In a major step towards better chemotherapy treatments, scientists have created tiny "smart bombs", which can deliver drugs only to specific cells inside the human body.
The researchers have revealed that each of these smart bombs is thousands of times smaller than the width of a human hair.
They say that the new approach may lead to more effective chemotherapy treatments with greatly reduced, or even eliminated side effects.
In a collaborative effort, Dr. Stefan Franzen, professor of chemistry, and Dr. Steven Lommel, professor of plant pathology and genetics, used the special properties of a fairly common and non-toxic plant virus as a means to convey drugs to the target cells.
According to the researchers, the virus is appealing in both its ability to survive outside of a plant host and its built-in "cargo space" of 17 nano-meters, which can be used to carry chemotherapy drugs directly to tumor cells.
They deployed the virus by attaching small proteins, called signal peptides, to its exterior that cause the virus to "seek out" particular cells, such as cancer cells.
The same signal peptides serve as "passwords" that allow the virus to enter the cancer cell, where it releases its cargo.
"We had tried a number of different nanoparticles as cell-targeting vectors. The plant virus is superior in terms of stability, ease of manufacture, ability to target cells and ability to carry therapeutic cargo," said Franzen.
Calcium is the key to keeping the virus' cargo enclosed. When the virus is in the bloodstream, calcium is also abundant.
However, inside individual cells, calcium levels are much lower, which allows the virus to open, delivering the cancer drugs only to the targeted cells.
"Another factor that makes the virus unique is the toughness of its shell. When the virus is in a closed state, nothing will leak out of the interior, and when it does open, it opens slowly, which means that the virus has time to enter the cell nucleus before deploying its cargo, which increases the drug's efficacy," said Lommel.
The researchers are hoping that their method will alleviate the side effects of common chemotherapy treatments, while maximizing the effectiveness of the treatment.