Development of a novel assay for drugs of abuse based on Molecularly Imprinted Polymers as synthetic antibodies

Over the last fifteen years the number of deaths from drug overdoses has increased significantly. According to the World Health Organisation (WHO), opioids were responsible for 160,000 of the 450,000 overdose deaths related to drug use in 2015. For this reason there is a rise in the demand for a rapid, ease to use and relatively inexpensive method of detection for drugs of abuse. The research presented here is focused on the development of a working assay for drugs of abuse using molecularly imprinted polymers (MIPs) as synthetic antibodies, with particular focus on detection of fentanyl. Molecularly imprinted nanoparticle assay (MINA) was successfully developed to detect and quantify the concentration of fentanyl over the range 7.4-598.2 ng/mL, with a detection limit of 7.38 ng/mL. The novel assay uses the magnetic field generated by magnetic inserts on the bottom of a modified 96-microtiter plate. Displacement and competitive formats of MINA were developed, with competition achieved through use of iron oxide nanoparticles (IO-NPs) conjugated with fentanyl. IO-NP functionalisation (silanisation and immobilisation) was optimised by quantifying surface amino groups using the Kaiser test in order to calculate the efficiency and stability of fentanyl immobilisation. The versatile assay developed has the potential to become an efficient alternative to immunoassays. It is very easy and straightforward for the end user, due to the mix-and-read format which allows rapid throughput of analytical samples.