New York: A nanocarrier engineered to be small enough to get past the blood-brain barrier could be targeted to deliver a chemotherapeutic drug more efficiently to tumour cells in the brain, a new study reveals. The blood-brain barrier is a protective barrier designed to keep a stable environment within and surrounding the brain. In experiments, the researchers found that the new method resulted in increased killing in the targeted cells. "I was very surprised by how efficiently and well it worked once we got the nanocarrier to those cells," said Ann-Marie Broome from Medical University of South Carolina in the US. The findings potentially point the way to a new treatment option for patients with certain conditions, such as glioblastoma multiforme (GBM), the focus of this study. Glioblastoma multiforme is a devastating disease with no curative options due to several challenges, Broome said. The brain tumour has a significant overall mortality, in part due to its location, difficulty of surgical treatment and the inability to get drugs through the blood-brain barrier. In 40 percent of cases, standard treatments will extend life expectancy four to seven months. That led the researchers engineer a micelle that is a phospholipid nanocarrier, "a bit of fat globule," to deliver a concentrated dose of the chemotherapy drug temozolomide (TMZ) to the deadly tumour cells. "Micelles of a certain size will cross the blood-brain barrier carrying a concentrated amount of TMZ," Broome explained about how the nanotechnology works. The study was published online in the international journal Nanomedicine - Future Medicine. In medicine, Broome said, researchers construct nanocarriers that are stable and stealthy. "Your immune cells can't attack them. They remain hidden. "When the package gets to where it's going, nanotechnologists have various methods to get the micelles to release their payloads -- one way is to use the acidic nature of a rapidly growing tumour," she said.