Physicists from the University of Bath have designed a new type of sensor platform using a gold nanoparticle array that is a 100 times more sensitive than existing similar sensors.
In the sensor, gold nanodisks are arranged in squares, shown on bottom-left. The arrangement causes the sensor to emit UV light (in blue). (V.K Valev and D.C Hooper)
The sensor is composed of a series of gold disk-shaped nanoparticles on a glass slide. The Bath team learned that when they shone an infra-red laser at a precise arrangement of the particles, they began to release unusual amounts of ultraviolet (UV) light.
This mechanism for producing UV light is influenced by molecules binding to the surface of the nanoparticles, providing a means of sensing a tiny amount of material.
The scientists, from the University of Bath’s Department of Physics, expect that in the future they can apply the technology to build new ultra-sensitive sensors for medical diagnostics or for air pollution.
This new mechanism has great potential for detecting small molecules. It is 100 times more sensitive than current methods. The gold nanoparticle disks are arranged on a glass slide in a very precise array—changing the thickness and separation of the disks completely changes the detected signal. When molecules bind to the surface of a gold nanoparticle, they affect the electrons at the gold surface, causing them to change the amount of UV light they emit. The amount of UV light emitted would depend on the type of molecules that bind to the surface. This technique could enable ultra-sensitive detection of molecules in tiny volumes. It could in the future be used for detecting very low concentrations of biological markers for the early diagnostic screening for diseases, such as cancer.
Dr Ventsislav Valev, Royal Society Research Fellow and Reader in Physics, University of Bath
Dr Valev led the research with Research Associate David Hooper. The research has established the proof of principle for this new sensing mechanism. Going forward the team would next like to test the sensing of different types of chemicals and expects the method to be accessible to other researchers to use within five years.
Scientists at Northwestern University, Illinois (USA) fabricated the nanoparticles.