Scientists discover that charcoal "points" are an effective antioxidant

Graphene quantum dots extracted from common charcoal can form the basis of an effective antioxidant for people with traumatic brain injury, stroke or heart attack.

Their ability to eliminate oxidative stress after such injuries is the subject of a study conducted by scientists at Rice University, the Texas A & M Health Science Center and the McGovern Medical School at the University of Texas Health Science. Houston Center (UTHealth).

Quantum dots are semiconductor materials small enough to exhibit quantum mechanical properties that only appear at the nanoscale.

Rice chemist James Tour, A & M neurologist Thomas Kent and UTHealth biochemist Ah-Lim Tsai and their teams discovered that biocompatible points, modified with a common polymer, effectively mimic the superoxide dismutase of the body, l? one of many natural enzymes that maintain oxidative stress. in check.

But as natural antioxidants can be overwhelmed by the rapid production of reactive oxygen species (ROS) capable of healing an injury, the team has been working for years to determine whether a rapid injection of nanomaterials reagents could limit the collateral damage that these free radicals could bring. cause healthy cells.

An earlier study of the trio had shown that hydrophilic clusters modified with polyethylene glycol (PEG) to improve their solubility and biological stability were effective in mitigating oxidative stress, since a single nanoparticle had the ability to neutralize thousands of ROS molecules.

"Replacing our anterior nanoparticles with quantum dots derived from coal makes the production of these potentially therapeutic substances much simpler and less expensive," Tour said. "This opens the door to more easily accessible therapies."

Tests performed on cell lines have shown that a mixture of quantum dots of graphene and PEG from common charcoal is just as effective in stopping the damage caused by superoxide and hydrogen peroxide as materials previous, but the points themselves are more explicit than ribbon-shaped clusters.

The results appear in the American Chemical Society newspaper. Applied materials and interfaces ACS.

The Tour laboratory first extracted quantum dots from coal in 2013 and reported on their potential for medical imaging, sensing, electronics and photovoltaics applications. A subsequent study has shown how they can be designed for specific semiconductor properties.

In the new study, the researchers evaluated the electrochemical, chemical, and biological points. The Rice laboratory chemically extracted cheap quantum dots of bituminous and anthracite coal, modified them with the polymer and tested their capabilities on rodent living cells.

The results showed that doses of quantum dots at different concentrations were very effective at protecting cells from oxidation, even though doses were delayed 15 minutes after researchers had added harmful hydrogen peroxide. to cell culture dishes.

The 3-5 nanometer quantum dots described above are smaller than the 10-20 nanometer anthracite dots. The researchers found that the level of protection depended on the dose for both types of particles, but that the larger anthracite-derived dots protected more cells at lower concentrations.

"Although they both work in cells, in vivo, the smaller ones are more effective," Tour said. "The bigger ones probably have trouble accessing the brain."