While treating breast cancer patients, drugs released into the body target healthy cells as well as tumor cells. Thus side effects are caused.
Now, Brown University researchers have developed a new way to deliver cancer-fighting drugs directly to the tumour cells.
They have created a twin nanoparticle that specifically targets the Her-2-positive tumor cell, a type of malignant cell that affects up to 30 percent of breast cancer patients.
The combination nanoparticle binds to the Her-2 tumor cell and unloads the cancer-fighting drug cisplatin directly into the infected cell.
The result is greater success at killing the cancer while minimizing the anti-cancer drug's side effects.
"Like a missile, you don't want the anti-cancer drugs to explode everywhere. You want it to target the tumor cells and not the healthy ones," said Shouheng Sun, a chemistry professor at Brown University and an author on the paper published online in The Journal of the American Chemical Society.
The researchers created the twin nanoparticle by binding one gold (Au) nanoparticle with an iron-oxide (Fe3O4) nanoparticle. On one end, they attached a synthetic protein antibody to the iron-oxide nanoparticle. On the other end, they attached cisplatin to the gold nanoparticle.
Visually, the whole contraption looks like an elongated dumbbell, but it may be better to think of it as a vehicle, equipped with a very good GPS system, that is ferrying a very important passenger.
In this case, the GPS comes from the iron-oxide nanoparticle, which homes in on a Her-2 breast-cancer cell like a guided missile. The attached antibody is critical, because it binds to the antigen, a protein located on the surface on the malignant cell.
Put another way, the nanoparticle vehicle 'docks' on the tumor cell when the antibody and the antigen become connected. Once docked, the vehicle unloads its "passenger," the cisplatin, into the malignant cell.
In a neat twist, the Brown-led team used a pH-sensitive covalent bond to connect the gold nanoparticle with the cisplatin to ensure that the drug was not released into the body but remained attached to the nanoparticle until it was time for it to be released into the malignant cell.
In laboratory experiments, the gold-iron oxide nanoparticle combination successfully targeted the cancer cells and released the anti-cancer drugs into the malignant cells, killing the cells in up to 80 percent of cases.