Scientists based in America have developed a group of rhodium-based compounds that can kill tumor cells and deactivate certain viruses when exposed to light.

The key advantage of these chemicals is that unlike the ordinary substances used for chemotherapy, they are not harmful to the body in general and only become lethal to DNA when activated by light of a specific frequency, Newswise reports.

Harry Morrison, professor of chemistry and former dean of Purdue's School of Science who is involved in the study, commented: "We have proven in principle that light and chemistry together can destroy tumor cells and the Sindbis virus, a member of a group of viruses that cause encephalitis, fever and arthritis.

"This research offers hope that someday we may be able to replace standard chemotherapy drugs with others that are far less generally harmful to a patient's body and guarantee safe, sterile blood for transfusions."

Platinum-based compounds have long been used in chemotherapy to poison cancer cells. These compounds work by binding DNA in the cellular nucleus, thereby preventing the cell from reproducing and effectively destroying it.

However, these chemicals also kill many other healthy cells in the body, which is obviously problematic.

The new compounds offer the potential to circumvent this problem by offering physicians control over when they become active.