Osteosarcoma is the most common form of bone cancer, and treatment normally involves surgery to remove the tumor, followed by chemotherapy or radiation therapy to kill off any remaining cancer cells. Even so, it often recurs at the same site, and when it does the prognosis is usually grim.

Now, scientists at Aston University have demonstrated a new method of treating osteosarcoma. It's based on a material called bioactive glass, which is made up of nanoparticles of glass mixed with metals, and has shown promise in strong, antibacterial dental fillings and bone implants.

This time the metal in question was gallium, which is toxic to cells. Putting that in your bones might sound like a bad idea, but gallium ions are known to enter cells through a particular receptor, which is extremely elevated in cancer. That means the "greedy" cancer cells gobble it up before the healthy bone cells can get to it.

In lab tests, the team cultured healthy bone cells alongside osteosarcoma cells, and treated them with the gallium bioactive glass. And sure enough, at concentrations of 5% gallium oxide, the glass was able to kill off 99% of the osteosarcoma cells after 10 days, without harming the healthy bone.

These bioactive glasses also show promise in regenerating bone. When incubated in simulated body fluid, new bone formation began to appear after a week.

"When we observed the glasses, we could see the formation of a layer of amorphous calcium phosphate/ hydroxy apatite layer on the surface of the bioactive glass particulates, which indicates bone growth," said Professor Richard Martin, lead author of the study.

Unfortunately, at this stage it seems that adding gallium oxide at concentrations required to kill the cancer cells also stymies regeneration of healthy bone cells, but that's a challenge that could be overcome with further work, using animal models.