Tag Archives: trees

Tree-on-a-chip

It’s usually organ-on-a-chip or lab-on-a-chip or human-on-a-chip; this is my first tree-on-a-chip.

Engineers have designed a microfluidic device they call a “tree-on-a-chip,” which mimics the pumping mechanism of trees and other plants. Courtesy: MIT

From a March 20, 2017 news item on phys.org,

Trees and other plants, from towering redwoods to diminutive daisies, are nature’s hydraulic pumps. They are constantly pulling water up from their roots to the topmost leaves, and pumping sugars produced by their leaves back down to the roots. This constant stream of nutrients is shuttled through a system of tissues called xylem and phloem, which are packed together in woody, parallel conduits.

Now engineers at MIT [Massachusetts Institute of Technology] and their collaborators have designed a microfluidic device they call a “tree-on-a-chip,” which mimics the pumping mechanism of trees and plants. Like its natural counterparts, the chip operates passively, requiring no moving parts or external pumps. It is able to pump water and sugars through the chip at a steady flow rate for several days. The results are published this week in Nature Plants.

A March 20, 2017 MIT news release by Jennifer Chu, which originated the news item, describes the work in more detail,

Anette “Peko” Hosoi, professor and associate department head for operations in MIT’s Department of Mechanical Engineering, says the chip’s passive pumping may be leveraged as a simple hydraulic actuator for small robots. Engineers have found it difficult and expensive to make tiny, movable parts and pumps to power complex movements in small robots. The team’s new pumping mechanism may enable robots whose motions are propelled by inexpensive, sugar-powered pumps.

“The goal of this work is cheap complexity, like one sees in nature,” Hosoi says. “It’s easy to add another leaf or xylem channel in a tree. In small robotics, everything is hard, from manufacturing, to integration, to actuation. If we could make the building blocks that enable cheap complexity, that would be super exciting. I think these [microfluidic pumps] are a step in that direction.”

Hosoi’s co-authors on the paper are lead author Jean Comtet, a former graduate student in MIT’s Department of Mechanical Engineering; Kaare Jensen of the Technical University of Denmark; and Robert Turgeon and Abraham Stroock, both of Cornell University.

A hydraulic lift

The group’s tree-inspired work grew out of a project on hydraulic robots powered by pumping fluids. Hosoi was interested in designing hydraulic robots at the small scale, that could perform actions similar to much bigger robots like Boston Dynamic’s Big Dog, a four-legged, Saint Bernard-sized robot that runs and jumps over rough terrain, powered by hydraulic actuators.

“For small systems, it’s often expensive to manufacture tiny moving pieces,” Hosoi says. “So we thought, ‘What if we could make a small-scale hydraulic system that could generate large pressures, with no moving parts?’ And then we asked, ‘Does anything do this in nature?’ It turns out that trees do.”

The general understanding among biologists has been that water, propelled by surface tension, travels up a tree’s channels of xylem, then diffuses through a semipermeable membrane and down into channels of phloem that contain sugar and other nutrients.

The more sugar there is in the phloem, the more water flows from xylem to phloem to balance out the sugar-to-water gradient, in a passive process known as osmosis. The resulting water flow flushes nutrients down to the roots. Trees and plants are thought to maintain this pumping process as more water is drawn up from their roots.

“This simple model of xylem and phloem has been well-known for decades,” Hosoi says. “From a qualitative point of view, this makes sense. But when you actually run the numbers, you realize this simple model does not allow for steady flow.”

In fact, engineers have previously attempted to design tree-inspired microfluidic pumps, fabricating parts that mimic xylem and phloem. But they found that these designs quickly stopped pumping within minutes.

It was Hosoi’s student Comtet who identified a third essential part to a tree’s pumping system: its leaves, which produce sugars through photosynthesis. Comtet’s model includes this additional source of sugars that diffuse from the leaves into a plant’s phloem, increasing the sugar-to-water gradient, which in turn maintains a constant osmotic pressure, circulating water and nutrients continuously throughout a tree.

Running on sugar

With Comtet’s hypothesis in mind, Hosoi and her team designed their tree-on-a-chip, a microfluidic pump that mimics a tree’s xylem, phloem, and most importantly, its sugar-producing leaves.

To make the chip, the researchers sandwiched together two plastic slides, through which they drilled small channels to represent xylem and phloem. They filled the xylem channel with water, and the phloem channel with water and sugar, then separated the two slides with a semipermeable material to mimic the membrane between xylem and phloem. They placed another membrane over the slide containing the phloem channel, and set a sugar cube on top to represent the additional source of sugar diffusing from a tree’s leaves into the phloem. They hooked the chip up to a tube, which fed water from a tank into the chip.

With this simple setup, the chip was able to passively pump water from the tank through the chip and out into a beaker, at a constant flow rate for several days, as opposed to previous designs that only pumped for several minutes.

“As soon as we put this sugar source in, we had it running for days at a steady state,” Hosoi says. “That’s exactly what we need. We want a device we can actually put in a robot.”

Hosoi envisions that the tree-on-a-chip pump may be built into a small robot to produce hydraulically powered motions, without requiring active pumps or parts.

“If you design your robot in a smart way, you could absolutely stick a sugar cube on it and let it go,” Hosoi says.

This research was supported, in part, by the Defense Advance Research Projects Agency [DARPA].

This research’s funding connection to DARPA reminded me that MIT has an Institute of Soldier Nanotechnologies.

Getting back to the tree-on-a-chip, here’s a link to and a citation for the paper,

Passive phloem loading and long-distance transport in a synthetic tree-on-a-chip by Jean Comtet, Kaare H. Jensen, Robert Turgeon, Abraham D. Stroock & A. E. Hosoi. Nature Plants 3, Article number: 17032 (2017)  doi:10.1038/nplants.2017.32 Published online: 20 March 2017

This paper is behind a paywall.

Cellulosic nanomaterials in automobile parts and a CelluForce update

The race to find applications for cellulosic nanomaterials continues apace. The latest entrant is from Clemson University in South Carolina (US). From a July 27, 2016 news item on Nanowerk,

Trees that are removed during forest restoration projects could find their way into car bumpers and fenders as part of a study led by Srikanth Pilla of Clemson University.

Pilla is collaborating on the study with researchers from the USDA Forest Service’s Forest Products Laboratory in Madison, Wisconsin.

The Madison researchers are converting some of those trees into liquid suspensions of tiny rod-like structures with diameters 20,000 times smaller than the width of a human hair. Pilla is using these tiny structures, known as cellulosic nanomaterials, to develop new composite materials that could be shaped into automotive parts with improved strength.

The auto parts would also be biorenewable, which means they could go to a composting facility instead of a landfill when their time on the road is done. The research could help automakers meet automotive recycling regulations that have been adopted in Europe and could be on the way to the United States.

Pilla, an assistant professor in the Department of Automotive Engineering at Clemson University, wants to use the composite materials he is creating to make bumpers and fenders that will be less likely to distort or break on impact.

“They will absorb the energy and just stay intact,” he said. “You won’t have to replace them because there will be no damage at all. Parts made with current materials might resist one impact. These will resist three or four impacts.”

A July 27, 2016 Clemson University media release, which originated the news item, describes the project and the reason for the support provides an interesting view of the politics behind the science (Note: A link has been removed),

The U.S. Department of the Agriculture’s National Institute of Food and Agriculture is funding the $481,000 research project for five years. Pilla’s research will be based out of the Clemson University International Center for Automotive Research in Greenville, South Carolina.

Craig Clemons, a materials research engineer at the Forest Products Laboratory and co-principal investigator on the project, said that the Forest Service wants to find large-volume uses for cellulosic nanomaterials.

“We find appropriate outlets for all kinds of forest-derived materials,” he said. “In this case, it’s cellulosic nanomaterials. We’re trying to move up the value chain with the cellulosic nanomaterials, creating high-value products out of what could otherwise be low-value wood. We’ll be producing the cellulosic nanomaterials, which are the most fundamental structural elements that you can get out of wood and pulp fibers. We’ll also be lending our more than 25 years of experience in creating composites from plastics and wood-derived materials to the project.”

The research is environmentally friendly from start to finish.

The cellulosic nanomaterials could come from trees that are removed during forest restoration projects. Removing this material from the forests helps prevent large, catastrophic wildfires. Researchers will have no need to cut down healthy trees that could be used for other purposes, Pilla said.

Ted Wegner, assistant director at the Forest Products Laboratory, said, “The use of cellulosic nanomaterials will help meet the needs of people for sustainable, renewable and lightweight products while helping to improve the health and condition of America’s forests. The United States possesses abundant forest resources and the infrastructure to support a large cellulosic nanomaterials industry. Commercialization of cellulosic nanomaterials has the potential to create jobs, especially in rural America.”

One of the technical challenges Pilla and Clemons face in their work is combining the water-friendly cellulosic nanomaterials with the water-unfriendly polymers. They will need to show that the material can be mass produced because automakers need to make thousands of parts.

“We will use supercritical fluid as a plasticizer, allowing the nanoreinforcements to disperse through the polymer,” Pilla said. “We can help develop a conventional technique that will be scalable in the automotive sector.”

Robert Jones, executive vice president for academic affairs and provost at Clemson, congratulated Pilla on the research, which touches on Jones’ area of expertise.

Jones has a bachelor’s in forest management, a master’s in forestry from Clemson and a doctorate in forest ecology from the State University of New York College of Environmental Science and Forestry, Syracuse University.

“The research that Srikanth Pilla is doing with the USDA Forest Service is a creative way of using what might otherwise be a low-value wood product to strengthen automobile parts,” Jones said. “It’s even better that these parts are biorenewable. The research is good for the Earth in more ways than one.”

This research could grow in importance if the United States were to follow the European Union’s lead in setting requirements on how much of a vehicle must be recovered and recycled after it has seen its last mile on the road.

“In the U.S., such legislation is not yet here,” Pilla said. “But it could make its way here, too.”

Pilla is quickly establishing himself as a leading expert in making next-generation automotive parts. He won the 2016 Robert J. Hocken Outstanding Young Manufacturing Engineer Award from the nonprofit student and professional organization SME.

Pilla is nearing the end of the first year of a separate $5.81-million, five-year grant from the Department of Energy. As part of that research, Pilla and his team are developing ultra-lightweight doors expected to help automakers in their race to meet federal fuel economy standards.

Zoran Filipi, chair of Clemson’s automotive engineering, said that Pilla is playing a key role in making Clemson the premiere place for automotive research.

“Dr. Pilla is doing research that helps Clemson and the auto industry stay a step ahead,” Filipi said. “He is anticipating needs automakers will face in the future and seeking solutions that could be put into place very quickly. His research with the USDA Forest Service is another example of that.”

Congratulations also came from Anand Gramopadhye, dean of Clemson’s College of Engineering, Computing and Applied Sciences.

“Dr. Pilla’s work continues to have an impact on automotive engineering, especially in the area of manufacturing,” Gramopadhye said. “His innovations are positioning Clemson, the state, and the nation for strength into the future.”

This search for applications is a worldwide competition. Cellulose is one of the most abundant materials on earth and can be derived from carrots, bananas, pineapples, and more. It just so happens that much of the research in the northern hemisphere focuses on cellulose derived from trees in an attempt to prop up or reinvigorate the failing forest products industry.

In Canada we have three production facilities for cellulosic nanomaterials. There’s a plant in Alberta (I’ve never seen a name for it), CelluForce in Windsor, Québec, and Blue Goose Biorefineries in Saskatchewan. I believe Blue Goose derives their cellulosic from trees and other plant materials while the Alberta and CelluForce plants use trees only.

CelluForce Update

CelluForce represents a big investment by the Canadian federal government. The other companies and production facilities have received federal funds but my understanding is that CelluForce has enjoyed significantly more. As well, the company has had a stockpile of cellulose nanocrystals (CNC) that I first mentioned here in an Oct. 3, 2013 post (scroll down about 75% of the way). A June 8, 2016 CelluForce news release provides more information about CelluForce activities and its stockpile,

  •  In the first half of 2016, Cellulose nanocrystals (CNC) shipments to industrial partners have reached their highest level since company inception.
  • Recent application developments in the oil & gas, the electronics and plastics sectors are expected to lead to commercial sales towards year end.
  • New website to enhance understanding of CelluForce NCCTM core properties and scope of performance in industrial applications is launched.

Montreal, Québec – June 8th 2016 – CelluForce, a clean technology company, is seeing growing interest in its innovative green chemistry product called cellulose nanocrystals (CNC) and has recorded, over the first half of 2016, the largest CNC shipment volumes since the company’s inception.

“Over the past year, we have been actively developing several industry-specific applications featuring CelluForce NCCTM, a form of cellulose nanocrystals which is produced in our Windsor plant.   Three of these applications have now reached a high level of technical and commercial maturity and have been proven to provide cost benefits and sustained performance in the oil & gas, electronics and plastics segments,” said Sebastien Corbeil [emphasis mine], President and CEO of CelluForce. “Our product development teams are extremely pleased to see CelluForce NCCTM [nanocrystalline cellulose; this is a trade name for CNC] now being used in full scale trials for final customer acceptance tests”.

With the current shipment volumes forecast, the company expects to deplete its CelluForce NCCTM inventory by mid-2017 [emphasis mine]. The inventory depletion will pave the way for the company to start commercial production of CNC at its Windsor plant next year.

CelluForce has built a strong network of researchers with academic and industrial partners and continues to invest time and resources to develop, refine and expand applications for CNC in key priority industrial markets. Beyond oil & gas, electronics and plastics, some of these markets are adhesives, cement, paints and coatings, as well as personal and healthcare.

Furthermore, as it progressively prepares for commercial production, CelluForce has revamped its digital platform and presence, with the underlying objective of developing a better understanding of its product, applications and its innovative green technology capabilities.  Its new brand image is meant to convey the innovative, versatile and sustainable properties of CNC.

Nice to see that there is sufficient demand that the stockpile can be eliminated soon. In my last piece about CelluForce (a March 30, 2015 post), I noted an interim president, René Goguen. An April 27, 2015 CelluForce news release announced Sebastien Corbeil’s then new appointment as company president.

One final note, nanocrystalline cellulose (NCC) was the generic name coined by Canadian scientists for a specific cellulose nanomaterial. Over time, cellulose nanocrystals (CNC) became the preferred term for the generic material and CelluForce decided to trademark NCC (nanocrystalline cellulose) as their commercial brand name for cellulose nanocrystals.

Cellulose nanocrystals and supercapacitors at McMaster University (Canada)

Photos: Xuan Yang and Kevin Yager.

Photos: Xuan Yang and Kevin Yager. Courtesy McMaster University

I love that featherlike structure holding up a tiny block of something while balanced on what appears to be a series of medallions. What it has to do with supercapacitors (energy storage) and cellulose nanocrystals is a mystery but that’s one of the images you’ll find illustrating an Oct. 7, 2015 news item on Nanotechnology Now featuring research at McMaster University,

McMaster Engineering researchers Emily Cranston and Igor Zhitomirsky are turning trees into energy storage devices capable of powering everything from a smart watch to a hybrid car.

The scientists are using cellulose, an organic compound found in plants, bacteria, algae and trees, to build more efficient and longer-lasting energy storage devices or supercapacitors. This development paves the way toward the production of lightweight, flexible, and high-power electronics, such as wearable devices, portable power supplies and hybrid and electric vehicles.

A Sept. 10, 2015 McMaster University news release, which originated the news item, describes the research in more detail,

Cellulose offers the advantages of high strength and flexibility for many advanced applications; of particular interest are nanocellulose-based materials. The work by Cranston, an assistant chemical engineering professor, and Zhitomirsky, a materials science and engineering professor, demonstrates an improved three-dimensional energy storage device constructed by trapping functional nanoparticles within the walls of a nanocellulose foam.

The foam is made in a simplified and fast one-step process. The type of nanocellulose used is called cellulose nanocrystals and looks like uncooked long-grain rice but with nanometer-dimensions. In these new devices, the ‘rice grains’ have been glued together at random points forming a mesh-like structure with lots of open space, hence the extremely lightweight nature of the material. This can be used to produce more sustainable capacitor devices with higher power density and faster charging abilities compared to rechargeable batteries.

Lightweight and high-power density capacitors are of particular interest for the development of hybrid and electric vehicles. The fast-charging devices allow for significant energy saving, because they can accumulate energy during braking and release it during acceleration.

For anyone interested in a more detailed description of supercapacitors, there’s my favourite one which involves Captain America’s shield along with some serious science in my April 28, 2014 posting.

Getting back to the research at McMaster, here’s a link to and a citation for the paper,

Cellulose Nanocrystal Aerogels as Universal 3D Lightweight Substrates for Supercapacitor Materials by Xuan Yang, Kaiyuan Shi, Igor Zhitomirsky, and Emily D. Cranston. Advanced Materials DOI: 10.1002/adma.201502284View/save citation First published online 2 September 2015

This paper is behind a paywall.

One final bit, cellulose nanocrystals (CNC) are sometimes referred to as nanocrystalline cellulose (NCC).

From monitoring glucose in kidneys to climate change in trees

That headline is almost poetic but I admit It’s a bit of a stretch rhymewise, kidneys/trees. In any event, a Feb. 6, 2015 news item on Azonano describes research into monitoring the effects of climate change on trees,

Serving as a testament to the far-reaching impact of Governor Andrew M. Cuomo’s commitment to maintaining New York State’s global leadership in nanotechnology innovation, SUNY Polytechnic Institute’s Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE) today announced the National Science Foundation (NSF) has awarded $837,000 to support development of a first of its kind nanoscale sensor to monitor the effects of climate change on trees.

A Feb. 5, 2015 SUNY Poly CNSE news release, which originated the news item, provides more details including information about the sensor’s link to measuring glucose in kidneys,

The NSF grant was generated through the Instrument Development for Biological Research (IDBR) program, which provides funds to develop new classes of devices for bio-related research. The NANAPHID, a novel aphid-like nanosensor, will provide real-time measurements of carbohydrates in live plant tissue. Carbohydrate levels in trees are directly connected to plant productivity, such as maple sap production and survival. The NANAPHID will enable researchers to determine the effects of a variety of environmental changes including temperature, precipitation, carbon dioxide, soil acidity, pests and pathogens. The nanosensor can also provide real-time monitoring of sugar concentration levels, which are of signficant importance in maple syrup production and apple and grape farming.

“The technology for the NANAPHID is rooted in a nanoscale sensor SUNY Poly CNSE developed to monitor glucose levels in human kidneys being prepared for transplant. Our team determined that certain adjustments would enable the sensor to provide similar monitoring for plants, and provide a critical insight to the effects of climate change on the environment,” said Dr. James Castracane, professor and head of the Nanobioscience Constellation at SUNY Polytechnic Institute. “This is a perfect example of the cycle of innovation made possible through the ongoing nanotechnology research and development at SUNY Poly CNSE’s NanoTech Complex.”

“This new sensor will be used in several field experiments on measuring sensitivity of boreal forest to climate warming. Questions about forest response to rising air and soil temperatures are extremely important for forecasting future atmospheric carbon dioxide levels, climate change and forest health,” said Dr. Andrei Lapenas, principal investigator and associate professor of climatology at the University at Albany. “At the same time, we already see some potential commercial application for NANAPHID-type sensors in agriculture, food industry and other fields. Our collaboration with SUNY Poly CNSE has been extremely productive and I look forward to continuing our work together.”

The NANAPHID project began in 2014 with a $135,000 SUNY Research Foundation Network of Excellence grant. SUNY Poly CNSE will receive $400,000 of the NSF award for the manufacturing aspects of the sensor array development and testing. The remaining funds will be shared between Dr. Lapenas and researchers Dr. Ruth Yanai (ESF), Dr. Thomas Horton (ESF), and Dr. Pamela Templer (Boston University) for data collection and analysis.

“With current technology, analyzing carbohydrates in plant tissues requires hours in the lab or more than $100 a sample if you want to send them out. And you can’t sample the same tissue twice, the sample is destroyed in the analysis,” said Dr. Yanai. “The implantable device will be cheap to produce and will provide continuous monitoring of sugar concentrations, which is orders of magnitude better in both cost and in the information provided. Research questions we never dreamed of asking before will become possible, like tracking changes in photosynthate over the course of a day or along the stem of a plant, because it’s a nondestructive assay.”

“I see incredible promise for the NANAPHID device in plant ecology. We can use the sensors at the root tip where plants give sugars to symbiotic fungi in exchange for soil nutrients,” said Dr. Horton. “Some fungi are believed to be significant carbon sinks because they produce extensive fungal networks in soils and we can use the sensors to compare the allocation of photosynthate to roots colonized by these fungi versus the allocation to less carbon demanding fungi. Further, the vast majority of these symbiotic fungi cannot be cultured in lab. These sensors will provide valuable insights into plant-microbe interactions under field conditions.”

“The creation of this new sensor will make understanding the effects of a variety of environmental changes, including climate change, on the health and productivity of forests much easier to measure,” said Dr. Templer. “For the first time, we will be able to measure concentrations of carbohydrates in living trees continuously and in real-time, expanding our ability to examine controls on photosynthesis, sap flow, carbon sequestration and other processes in forest ecosystems.”

Fascinating, eh? I wonder who made the connection between human kidneys and plants and how that person made the connection.