The theory goes that the amount of infrared light can be varied to control the amount of drug that is released from the gold-coated liposomes.
"By using more or less light, you can release more or less of the drug and time the responses as well, so when you trigger light, some drug will leak, you can trigger it again and have more drug leak, or you can wait a little while, let the drug disperse, do its thing, then trigger it again. It allows for a lot more freedom with the release process," said Leung. "By having this very triggered response you can hit that therapeutic window."
Despite increased blood-flow to tumor cells and the key-in-lock action of the ligands, some liposomes may still end up inside healthy cells. In that case, the gold-coating could potentially act to prevent release of the toxic drug to the healthy cells.
By selectively shining the infrared light only in the tumor region, doctors could make sure only liposomes in the tumor region are able to release the drug.
"Once you know where the tumors are, you can go ahead and point your light source toward those areas. Whatever else is left will leave the body or may be slowly released, but not to as high or as toxic of levels as it would be if you just injected the drug systemically," said Leung.
The invention has another bonus: "The gold-coated liposome is biodegradable, which is one of the best parts of our system," said Leung. Currently there are no approved chemotherapeutic treatments that allow the gold nanostructures to be eliminated from the body by the body's own mechanisms, said Leung.
Kidneys, the organs that normally filter waste molecules out of the blood, have a limit as to the size of molecule they can filter. "Because of the size it degrades into, our system should be clearable via the kidney, which is really unique," said Leung.
|Contact: Daniel Stolte|
University of Arizona