Part of the show Repairing the Retina and Spinal Cord
This week we've been hearing about the radioactive Polonium poisoning that killed Russian Alexander Litvinenko. Although that's extremely rare, doctors are often faced with patients that have been poisoned with more common substances, or have taken drugs overdoses. For treatment to be effective, it's very important to know as quickly as possible what they have taken. But sometimes this can take long and complex lab tests, using up vital time. Now a team of scientists at the University of Illinois in the States have developed a testing technology that's simple and fast. You simply dunk a test strip in a sample of saliva, urine or blood plasma. The secret behind the strips is "bling" technology. They rely on gold particles and tiny pieces of DNA called aptamers, designed to stick very specifically to the target poison. In the test strip, the DNA aptamers hold together tiny particles of gold. But when the stick is dipped into a samples containing the poison or drug, the aptamers bind to it very tightly instead, releasing the gold particles. Thanks to some clever biochemistry, the gold particles then travel up the strip and are trapped, forming a distinct red band. So far, the team have developed a test to detect cocaine, and the strips seem to be as effective as lab tests. The lead researcher Li Yu hopes that they will be able to use their method to detect a wide rang of drugs or poisons, because it is easy to screen large numbers of different DNA aptamers to find the ones that stick to specific targets. The technology could also be used to detect biological molecules in blood, saliva or urine for diagnostic tests in hospitals, or for monitoring toxins in the environment.