Unmodified gold nanoparticles as a colorimetric probe for visual methamphetamine detection

In recent years, in addition to the classic drugs, addiction to a series of new drug classes known as club drugs has increased significantly. Fast and low-cost bioassay for the detection of amphetamine-based drugs can be an effective strategy towards reducing their abuse. In this study, we designed a sensitive bioassay strategy using gold nanoparticles (GNPs) and the aptamers that possess high affinity toward methamphetamine (MA). It is suggested that the aptamer adopts different tertiary structures in the presence and/or absence of its specific target and GNPs can effectively differentiate between these two states by their characteristic surface plasmon resonance-based colour change. Visual detection of MA and 3,4-methylenedioxy-N-methylamphetamine (MDMA) in the low micromolar range is possible within minutes with the use of this method.