'Nanospring pill' could detect cancer cells

A tiny structure developed by scientists at Georgia Tech could be used to detect single molecules, or as a key component in nano-devices

Scientists at the US Georgia Institute of Technology (Georgia Tech) have developed a tiny "nanospring" structure that could be used to detect individual molecules, possibly creating an extremely sensitive method of detecting cancer. The nanosprings could also be used to activate devices built on a molecular scale.

Georgia Tech's Center for Nanoscience and Nanotechnology said the nanosprings are smaller than any comparable structure, including the "nanobelts" developed by Georgia Tech in 2001.

Much research into the area of nanotechnology -- or devices constructed on a molecular scale -- has focussed on creating smaller and more efficient microchips. Nanosprings and nanobelts could make an impact on an area that has lagged and includes devices such as sensors, which interact with forces and molecules in the surrounding environment.

Georgia Tech researchers Xiang Yang Kong and Zhong Lin Wang are currently developing the first application for the nanospring, a micron-sized "pill" that would distribute millions of the nanosprings throughout the body. When the structures encountered even a single cancer-protein molecule, they would send a radio signal through the skin, the researchers said. A prototype is planned by the end of the year, the researchers said.

"We would like to use these materials for in-situ, real-time, non-destructive monitoring within the body with high levels of sensitivity," Wang said in a statement.

The zinc oxide-based nanosprings are 10 to 60 nanometres wide and five to 20 nanometres thick, but up to several millimetres long. One nanometer is one billionth of a metre, or 0.000000001m.

The nanosprings are made useful by their piezoelectric and electrostatic polarisation properties. Piezoelectric materials, which include quartz, Rochelle salt and various synthetic crystals, produce a voltage when a mechanical stress is applied, making them suitable for devices such as phonograph cartridges, microphones and strain gauges. Nanomaterials with electrostatic polarisation can be used to attract specific molecules, making them potentially usable as biosensors.

The research was first publicised last month.