From correspondents in Washington, United States, 03:31 PM IST

A revolutionary nano-needle, developed by researchers, not only peers into individual cells, but also acts as electro-chemical probe and optical biosensor.

'Nano-needle-based delivery is a powerful new tool for studying biological processes and biophysical properties at the molecular level inside living cells,' said Min-Feng Yu, professor of mechanical science and study coauthor, University of Illinois (U of I).

Yu and associates described how nano-needles deliver, detect and track individual fluorescent quantum dots in a cell's cytoplasm and nucleus. The quantum dots can be used for studying molecular mechanics and physical properties inside cells.

To create a nano-needle, the researchers begin with a rigid but resilient boron-nitride nanotube. The nanotube is then attached to one end of a glass pipette for easy handling, and coated with a thin layer of gold.

Molecular cargo is then attached to the gold surface via 'linker' molecules. When placed in a cell's cytoplasm or nucleus, the bonds with the linker molecules break, freeing the cargo.

With a diameter of approximately 50 nanometres, the nano-needle introduces minimal intrusiveness in penetrating cell membranes and accessing the interiors of live cells.

The delivery process can be precisely controlled, monitored and recorded - goals that have not been achieved in prior studies, said an U of I release.

'The nano-needle provides a mechanism by which we can quantitatively examine biological processes occurring within a cell's nucleus or cytoplasm,' said Yang Xiang, professor of molecular and integrative physiology and co-author of the paper.

'By studying how individual proteins and molecules of DNA or RNA mobilise, we can better understand how the system functions as a whole,' he added.

The study is slated for publication in Nano Letters and is posted on the journal's website.

(Staff Writer, © IANS)