New Nanocapsules Offers Hope

by Aruna on Jun 29 2009 1:31 PM

Tiny containers about the size of a virus that can deliver medicines to targeted cells in the bloodstream with almost 100 percent efficiency, has been devised by scientist.

The breakthrough achieved by a collaborative team of Cornell and Shenzhen University researchers gives new hope that this technique may one day be used to deliver vaccines, drugs or genetic material to treat cancer and blood and immunological disorders.

"We can introduce just about any drug or genetic material that can be encapsulated, and it is delivered to any circulating cells that are specifically targeted," said Michael King, Cornell associate professor of biomedical engineering, who co-authored the study with lead author Zhong Huang, a former Cornell research associate who is now an assistant professor at the Shenzhen University School of Medicine in China.

The technique involves filling the tiny lipid containers, or nanoscale capsules, with a molecular cargo and coating the capsules with adhesive proteins called selectins that specifically bind to target cells.

A shunt coated with the capsules is then inserted between a vein and an artery. Much as burrs attach to clothing in a field, the selectin-coated capsules adhere to targeted cells in the bloodstream.

After rolling along the shunt wall, the cells break free from the wall with the capsules still attached and ingest their contents.

The study shows that since only the targeted cells ingest the contents of the nanocapsules, the technique could greatly reduce the adverse side effects caused by some drugs.

The study also shows that genetic material can be delivered to targeted cells to turn off specific genes and interfere with processes that lead to disease.

The researchers filled nanocapsules with a small-interfering RNA (siRNA) and targeted them to specific circulating cells. When the targeted cells ingested the capsules, the siRNA turned off a gene that produces an enzyme that contributes to the degradation of cartilage in arthritis.

King said that in a similar manner, the method could be used to target the delivery of chemotherapy drugs, vaccine antigens to white blood cells, specific molecules that mitigate autoimmune disorders and more.

The research has been published online at the Web site of the journal Gene Therapy.