Cocaine Detection by a Laser-Induced Immunofluorometric Biosensor

Martin Paul,Michael G Weller,Robert Tannenberg,Marco Ponader,Georg Tscheuschner

doi:10.3390/bios11090313

Martin Paul, Michael G Weller + Show 3 more

Open Access

https://doi.org/10.3390/bios11090313

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Abstract

The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue for public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 7 ppt (23 pM) of cocaine with a response time of 90 s and a total assay time below 3 min. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement.

Highlights

In the recent European Drug Report 2021 [1], it was stated that the market for cocaine in Europe is still growing
In order to synthesize the hapten for the affinity column and the indirect ELISA, the NHS activation route with BEC was chosen [42]
Benzoylecgonine tetrahydrate was dried with DSC in DMF to remove water [47] and subsequently activated with DIC and NHS

Summary

Introduction

In the recent European Drug Report 2021 [1], it was stated that the market for cocaine in Europe is still growing. One of the main tasks of police and customs authorities at harbors, airports, and borders is the control of illegal drug trafficking. Sometimes of high sophistication, have been tried and used to transport and distribute illegal drugs. Despite the enormous efforts to reduce the import of illegal drugs, these activities cannot be very effective. The presence of masking substances effectively hinders the detection of cocaine by color tests and mid-infrared analysis (MIR) [3]. This situation puts some pressure on the development of improved methods for drug detection;

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