Tag Archives: lignin

Mushroom compost as a biobased nanocarrier for curing plant diseases

Scientists in Europe have just cured a plant disease Esca (fungi that destroy grapevines) for the first time ever. A May 22, 2019 news item on Nanowerk announces the research success,

Plant diseases, though a normal part of nature, can have disastrous effects in agriculture. They reduce food for people and revenues in rural areas. In the worst cases they result in hunger and starvation, as many famines in history show. About 16% of all crops are lost to plant diseases each year across the world.

The Max Planck Institute for Polymer Research in Mainz has just delivered a double novelty to the scientific world: nanocarriers made of “waste”, which release drugs in a way that cured a plant disease for the first time.

Nanocarriers are very tiny degradable capsules that have been studied for medical applications in the last 30 years. These nanocapsules are considered the “magic bullet” to cure human cancer, because they discharge the drug directly to the targeted cells.

A May 20, 2019 BIOrescue project press release, which originated the news item, delves further into the research,

Treating plant diseases that have never been cured before

Thanks to the European research funds of the BIOrescue project, the researchers at the Max Plank Institute investigated the possibility to transpose the same principle to cure plant diseases. They have been testing these nanocapsules to treat ESCA, a fungi disease that affects 2 billion grapevine plants across the world for which there has not been a cure so far.
Dr Frederik Wurm, who is leading this research at Max Planck said “After two years of testing in our labs and then on Riesling vineyards in Germany, it looks like we have managed to reduce the symptoms of the disease. Further tests will confirm if this cure is a solution in the long term. If the effects are confirmed the same method can be extended potentially to any other disease in agriculture”.

“Circular” nanocarriers made of waste

The second novelty of these nanoscopic capsules is that they can be made of waste material – in this case used mushrooms compost.

“Normally nanocarriers are made of polymers based on fossil fuels. In the past, we have developed biobased nanocarriers made of lignin coming from the paper and pulp industry. But this is the very first time we try to develop them from agricultural residues, which makes them a truly “circular” product, from used plant fertiliser to plant cure. Nothing is going to be wasted!” said Wurm.

To obtain these tiny biodegradable capsules, the Max Planck researchers carried out a chemical conversion to transform the soluble lignin obtained after the pretreatment of used mushroom compost.

Afterwards the nanocarriers have been loaded with the drug that is usually sprayed on the plant with very limited effects. Thanks to the natural enzymatic degradation of the nanocarriers, the drug is released inside the plant in a controlled and progressive way. With this effective method the drug only targets the fungi, which destroy the plant from inside. Tests demonstrated that these nanocarriers are not toxic for the plants and do not reach the crop.

“Beyond the agricultural sector, the capsules have a myriad of other potential applications from food enhancement to pharmaceutical products. It’s only a matter of time until we find biobased nanocarriers available on the market for any of these uses” said Wurm.

Bio-based nanocarrier Courtesy: BIOrescue

You can find out more about the BIOrescue project here, including interesting facts such as this,

To satisfy consumer demand for mushrooms, European farmers use over three million tonnes of compost each year. Though the compost contains valuable organic components, it is only suitable for one to three mushroom harvests, and disposing of it creates significant economic and logistical problems for Europe’s farmers.

Apparently, this is is a ‘circular economy’ project. ‘Circular economy’ being one of the latest buzz terms. Let’s hope it graduates to something ‘beyond buzz’, as it were.

Do you want that coffee with some graphene on toast?

These scientists are excited:

For those who prefer text, here’s the Rice University Feb. 13, 2018 news release (received via email and available online here and on EurekAlert here) Note: Links have been removed),

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

Rice alumnus Ruquan Ye is co-lead author of the study. Co-authors are Rice graduate student Yilun Li and postdoctoral fellow Swatantra Pratap Singh and Professor Christopher Arnusch of Ben-Gurion University of the Negev, Israel. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research supported the research.

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

Laser-Induced Graphene by Multiple Lasing: Toward Electronics on Cloth, Paper, and Food by Yieu Chyan, Ruquan Ye†, Yilun Li, Swatantra Pratap Singh, Christopher J. Arnusch, and James M. Tour. ACS Nano DOI: 10.1021/acsnano.7b08539 Publication Date (Web): February 13, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

h/t Feb. 13, 2018 news item on Nanowerk

Wood’s natural nanotechnology

“Wood’s natural nanotechnology: is an unusual term and it comes at the end of this February 7, 2018 University of Maryland (US) news release about a technique which will make wood stronger than titanium alloy,

Engineers at the University of Maryland in College Park have found a way to make wood more than ten times times stronger and tougher than before, creating a natural substance that is stronger than titanium alloy.

“This new way to treat wood makes it twelve times stronger than natural wood and ten times tougher,” said Liangbing Hu, the leader of the team that did the research, to be published on Thursday [February 7, 2018] in the journal Nature. “This could be a competitor to steel or even titanium alloys, it is so strong and durable. It’s also comparable to carbon fiber, but much less expensive.” Hu is an associate professor of materials science and engineering and a member of the Maryland Energy Innovation Institute.

“It is both strong and tough, which is a combination not usually found in nature,” said Teng Li, the co-leader of the team and the Samuel P. Langley associate professor of mechanical engineering at the University of Maryland. His team measured the dense wood’s mechanical properties.  “It is as strong as steel, but six times lighter. It takes 10 times more energy to fracture than natural wood. It can even be bent and molded at the beginning of the process.”

The team’s process begins by removing the wood’s lignin, the part of the wood that makes it both rigid and brown in color. Then it is compressed under mild heat, at about 150 F. This causes the cellulose fibers to become very tightly packed. Any defects like holes or knots are crushed together.  The treatment process was extended a little further with a coat of paint.

The scientists found that the wood’s fibers are pressed together so tightly that they can form strong hydrogen bonds, like a crowd of people who can’t budge – who are also holding hands. The compression makes the wood five times thinner than its original size.

The team also tested the material by shooting a bullet-like projectile at it. Unlike natural wood, which was blown straight through, the fully treated wood actually stopped the projectile partway through.

“Soft woods like pine or balsa, which grow fast and are more environmentally friendly, could replace slower-growing but denser woods like teak, in furniture or buildings,” Hu said.

“The paper provides a highly promising route to the design of light weight high performance structural materials, with tremendous potential for a broad range of applications where high strength, large toughness and superior ballistic resistance are desired, “ said Dr. Huajian Gao, a professor at Brown University, who was not involved in the study. “It is particularly exciting to note that the method is versatile for various species of wood and fairly easy to implement.”

“This kind of wood could be used in cars, airplanes, buildings – any application where steel is used,” Hu said.

“The two-step process reported in this paper achieves exceptionally high strength, much beyond what [is] reported in the literature,” said Dr. Zhigang Suo, a professor of mechanics and materials at Harvard University, also not involved with the study. “Given the abundance of wood, as well as other cellulose-rich plants, this paper inspires imagination.”

“The most outstanding observation, in my view, is the existence of a limiting concentration of lignin, the glue between wood cells, to maximize the mechanical performance of the densified wood. Too little or too much removal lower the strength compared to a maximum value achieved at intermediate or partial lignin removal. This reveals the subtle balance between hydrogen bonding and the adhesion imparted by such polyphenolic compound. Moreover, of outstanding interest, is the fact that that wood densification leads to both, increased strength and toughness, two properties that usually offset each other,” said Orlando J. Rojas, a professor at Aalto University in Finland.

Hu’s research has explored the capacities of wood’s natural nanotechnology [emphasis mine]. They previously made a range of emerging technologies out of nanocellulose related materials: (1) super clear paper for replacing plastic; (2) photonic paper for improving solar cell efficiency by 30%; (3) a battery and a supercapacitor out of wood; (4) a battery from a leaf; (5) transparent wood for energy efficient buildings; (6) solar water desalination for drinking and specifically filtering out toxic dyes. These wood-based emerging technologies are being commercialized through a UMD spinoff company, Inventwood LLC.

At a guess, “wood’s natural nanotechnology” refers to the properties of wood and other forms of cellulose at the nanoscale.

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

Processing bulk natural wood into a high-performance structural material by Jianwei Song, Chaoji Chen, Shuze Zhu, Mingwei Zhu, Jiaqi Dai, Upamanyu Ray, Yiju Li, Yudi Kuang, Yongfeng Li, Nelson Quispe, Yonggang Yao, Amy Gong, Ulrich H. Leiste, Hugh A. Bruck, J. Y. Zhu, Azhar Vellore, Heng Li, Marilyn L. Minus, Zheng Jia, Ashlie Martini, Teng Li, & Liangbing Hu. Nature volume 554, pages 224–228 (08 February 2018) doi:10.1038/nature25476 Published online: 07 February 2018

This paper is behind a paywall.

h/t Feb. 7, 2018 news item on Nanowerk and, finally, you can find out more about the wood-based emerging technologies being commcercialized by the University of Maryland here on the Inventwood website.

nano tech 2017 being held in Tokyo from February 15-17, 2017

I found some news about the Alberta technology scene in the programme for Japan’s nano tech 2017 exhibition and conference to be held Feb. 15 – 17, 2017 in Tokyo. First, here’s more about the show in Japan from a Jan. 17, 2017 nano tech 2017 press release on Business Wire (also on Yahoo News),

The nano tech executive committee (chairman: Tomoji Kawai, Specially Appointed Professor, Osaka University) will be holding “nano tech 2017” – one of the world’s largest nanotechnology exhibitions, now in its 16th year – on February 15, 2017, at the Tokyo Big Sight convention center in Japan. 600 organizations (including over 40 first-time exhibitors) from 23 countries and regions are set to exhibit at the event in 1,000 booths, demonstrating revolutionary and cutting edge core technologies spanning such industries as automotive, aerospace, environment/energy, next-generation sensors, cutting-edge medicine, and more. Including attendees at the concurrently held exhibitions, the total number of visitors to the event is expected to exceed 50,000.

The theme of this year’s nano tech exhibition is “Open Nano Collaboration.” By bringing together organizations working in a wide variety of fields, the business matching event aims to promote joint development through cross-field collaboration.

Special Symposium: “Nanotechnology Contributing to the Super Smart Society”

Each year nano tech holds Special Symposium, in which industry specialists from top organizations from Japan and abroad speak about the issues surrounding the latest trends in nanotech. The themes of this year’s Symposium are Life Nanotechnology, Graphene, AI/IoT, Cellulose Nanofibers, and Materials Informatics.

Notable sessions include:

Life Nanotechnology
“Development of microRNA liquid biopsy for early detection of cancer”
Takahiro Ochiya, National Cancer Center Research Institute Division of Molecular and Cellular Medicine, Chief

AI / IoT
“AI Embedded in the Real World”
Hideki Asoh, AIST Deputy Director, Artificial Intelligence Research Center

Cellulose Nanofibers [emphasis mine]
“The Current Trends and Challenges for Industrialization of Nanocellulose”
Satoshi Hirata, Nanocellulose Forum Secretary-General

Materials Informatics
“Perspective of Materials Research”
Hideo Hosono, Tokyo Institute of Technology Professor

View the full list of sessions:
>> http://nanotech2017.icsbizmatch.jp/Presentation/en/Info/List#main_theater

nano tech 2017 Homepage:
>> http://nanotechexpo.jp/

nano tech 2017, the 16th International Nanotechnology Exhibition & Conference
Date: February 15-17, 2017, 10:00-17:00
Venue: Tokyo Big Sight (East Halls 4-6 & Conference Tower)
Organizer: nano tech Executive Committee, JTB Communication Design

As you may have guessed the Alberta information can be found in the .Cellulose Nanofibers session. From the conference/seminar program page; scroll down about 25% of the way to find the Alberta presentation,

Production and Applications Development of Cellulose Nanocrystals (CNC) at InnoTech Alberta

Behzad (Benji) Ahvazi
InnoTech Alberta Team Lead, Cellulose Nanocrystals (CNC)

[ Abstract ]

The production and use of cellulose nanocrystals (CNC) is an emerging technology that has gained considerable interest from a range of industries that are working towards increased use of “green” biobased materials. The construction of one-of-a-kind CNC pilot plant [emphasis mine] at InnoTech Alberta and production of CNC samples represents a critical step for introducing the cellulosic based biomaterials to industrial markets and provides a platform for the development of novel high value and high volume applications. Major key components including feedstock, acid hydrolysis formulation, purification, and drying processes were optimized significantly to reduce the operation cost. Fully characterized CNC samples were provided to a large number of academic and research laboratories including various industries domestically and internationally for applications development.

[ Profile ]

Dr. Ahvazi completed his Bachelor of Science in Honours program at the Department of Chemistry and Biochemistry and graduated with distinction at Concordia University in Montréal, Québec. His Ph.D. program was completed in 1998 at McGill Pulp and Paper Research Centre in the area of macromolecules with solid background in Lignocellulosic, organic wood chemistry as well as pulping and paper technology. After completing his post-doctoral fellowship, he joined FPInnovations formally [formerly?] known as PAPRICAN as a research scientist (R&D) focusing on a number of confidential chemical pulping and bleaching projects. In 2006, he worked at Tembec as a senior research scientist and as a Leader in Alcohol and Lignin (R&D). In April 2009, he held a position as a Research Officer in both National Bioproducts (NBP1 & NBP2) and Industrial Biomaterials Flagship programs at National Research Council Canada (NRC). During his tenure, he had directed and performed innovative R&D activities within both programs on extraction, modification, and characterization of biomass as well as polymer synthesis and formulation for industrial applications. Currently, he is working at InnoTech Alberta as Team Lead for Biomass Conversion and Processing Technologies.

Canada scene update

InnoTech Alberta was until Nov. 1, 2016 known as Alberta Innovates – Technology Futures. Here’s more about InnoTech Alberta from the Alberta Innovates … home page,

Effective November 1, 2016, Alberta Innovates – Technology Futures is one of four corporations now consolidated into Alberta Innovates and a wholly owned subsidiary called InnoTech Alberta.

You will find all the existing programs, services and information offered by InnoTech Alberta on this website. To access the basic research funding and commercialization programs previously offered by Alberta Innovates – Technology Futures, explore here. For more information on Alberta Innovates, visit the new Alberta Innovates website.

As for InnoTech Alberta’s “one-of-a-kind CNC pilot plant,” I’d like to know more about it’s one-of-a-kind status since there are two other CNC production plants in Canada. (Is the status a consequence of regional chauvinism or a writer unfamiliar with the topic?). Getting back to the topic, the largest company (and I believe the first) with a CNC plant was CelluForce, which started as a joint venture between Domtar and FPInnovations and powered with some very heavy investment from the government of Canada. (See my July 16, 2010 posting about the construction of the plant in Quebec and my June 6, 2011 posting about the newly named CelluForce.) Interestingly, CelluForce will have a booth at nano tech 2017 (according to its Jan. 27, 2017 news release) although the company doesn’t seem to have any presentations on the schedule. The other Canadian company is Blue Goose Biorefineries in Saskatchewan. Here’s more about Blue Goose from the company website’s home page,

Blue Goose Biorefineries Inc. (Blue Goose) is pleased to introduce our R3TM process. R3TM technology incorporates green chemistry to fractionate renewable plant biomass into high value products.

Traditionally, separating lignocellulosic biomass required high temperatures, harsh chemicals, and complicated processes. R3TM breaks this costly compromise to yield high quality cellulose, lignin and hemicellulose products.

The robust and environmentally friendly R3TM technology has numerous applications. Our current product focus is cellulose nanocrystals (CNC). Cellulose nanocrystals are “Mother Nature’s Building Blocks” possessing unique properties. These unique properties encourage the design of innovative products from a safe, inherently renewable, sustainable, and carbon neutral resource.

Blue Goose assists companies and research groups in the development of applications for CNC, by offering CNC for sale without Intellectual Property restrictions. [emphasis mine]

Bravo to Blue Goose! Unfortunately, I was not able to determine if the company will be at nano tech 2017.

One final comment, there was some excitement about CNC a while back where I had more than one person contact me asking for information about how to buy CNC. I wasn’t able to be helpful because there was, apparently, an attempt by producers to control sales and limit CNC access to a select few for competitive advantage. Coincidentally or not, CelluForce developed a stockpile which has persisted for some years as I noted in my Aug. 17, 2016 posting (scroll down about 70% of the way) where the company announced amongst other events that it expected deplete its stockpile by mid-2017.

Transparent wood instead of glass for window panes?

The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

Not quite ready as a replacement for some types of glass window panes, nonetheless, transparent (more like translucent) wood is an impressive achievement. According to a March 30, 2016 news item on ScienceDaily size is what makes this piece of transparent wood newsworthy,

Windows and solar panels in the future could be made from one of the best — and cheapest — construction materials known: wood. Researchers at Stockholm’s KTH Royal Institute of Technology [Sweden] have developed a new transparent wood material that’s suitable for mass production.

Lars Berglund, a professor at Wallenberg Wood Science Center at KTH, says that while optically transparent wood has been developed for microscopic samples in the study of wood anatomy, the KTH project introduces a way to use the material on a large scale. …

A March 31 (?), 2016 KTH Institute of Technology press release, which originated the news item, provides more detail,

“Transparent wood is a good material for solar cells, since it’s a low-cost, readily available and renewable resource,” Berglund says. “This becomes particularly important in covering large surfaces with solar cells.”

Berglund says transparent wood panels can also be used for windows, and semitransparent facades, when the idea is to let light in but maintain privacy.

The optically transparent wood is a type of wood veneer in which the lignin, a component of the cell walls, is removed chemically.

“When the lignin is removed, the wood becomes beautifully white. But because wood isn’t not naturally transparent, we achieve that effect with some nanoscale tailoring,” he says.

The white porous veneer substrate is impregnated with a transparent polymer and the optical properties of the two are then matched, he says.

“No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings,” he says

Among the work to be done next is enhancing the transparency of the material and scaling up the manufacturing process, Berglund says.

“We also intend to work further with different types of wood,” he adds.

“Wood is by far the most used bio-based material in buildings. It’s attractive that the material comes from renewable sources. It also offers excellent mechanical properties, including strength, toughness, low density and low thermal conductivity.”

The American Chemical Society has a March 30, 2016 news release about the KTH achievement on EurekAlert  highlighting another potential use for transparent wood,

When it comes to indoor lighting, nothing beats the sun’s rays streaming in through windows. Soon, that natural light could be shining through walls, too. Scientists have developed transparent wood that could be used in building materials and could help home and building owners save money on their artificial lighting costs. …

Homeowners often search for ways to brighten up their living space. They opt for light-colored paints, mirrors and lots of lamps and ceiling lights. But if the walls themselves were transparent, this would reduce the need for artificial lighting — and the associated energy costs. Recent work on making transparent paper from wood has led to the potential for making similar but stronger materials. Lars Berglund and colleagues wanted to pursue this possibility.

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

Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance by Yuanyuan Li, Qiliang Fu, Shun Yu, Min Yan, and Lars Berglund. Biomacromolecules, Article ASAP DOI: 10.1021/acs.biomac.6b00145 Publication Date (Web): March 4, 2016

Copyright © 2016 American Chemical Society

This paper appears to be open access.

Greening silver nanoparticles with lignin

A July 13, 2015 news item on phys.org highlights a new approach to making silver nanoparticles safer in the environment,

North Carolina State University researchers have developed an effective and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin, a ubiquitous substance found in all plant cells. The findings introduce ideas for better, greener and safer nanotechnology and could lead to enhanced efficiency of antimicrobial products used in agriculture and personal care.

A July 13, 2015 North Carolina State University (NCSU) news release (also on EurekAlert), which originated the news item, adds a bit more information,

As the nanoparticles wipe out the targeted bacteria, they become depleted of silver. The remaining particles degrade easily after disposal because of their biocompatible lignin core, limiting the risk to the environment.

“People have been interested in using silver nanoparticles for antimicrobial purposes, but there are lingering concerns about their environmental impact due to the long-term effects of the used metal nanoparticles released in the environment,” said Velev, INVISTA Professor of Chemical and Biomolecular Engineering at NC State and the paper’s corresponding author. “We show here an inexpensive and environmentally responsible method to make effective antimicrobials with biomaterial cores.”

The researchers used the nanoparticles to attack E. coli, a bacterium that causes food poisoning; Pseudomonas aeruginosa, a common disease-causing bacterium; Ralstonia, a genus of bacteria containing numerous soil-borne pathogen species; and Staphylococcus epidermis, a bacterium that can cause harmful biofilms on plastics – like catheters – in the human body. The nanoparticles were effective against all the bacteria.

The method allows researchers the flexibility to change the nanoparticle recipe in order to target specific microbes. Alexander Richter, the paper’s first author and an NC State Ph.D. candidate who won a 2015 Lemelson-MIT prize, says that the particles could be the basis for reduced risk pesticide products with reduced cost and minimized environmental impact.

“We expect this method to have a broad impact,” Richter said. “We may include less of the antimicrobial ingredient without losing effectiveness while at the same time using an inexpensive technique that has a lower environmental burden. We are now working to scale up the process to synthesize the particles under continuous flow conditions.”

I don’t quite understand how the silver nanoparticles/ions are rendered greener. I gather the lignin is harmless but where do the silver nanoparticles/ions go after they’ve been stripped of their lignin cover and have killed the bacteria? I did try reading the paper’s abstract (not much use for someone with my science level),

Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to silver nanoparticles. The polyelectrolyte layer promotes the adhesion of the particles to bacterial cell membranes and, together with silver ions, can kill a broad spectrum of bacteria, including Escherichia coli, Pseudomonas aeruginosa and quaternary-amine-resistant Ralstonia sp. Ion depletion studies have shown that the bioactivity of these nanoparticles is time-limited because of the desorption of silver ions. High-throughput bioactivity screening did not reveal increased toxicity of the particles when compared to an equivalent mass of metallic silver nanoparticles or silver nitrate solution. Our results demonstrate that the application of green chemistry principles may allow the synthesis of nanoparticles with biodegradable cores that have higher antimicrobial activity and smaller environmental impact than metallic silver nanoparticles.

If you can explain what happens to the silver nanoparticles, please let me know.

Meanwhile, here’s a link to and a citation for the paper,

An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core by Alexander P. Richter, Joseph S. Brown, Bhuvnesh Bharti, Amy Wang, Sumit Gangwal, Keith Houck, Elaine A. Cohen Hubal, Vesselin N. Paunov, Simeon D. Stoyanov, & Orlin D. Velev. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.141 Published online 13 July 2015

This paper is behind a paywall.

Good lignin, bad lignin: Florida researchers use plant waste to create lignin nanotubes while researchers in British Columbia develop trees with less lignin

An April 4, 2014 news item on Azonano describes some nanotube research at the University of Florida that reaches past carbon to a new kind of nanotube,

Researchers with the University of Florida’s [UF] Institute of Food and Agricultural Sciences took what some would consider garbage and made a remarkable scientific tool, one that could someday help to correct genetic disorders or treat cancer without chemotherapy’s nasty side effects.

Wilfred Vermerris, an associate professor in UF’s department of microbiology and cell science, and Elena Ten, a postdoctoral research associate, created from plant waste a novel nanotube, one that is much more flexible than rigid carbon nanotubes currently used. The researchers say the lignin nanotubes – about 500 times smaller than a human eyelash – can deliver DNA directly into the nucleus of human cells in tissue culture, where this DNA could then correct genetic conditions. Experiments with DNA injection are currently being done with carbon nanotubes, as well.

“That was a surprising result,” Vermerris said. “If you can do this in actual human beings you could fix defective genes that cause disease symptoms and replace them with functional DNA delivered with these nanotubes.”

An April 3, 2014 University of Florida’s Institute of Food and Agricultural Sciences news release, which originated the news item, describes the lignin nanotubes (LNTs) and future applications in more detail,

The nanotube is made up of lignin from plant material obtained from a UF biofuel pilot facility in Perry, Fla. Lignin is an integral part of the secondary cell walls of plants and enables water movement from the roots to the leaves, but it is not used to make biofuels and would otherwise be burned to generate heat or electricity at the biofuel plant. The lignin nanotubes can be made from a variety of plant residues, including sorghum, poplar, loblolly pine and sugar cane. [emphasis mine]

The researchers first tested to see if the nanotubes were toxic to human cells and were surprised to find that they were less so than carbon nanotubes. Thus, they could deliver a higher dose of medicine to the human cell tissue.  Then they researched if the nanotubes could deliver plasmid DNA to the same cells and that was successful, too. A plasmid is a small DNA molecule that is physically separate from, and can replicate independently of, chromosomal DNA within a cell.

“It’s not a very smooth road because we had to try different experiments to confirm the results,” Ten said. “But it was very fruitful.”

In cases of genetic disorders, the nanotube would be loaded with a functioning copy of a gene, and injected into the body, where it would target the affected tissue, which then makes the missing protein and corrects the genetic disorder.

Although Vermerris cautioned that treatment in humans is many years away, among the conditions that these gene-carrying nanotubes could correct include cystic fibrosis and muscular dystrophy. But, he added, that patients would have to take the corrective DNA via nanotubes on a continuing basis.

Another application under consideration is to use the lignin nanotubes for the delivery of chemotherapy drugs in cancer patients. The nanotubes would ensure the drugs only get to the tumor without affecting healthy tissues.

Vermerris said they created different types of nanotubes, depending on the experiment. They could also adapt nanotubes to a patient’s specific needs, a process called customization.

“You can think about it as a chest of drawers and, depending on the application, you open one drawer or use materials from a different drawer to get things just right for your specific application,” he said.  “It’s not very difficult to do the customization.”

The next step in the research process is for Vermerris and Ten to begin experiments on mice. They are in the application process for those experiments, which would take several years to complete.  If those are successful, permits would need to be obtained for their medical school colleagues to conduct research on human patients, with Vermerris and Ten providing the nanotubes for that research.

“We are a long way from that point,” Vermerris said. “That’s the optimistic long-term trajectory.”

I hope they have good luck with this work. I have emphasized the plant waste the University of Florida scientists studied due to the inclusion of poplar, which is featured in the University of British Columbia research work also being mentioned in this post.

Getting back to Florida for a moment, here’s a link to and a citation for the paper,

Lignin Nanotubes As Vehicles for Gene Delivery into Human Cells by Elena Ten, Chen Ling, Yuan Wang, Arun Srivastava, Luisa Amelia Dempere, and Wilfred Vermerris. Biomacromolecules, 2014, 15 (1), pp 327–338 DOI: 10.1021/bm401555p Publication Date (Web): December 5, 2013
Copyright © 2013 American Chemical Society

This is an open access paper.

Meanwhile, researchers at the University of British Columbia (UBC) are trying to limit the amount of lignin in trees (specifically poplars, which are not mentioned in this excerpt but in the next). From an April 3, 2014 UBC news release,

Researchers have genetically engineered trees that will be easier to break down to produce paper and biofuel, a breakthrough that will mean using fewer chemicals, less energy and creating fewer environmental pollutants.

“One of the largest impediments for the pulp and paper industry as well as the emerging biofuel industry is a polymer found in wood known as lignin,” says Shawn Mansfield, a professor of Wood Science at the University of British Columbia.

Lignin makes up a substantial portion of the cell wall of most plants and is a processing impediment for pulp, paper and biofuel. Currently the lignin must be removed, a process that requires significant chemicals and energy and causes undesirable waste.

Researchers used genetic engineering to modify the lignin to make it easier to break down without adversely affecting the tree’s strength.

“We’re designing trees to be processed with less energy and fewer chemicals, and ultimately recovering more wood carbohydrate than is currently possible,” says Mansfield.

Researchers had previously tried to tackle this problem by reducing the quantity of lignin in trees by suppressing genes, which often resulted in trees that are stunted in growth or were susceptible to wind, snow, pests and pathogens.

“It is truly a unique achievement to design trees for deconstruction while maintaining their growth potential and strength.”

The study, a collaboration between researchers at the University of British Columbia, the University of Wisconsin-Madison, Michigan State University, is a collaboration funded by Great Lakes Bioenergy Research Center, was published today in Science.

Here’s more about lignin and how a decrease would free up more material for biofuels in a more environmentally sustainable fashion, from the news release,

The structure of lignin naturally contains ether bonds that are difficult to degrade. Researchers used genetic engineering to introduce ester bonds into the lignin backbone that are easier to break down chemically.

The new technique means that the lignin may be recovered more effectively and used in other applications, such as adhesives, insolation, carbon fibres and paint additives.

Genetic modification

The genetic modification strategy employed in this study could also be used on other plants like grasses to be used as a new kind of fuel to replace petroleum.

Genetic modification can be a contentious issue, but there are ways to ensure that the genes do not spread to the forest. These techniques include growing crops away from native stands so cross-pollination isn’t possible; introducing genes to make both the male and female trees or plants sterile; and harvesting trees before they reach reproductive maturity.

In the future, genetically modified trees could be planted like an agricultural crop, not in our native forests. Poplar is a potential energy crop for the biofuel industry because the tree grows quickly and on marginal farmland. [emphasis mine] Lignin makes up 20 to 25 per cent of the tree.

“We’re a petroleum reliant society,” says Mansfield. “We rely on the same resource for everything from smartphones to gasoline. We need to diversify and take the pressure off of fossil fuels. Trees and plants have enormous potential to contribute carbon to our society.”

As noted earlier, the researchers in Florida mention poplars in their paper (Note: Links have been removed),

Gymnosperms such as loblolly pine (Pinus taeda L.) contain lignin that is composed almost exclusively of G-residues, whereas lignin from angiosperm dicots, including poplar (Populus spp.) contains a mixture of G- and S-residues. [emphasis mine] Due to the radical-mediated addition of monolignols to the growing lignin polymer, lignin contains a variety of interunit bonds, including aryl–aryl, aryl–alkyl, and alkyl–alkyl bonds.(3) This feature, combined with the association between lignin and cell-wall polysaccharides, which involves both physical and chemical interactions, make the isolation of lignin from plant cell walls challenging. Various isolation methods exist, each relying on breaking certain types of chemical bonds within the lignin, and derivatizations to solubilize the resulting fragments.(5) Several of these methods are used on a large scale in pulp and paper mills and biorefineries, where lignin needs to be removed from woody biomass and crop residues(6) in order to use the cellulose for the production of paper, biofuels, and biobased polymers. The lignin is present in the waste stream and has limited intrinsic economic value.(7)

Since hydroxyl and carboxyl groups in lignin facilitate functionalization, its compatibility with natural and synthetic polymers for different commercial applications have been extensively studied.(8-12) One of the promising directions toward the cost reduction associated with biofuel production is the use of lignin for low-cost carbon fibers.(13) Other recent studies reported development and characterization of lignin nanocomposites for multiple value-added applications. For example, cellulose nanocrystals/lignin nanocomposites were developed for improved optical, antireflective properties(14, 15) and thermal stability of the nanocomposites.(16) [emphasis mine] Model ultrathin bicomponent films prepared from cellulose and lignin derivatives were used to monitor enzyme binding and cellulolytic reactions for sensing platform applications.(17) Enzymes/“synthetic lignin” (dehydrogenation polymer (DHP)) interactions were also investigated to understand how lignin impairs enzymatic hydrolysis during the biomass conversion processes.(18)

The synthesis of lignin nanotubes and nanowires was based on cross-linking a lignin base layer to an alumina membrane, followed by peroxidase-mediated addition of DHP and subsequent dissolution of the membrane in phosphoric acid.(1) Depending upon monomers used for the deposition of DHP, solid nanowires, or hollow nanotubes could be manufactured and easily functionalized due to the presence of many reactive groups. Due to their autofluorescence, lignin nanotubes permit label-free detection under UV radiation.(1) These features make lignin nanotubes suitable candidates for numerous biomedical applications, such as the delivery of therapeutic agents and DNA to specific cells.

The synthesis of LNTs in a sacrificial template membrane is not limited to a single source of lignin or a single lignin isolation procedure. Dimensions of the LNTs and their cytotoxicity to HeLa cells appear to be determined primarily by the lignin isolation procedure, whereas the transfection efficiency is also influenced by the source of the lignin (plant species and genotype). This means that LNTs can be tailored to the application for which they are intended. [emphasis mine] The ability to design LNTs for specific purposes will benefit from a more thorough understanding of the relationship between the structure and the MW of the lignin used to prepare the LNTs, the nanomechanical properties, and the surface characteristics.

We have shown that DNA is physically associated with the LNTs and that the LNTs enter the cytosol, and in some case the nucleus. The LNTs made from NaOH-extracted lignin are of special interest, as they were the shortest in length, substantially reduced HeLa cell viability at levels above approximately 50 mg/mL, and, in the case of pine and poplar, were the most effective in the transfection [penetrating the cell with a bacterial plasmid to leave genetic material in this case] experiments. [emphasis mine]

As I see the issues presented with these two research efforts, there are environmental and energy issues with extracting the lignin while there seem to be some very promising medical applications possible with lignin ‘waste’. These two research efforts aren’t necessarily antithetical but they do raise some very interesting issues as to how we approach our use of resources and future policies.

ETA May 16, 2014: The beat goes on with the Georgia (US) Institute of Technology issues a roadmap for making money from lignin. From a Georgia Tech May 15, 2014 news release on EurekAlert,

When making cellulosic ethanol from plants, one problem is what to do with a woody agricultural waste product called lignin. The old adage in the pulp industry has been that one can make anything from lignin except money.

A new review article in the journal Science points the way toward a future where lignin is transformed from a waste product into valuable materials such as low-cost carbon fiber for cars or bio-based plastics. Using lignin in this way would create new markets for the forest products industry and make ethanol-to-fuel conversion more cost-effective.

“We’ve developed a roadmap for integrating genetic engineering with analytical chemistry tools to tailor the structure of lignin and its isolation so it can be used for materials, chemicals and fuels,” said Arthur Ragauskas, a professor in the School of Chemistry and Biochemistry at the Georgia Institute of Technology. Ragauskas is also part of the Institute for Paper Science and Technology at Georgia Tech.

The roadmap was published May 15 [2014] in the journal Science. …

Here’s a link to and citation for the ‘roadmap’,

Lignin Valorization: Improving Lignin Processing in the Biorefinery by  Arthur J. Ragauskas, Gregg T. Beckham, Mary J. Biddy, Richard Chandra, Fang Chen, Mark F. Davis, Brian H. Davison, Richard A. Dixon, Paul Gilna, Martin Keller, Paul Langan, Amit K. Naskar, Jack N. Saddler, Timothy J. Tschaplinski, Gerald A. Tuskan, and Charles E. Wyman. Science 16 May 2014: Vol. 344 no. 6185 DOI: 10.1126/science.1246843

This paper is behind a paywall.

Wooden batteries in Maryland (US)

There seems to be a gusher of interest in making wooden batteries. Last year, there was news from a joint Polish-Swedish research team (my Aug. 14, 2012 posting) who’d combined lignin with a conductive polymer (polypyrrole) to create a battery cathode. Today, June 19, 2013, Nanowerk featured a news item about a team at the University of Maryland (US) who are also using wood to make battery components (Note: A link has been removed),

A sliver of wood coated with tin could make a tiny, long-lasting, efficient and environmentally friendly battery (“Tin Anode for Sodium-Ion Batteries Using Natural Wood Fiber as a Mechanical Buffer and Electrolyte Reservoir”).

But don’t try it at home yet– the components in the battery tested by scientists at the University of Maryland are a thousand times thinner than a piece of paper. Using sodium instead of lithium, as many rechargeable batteries do, makes the battery environmentally benign. Sodium doesn’t store energy as efficiently as lithium, so you won’t see this battery in your cell phone — instead, its low cost and common materials would make it ideal to store huge amounts of energy at once – such as solar energy at a power plant.

The June 19, 2013 University of Maryland news release, which originated the news item, explains why this work with wood is so exciting (Note: Links have been removed),

Existing batteries are often created on stiff bases, which are too brittle to withstand the swelling and shrinking that happens as electrons are stored in and used up from the battery. Liangbing Hu, Teng Li and their team found that wood fibers are supple enough to let their sodium-ion battery last more than 400 charging cycles, which puts it among the longest lasting nanobatteries.

“The inspiration behind the idea comes from the trees,” said Hu, an assistant professor of materials science. “Wood fibers that make up a tree once held mineral-rich water, and so are ideal for storing liquid electrolytes, making them not only the base but an active part of the battery.”

Lead author Hongli Zhu and other team members noticed that after charging and discharging the battery hundreds of times, the wood ended up wrinkled but intact. Computer models showed that that the wrinkles effectively relax the stress in the battery during charging and recharging, so that the battery can survive many cycles.

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

Tin Anode for Sodium-Ion Batteries Using Natural Wood Fiber as a Mechanical Buffer and Electrolyte Reservoir by Hongli Zhu, Zheng Jia, Yuchen Chen, Nicholas Weadock, Jiayu Wan, Oeyvind Vaaland, Xiaogang Han, Teng Li, and Liangbing Hu. Nano Lett., Article ASAP DOI: 10.1021/nl400998t Publication Date (Web): May 29, 2013

Copyright © 2013 American Chemical Society

This paper is behind a paywall.

Blue Goose Biorefineries scales up production of cellulose nanocrystals (CNC) and more

I last mentioned Saskatchewan’s (Canada) Blue Goose Biorefineries in a Jan. 22, 2013 posting about its activities with regard to cellulose nanocrystals. I’m a little late to the party but there’s an Apr. 11, 2013 news release on the Advanced Foods and Materials website which notes that Blue Goose Biorefineries’ production of cellulose nanocrystals (CNC also sometimes known as nanocrystalline cellulose, NCC) has been scaled up,

Advanced Foods and Materials (AFM) Canada and Blue Goose Biorefineries Inc. (BGB), are pleased to announce the successful scale up of biorefining technology for the production of high value microcrystalline cellulose (MCC), cellulose nanocrystals (CNC), lignin, and green platform chemicals from flax and hemp straw.

In collaboration with the University of Saskatchewan’s College of Agriculture and Bioresources Bioprocessing Pilot Plant, and POS Bio-Sciences, BGB’s proprietary Renewable Residuals RefiningTM (R3TM) biorefining technology was successfully scaled up to process 100 kg of pulp in a reaction volume of 2500L to produce microcrystalline cellulose and cellulose nanocrystals of high purity, along with lignin and green platform chemicals as by-products. Throughout this process, the technology has shown promising advantages over existing biorefining methods including cost, yield, environmental impact, and flexibility. Necessary process steps demonstrated include biomass preparation, dewatering and washing, reaction mixing and crystalline cellulose washing. The project also successfully demonstrated the spray drying of the cellulose crystals at POS Bio-Sciences.

It’s exciting to hear that there might be more production of CNC in Canada, as well as, microcrystalline cellulose, lignin, and other by-products,. It seems where CNC is concerned that demand exceeds supply (I get the occasional query from someone trying to find a supplier).

I have more information about Advanced Foods and Materials Canada in my Jan. 22, 2013 posting. As well, here are links to the POS Bio-Sciences website and more information about the University of Saskatchewan’s Bioprocessing Pilot Plant.

ETA May 7, 2013 4:30 pm PDT: Dr. Bernard Laarveld of Blue Goose Biorefineries (BGB) very kindly noted this in an email to me today,

… we are now planning to develop a pilot plant for the production of NCC (aka CNC) and MCC and are raising the funding. This development through BGB is more driven from the private sector in partnership with Advanced Food Materials Canada.  We intend to process about 500 kg  of flax or hemp straw per day, and this would generate about 250 kg per day of crystalline cellulose. BGB has an advantage through low cost of production.

Very exciting news and I wish the Dr. Laarveld and the folks at BGB all the best.

Batteries made of wood and the mechanical properties of plants

According to Ariel Schwartz in an Aug. 14, 2012 (?) article for Fast Company’s Co.Exist website, batteries made from wood waste may be in our future (Note: I have removed a link),

Researchers from Poznan University of Technology in Poland and Linköping University in Sweden have figured out how to combine lignin with polypyrrole (a conductive polymer) to create a battery cathode that could one day be used in energy storage. The lignin acts as an insulator, while the polypyrrole holds an electric charge.

The discovery is a potential boon for the renewable energy world. As the researchers explain in the journal Science, “Widespread application of electrical power storage may require more abundant materials than those available in inorganics (which often require rare metals), and at a lower cost. Materials for charge storage are desired from easily accessible and renewable sources. Combining cellulose materials and conjugated polymers for charge storage has … attracted attention.”

For anyone (like me) who’s heard the word lignin but doesn’t know the precise meaning, here’s a definition from a Wikipedia essay (Note: I have removed links and footnotes),

Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose, employing 30% of non-fossil organic carbon, and constituting from a quarter to a third of the dry mass of wood.

This next item also mentions lignin but in reference to mechanical properties that engineers are observing in plant cells.  From the Aug. 14, 2012 news item on Nanowerk,

From an engineer’s perspective, plants such as palm trees, bamboo, maples and even potatoes are examples of precise engineering on a microscopic scale. Like wooden beams reinforcing a house, cell walls make up the structural supports of all plants. Depending on how the cell walls are arranged, and what they are made of, a plant can be as flimsy as a reed, or as sturdy as an oak.

An MIT researcher has compiled data on the microstructures of a number of different plants, from apples and potatoes to willow and spruce trees, and has found that plants exhibit an enormous range of mechanical properties, depending on the arrangement of a cell wall’s four main building blocks: cellulose, hemicellulose, lignin and pectin.

The news item was originated at the Massachusetts Institute of Technology (MIT) by Jennifer Chu’s Aug. 14, 2012 news release,

Lorna Gibson, the [researcher] at MIT, says understanding plants’ microscopic organization may help engineers design new, bio-inspired materials.

“If you look at engineering materials, we have lots of different types, thousands of materials that have more or less the same range of properties as plants,” Gibson says. “But here the plants are, doing it arranging just four basic constituents. So maybe there’s something you can learn about the design of engineered materials.”

A paper detailing Gibson’s findings has been published this month [freely accessible] in the Journal of the Royal Society Interface.

To Gibson, a cell wall’s components bear a close resemblance to certain manmade materials. For example, cellulose, hemicellulose and lignin can be as stiff and strong as manufactured polymers. A plant’s cellular arrangement can also have engineering parallels: cells in woods, for instance, are aligned, similar to engineering honeycombs, while polyhedral cell configurations, such as those found in apples, resemble some industrial foams.

To explore plants’ natural mechanics, Gibson focused on three main plant materials: woods, such as cedar and oak; parenchyma cells, which are found in fruits and root vegetables; and arborescent palm stems, such as coconut trees. She compiled data from her own and other groups’ experiments and analyzed two main mechanical properties in each plant: stiffness and strength.

Among all plants, Gibson observed wide variety in both properties. Fruits and vegetables such as apples and potatoes were the least stiff, while the densest palms were 100,000 times stiffer. Likewise, apples and potatoes fell on the lower end of the strength scale, while palms were 1,000 times stronger.

“There are plants with properties over that whole range,” Gibson says. “So it’s not like potatoes are down here, and wood is over there, and there’s nothing in between. There are plants with properties spanning that whole huge range. And it’s interesting how the plants do that.”

Since I’m always interested in trees, from Chu’s news release,

In trees such as maples and oaks, cells grow and multiply in the cambium layer, just below the bark, increasing the diameter of the trees. The cell walls in wood are composed of a primary layer with cellulose fibers randomly spread throughout it. Three secondary layers lie underneath, each with varying compositions of lignin and cellulose that wind helically through each layer.

Taken together, the cell walls occupy a large portion of a cell, providing structural support. The cells in woods are organized in a honeycomb pattern — a geometric arrangement that gives wood its stiffness and strength.

Parenchyma cells, found in fruits and root vegetables, are much less stiff and strong than wood. The cell walls of apples, potatoes and carrots are much thinner than in wood cells, and made up of only one layer. Cellulose fibers run randomly throughout this layer, reinforcing a matrix of hemicellulose and pectin. Parenchyma cells have no lignin; combined with their thin walls and the random arrangement of their cellulose fibers, Gibson says, this may explain their cell walls’ low stiffness. The cells in each plant are densely packed together, similar to industrial foams used in mattresses and packaging.

Unlike woody trees that grow in diameter over time, the stems of arborescent palms such as coconut trees maintain similar diameters throughout their lifetimes. Instead, as the stem grows taller, palms support this extra weight by increasing the thickness of their cell walls. A cell wall’s thickness depends on where it is along a given palm stem: Cell walls are thicker at the base and periphery of stems, where bending stresses are greatest.

There’s even a nanotechnology slant to this story, from Chu’s news release,

Gibson sees plant mechanics as a valuable resource for engineers designing new materials. For instance, she says, researchers have developed a wide array of materials, from soft elastomers to stiff, strong alloys. Carbon nanotubes have been used to reinforce composite materials, and engineers have made honeycomb-patterned materials with cells as small as a few millimeters wide. But researchers have been unable to fabricate cellular composite materials with the level of control that plants have perfected.

“Plants are multifunctional,” Gibson says. “They have to satisfy a number of requirements: mechanical ones, but also growth, surface area for sunlight and transport of fluids. The microstructures plants have developed satisfy all these requirements. With the development of nanotechnology, I think there is potential to develop multifunctional engineering materials inspired by plant microstructures.”

Given the problems with the forestry sector, these developments (wooden batteries and engineering materials inspired by plant cell walls) should excite some interest.