Researchers at the University of East Anglia have found that gold nanoparticles are very effective detectors of biological toxins. These particles they say reveal the presence of poisons far faster than existing techniques that often involve shipping samples back to a lab. This they hope would help in aiding investigations at crime scenes.
Researchers led by Professor David Russell use of gold nanoparticles that are only 16 nanometres in diameter - roughly 1/5000th the width of a human hair. Once made, the particles are coated with sugars tailored to detect different biological substances. When the poison (target substance) are mixed with a weak solution of the sugarcoated nanoparticles, they binds to the sugar. This changes the properties of the solution and makes it change colour.
Professor Russell said pure solutions of the gold nanoparticles are a strong red colour but they instantly change to blue when the target substance is present. He said they are working with solutions of particles tailored for just one toxin as well as mixtures of nanoparticles. The scientists say that the colour changes were less pronounced with mixtures of nanoparticles but were still significant enough to easily spot. They also said that the extent of the colour change can also reveal how much of particular toxins were present.
Professor Russell's work was presented at a conference in London organised by the Engineering and Physical Sciences Research Council (EPSRC).