Nanosponges Show Promise in Killing Tumors

Oftentimes, the drugs doctors inject in cancer patients are rendered inefficient, and exert few of their capabilities on the cancer cells themselves. This happens mainly for two reasons – either they can't get to the tumor site, or they are attacked and dismembered by the immune system. This obstacle has claimed many lives over the years, but now scientists believe they may have found a way around this. Experts at the Vanderbilt University say that fixing drugs into nanoscale sponges (nanosponges) ensures that the chemicals reach their destination in large amounts.

In a set of experiments, it was evidenced that the new approach is between 300 and 500 percent more efficient at halting or reducing tumor growth than injecting drugs directly into the body. “Effective targeted drug delivery systems have been a dream for a long time now but it has been largely frustrated by the complex chemistry that is involved. We have taken a significant step toward overcoming these obstacles,” says Vanderbilt assistant professor of chemistry Eva Harth, who is the scientist behind the new delivery system. Details of the work appear in the June 1 issue of the top scientific journal Cancer Research.

“We call the material nanosponge, but it is really more like a three-dimensional network or scaffold,” the scientist explains. The basis is formed by a length of polyester, which is then mixed into a solution containing cross-linkers. These are very small molecules that act as grappling hooks. When combined with the polyester, they tie various regions of the base material together, creating larger, sphere-shaped particles filled with cavities. These holes can then be filled with drugs, which are released over time, in a predictable manner. This is possible because the nanosponges are biodegradable. “Predictable release is one of the major advantages of this system compared to other nanoparticle delivery systems under development,” Harth says.

“Many other drug delivery systems require complicated chemistry that will be difficult to scale up for commercial production, but we have continually kept this in mind,” she adds. Scientists from Harth's laboratory collaborated with colleagues from the lab of Washington University School of Medicine Dennis E. Hallahan, who is a former professor of radiation oncology at Vanderbilt. Expert Roberto Diaz, who is based at the Emory University, also contributed to the work, and is also a corresponding author of the Cancer Research paper.