Tag Archives: James Tour

Turning asphaltene into graphene

Asphaltene (or asphaltenes are) is waste material that can be turned into graphene according to scientists at Rice University (Texas, US), from a November 18, 2022 news item on ScienceDaily,

Asphaltenes, a byproduct of crude oil production, are a waste material with potential. Rice University scientists are determined to find it by converting the carbon-rich resource into useful graphene.

Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic (loosely aligned) graphene and mix it into composites for thermal, anti-corrosion and 3D-printing applications.

The process makes good use of material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills. Using at least some of the world’s reserve of more than 1 trillion barrels of asphaltene as a feedstock for graphene would be good for the environment as well.

A November 17, 2022 Rice University news release (also on EurekAlert), which originated the news item, expands on this exciting news, Note: Links have been removed,

“Asphaltene is a big headache for the oil industry, and I think there will be a lot of interest in this,” said Rahman, who characterized the process as both a scalable and sustainable way to reduce carbon emissions from burning asphaltene.

Rahman is a lead corresponding author of the paper in Science Advances co-led by Rice chemist James Tour, whose lab developed flash Joule heating, materials scientist Pulickel Ajayan and Md Golam Kibria, an assistant professor of chemical and petroleum engineering at the University of Calgary, Canada.

Asphaltenes are 70% to 80% carbon already. The Rice lab combines it with about 20% of carbon black to add conductivity and flashes it with a jolt of electricity, turning it into graphene in less than a second. Other elements in the feedstock, including hydrogen, nitrogen, oxygen and sulfur, are vented away as gases.

“We try to keep the carbon black content as low as possible because we want to maximize the utilization of asphaltene,” Rahman said.

“The government has been putting pressure on the petroleum industries to take care of this,” said Rice graduate student and co-lead author M.A.S.R. Saadi. “There are billions of barrels of asphaltene available, so we began working on this project primarily to see if we could make carbon fiber. That led us to think maybe we should try making graphene with flash Joule heating.”

Assured that Tour’s process worked as well on asphaltene as it did on various other feedstocks, including plastic, electronic waste, tires, coal fly ash and even car parts, the researchers set about making things with their graphene. 

Saadi, who works with Rahman and Ajayan, mixed the graphene into composites, and then into polymer inks bound for 3D printers. “We’ve optimized the ink rheology to show that it is printable,” he said, noting the inks have no more than 10% of graphene mixed in. Mechanical testing of printed objects is forthcoming, he said.

Rice graduate student Paul Advincula, a member of the Tour lab, is co-lead author of the paper. Co-authors are Rice graduate students Md Shajedul Hoque Thakur, Ali Khater, Jacob Beckham and Minghe Lou, undergraduate Aasha Zinke and postdoctoral researcher Soumyabrata Roy; research fellow Shabab Saad, alumnus Ali Shayesteh Zeraati, graduate student Shariful Kibria Nabil and postdoctoral associate Md Abdullah Al Bari of the University of Calgary; graduate student Sravani Bheemasetti and Venkataramana Gadhamshetty, an associate professor, at the South Dakota School of Mines and Technology and its 2D Materials of Biofilm Engineering Science and Technology Center; and research assistant Yiwen Zheng and Aniruddh Vashisth, an assistant professor of mechanical engineering, of the University of Washington.

The research was funded by the Alberta Innovates for Carbon Fiber Grand Challenge programs, the Air Force Office of Scientific Research (FA9550-19-1-0296), the U.S. Army Corps of Engineers (W912HZ-21-2-0050) and the National Science Foundation (1849206, 1920954).  

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

Sustainable valorization of asphaltenes via flash joule heating by M.A.S.R. Saadi, Paul A. Advincula, Md Shajedul Hoque Thakur, Ali Zein Khater, Shabab Saad, Ali Shayesteh Zeraati, Shariful Kibria Nabil, Aasha Zinke, Soumyabrata Roy, Minghe Lou, Sravani N. Bheemasetti, Md Abdullah Al Bari, Yiwen Zheng, Jacob L. Beckham, Venkataramana Gadhamshetty, Aniruddh Vashisth, Md Golam Kibria, James M. Tour, Pulickel M. Ajayan, and Muhammad M. Rahman. Science Advances 18 Nov 2022 Vol 8, Issue 46 DOI: 10.1126/sciadv.add3555

This paper is open access.

3D-printed ‘smart helmets’ for the military

Caption: The Rice University-designed smart helmet is intended to modernize standard-issue military helmets by 3D-printing a nanomaterial-enhanced exoskeleton with embedded sensors to actively protect the brain against kinetic or directed-energy effects. Credit: Rice University

Hopefully this will limit the number of head injuries suffered by soldiers.

Some years ago I was at dinner with friends when one of them, a doctor at the local hospital, told me that the Canadian military, which was in Afghanistan at the time, was dealing with a high number of head injury cases, in part due to the soldiers’ own protective gear.

For example, the protective helmet meant you were less likely to receive a catastrophic injury to your cranium (e.g., metal cracking through bone) but your head would be shaken and that isn’t good for anyone’s brain.

It would seem this project at Rice University (Texas, US) is designed to limit the problem of your own protective gear causing injury, from a November 10, 2021 Rice University news release (also on EurekAlert), Note: Links have been removed,

Rice University researchers have received $1.3 million from the Office of Naval Research through the Defense Research University Instrumentation Program to create the world’s first printable military “smart helmet” using industrial-grade 3D printers. 

Led by principal investigator Paul Cherukuri, executive director of Rice’s Institute of Biosciences and Bioengineering, the Smart Helmet program aims to modernize standard-issue military helmets by 3D-printing a nanomaterial-enhanced exoskeleton with embedded sensors to actively protect the brain against kinetic or directed-energy effects. 

Rice will utilize Carbon Inc.’s L1 printer to develop a strong-but-light military-grade helmet that incorporates advances in materials, image processing, artificial intelligence, haptic feedback and energy storage. The printer enables rapid prototyping that in turn simplifies the process of incorporating the sensors, cameras, batteries and wiring harnesses the program requires, Cherukuri said. 

“Current helmets have evolved little since the last century and are still heavy, bulky, passive devices,” he said. “Because of advances in sensors and additive manufacturing, we’re now reimagining the helmet as a 3D-printed, AI-enabled, ‘always-on’ wearable that detects threats near or far and is capable of launching countermeasures to protect soldiers, sailors, airmen and Marines. Essentially, we’re building J.A.R.V.I.S.”

The Smart Helmet program will use technology drawn from projects like the FlatCam, a system developed by co-investigator and electrical and computer engineer Ashok Veeraraghavan and his colleagues that incorporates sophisticated image processing to eliminate the need for bulky lenses, as well as Cherukuri’s Teslaphoresis, a kind of tractor beam for nanomaterials that could help create physical and electromagnetic shields inside the helmets. 

“A smart helmet task force has been assembled from some of the finest minds at Rice to tackle the challenge of creating a self-contained, intelligent system that protects the warfighter at all times,” Cherukuri said. The task force includes the labs of materials scientist Pulickel Ajayan, civil and environmental engineer and Rice Provost Reginald DesRoches, mechanical engineer Marcia O’Malley, chemist James Tour and Veeraraghavan.

While the location of the L1 has yet to be determined, a Carbon M2 printer will be located at the Oshman Engineering Design Kitchen (OEDK), where it will be available for projects other than the helmet. Rice undergraduates who design and build their mandated capstone projects at the OEDK are taking part in the helmet project, working alongside graduate students and postdoctoral researchers to develop the heads-up display.   

“We’ve got a lot of innovative tech in university labs that has never seen the light of day,” Cherukuri said. “We’re simply developing that technology into a device that gives the men and women protecting our country a real chance at coming home safe and sound. This is for them.”

Stronger concrete with graphene derived from tires

I’ve become strangely fascinated with concrete these last few months. Possibly, this is a consequence of a lot more ‘concrete’ research being published. Here’s a March 29, 2021 news item on phys.org featuring work from Rice University (Texas, US),

This could be where the rubber truly hits the road.

Rice University scientists have optimized a process to convert waste from rubber tires into graphene that can, in turn, be used to strengthen concrete.

The environmental benefits of adding graphene to concrete are clear, chemist James Tour said.

“Concrete is the most-produced material in the world, and simply making it produces as much as 9% of the world’s carbon dioxide emissions,” Tour said. “If we can use less concrete in our roads, buildings and bridges, we can eliminate some of the emissions at the very start.”

A March 29, 2021 Rice University news release (also on EurekAlert), which originated the news item, provides context for the work and more technical details,

Recycled tire waste is already used as a component of Portland cement, but graphene has been proven to strengthen cementitious materials, concrete among them, at the molecular level.

While the majority of the 800 million tires discarded annually are burned for fuel or ground up for other applications, 16% of them wind up in landfills.

“Reclaiming even a fraction of those as graphene will keep millions of tires from reaching landfills,” Tour said.

The “flash” process introduced by Tour and his colleagues in 2020 has been used to convert food waste, plastic and other carbon sources by exposing them to a jolt of electricity that removes everything but carbon atoms from the sample.

Those atoms reassemble into valuable turbostratic graphene, which has misaligned layers that are more soluble than graphene produced via exfoliation from graphite. That makes it easier to use in composite materials.

Rubber proved more challenging than food or plastic to turn into graphene, but the lab optimized the process by using commercial pyrolyzed waste rubber from tires. After useful oils are extracted from waste tires, this carbon residue has until now had near-zero value, Tour said.

Tire-derived carbon black or a blend of shredded rubber tires and commercial carbon black can be flashed into graphene. Because turbostratic graphene is soluble, it can easily be added to cement to make more environmentally friendly concrete.

The research led by Tour and Rouzbeh Shahsavari of C-Crete Technologies is detailed in the journal Carbon.

The Rice lab flashed tire-derived carbon black and found about 70% of the material converted to graphene. When flashing shredded rubber tires mixed with plain carbon black to add conductivity, about 47% converted to graphene. Elements besides carbon were vented out for other uses.

The electrical pulses lasted between 300 milliseconds and 1 second. The lab calculated electricity used in the conversion process would cost about $100 per ton of starting carbon.

The researchers blended minute amounts of tire-derived graphene — 0.1 weight/percent (wt%) for tire carbon black and 0.05 wt% for carbon black and shredded tires — with Portland cement and used it to produce concrete cylinders. Tested after curing for seven days, the cylinders showed gains of 30% or more in compressive strength. After 28 days, 0.1 wt% of graphene sufficed to give both products a strength gain of at least 30%.

“This increase in strength is in part due to a seeding effect of 2D graphene for better growth of cement hydrate products, and in part due to a reinforcing effect at later stages,” Shahsavari said.

Set of tires on a sky background

I’m not sure where I got this stock shot but it is pretty (if tires can ever be described that way).

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

Flash Graphene from Rubber Waste by Paul A. Advincula, Duy Xuan Luong, Weiyin Chen, Shivaranjan Raghuraman, Rouzbeh Shahsavari, James M.Tour. Carbon Available online 28 March 2021 In Press, Journal Pre-proof DOI: https://doi.org/10.1016/j.carbon.2021.03.020

This paper is behind a paywall.

Where do I stand? a graphene artwork

A May 2,2019 news item on Nanowerk describes some graphene-based artwork being created at Rice University (Texas, US), Note: A link has been removed,

When you read about electrifying art, “electrifying” isn’t usually a verb. But an artist working with a Rice University lab is in fact making artwork that can deliver a jolt.

The Rice lab of chemist James Tour introduced laser-induced graphene (LIG) to the world in 2014, and now the researchers are making art with the technique, which involves converting carbon in a common polymer or other material into microscopic flakes of graphene.

The “ink” in “Where Do I Stand?” by artist Joseph Cohen is actually laser-induced graphene (LIG). The design shows Cohen’s impression of what LIG looks like at the microscopic level. The work was produced in the Rice University lab where the technique of creating LIG was invented. Photo by Jeff Fitlow
A detail from “Where Do I Stand?” by artist Joseph Cohen, who created the work at Rice University using laser-induced graphene as the medium. Photo by Jeff Fitlow

A May 2, 2019 Rice university news release (also received via email), which originated the news item, describes laser-induced graphene (LIG) and the art in more detail (Note: Links have been removed),

LIG is metallic and conducts electricity. The interconnected flakes are effectively a wire that could empower electronic artworks.

The paper in the American Chemical Society journal ACS Applied Nano Materials – simply titled “Graphene Art” – lays out how the lab and Houston artist and co-author Joseph Cohen generated LIG portraits and prints, including a graphene-inspired landscape called “Where Do I Stand?”

While the work isn’t electrified, Cohen said it lays the groundwork for future possibilities.

“That’s what I would like to do,” he said. “Not make it kitsch or play off the novelty, but to have it have some true functionality that allows greater awareness about the material and opens up the experience.”

Cohen created the design in an illustration program and sent it directly to the industrial engraving laser Tour’s lab uses to create LIG on a variety of materials. The laser burned the artist’s fine lines into the substrate, in this case archive-quality paper treated with fire retardant.

The piece, which was part of Cohen’s exhibit at Rice’s BioScience Research Collaborative last year, peers into the depths of what a viewer shrunken to nanoscale might see when facing a field of LIG, with overlapping hexagons – the basic lattice of atom-thick graphene – disappearing into the distance.

“You’re looking at this image of a 3D foam matrix of laser-induced graphene and it’s actually made of LIG,” he said. “I didn’t base it on anything; I was just thinking about what it would look like. When I shared it with Jim, he said, ‘Wow, that’s what it would look like if you could really blow this up.’”

Cohen said his art is about media specificity.

“In terms of the artistic application, you’re not looking at a representation of something, as traditionally we would in the history of art,” he said. “Each piece is 100% original. That’s the key.”

He developed an interest in nanomaterials as media for his art when he began work with Rice alumnus Daniel Heller, a bioengineer at Memorial Sloan Kettering Cancer Center in New York who established an artist-in-residency position in his lab.

After two years of creating with carbon nanotube-infused paint, Cohen attended an Electrochemical Society conference and met Tour, who in turn introduced him to Rice chemists Bruce Weisman and Paul Cherukuri, who further inspired his investigation of nanotechnology.

The rest is art history.

It would be incorrect to think of the process as “printing,” Tour said. Instead of adding a substance to the treated paper, substance is burned away as the laser turns the surface into foamlike flakes of interconnected graphene.

The art itself can be much more than eye candy, given LIG’s potential for electronic applications like sensors or as triboelectric generators that turn mechanical actions into current.

“You could put LIG on your back and have it flash LEDs with every step you take,” Tour said.

The fact that graphene is a conductor — unlike paint, ink or graphite from a pencil — makes it particularly appealing to Cohen, who expects to take advantage of that capability in future works.

“It’s art with a capital A that is trying to do the most that it can with advancements in science and technology,” he said. “If we look back historically, from the Renaissance to today, the highest forms of art push the limits of human understanding.”

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

Graphene Art by Yieu Chyan, Joseph Cohen, Winston Wang, Chenhao Zhang, and James M. Tour. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.9b00391 Publication Date (Web): April 23, 2019

Copyright © 2019 American Chemical Society

This paper appears to be open access.

Because I can’t resist the delight beaming from these faces,

maging with laser-induced graphene (LIG) was taken to a new level in a Rice University lab. From left, chemist James Tour, holding a portrait of himself in LIG; artist Joseph Cohen, holding his work “Where Do I Stand?”; and Yieu Chyan, a Rice graduate student and lead author of a new paper detailing the process used to create the art. Photo by Jeff Fitlow

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

Nanocar Race winners: The US-Austrian team

Sadly, I didn’t stumble across the news about the US-Austrian team sooner but it was not published until a May 8, 2017 news item on Nanowerk,

Rice University chemist James Tour and his international team have won the first Nanocar Race.

The Rice and University of Graz team finished first in the inaugural Nanocar Race in Toulouse, France, April 28, completing a 150-nanometer course — roughly a thousandth of the width of a human hair — in about 1½ hours. (The race was declared over after 30 hours.)

Interestingly the Rice University news release announcing the win was issued prior to the ‘winning’ Swiss team’s and it explains why the Swiss team was declared a co-winner despite the additional hours (6.5 hours as compared to 1.5 hours [see my May 9, 2017 posting: Nanocar Race winners! where the Swiss appear to claiming they raced 38 hours]) before completing the race. From an April 28, 2017 Rice University news release,

The team led by Tour and Graz physicist Leonhard Grill deployed a two-wheeled, single-molecule vehicle with adamantane tires on its home track in Graz, Austria, achieving an average speed of 95 nanometers per hour. Tour said the speed ranged from more than 300 to less than 1 nanometer per hour, depending upon the location along the course.

The Swiss Nano Dragster team finished next, five hours later. But organizers at the French National Center for Scientific Research declared them a co-winner of first place as they were tops among teams that raced on a gold track.

Because the scanning tunneling microscope track in Toulouse could only accommodate four cars, two of the six competing international teams — Ohio University and Rice-Graz — ran their vehicles on their home tracks (Ohio on gold) and operated them remotely from the Toulouse headquarters.

The Dipolar Racer designed at Rice.

The Dipolar Racer designed at Rice.

Five cars were driven across gold surfaces in a vacuum near absolute zero by electrons from the tips of microscopes in Toulouse and Ohio, but the Rice-Graz team got permission to use a silver track at Graz. “Gold was the surface of choice, so we tested it there, but it turns out it’s too fast,” Grill said. “It’s so fast, we can’t even image it.”

The team got permission from organizers in advance of the race to use the slower silver surface, but with an additional handicap. “We had to go 150 nanometers around two pylons instead of 100 nanometers since our car was so much faster,” Tour said.

Tour said the race directors used the Paris-Rouen auto race in 1894, considered by some to be the world’s first auto race, as precedent for their decision April 29. “I am told there will be two first prizes regardless of the time difference and handicap,” he said.

The Rice-Graz car, called the Dipolar Racer, was designed by Tour and former Rice graduate student Victor Garcia-Lopez and raced by the Graz team, which included postdoctoral researcher and pilot Grant Simpson and undergraduate and co-pilot Philipp Petermeier.

The silver track under the microscope. Two Rice nanocars are in the blue circle at top. The lower car was the first to run the race, finishing in an hour-and-a-half. The top car was put through the course later, finishing in 2 hours.

The silver track under the microscope. Two Rice nanocars are in the blue circle at top. The lower car was the first to run the race, finishing in a 1½ hours. The top car was put through the course later, finishing in 2 hours. Click on the image for a larger version.

The purpose of the competition, according to organizers, was to push the science of how single molecules can be manipulated as they interact with surfaces.

“We chose our fastest wheels and our strongest dipole so that it could be pulled by the electric field more efficiently,” said Tour, whose lab has been designing nanocars since 1998. ‘We gave it two (side-by-side) wheels to minimize interaction with the surface and to lower the molecular weight.

“We built in every possible design parameter that we could to optimize speed,” he said.

While details of the Dipolar Racer remained a closely held secret until race time, Tour and Grill said they will be revealed in a forthcoming paper.

“This is the beginning of our ability to demonstrate nanoscale manipulation with control around obstacles and speed and will pave the way for much faster paces and eventually for carrying cargo and doing bottom-up assembly.

“It’s a great day for nanotechnology,” Tour said. “And a great day for Rice University and the University of Graz.”

Clearly all the winners were very excited. Still, there’s a little shade being thrown (one of the scientists is just a tiny bit miffed) as you can see in James Tour’s quote given after noting the US-Austrian racer was too fast for the gold surface so the team used the slower silver surface and were given another handicap. As per the Rice University news release: ““I am told [emphasis mine] there will be two first prizes regardless of the time difference and handicap,” he said.” Of course, the Swiss team’s news release didn’t mention the US-Austrian team’s speedier finish nor did it name (Dipolar Racer) the US-Austrian racer. As I noted before, scientists are people too.

Tattoo therapy for chronic disease?

It’s good to wake up to something truly new. In this case, it’s using tattoos and nanoparticles for medical applications. From a Sept. 22, 2016 news item on ScienceDaily,

A temporary tattoo to help control a chronic disease might someday be possible, according to scientists at Baylor College of Medicine [Texas, US] who tested antioxidant nanoparticles created at Rice University [Texas, US].

A Sept. 22, 2016 Rice University news release, which originated the news item, provides more information and some good explanations of the terms used (Note: Links have been removed),

A proof-of-principle study led by Baylor scientist Christine Beeton published today by Nature’s online, open-access journal Scientific Reports shows that nanoparticles modified with polyethylene glycol are conveniently choosy as they are taken up by cells in the immune system.

That could be a plus for patients with autoimmune diseases like multiple sclerosis, one focus of study at the Beeton lab. “Placed just under the skin, the carbon-based particles form a dark spot that fades over about one week as they are slowly released into the circulation,” Beeton said.

T and B lymphocyte cells and macrophages are key components of the immune system. However, in many autoimmune diseases such as multiple sclerosis, T cells are the key players. One suspected cause is that T cells lose their ability to distinguish between invaders and healthy tissue and attack both.

In tests at Baylor, nanoparticles were internalized by T cells, which inhibited their function, but ignored by macrophages. “The ability to selectively inhibit one type of cell over others in the same environment may help doctors gain more control over autoimmune diseases,” Beeton said.

“The majority of current treatments are general, broad-spectrum immunosuppressants,” said Redwan Huq, lead author of the study and a graduate student in the Beeton lab. “They’re going to affect all of these cells, but patients are exposed to side effects (ranging) from infections to increased chances of developing cancer. So we get excited when we see something new that could potentially enable selectivity.” Since the macrophages and other splenic immune cells are unaffected, most of a patient’s existing immune system remains intact, he said.

The soluble nanoparticles synthesized by the Rice lab of chemist James Tour have shown no signs of acute toxicity in prior rodent studies, Huq said. They combine polyethylene glycol with hydrophilic carbon clusters, hence their name, PEG-HCCs. The carbon clusters are 35 nanometers long, 3 nanometers wide and an atom thick, and bulk up to about 100 nanometers in globular form with the addition of PEG. They have proven to be efficient scavengers of reactive oxygen species called superoxide molecules, which are expressed by cells the immune system uses to kill invading microorganisms.

T cells use superoxide in a signaling step to become activated. PEG-HCCs remove this superoxide from the T cells, preventing their activation without killing the cells.

Beeton became aware of PEG-HCCs during a presentation by former Baylor graduate student Taeko Inoue, a co-author of the new study. “As she talked, I was thinking, ‘That has to work in models of multiple sclerosis,’” Beeton said. “I didn’t have a good scientific rationale, but I asked for a small sample of PEG-HCCs to see if they affected immune cells.

“We found they affected the T lymphocytes and not the other splenic immune cells, like the macrophages. It was completely unexpected,” she said.

The Baylor lab’s tests on animal models showed that small amounts of PEG-HCCs injected under the skin are slowly taken up by T lymphocytes, where they collect and inhibit the cell’s function. They also found the nanoparticles did not remain in T cells and dispersed within days after uptake by the cells.

“That’s an issue because you want a drug that’s in the system long enough to be effective, but not so long that, if you have a problem, you can’t remove it,” Beeton said. “PEG-HCCs can be administered for slow release and don’t stay in the system for long. This gives us much better control over the circulating half-life.”

“The more we study the abilities of these nanoparticles, the more surprised we are at how useful they could be for medical applications,” Tour said. The Rice lab has published papers with collaborators at Baylor and elsewhere on using functionalized nanoparticles to deliver cancer drugs to tumors and to quench the overproduction of superoxides after traumatic brain injuries.

Beeton suggested delivering carbon nanoparticles just under the skin rather than into the bloodstream would keep them in the system longer, making them more available for uptake by T cells. And the one drawback – a temporary but visible spot on the skin that looks like a tattoo – could actually be a perk to some.

“We saw it made a black mark when we injected it, and at first we thought that’s going to be a real problem if we ever take it into the clinic,” Beeton said. “But we can work around that. We can inject into an area that’s hidden, or use micropattern needles and shape it.

“I can see doing this for a child who wants a tattoo and could never get her parents to go along,” she said. “This will be a good way to convince them.”

The research was supported by Baylor College of Medicine, the National Multiple Sclerosis Society, National Institutes of Health, the Dan L. Duncan Cancer Center, John S. Dunn Gulf Coast Consortium for Chemical Genomics and the U.S. Army-funded Traumatic Brain Injury Consortium.

That’s an interesting list of funders at the end of the news release.

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

Preferential uptake of antioxidant carbon nanoparticles by T lymphocytes for immunomodulation by Redwan Huq, Errol L. G. Samuel, William K. A. Sikkema, Lizanne G. Nilewski, Thomas Lee, Mark R. Tanner, Fatima S. Khan, Paul C. Porter, Rajeev B. Tajhya, Rutvik S. Patel, Taeko Inoue, Robia G. Pautler, David B. Corry, James M. Tour, & Christine Beeton. Scientific Reports 6, Article number: 33808 (2016) doi:10.1038/srep33808 Published online: 22 September 2016

This paper is open access.

Here’s an image provided by the researchers,

Polyethylene glycol-hydrophilic carbon clusters developed at Rice University were shown to be selectively taken up by T cells, which inhibits their function, in tests at Baylor College of Medicine. The researchers said the nanoparticles could lead to new strategies for controlling autoimmune diseases like multiple sclerosis. (Credit: Errol Samuel/Rice University) - See more at: http://news.rice.edu/2016/09/22/tattoo-therapy-could-ease-chronic-disease/#sthash.sIfs3b0S.dpuf

Polyethylene glycol-hydrophilic carbon clusters developed at Rice University were shown to be selectively taken up by T cells, which inhibits their function, in tests at Baylor College of Medicine. The researchers said the nanoparticles could lead to new strategies for controlling autoimmune diseases like multiple sclerosis. (Credit: Errol Samuel/Rice University)

Carbon capture with asphalt

I wish I could turn back the clock a few years, so I could mention this research from Rice University (Texas, US) on using asphalt for carbon capture (more on why at the end of this post). From a Sept. 13, 2016 news item on Nanowerk (Note: A link has been removed),

Rice University laboratory has improved its method to turn plain asphalt into a porous material that can capture greenhouse gases from natural gas.

In research detailed this month in Advanced Energy Materials (“Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures”), Rice researchers showed that a new form of the material can sequester 154 percent of its weight in carbon dioxide at high pressures that are common at gas wellheads.

A Sept. 12, 2016 Rice University news release, which originated the news item, further describes the work (Note: Links have been removed),

Raw natural gas typically contains between 2 and 10 percent carbon dioxide and other impurities, which must be removed before the gas can be sold. The cleanup process is complicated and expensive and most often involves flowing the gas through fluids called amines that can soak up and remove about 15 percent of their own weight in carbon dioxide. The amine process also requires a great deal of energy to recycle the fluids for further use.

“It’s a big energy sink,” said Rice chemist James Tour, whose lab developed a technique last year to turn asphalt into a tough, sponge-like substance that could be used in place of amines to remove carbon dioxide from natural gas as it was pumped from ocean wellheads.

Initial field tests in 2015 found that pressure at the wellhead made it possible for that asphalt material to adsorb, or soak up, 114 percent of its weight in carbon at ambient temperatures.

Tour said the new, improved asphalt sorbent is made in two steps from a less expensive form of asphalt, which makes it more practical for industry.

“This shows we can take the least expensive form of asphalt and make it into this very high surface area material to capture carbon dioxide,” Tour said. “Before, we could only use a very expensive form of asphalt that was not readily available.”

The lab heated a common type asphalt known as Gilsonite at ambient pressure to eliminate unneeded organic molecules, and then heated it again in the presence of potassium hydroxide for about 20 minutes to synthesize oxygen-enhanced porous carbon with a surface area of 4,200 square meters per gram, much higher than that of the previous material.

The Rice lab’s initial asphalt-based porous carbon collected carbon dioxide from gas streams under pressure at the wellhead and released it when the pressure was released. The carbon dioxide could then be repurposed or pumped back underground while the porous carbon could be reused immediately.

In the latest tests with its new material, Tours group showed its new sorbent could remove carbon dioxide at 54 bar pressure. One bar is roughly equal to atmospheric pressure at sea level, and the 54 bar measure in the latest experiments is characteristic of the pressure levels typically found at natural gas wellheads, Tour said.

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

Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures by Almaz S. Jalilov, Yilun Li, Jian Tian, James M. Tour.  Advanced Energy Materials DOI: 10.1002/aenm.201600693  First published [online]: 8 September 2016

This paper is behind a paywall.

Finishing the story I started at the beginning of this post, I was at an early morning political breakfast a few years back when someone seated at our table asked me if there were any nanotechnology applications for carbon sequestration/capture. At the time, I could not bring any such applications to mind. (Sigh) Now I have an answer.

Graphene ribbons in solution bending and twisting like DNA

An Aug. 15, 2016 news item on ScienceDaily announces research into graphene nanoribbons and their DNA (deoxyribonucleic acid)-like properties,

Graphene nanoribbons (GNRs) bend and twist easily in solution, making them adaptable for biological uses like DNA analysis, drug delivery and biomimetic applications, according to scientists at Rice University.

Knowing the details of how GNRs behave in a solution will help make them suitable for wide use in biomimetics, according to Rice physicist Ching-Hwa Kiang, whose lab employed its unique capabilities to probe nanoscale materials like cells and proteins in wet environments. Biomimetic materials are those that imitate the forms and properties of natural materials.

An Aug. 15, 2016 Rice University (Texas, US) news release (also on EurekAlert), which originated the news item, describes the ribbons and the research in more detail,

Graphene nanoribbons can be thousands of times longer than they are wide. They can be produced in bulk by chemically “unzipping” carbon nanotubes, a process invented by Rice chemist and co-author James Tour and his lab.

Their size means they can operate on the scale of biological components like proteins and DNA, Kiang said. “We study the mechanical properties of all different kinds of materials, from proteins to cells, but a little different from the way other people do,” she said. “We like to see how materials behave in solution, because that’s where biological things are.” Kiang is a pioneer in developing methods to probe the energy states of proteins as they fold and unfold.

She said Tour suggested her lab have a look at the mechanical properties of GNRs. “It’s a little extra work to study these things in solution rather than dry, but that’s our specialty,” she said.

Nanoribbons are known for adding strength but not weight to solid-state composites, like bicycle frames and tennis rackets, and forming an electrically active matrix. A recent Rice project infused them into an efficient de-icer coating for aircraft.

But in a squishier environment, their ability to conform to surfaces, carry current and strengthen composites could also be valuable.

“It turns out that graphene behaves reasonably well, somewhat similar to other biological materials. But the interesting part is that it behaves differently in a solution than it does in air,” she said. The researchers found that like DNA and proteins, nanoribbons in solution naturally form folds and loops, but can also form helicoids, wrinkles and spirals.

Kiang, Wijeratne [Sithara Wijeratne, Rice graduate now a postdoctoral researcher at Harvard University] and Jingqiang Li, a co-author and student in the Kiang lab, used atomic force microscopy to test their properties. Atomic force microscopy can not only gather high-resolution images but also take sensitive force measurements of nanomaterials by pulling on them. The researchers probed GNRs and their precursors, graphene oxide nanoribbons.

The researchers discovered that all nanoribbons become rigid under stress, but their rigidity increases as oxide molecules are removed to turn graphene oxide nanoribbons into GNRs. They suggested this ability to tune their rigidity should help with the design and fabrication of GNR-biomimetic interfaces.

“Graphene and graphene oxide materials can be functionalized (or modified) to integrate with various biological systems, such as DNA, protein and even cells,” Kiang said. “These have been realized in biological devices, biomolecule detection and molecular medicine. The sensitivity of graphene bio-devices can be improved by using narrow graphene materials like nanoribbons.”

Wijeratne noted graphene nanoribbons are already being tested for use in DNA sequencing, in which strands of DNA are pulled through a nanopore in an electrified material. The base components of DNA affect the electric field, which can be read to identify the bases.

The researchers saw nanoribbons’ biocompatibility as potentially useful for sensors that could travel through the body and report on what they find, not unlike the Tour lab’s nanoreporters that retrieve information from oil wells.

Further studies will focus on the effect of the nanoribbons’ width, which range from 10 to 100 nanometers, on their properties.

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

Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution by Sithara S. Wijeratne, Evgeni S. Penev, Wei Lu, Jingqiang Li, Amanda L. Duque, Boris I. Yakobson, James M. Tour, & Ching-Hwa Kiang. Scientific Reports 6, Article number: 31174 (2016)  doi:10.1038/srep31174 Published online: 09 August 2016

This paper is open access.