Shape of nano particles adds edge to cancer therapy

Washington, Aug 5 : In nanotechnology, size does matter, but shape even more so. It has a vital bearing on treatment of cancer, diabetes and arthritis, says a new study.

A team of researchers led by Joseph DeSimone, professor of chemistry in University of North Carolina (UNC), has demonstrated that nanoparticles designed with a specific shape, size and surface chemistry behave differently within the cells depending on these attributes.

Researchers are looking towards using nanoparticles to combat cancer. Previously, treating it involved injecting patients with toxic drugs. Only a fraction reached the intended target, killing healthy cells and causing harmful side-effects.

Studies have shown that drug-carrying nanoparticles can directly target tumours, thanks to their infinitesimal size - less than 100 nanometres (a nanometre is a billionth of a metre) - which helps allow them to pass through cell membranes.

However, till now, existing techniques have meant that targeting agents could only be delivered using spherical or granular shaped particles.

Using PRINT (Particle Replication in Non-wetting Templates) technology - a technique developed by DeSimone's lab allowing scientists to produce "custom-made" nanoparticles - UNC researchers made particles with specific shapes, sizes and surface charges.

"This would mean that we could deliver lower dosages of drugs to specific cells and tissues in the body and actually be more effective in treating the cancer," said DeSimone, member of UNC's Lineberger Comprehensive Cancer Centre.

Scientists discovered that long, rod-shaped nano particles were internalised by cells four times faster than bigger nano-sized particles and travelled much further into the cells as well.

Stephanie Gratton of DeSimone Lab noted the same phenomenon is found in natural organisms.

"The long rod-shaped structure of bacteria may help explain why PRINT particles of higher aspect ratios are internalised more rapidly and effectively than lower aspect ratio particles," she said.

Their findings appear in this week's online edition of PNAS.