A rapid and low cost approach based on paper microfluidic technology for presumptive drug detection

A paper microfluidic device (microPAD) has been developed for the presumptive testing of seized drugs. The microPAD was composed by hydrophilic channels on chromatographic paper by means wax printing and thermal lamination. Six different lanes were connected to a single stem. A different colorimetric reaction occurred within each lane, permitting the multiplexed detection of different substances including cocaine, opiates, ketamine, and various phenethylamines. Furthermore, the orientation allowed for using series of reactants in each channel, enhancing stability and permitting a sequential interaction with the analyte. The microPAD was evaluated for sensitivity and tested with common interferences and drug diluents. A further development of this approach for drug detecting was the coupling of the paper microfluidic device with gold nanoparticles and anti-cocaine aptamers to make the detection of cocaine more sensitive and specific. The operation of the device is easy and rapid, and does not require extensive training or instrumentation. In addition, all of the materials used in the device are safe and environmentally friendly. For these reasons, the microPAD should prove a useful tool for the screening of seized drugs.