According to a study published on Monday, scientists found a way to kill cancer cells by injecting tiny particles, loaded with medication, attacking diseased cells while leaving healthy cells untouched. The team of researchers working at MIT used particles firstly on cells growing in laboratory dishes and then on mice bearing human prostate tumors. The tumors shrank dramatically, and all of the treated mice survived the study. Even if all the parts of this equation are safe, they still need to be proven safe for humans, scientists needing tests on larger animals, and eventually on humans. Some reports said that, because of their small size, nanoparticles might cause damage to cells and pose a danger to health, while other experts requested more research before they come into wide use. The nanoparticles bear the drug docetaxel and are designed to dissolve in the internal fluids of a cell, releasing the anti-cancer drug. To make sure only cancerous cells are hit, these particles have aptamers (DNA or RNA molecules that have been selected from random pools based on their ability to bind other molecules) which recognize the surface molecules on cancer cells, avoiding healthy cells. Nanoparticles were chosen because their small size causes living cells to swallow them when they arrive at the cell's surface."A single injection of our nanoparticles completely eradicated the tumors in five of the seven treated animals, and the remaining animals also had significant tumor reduction, compared to the controls," said Dr. Omid C. Farokhzad, assistant professor at Harvard Medical School, involved in the study.