"Smart" nanoparticles have been developed that use a tumor's acidity to deliver drugs to cancerous cells while sparing healthy.
The technology, developed by researchers at Singapore's Institute of Bioengineering and Nanotechnology (IBN), could reduce side-effects associated with many cancer chemotherapies.
Such chemotherapies can cause nausea, hair loss and other undesirable problems due to their effects on noncancerous as well as cancerous cells.
For more targeted delivery, researchers are working to encapsulate cancer drugs in nanoparticles and then, using various approaches, get the nanoparticles to target only cancerous cells.
IBN researchers led by Yi-Yan Yang now report creating polymeric core nanoparticles that can target tumors using both acidity and temperature.
In slightly acidic environments characteristic of tumor tissues and endosomes (a cell component), the nanoparticles deform and release enclosed drug molecules.
"Previous attempts by other scientists involved the use of core-shell nanoparticles that were only sensitive to temperature," says Yang. "The novelty of our invention compared to carriers that are only temperature-sensitive is the ability of IBN's core-shell nanoparticles to target drugs to deep tissues or cell compartments without changes in temperature."
When the nanoparticles encounter cancerous tissue, they form a shell that lets them adhere to tumors. They are also tagged with biological signals to help them seek tumor sites.
When taken up by cancerous cells, the particles absorb protons in endosomes and release their drug payload into cells.
So far, the researchers have shown that the nanoparticles can deliver an anticancer drug into breast tumor tissue in mice better than free-floating forms of the drug.