| This drawing depicts an array of nanoscale gold double dots on glass; when covered by slightly hydrogenated graphene, the array can sense individual organic molecules (shown as the odd-looking objects resting on top of the double dots). (Image: University of Manchester) |
Manchester, England--Scientists at the University of Manchester, working with colleagues from Aix-Marseille University (Marseille, France), have created a device which potentially can see one molecule though a simple optical system and quickly analyze its components.1 The device is based on a plasmonic nanoarray of gold double dots on glass, all covered by a layer of slightly hydrogenated graphene. Diffraction from a light beam striking the array at an angle shows phase anomalies when the test molecule is present.
The researchers, led by Sasha Grigorenko, produced a new type of sensing device that has so-called "topological darkness." The device shows extremely high response to an attachment of just one relatively small molecule. This high sensitivity relies on topological properties of light phase.
The breakthrough could lead to rapid and more accurate drug testing for professional athletes, testing for the presence of explosives, or detecting viruses. Testing for toxins or drugs could be done using a simple blood test, with highly accurate results in minutes. The researchers found that the sensitivity of their devices is three orders of magnitude better than that of existing models, sensing materials at a level of only femtograms per square millimeter.
“The whole idea of this device is to see single molecules, and really see them, under a simple optical system -- say a microscope," says Grigorenko.
REFERENCE:
1. V. G. Kravets et al., Nature Materials (2013); doi:10.1038/nmat3537
Source: University of Manchester