Originally Published MDDI June 2005

R&D DIGEST

Maria Fontanazza

Are nanocarriers the future of drug-delivery devices? Researchers in Singapore are developing devices that transport anticancer drugs to target cancer cells without affecting healthy ones. They hope to reduce the unpleasant side effects of chemotherapy, which include nausea, weakness, and hair loss. The team hopes that the technology may also be useful for treating other diseases.

“Toxic drugs expected to kill only diseased cells and not healthy cells would require delivery devices with a drug-targeting function,” says Yi-Yan Yang, PhD, group leader of the delivery of drugs, proteins, and genes research program at Singapore's Institute of Bioengineering and Nanotechnology (IBN). “After certain refinements, our nanocarriers may be used for a variety of applications in drug delivery.”

The technology involves employing bioactive compounds encased in a shell. The shell protects against bodily fluids and breakdown. Because the nanocarriers are temperature- and pH-sensitive, they can detect the acidic environments typical in cancerous tissue. Upon finding this tissue, the nanocarriers develop a hydrophobic shell that provides adhesion to the tumor. They're able to focus on a tumor through biological signals that attach to the shell. Then the nanocarriers absorb protons in the cell and release the drugs.

Although treating diseased cells without damaging the surrounding ones could extend to a variety of applications, it would require altering the device. “To enable the nanocarriers to be used for drug delivery to treat other ailments, such as inflammatory tissues, a different biological signal needs to be conjugated to the surface of the nanocarriers to target the diseased tissues or cells,” says Yang.

IBN's current method hasn't shown considerable cytotoxicity. The researchers have also shown that when the nanocarriers are loaded with the anticancer drug doxorubicin, they can suppress tumor growth better than free doxorubicin.

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