New security sensor devices made possible by metallic nanostructures

Chemical weapons and explosives present immediate threats to public health and safety. While several detection methods are available, advances in technology for cheap fast and accurate detection of explosives and chemicals in different environments is ongoing.

 

Last week London researchers published details of new sensor structures, which they claim could be used in novel security devices to detect poisons and explosives or proteins in patients' blood.

 

The nanosensors could be tailor-made to instantly detect the presence of particular chemicals, by decorating the nanostructure surface with specific 'molecular traps' that bind the chosen target molecules. Once bound, the target molecules would change the colors that the device absorbs and scatters, alerting the sensor to their presence.

 

The team led by Imperial College London showed that by putting together two specific 'nanostructures' made of gold or silver, they can make an early prototype device which, once optimized, should exhibit a highly sensitive ability to detect particular chemicals in the immediate surroundings.

 

The nanostructures are each about 500 times smaller than the width of a human hair. One is shaped like a flat circular disk while the other looks like a doughnut with a hole in the middle. When brought together they interact with light very differently to the way they behave on their own.

 

The scientists have observed that when they are paired up they scatter some specific colors within white light much less, leading to an increased amount of light passing through the structure undisturbed. This is distinctly different to how both structures scatter light separately. This decrease in the interaction with light is in turn affected by the composition of molecules in close proximity to the structures - the researchers hope that this effect can be harnessed to produce sensor devices.

 

The team's next step is to test whether the pair of nanostructures can detect chosen substances in lab experiments.