A new nanomaterial developed by scientists at the University of Bath could solve a conundrum faced by scientists probing some of the most promising types of future pharmaceuticals (Nanoscale Horizons, “Measuring optical activity in the far-field from a racemic nanomaterial: diffraction spectroscopy from plasmonic nanogratings”).

Scientists who study the nanoscale – with molecules and materials 10,000 smaller than a pinhead – need to be able to test the way that some molecules twist, known as their chirality, because mirror image molecules with the same structure can have very different properties. For instance one kind of molecule smells of lemons when it twists in one direction, and oranges when twisted the other way.

Detecting these twists is especially important in some high-value industries such as pharmaceuticals, perfumes, food additives and pesticides.
Recently, a new class of nanoscale materials have been developed to help distinguish the chirality of molecules. These so-called ‘nanomaterials’ usually consist of tiny twisted metal wires, that are chiral themselves.

However, it has become very hard to distinguish the twist of the nanomaterials from the twist of the molecules they are supposed to help study.
To solve this problem the team from the University of Bath’s Department of Physics created a nanomaterial that is both twisted and it is not. This nanomaterial has equal number of opposite twists – meaning they cancel each other out. Usually, upon interacting with light, such material appears without any twist; how then could it be optimised to interact with molecules?

Image Credit:  Ventsislav Valev and Alex Murphy