August 6, 2008

Shape and Size Important in Nanomedicine

U.S. scientists say they've determined shape, not just size, has a substantial impact on the effectiveness of emerging nanomedicine therapies.

The researchers at the University of North Carolina at Chapel Hill say their finding could lead to more effective methods of treating cancer, diabetes, multiple sclerosis, arthritis, obesity and other diseases.

The scientists, led by Professors Joseph DeSimone and William Kenan Jr., found nanoparticles with specific shape, size and surface chemistry are taken up into cells and behave differently within the cells.

For example, they discovered long, rod-shaped particles are internalized by cells approximately four times faster than lower aspect ratio particles and travel significantly further into the cells.

"The long rod-shaped structure of bacteria may help explain why Â… particles of higher aspect ratios are internalized more rapidly and effectively than lower aspect ratio particles," said graduate student Stephanie Gratton, one of the researchers. "If we can design particles that rely on the same mechanisms that nature has perfected for bacteria, we may unlock the key for delivering therapeutics more efficiently and effectively to treat and cure disease."

The findings are reported in the early online edition of the Proceedings of the National Academy of Sciences.