Scientists are making huge advances in developing special nanotubes which make use of platinum as they target tumour cells or clogged arteries in the body, it was reported yesterday (29th October).

Nanomotors, as they are more broadly known, can move forwards through liquid, transporting pharmaceutical agents to specific areas or facilitating the movement of specimen molecules via microchip.

The best-performing of these is a tiny catalytic nanotube which contains platinum at one end and gold at the other and is propelled through a medium that contains the fuel it needs, which is often hydrogen peroxide.

Previously, it could attain speeds of ten to 20 micrometres per second, but now a team led by Joseph Wang at the University of California and Arizona State University has made rapid improvements.

They decided to replace the gold section of the tube with an alloy of silver and gold, and subsequent tests showed that the speed of travel was increased to over 150 micrometres per second.

Commenting on the results, which appear in the journal Angewandte Chemie, Mr Wang said: "These nanorods travel about 75 times their own length in one second. We are approaching the speed of the most efficient biological nanomotors, including flagellated bacteria."

The platinum segment plays a valuable role in the process by catalysing the splitting of hydrogen peroxide into oxygen and protons, while also absorbing the excess electrons.

The silver and gold alloy enables the fuel to be decomposed faster - thus accelerating the nanotube quicker - and Mr Wang also explained that it can be made to go even faster by altering the proportion of silver.



Source:

Turbocharged Nanomotors (29/10/08)
http://www.physorg.com/news144479498.html