Boffins at the University of Nebraska-Lincoln in the US are developing a technology which could give robots the power of human touch.

Ravi Saraf, a professor of engineering at Nebraska-Lincoln, and his doctoral student Vivek Maheshwari have developed a self-assembling nano-particle device that has touch sensitivity comparable to that of the human finger.

The scientists claim that the breakthrough brings a capability far beyond any mechanical devices currently available.

Medicine is the most likely application for the technology, according to Professor Saraf. One of the trickiest decisions facing a cancer surgeon today is where to stop cutting.

The surgeon does not want to stop too soon and leave cancer cells in the patient's body, but does not want to take too many cells and risk unnecessary damage to organs.

The high-resolution touch sensor could allow surgeons to tell at the level of a single layer of cells whether or not they have excised a cancerous tumour in its entirety.

"I am excited about this because I want to try to decipher cancer at the single-cell level," said Professor Saraf.

"Because in some cases cancer tissues are harder than normal tissues, if you take a tissue sample and press on it, you would be able to see a cluster of just a few [cancer] cells with this method because it can sense down to about 10 microns.

"Surgeons will be able to know if they have taken out all of the cancer. If they haven't, they'll know where to make the next cut."

Professor Saraf explained that the device will be relatively cheap because it self-assembles at room temperature. It can also be made to cover an area of 1 square metre or larger, and is flexible enough to cover complex shapes.

As a demonstration Professor Saraf and Maheshwari pressed a US penny against a sample device and, using a charged-couple device camera, were able to decipher fine features such as wrinkles in Abraham Lincoln's clothing.

"Touch is a sensation they want in robotics because to tell the difference between a cube and a sphere, an ordinary robot takes forever to do it with vision because it has to look from all directions," said Saraf.

"With touch, it would 'feel' the sharp edges and say: 'Oh, this is a cube.' And then, of course, the big thing for the military is to manoeuvre in darkness. Similar to a blind person [this device] would allow you to touch and find your way through."