A cost-effective fluorescence biosensor for cocaine based on a "mix-and-detect" strategy

Area of Science:

• Analytical Chemistry
• Biochemistry
• Forensic Science

Background:

• Efficient detection of illicit drugs like cocaine is crucial for combating drug trafficking.
• Current detection methods may lack speed, specificity, or require complex procedures.

Purpose of the Study:

• To develop a rapid, one-step, label-free method for specific cocaine detection.
• To utilize a fluorescence-based strategy employing aptamers and Thioflavin T.

Main Methods:

• A novel anti-cocaine aptamer (coc.ap2-GC) was developed and optimized.
• Thioflavin T (ThT) was used as a fluorescence indicator bonded with the aptamer.
• Cocaine detection was achieved through a competitive binding assay causing fluorescence quenching.

Main Results:

• The optimized aptamer (coc.ap2-GC) demonstrated higher affinity and enhanced ThT binding fluorescence.
• A significant fluorescence reduction was observed upon cocaine binding, indicating successful detection.
• The method achieved a low detection limit of 250 nM for cocaine.
• Practical sample analysis in human urine and saliva showed good precision and high sensitivity.

Conclusions:

• A sensitive and rapid "mix-and-detect" fluorescence assay for cocaine detection was successfully established.
• The label-free, aptamer-ThT based method shows promise for real-time illicit drug monitoring.
• This approach offers a valuable tool for forensic and anti-drug trafficking applications.