Tag Archives: William K.A. Sikkema

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)

A de-icer and a preventative for airplane wings from Rice University

I last mentioned this graphene-based work (from James Tour at Rice University in Texas, US) on de-icing not just airplane wings but also windshields, skyscrapers and more in a Sept. 17, 2014 posting. The latest study indicates the technology could be used as a preventative according to a May 23, 2016 news item on phys.org,

Rice University scientists have advanced their graphene-based de-icer to serve a dual purpose. The new material still melts ice from wings and wires when conditions get too cold. But if the air is above 7 degrees Fahrenheit, ice won’t form at all.

A May 23, 2016 Rice University news release (also on EurekAlert), which originated the news item, goes on to describe the work in more detail,

The Rice lab of chemist James Tour gave its de-icer superhydrophobic (water-repelling) capabilities that passively prevent water from freezing above 7 degrees. The tough film that forms when the de-icer is sprayed on a surface is made of atom-thin graphene nanoribbons that are conductive, so the material can also be heated with electricity to melt ice and snow in colder conditions.

The material can be spray-coated, making it suitable for large applications like aircraft, power lines, radar domes and ships, according to the researchers. …

“We’ve learned to make an ice-resistant material for milder conditions in which heating isn’t even necessary, but having the option is useful,” Tour said. “What we now have is a very thin, robust coating that can keep large areas free of ice and snow in a wide range of conditions.”

Tour, lead authors Tuo Wang, a Rice graduate student, and Yonghao Zheng, a Rice postdoctoral researcher, and their colleagues tested the film on glass and plastic.

Materials are superhydrophobic if they have a water-contact angle larger than 150 degrees. The term refers to the angle at which the surface of the water meets the surface of the material. The greater the beading, the higher the angle. An angle of 0 degrees is basically a puddle, while a maximum angle of 180 degrees defines a sphere just touching the surface.

The Rice films use graphene nanoribbons modified with a fluorine compound to enhance their hydrophobicity. They found that nanoribbons modified with longer perfluorinated chains resulted in films with a higher contact angle, suggesting that the films are tunable for particular conditions, Tour said.

Warming test surfaces to room temperature and cooling again had no effect on the film’s properties, he said.

The researchers discovered that below 7 degrees, water would condense within the structure’s pores, causing the surface to lose both its superhydrophobic and ice-phobic properties. At that point, applying at least 12 volts of electricity warmed them enough to retain its repellant properties.

Applying 40 volts to the film brought it to room temperature, even if the ambient temperature was 25 degrees below zero. Ice allowed to form at that temperature melted after 90 seconds of resistive heating.

The researchers found that while effective, the de-icing mode did not remove water completely, as some remained trapped in the pores between linked nanoribbon bundles. Adding a lubricant with a low melting point (minus 61 degrees F) to the film made the surface slippery, sped de-icing and saved energy.

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

Passive Anti-icing and Active Deicing Films by Tuo Wang, Yonghao Zheng, Abdul-Rahman O. Raji, Yilun Li, William K.A. Sikkema, and James M. Tour. ACS Appl. Mater. Interfaces, Just Accepted Manuscript DOI: 10.1021/acsami.6b03060 Publication Date (Web): May 18, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.