Cocaine Detection by a Laser-Induced Immunofluorometric Biosensor

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.

Microfluidic nanodevices for drug sensing and screening applications

“…The analysis of illicit drugs usually needs to overcome several problems. First, a low target analyte concentration must be detectible ( Hilton et al, 2011 ; Jang et al, 2012 ; Kong et al, 2018 ; Paul et al, 2021 ). Second, the matrix present in real samples may influence the analysis and detection accuracy.…”

Recent Developments in the Field of Optical Immunosensors Focusing on a Label-Free, White Light Reflectance Spectroscopy-Based Immunosensing Platform

“…Then, either electrochemical impedance spectroscopy or SPR were combined with the antibody-gold nanoparticles and the relevant immunosensors were developed [72]. A SPR immunosensor for programmed death ligand 1 (PD-L1) was described based on both an aptamer conjugated to magnetite nanorods containing ordered mesocages and silver nanoclusters (MNOM@AgNPs) and an anti-analyte antibody immobilized on the surface of a gold chip properly treated with para-sulfonatocalix [4]arene, thus leading to highly specific recognition of PD-L1 [73]. A SPR immunosensor for cortisol was reported which employed an unclad plastic optical fiber coated with a gold/palladium alloy on which an anti-analyte antibody was covalently linked [74].…”

“…Early optical immunosensors used specific labels that were linked to a suitable assay-biomolecule, enabling detection of the analyte–antibody interactions and quantification of the analyte based on appropriate characteristics of the optical signal these labels emit. The most widely used labels are fluorescent, ranging from well-known classical dyes such as Cy5 [ 3 ] or Dy654 [ 4 ] to specially-prepared quantum dots [ 5 ]. Based on various criteria, fluorescent immunosensors can be further subdivided, e.g., into sensors based on fluorescence quenching, which mostly depends on binding or removal of the analyte to/from the specific antibody [ 5 , 6 , 7 ].…”

Developing GLAD Parameters to Control the Deposition of Nanostructured Thin Film

“…Therefore, the possibility to deposit a gas-sensing layer of a nanocolumnar shape under controlled conditions is a powerful tool. Moreover, physical vapor deposition can be easily adapted to complementary metal-oxide semiconductor (CMOS) technology; therefore, front-end electronics compounds can be realized by using the same technology [16][17][18]. Stability is also an important feature of gas sensors; however, more aspects than the gas-sensing layer itself are responsible for a suitable stability, e.g., gas-sensor substrate, electrodes, front-end electronic circuits.…”