Australasian Science: Australia's authority on science since 1938

Helium Beam Sifts Molecules

Scientists have found an exciting new way to manipulate and design new materials at the atomic level, and change the way they behave at a larger scale, opening the way to new applications such as early cancer biomarkers.

They say that the creation of nano “sieves” can help separate molecules down to an unprecedented size 10,000 times finer than a human hair.

“We discovered that a beam of energetic helium ions generated in a helium ion microscope rearranged a nanoporous anodised alumina material on the atomic scale and shrank its pores to various, unprecedented tiny sizes,” said Prof Kostya Ostrikov of Queensland University of Technology. “These tiny pores mean scientists could potentially ‘sift’ molecules into different sizes to study them individually. It could open the way to early detection of cancer, for example, through a blood test that could detect DNA produced by a cancer before the tumour developed.

“This new ion-assisted manipulation of matter on the tiniest of length scales completely changed the behaviour of the aluminium oxide. When we applied moderate exposure to helium ions, its pores shrank. When we increased exposure to the ions, this normally brittle and porous ceramic turned into a superplastic and gained the ability to stretch more than twice without breaking.”

Dr Annalena Wolff said the discovery would allow scientists to play with materials and see their properties change in real time. “We can now play with atomic bonds and see how we can use them to influence the manipulation of matter on the nanometric scale,” she said.

Dr Morteza Aramesh, the lead author of the study published in Nature Communications (, said: “This new way of redesigning materials will help researchers and engineers to create novel smart materials with different functions, for example new pharmaceuticals, disease diagnostics and quantum computing. We can use helium ion microscopes to image almost any material and to build structures that are as small as a DNA strand – so small that you could fit 64 billion of them in a single raindrop.

“Now we can see and manipulate matter on the nanometre scale we are limited only by our imagination in material design,” Aramesh said.