The detection of new psychoactive substances using microfluidic devices

Pearson, Catherine (2015) The detection of new psychoactive substances using microfluidic devices. Masters by Research thesis (MSc), Manchester Metropolitan University.

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Abstract

Due to revisions in certain drugs laws and tightening in regulations, there has been a rise in the amount of new psychoactive substances entering the market. In order to combat this increase, investigations have begun into creating new and effective portable devices that are capable of producing rapid positive or negative responses for the presence of these types of drugs. The main aim of this project was to convert a basic enzyme linked immunoassay onto a microfluidic device in order to create a system for detecting mephedrone and it metabolites. Small detection zones, capable of containing micro volumes of reagent, were created using liquid wax on analytical grade filter paper before being optimised using a glutaraldehyde activated chitosan surface. Using these wax printed microfluidic paper analytical devices (μPADs) and an enzyme-linked immunoassay it has been possible to detect a horseradish peroxidase (HRP) labelled cathinone sample within aqueous and biological media. The same method was then applied to the detection of mephedrone and was successfully able to detect mephedrone in urine at clinically relevant concentrations, giving an LOD 4.078 μg/mL of and an LOQ of 1.597 μg/mL. This method has also shown positive results in detecting and distinguishing between mephedrone, methcathinone, cathinone, ephedrine and 4-methylephedrine. As well as being robust enough to be able to differentiate between the cathinones it also proved highly selective, producing negative responses for other illegal drugs, such as cocaine and ketamine, as well as legal drug and potential cutting agents, such as paracetamol and caffeine.