MIT engineers pick an artificial nose

William Atkins
Tuesday, 30 September 2008 23:06

Science - Health

In order to accomplish the development of this artificial nose, the team had to deal with the olfactory receptors within the nose, a part of the olfactory system of the human nose with nearly 400 genes.

Proteins within the receptors actually detect the tens of thousands of different smells possible with the human nose. However, how the nose actually does the smelling, is unknown to scientists.

The team had to make sufficient numbers of olfactory receptors. On top of this, they had to make all of them pure and of an equal quality.

The MIT News article states, “The olfactory receptors that bind to odor molecules are membrane proteins, which span the cell surface. Since cell membranes are composed of a bilayer of fatty lipid molecules, the receptor proteins are highly hydrophobic (water-fearing).”

It continues, “Remove these proteins from the cell and place them in water-based solutions, they clump up and lose their structure, said Liselotte Kaiser, lead author of the PNAS paper. That makes it very difficult to isolate the proteins in quantities large enough to study them in detail.”

However, the team researched for numerous years to develop an effective method. They finally found a way to isolate and purify the proteins in a series of hydrophobic detergent solutions. This technique permits the proteins to maintain their structure and, therefore, their integrity.

The MIT article continues, “The technique involves a cell-free synthesis using commercially available wheat germ extract to produce a particular receptor, then isolating the protein through several purification steps. The method can rapidly produce large amounts of protein -- enough to start structural and functional studies.”

The MIT team is planning to next develop a portable microfluidic device that identifies different odors.

This futuristic device may be able to take over for dogs, which are used to sniff harmful and dangerous odors at airports and other areas. It may also be used to identify diseases within the human body that have their own specific smell.