The production of olfactory receptors is a step towards an "artificial" nose
The sense of smell is one of the oldest and most primitive senses, but the principles of its operation are still largely unclear. Deciphering these mechanisms will make it possible to create "artificial noses" that will replace dogs used to search for drugs and explosives, as well as facilitate the solution of various tasks, including medical ones.
Scientists at the Massachusetts Institute of Technology have developed a method for mass production of olfactory receptors in the laboratory. This achievement is not only a step towards the creation of an "artificial nose" that can help solve many problems, but also brings scientists closer to deciphering the mechanisms by which the sense of smell allows humans and animals to distinguish an almost infinitely large range of odors.
Until now, attempts to study the molecular basis of olfaction have been hindered by difficulties in working with olfactory receptors – proteins that provide odor recognition. Scientists have not been able to synthesize enough of these proteins and purify them to a homogeneous state.
The olfactory system is extremely complex, in humans it includes about 400 functional genes (none of the other functions of the body is provided by so many genes). In animals, such as dogs and mice, the number of functional olfactory receptor genes reaches 1000.
Such a variety of receptors allows humans and animals to distinguish tens of thousands of different odors. Each smell activates many receptors, and the resulting activation profile is recognized by the brain as a specific smell.
Olfactory receptors that bind to "smelling" molecules are membrane proteins that cover the surface of cells. Since the cell membrane is based on a lipid bilayer, receptor proteins have pronounced hydrophobic properties.
When removed from the cell and placed in aqueous solutions, these proteins aggregate and lose their structure, which makes it impossible to isolate them in quantities sufficient for detailed study. The authors have spent several years developing a multi-stage method for isolating and purifying olfactory receptor proteins in hydrophobic detergent solutions.
The technique they currently propose is a cell-free synthesis of one of the receptors using a commercially available wheat germ extract and subsequent protein isolation through several stages of enrichment. The method allows you to quickly obtain an amount of protein sufficient for structural and functional analysis.
In August, the authors also published a method of olfactory receptor synthesis using genetically modified mammalian cells. This method is more time-consuming and time-consuming than the cell-free approach, but its advantage is that the receptor is synthesized in a more natural way.
In the future, the authors plan to enter into cooperation with researchers from other countries in order to develop a portable microfluidic device that allows identifying a certain range of odors. In addition to the many applications of an "artificial nose" in industry, such a device can be used in medicine for the early diagnosis of certain diseases with characteristic odors, such as diabetes and cancer of the lungs, bladder and skin.
Portal "Eternal youth" http://vechnayamolodost.ru / based on ScienceDaily – 'Artificial Nose' Progress: Engineers Mass-produce Smell Receptors02.10.2008