A team of scientists from the U.S. and China have devised a type of nanoparticle containing yet more nanoparticles, which together form a "cluster-bomb" to improve tumor penetration.
The researchers from the University of Science and Technology of China along with those from Georgia Tech and Emory University packed the chemotherapy drug cisplatin into nanoparticles just 5 nanometers in diameter and then packed those particles into a relatively larger nanoparticle 100 nanometers wide. The larger vehicle allowed for the safe transport across leaky blood vessels at the tumor site, which tends to be of higher acidity than healthier parts of the body and breaks down the 100-nanometer particle, releasing the smaller ones.
These smaller, drug-carrying particles then penetrate the tumor cells, ultimately releasing the cisplatin, which kills the cells from the inside via platinum-based cross-linking. Normally, cisplatin is quite toxic when it reaches healthy organs, but the targeted approach decreased the toxicity significantly.
In mice with human pancreatic tumors, the clustered particle enhanced cisplatin accumulation in the cancer cells. With the same dose resulting in 7 times the amount of cisplatin in the tumor, treatments would not have to be as limited to achieve the same outcome. And the nanotech approach also demonstrated effectiveness in lung cancer and breast cancer models that normally do not respond to cisplatin, prolonging survival by weeks.
The researchers published their results in the journal PNAS.
"The negative side effects of cisplatin are a long-standing limitation for conventional chemotherapy," team member Jinzhi Du said in a statement. "In our study, the delivery system was able to improve tumor penetration to reach more cancer cells, as well as release the drugs specifically inside cancer cells through their size-transition property."