By Sahana Ghosh

Oct 18 (IANS): Scientists from India and Russia have crafted star-shaped gold nanoparticles that can selectively destroy cancer cells. These stable, inexpensive and non-toxic particles will also make it possible to detect cancer at an early stage.

The development was reported by scientists from the National University of Science and Technology MISIS (NUST MISIS), Moscow, and the Saha Institute of Nuclear Physics, Kolkata, recently in the journal Chemical Communications.

"The focus of the research was to formulate a benign nanostructure suitable for medicinal purpose," Dulal Senapati from the Saha Institute of Nuclear Physics and head of the NUST MISIS infrastructure project, told IANS.

Star-shaped nanoparticles appear to be the most efficient in photothermal therapy (PTT) that uses light radiation for the treatment of many medical conditions, including cancer.

In this process, nanoparticles embedded within tumours generate heat in response to externally applied laser light. It has been well documented as an independent strategy for highly selective cancer treatment.

Senapati said when a nanoparticle reaches the affected area, the area is blasted with a laser pulse. The nanoparticle absorbs the light and focuses it like a lens, directing it straight to the star's sharp edge.

This light is then converted into heat (of about 4,500-5,000 degrees Celsius), which is concentrated at the star's tip. The generated heat flow breaks the membrane of a cancer cell and destroys it while not harming the healthy cells.

"Our star-shaped nanoparticles absorb light at a wavelength of 600-900 nanometers, which is very good because our bodies are more transparent to the radiation in this range. Most biological molecules cannot absorb light in this range."

Senapati said these nano stars, technically dubbed as plasmonic nanoparticles, scatter light vigorously, and hence can be identified easily under dark-field illumination and other sensing techniques.

"Tracking of these nanoparticles is also possible using surface-enhanced Raman microscopy as they often enhance the scattering of light to many folds," he said.

Gold nanoparticles are synthesised in a water solution of vitamin C, which makes them inexpensive and non-toxic. According to preliminary estimates, the net cost of 100 microlitres is about 50 rubles (Rs 56).

"Young scientists from the NUST MISIS Energy Efficiency Center, under the supervision of Professor Dulal Senapati from the Saha Institute of Nuclear Physics, have managed to solve this problem," said NUST MISIS Rector Alevtina Chernikova.

"They have synthesised stable gold nanoparticles that do not aggregate in blood and are highly efficient in Raman spectroscopy."

Experts from the Blokhin Russian Cancer Research Center also participated in the development. Scientists are currently working on improving the particles by creating various types of "stars."