BUCKYBALL DEFENCE

Biplab Das is on a form of carbon that can 
resist decay of nerve cells more effectively

As the years go by, our minds lose their sharpness and muscles their coordination. Quick reflexes are replaced by slow, deliberate movements, reminding the person at every step that age is catching up.

The degeneration of tissues in the human body is caused by the action of free radicals, which are reactive by-products of metabolism. Nerve cells are the worst-affected by the onslaught of free radicals. Conditions like ALS (asymptomatic lateral sclerosis or Lou Gehrig's disease) and Alzheimer's disease are chracterised by the gradual degeneration of nerve cells, until patients become paralysed or lose their minds.

Buckminsterfullerene, a form of carbon whose molecular shape resembles a soccer ball, can effectively be used to mop up free radicals from the nervous system. Buckyballs or Carbon 60 (one buckyball contains 60 carbon atoms), were discovered by Robert F. Curl, Harold W. Croto and Richard E. Smalley, who won the'96 Nobel Prize for chemistry.

In a recent paper published in the Proceedings of the National Academy of Sciences, Dr. Dugan, Tom Lin and fellow researchers at Washington University in St. Louis, Missouri, and National Taiwan University in Taipei claim to have successfully used buckyballs to protect nerve cells from the damaging effect of free radicals.

Due to their molecular structure, buckyballs are exceptionally good at mopping up free radicals. The carbon atoms in a buckyball are arranged in such a manner that their electrons club together to form a film of electric charge around its surface.

The reactivity of free radicals is owing to its deficiency of electrons. On encountering a buckyball, a free radical, which is actually an electron-hungry species, attacks the bucky's electron-rich surface. It fails to break the surface, but remains stuck to it.

At the same time, buckyballs are chemically inert, which means that they cannot react with any biochemical present in the bloodstream. For the same reason, pure buckyballs are of little medical use. For buckminsterfullerene to enter the interstitial spaces within the body, it has to dissolve in water. Dr. Dugan and her team overcame this hurdle using malonic acid, which serves as an extra-molecular handle for buckyballs. Water molecules can hold on to malonic acid, whose molecules can in turn bind to Carbon 60.

To test the applicability of buckyballs, the researchers carried out experiments on mice suffering from a version of the ALS. Carboxyfullerens (buckyballs with malonic acid) cleared up free radicals between 10 to 100 times more effectively than traditional antioxidants such as vitamin E. They also protected nerve cells doused with an amyloid peptide - a protein that sends self-destruct signals to nerve cells through free radicals in patients of Alzheimer's disease.

Scientists are strongly advocating the effectiveness of buckminsterfullerene for protecting nerve cells from free radical damage. Dr. Dugan and her team are currently working on applying fullerenes (chemical compounds that contain C 60) to probe the working of the nervous system.