Together, these technologies could help ensure that new drugs are safe and pure
- Ventsislav Valev
A direct relationship between the way in which light is twisted by nanoscale structures and the nonlinear way in which it interacts with matter could be used to ensure greater purity for pharmaceuticals, allowing for ‘evil twins’ of drugs to be identified with much greater sensitivity.
Researchers from the University of Cambridge have used this relationship, in combination with powerful lasers and nanopatterned gold surfaces, to propose a sensing mechanism that could be used to identify the right-handed and left-handed versions of molecules.
Some molecules are symmetrical, so their mirror image is an exact copy. However, most molecules in nature have a mirror image that differs - try putting a left-handed glove on to your right hand and you’ll see that your hands are not transposable one onto the other. Molecules whose mirror-images display this sort of “handedness” are known as chiral.
The chirality of a molecule affects how it interacts with its surroundings, and different chiral forms of the same molecule can have completely different effects. Perhaps the best-known instance of this is Thalidomide, which was prescribed to pregnant women in the 1950s and 1960s. One chiral form of Thalidomide worked as an effective treatment for morning sickness in early pregnancy, while the other form, like an ‘evil twin’, prevented proper growth of the foetus. The drug that was prescribed to patients however, was a mix of both forms, resulting in more than 10,000 children worldwide being born with serious birth defects, such as shortened or missing limbs.
When developing new pharmaceuticals, identifying the correct chiral form is crucial. Specific molecules bind to specific receptors, so ensuring the correct chiral form is present determines the purity and effectiveness of the end product. However, the difficulty with achieving chiral purity is that usually both forms are synthesised in equal quantities.
Researchers from the University of Cambridge have designed a new type of sensing mechanism, combining a unique twisting property of light with frequency doubling to identify different chiral forms of molecules with extremely high sensitivity, which could be useful in the development of new drugs. The results are published in the journal Advanced Materials.
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Image: When twisted light matches the twist of nanostructures, strong interactions with chiral molecules could arise
Credit: Ventsislav Valev
Reproduced courtesy of University of Cambridge
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