Tiny Device Detects Methamphetamines

Methamphetamines are major drugs of abuse and are difficult to detect as a class of compounds. A variety of analytical techniques including chromatography-mass spectrometry can already detect these nervous system stimulants. But existing tests often require long operation time and difficult sample preparation steps and generally detect specific compounds rather than the entire family. A group led by Paolo Bergese of the University of Brescia and Enrico Dalcanale of the University of Parma, both in Italy, has now made a start toward developing a relatively simple device that could make it possible to rapidly detect methamphetamines as a class in water (Angew. Chem. Int. Ed. 2014, DOI: 10.1002/anie.201404774). The device is based on a tetraphosphonate cavitand receptor, which binds the ⁺NH₂CH₃ group present in all methamphetamine salts with high selectivity. A derivatized version of the cavitand is grafted onto the face of a silicon microcantilever. Drugs from a solution in contact with the microcantilever bind to the cavitand and cause the microcantilever to deflect. Using a laser beam to record the deflections enables the drugs to be detected. The device, which tested well with real street samples, could lead to a sensor for screening illicit drugs.