Sensing Devices for Illicit Drug Detection

Abstract

This project is an initiative of the Future Industries Institute (FII) in collaboration with Alcolizer to design and build a novel biosensor for the detection of illicit drug, specifically tetrahydrocannabinol (THC). This report covers the requirements of such device, literature review, methodology and further work consideration. With increasing cases of drug abuse, the demand of various sensing devices continues to increase. Chemists and engineers are contributing immensely to develop devices that can detect drugs with high selectivity and sensitivity. Biosensors have grown from a niche academic discipline with a couple of minor products in 1970’s to a major commercial area with thousands of researchers active in the field. However, only a fraction of their real potential has been exploited in clinical diagnostics, pharmaceutical developments and applications, food and process controls, environmental monitoring, defense and security. In last few years, scientists have been significantly working in the development of electrochemical biosensors for the detection of illicit drugs. Herein we report on the development of a disposable amperometric magneto immunosensor for the detection of tetrahydrocannabinol (THC) in saliva. The biosensor involves the use of selective capture antibodies immobilized on the surface of Protein G modified magnetic particles for specific detection of THCs. Competition takes place between THC, free in solution, and using horseradish peroxidase (HRP)-conjugated THC, added at a fixed concentration, for their binding to the anti-THC modified magnetic particles. The HRP used as an enzymatic label, enables the amperometric detection by measuring the current intensity at -0.2V against Ag pseudo reference electrode upon addition of the enzymatic substrate using hydroquinone (HQ) as electron mediator. We have successfully shown that using this methodology THC can be detected at very low concentration and shorter analysis time.