Discovery of phenomenon for through-space determination of biomolecules’ chirality
9 October 2015
A new phenomenon, involving the determination of a molecule’s chirality through the plasmonic enhancement of a non-chiral molecule, has been discovered in research involving the University of Strathclyde.
The study revealed a means of reporting through space on molecules’ chirality, in which they have a non-superimposable mirror image - with one form of the molecule enantiomer being left-handed and the other right-handed.
However, rather than directly measuring the chirality of the enantiomer, the chirality is transferred to a non-chiral molecule attached to a metal surface.
This outcome was achieved through a combination of metal plasmonic surface functionalised with an achiral- neither left- nor right-handed – dye molecule and Raman-based detection techniques which, between them, gave a signal strong enough to determine the ‘left-handedness’ or ‘right-handedness,’ of amino acids.
The unique aspect of this phenomenon is the manner in which the chirality of the achiral molecule changes. This depends on the chirality of the molecule held in close proximity to it.
The findings could have potential applications in medical analysis where the chirality of molecules have an important effect.
The study was led by Prof Ewan Blanch at the University of Manchester and also involved the Institute of Chemical Technology in Prague and RMIT University in Melbourne. The paper has been published in the journal Nature Chemistry.
Professor Duncan Graham, of Strathclyde’s Department of Pure and Applied Chemistry, was a partner in the research. He said: “This was an unexpected finding but could be significant. The effect could be likened to making a footprint in mud and seeing the footprint in the bedrock several metres below, or to making a handprint in paint on one side of a door and being able to see it on the other side.
“Our Raman detection system - surface-enhanced resonance Raman scattering - is very sensitive and uses silver nanoparticles, while our research partners’ method, Raman optical activity, is weak but very informative about the chirality of a molecule. We measured signals from a molecule which had appeared to become chiral and the only way we have been able to explain this is that the molecule is reflecting the chirality of the biomolecule being studied in a non-contact way.
“We think we have induced chirality in the silver surface electrons and the way we have done it is a new phenomenon that is fundamentally different to previously reported mechanisms. It’s an optical phenomenon which is reproducible and we are interested in understanding more about it, as well as more about the stereochemistry implications.”
Health Technologies is a key area of expertise within the University of Strathclyde’s £89 million Technology and Innovation Centre, officially opened by HM The Queen and HRH The Duke of Edinburgh on 3 July 2015.This health research supports the discovery of new drugs, improvements in manufacture of drugs, and better delivery of more effective treatments, using technology developed at Strathclyde.
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