Featured Research

from universities, journals, and other organizations

Scientists create a super antioxidant

Date:
October 15, 2013
Source:
Rice University
Summary:
Scientists are enhancing the natural antioxidant properties of an element found in a car's catalytic converter to make it useful for medical applications.

Scientists at Rice University are enhancing the natural antioxidant properties of an element found in a car's catalytic converter to make it useful for medical applications.

Related Articles


Rice chemist Vicki Colvin led a team that created small, uniform spheres of cerium oxide and gave them a thin coating of fatty oleic acid to make them biocompatible. The researchers say their discovery has the potential to help treat traumatic brain injury, cardiac arrest and Alzheimer's patients and can guard against radiation-induced side effects suffered by cancer patients.

Their nanoparticles also have potential to protect astronauts from long-term exposure to radiation in space and perhaps even slow the effects of aging, they reported.

The research appears this month in the American Chemical Society journal ACS Nano.

Cerium oxide nanocrystals have the ability to absorb and release oxygen ions -- a chemical reaction known as reduction oxidation, or redox, for short. It's the same process that allows catalytic converters in cars to absorb and eliminate pollutants.

The particles made at Rice are small enough to be injected into the bloodstream when organs need protection from oxidation, particularly after traumatic injuries, when damaging reactive oxygen species (ROS) increase dramatically.

The cerium particles go to work immediately, absorbing ROS free radicals, and they continue to work over time as the particles revert to their initial state, a process that remains a mystery, she said. The oxygen species released in the process "won't be super reactive," she said.

Colvin said cerium oxide, a form of the rare earth metal cerium, remains relatively stable as it cycles between cerium oxide III and IV. In the first state, the nanoparticles have gaps in their surface that absorb oxygen ions like a sponge. When cerium oxide III is mixed with free radicals, it catalyzes a reaction that effectively defangs the ROS by capturing oxygen atoms and turning into cerium oxide IV. She said cerium oxide IV particles slowly release their captured oxygen and revert to cerium oxide III, and can break down free radicals again and again.

Colvin said the nanoparticles' tiny size makes them effective scavengers of oxygen.

"The smaller the particles, the more surface area they have available to capture free radicals," Colvin said. "A gram of these nanoparticles can have the surface area of a football field, and that provides a lot of space to absorb oxygen."

None of the cerium oxide particles made before Rice tackled the problem were stable enough to be used in biological settings, she said. "We created uniform particles whose surfaces are really well-defined, and we found a water-free production method to maximize the surface gaps available for oxygen scavenging."

Colvin said it's relatively simple to add a polymer coating to the 3.8-nanometer spheres. The coating is thin enough to let oxygen pass through to the particle, but robust enough to protect it through many cycles of ROS absorption.

In testing with hydrogen peroxide, a strong oxidizing agent, the researchers found their most effective cerium oxide III nanoparticles performed nine times better than a common antioxidant, Trolox, at first exposure, and held up well through 20 redox cycles.

"The next logical step for us is to do some passive targeting," Colvin said. "For that, we plan to attach antibodies to the surface of the nanoparticles so they will be attracted to particular cell types, and we will evaluate these modified particles in more realistic biological settings."

Colvin is most excited by the potential to help cancer patients undergoing radiation therapy.

"Existing radioprotectants have to be given in incredibly high doses," she said. "They have their own side effects, and there are not a lot of great options."

She said a self-renewing antioxidant that can stay in place to protect organs would have clear benefits over toxic radioprotectants that must be eliminated from the body before they damage good tissue.

"Probably the neatest thing about this is that so much of nanomedicine has been about exploiting the magnetic and optical properties of nanomaterials, and we have great examples of that at Rice," Colvin said. "But the special properties of nanoparticles have rarely been leveraged in medical applications.

"What I like about this work is that it opens a part of nanochemistry -- namely catalysis -- to the medical world. Cerium III and IV are electron shuttles that have broad applications if we can make the chemistry accessible in a biological setting.

"And of all things, this humble material comes from a catalytic converter," she said.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Seung Soo Lee, Wensi Song, Minjung Cho, Hema L. Puppala, Phuc Nguyen, Huiguang Zhu, Laura Segatori, Vicki L. Colvin. Antioxidant Properties of Cerium Oxide Nanocrystals as a Function of Nanocrystal Diameter and Surface Coating. ACS Nano, 2013; 130930105903002 DOI: 10.1021/nn4026806

Cite This Page:

Rice University. "Scientists create a super antioxidant." ScienceDaily. ScienceDaily, 15 October 2013. <www.sciencedaily.com/releases/2013/10/131015123700.htm>.
Rice University. (2013, October 15). Scientists create a super antioxidant. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2013/10/131015123700.htm
Rice University. "Scientists create a super antioxidant." ScienceDaily. www.sciencedaily.com/releases/2013/10/131015123700.htm (accessed October 24, 2014).

Share This



More Matter & Energy News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins