitating Risk Management in the Workplace, 2nd Edition‘ webpage.

Stronger than steel and spider silk: artificial, biodegradable, cellulose nanofibres

This is an artificial and biodegradable are two adjectives you don’t usually see united by the conjunction, and. However, it is worth noting that the artificial material is initially derived from a natural material, cellulose. Here’s more from a May 16, 2018 news item on ScienceDaily,

At DESY’s [Deutsches Elektronen-Synchrotron] X-ray light source PETRA III, a team led by Swedish researchers has produced the strongest bio-material that has ever been made. The artifical, but bio-degradable cellulose fibres are stronger than steel and even than dragline spider silk, which is usually considered the strongest bio-based material. The team headed by Daniel Söderberg from the KTH Royal Institute of Technology in Stockholm reports the work in the journal ACS Nano of the American Chemical Society.

A May 16, 2018 DESY press release (also on EurekAlert), which originated the news item, provides more detail,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

(There are some terminology and spelling issues, which are described at the end of this post.)

Let’s get back to a material that rivals spider silk and steel for strength (for some reason that reminded me of an old carnival game where you’d test your strength by swinging a mallet down on a ‘teeter-totter-like’ board and sending a metal piece up a post to make a bell ring). From a May 16, 2018 DESY press release (also on EurekAlert), which originated the news item,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

Here’s a link to and a citation for the paper,

Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers by Nitesh Mittal, Farhan Ansari, Krishne Gowda V, Christophe Brouzet, Pan Chen, Per Tomas Larsson, Stephan V. Roth, Fredrik Lundell, Lars Wågberg, Nicholas A. Kotov, and L. Daniel Söderberg. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b01084 Publication Date (Web): May 9, 2018

Copyright © 2018 American Chemical Society

This paper is open access and accompanied by this image illustrating the work,

Courtesy: American Chemical Society and the researchers [Note: The bottom two images of cellulose nanofibres, which are constittuents of an artificial cellulose fibre, appear to be from a scanning tunneling microsscope. Credit: Nitesh Mittal, KTH Stockholm

This news has excited interest at General Electric (GE) (its Wikipedia entry), which has highlighted the work in a May 25, 2018 posting (The 5 Coolest Things On Earth This Week) by Tomas Kellner on the GE Reports blog.

Terminology and spelling

I’ll start with spelling since that’s the easier of the two. In some parts of the world it’s spelled ‘fibres’ and in other parts of the world it’s spelled ‘fibers’. When I write the text in my post, it tends to reflect the spelling used in the news/press releases. In other words, I swing in whichever direction the wind is blowing.

For diehards only

As i understand the terminology situation, nanocellulose and cellulose nanomaterials are interchangeable generic terms. Further, cellulose nanofibres (CNF) seems to be another generic term and it encompasses both cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). Yes, there appear to be two CNFs. Making matters more interesting is the fact that cellulose nanocrystals were originally christened nanocrystalline cellulose (NCC). For anyone who follows the science and technology scene, it becomes obvious that competing terminologies are the order of the day. Eventually the dust settles and naming conventions are resolved. More or less.

Ordinarily I would reference the Nanocellulose Wikipedia entry in my attempts to clarify the issues but it seems that the writers for the entry have not caught up to the current naming convention for cellulose nanocrystals, still referring to the material as nanocrystalline cellulose. This means, I can’t trust the rest of the entry, which has only one CNF (cellulose nanofibres).

I have paid more attention to the NCC/CNC situation and am not as familiar with the CNF situation. Using, NCC/CNC as an example of a terminology issue, I believe it was first developed in Canada and it was Canadian researchers who were pushing their NCC terminology while the international community pushed back with CNC.

In the end, NCC became a brand name, which was trademarked by CelluForce, a Canadian company in the CNC market. From the CelluForce Products page on Cellulose Nanocrystals,

CNC are not all made equal. The CNC produced by CelluForce is called CelluForce NCCTM and has specific properties and are especially easy to disperse. CelluForce NCCTM is the base material that CelluForce uses in all its products. This base material can be modified and tailored to suit the specific needs in various applications.

These, days CNC is almost universally used but NCC (not as a trademark) is a term still employed on occasion (and, oddly, the researchers are not necessarily Canadian).

Should anyone have better information about terminology issues, please feel free to comment.