|
A dip-test for illicit drugs and poisons that is as quick and easy as a home pregnancy test-kit could save many lives according to US researchers. The team used UV-Vis spectroscopy to verify the performance of a proof of principle test on cocaine. "Based on this principle, we should be able to develop rapid tests for the emergency diagnosis of a large number of drugs and poisons," says Yi Lu of the University of Illinois in Urbana. The same approach could also be used to test for physiological molecules and environmental monitoring, he adds. Incidences of poisoning and drugs overdoses are common in hospital emergency rooms the world over. But, one thing medical staff lack to deal with such cases is a quick and easy way to identify the particular poison. For an initial diagnosis, they usually rely on circumstantial evidence provided by anyone accompanying the patient or the victims themselves. Laboratory tests on saliva, urine, or blood samples can be long winded and often the definitive identification of the poison is possible only post mortem, which is obviously too late for the victim. Now, Lu and his colleagues have laid the foundations for an entirely new rapid approach to poisoning diagnostics based on a test strip not dissimilar to the home pregnancy tests. These reveal the putative mother's condition through a visible coloured band that appears as compounds present in the woman's urine only during pregnancy react with an indicator on the test strip. These test strips are as reliable as laboratory methods. "Our method is based on gold nanospheres and aptamers," says Lu. Aptamers are single-stranded nucleic acids that bind to certain target molecules with the same strength and specificity as antibodies. It is possible to identify at least one aptamer from a random sequence DNA library that will bind to a specific target molecule, in this case cocaine. When the experimental test-strip for cocaine is dipped into a sample, the liquid diffuses across the surface until it reaches the gold nanoparticles-aptamer aggregates held together by a number of DNA aptamers. Any cocaine molecules in the sample will bind more strongly to their target aptamer breaking the bonds holding the nanosphere aggregates together and turning the previously blue aggregates into individual red particles as the free nanoparticles reflect red light. A narrow strip of streptavidin, binds to the gold-nanoparticles' biotin coating concentrating the bright red gold spheres into a narrow band, making them immediately visible to the naked eye. The test works within minutes rather than the possible hours it takes to carry out a laboratory-scale test on a sample. Moreover, test kits for a range of possible illicit drugs and likely poisons could be made available cheaply and easily to emergency rooms. Unfortunately, a dip-test for radioactive compounds such as polonium-210 is not likely to be available, although thankfully poisoning with this chemical is a lot rare than a cocaine overdose. Related links: The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.
|
|
