Study bolsters quantum vibration theory of smell

A new study may bolster a controversial new theory of how our sense of smell works - that our noses use quantum mechanisms to sense vibrations of odor molecules.

 

The quantum-vibration theory challenges the present theory that likens odorants - odor molecules - to puzzle pieces that bind to receptors in the nose, Scientific American reported.

 

Scientific American new research published in PLoS ONE that human noses can sniff out the presence of at least some kinds of deuterium - researchers learned regular musk molecules smelled different from ones that contain deuterium.

 

Researcher Luca Turin of the Alexander Fleming Biomedical Sciences Research Center in Greece said "deuterated" musks lose much of their musky odor and instead contain overtones of burnt candle wax, it said.

 

It quoted Turin as saying the finding represents a victory for the vibration theory.

 

"Olfaction is trying to be like an analytical chemist ... It's trying to identify unknowns," he said.

 

Also, Scientific American cited a 2011 finding in Proceedings of the National Academy of Sciences indicating that drosophila flies can also smell the difference between a molecule called acetophenone (smells sweet) and its deuterated cousin.

 

Molecular twist

 

A twist, however, is that odorant molecules typically contain many hydrogen atoms, and hydrogen comes in multiple forms.

 

Yet those different isotopes of hydrogen affect how a molecule vibrates, such that deuterium containing a hydrogen nucleus may help scientists discriminate between the proposed vibration and standard chemical binding theories of smell.

 

On the other hand, Eric Block, professor of chemistry at the University at Albany in New York State, said the new finding hardly proves the vibration theory.

 

Block said Turin once claimed humans, like drosophilia, could sniff out a deuterated version of the molecule acetophenone from the regular stuff - but in 2004 Nature Neuroscience published a contrary claim, that human noses can't smell the presence of deuterium in acetophenone.

 

Scientific American said Turin himself says in his new paper that he has confirmed the negative 2004 finding, although he explained the failure as due to deuterated acetophenone having relatively few deuteriums in it and thus may generate a weak vibrational signal too weak for humans to detect.

 

For his part, smell biologist Tim Jacob of Cardiff University in Wales said the smell of rotten egg smell is a good example of the vibration theory's appeal.

 

Sulfur adds signature vibrations to a molecule that a molecular vibration–sensitive nose might detect.

 

"I do all my research without needing to know which model most accurately describes what's going on ... From a biological point of view it (vibration theory) has great interest," Jacob said.  — ELR, GMA News