25 August 2009

A safe nanotechnology process

There has been a call for safe and green methods to manufacture products using nanotechnology. There is now under development a non-toxic and environmentally friendly way to make tiny nanorods of zinc oxide. This new approach could allow nanorods to safely see use in medical and other applications.

Zinc oxide has quite a few uses when fabricated as nanoparticles and nanorods, just 100 nanometers in diameter. In such as nanoscopic form, it can go in food products, such as breakfast cereals as a source of zinc, a necessary nutrient. It can also work in dentistry and cosmetic ointments, creams, and lotions to protect against sunburn and skin damage caused by ultraviolet light.

Zinc oxide can also act as a sensor for detecting changes in electric current due to absorption of gas molecules and can be a warning device for gas leaks. In electronics, the same material has wrought a revolution in lasers and light emitting diodes (LEDs). And as a biosensor, it can be a biomimic membrane to immobilize and modify biomolecules.

Now, there is a safe and biocompatible route for the synthesis of zinc oxide nano rods, said M.A. Shah and M.S. Al-Shahry of the King Khalid University, in Abha, Saudi Arabia and A.M. Asiri of the King Abdul-Aziz University, in Jeddah, Saudi Arabia. The basis of their route comes from the simple reaction of water and zinc powder at a relatively low temperature.

“Since water is regarded as a benign solvent and non-toxic, the product (nanorods) could be used safely for biomedical and other applications,” Shah said.

The approach is versatile for making different kinds of zinc oxide nanostructures and critically avoids the use of toxic organic solvents.

In the new approach, researchers add zinc powder water, blasted with ultrasound for few minutes and then warmed at a temperature of 200°C for 24 hours. The team has used the analytical techniques of X-ray and field emission electron microscopy to reveal the structure of the product.

Researchers found they can produce uniform nanorods of 30 to 100 nanometers. They have also found they can use pure water in what they said is a “simple and straightforward approach … suitable for large scale production.” The proposed method is novel, rapid, economical, environmentally benign, and produces no pollutants, Shah said.

For related information, go to www.isa.org/manufacturing_automation.