Aptamer-Based, Exonuclease-Amplified, Paper Device for Point of Collection Screening of Cocaine and Methamphetamine in Oral Fluid

The project's plan was to generate new aptamers that specifically bind to the targeted drug so as to achieve better specificity than immunoassays. Exonuclease III (Exo III) was used to digest the target/aptamer complex and recycle the target, resulting in high sensitivity and a reduction in false negatives. Detection was to be achieved with a color change that results from gold Nan particle (AuNP) aggregation. By transferring this assay into a portable, postage-stamp-sized, paper-based device, the project anticipated achieving instrument-free, simultaneous detection of cocaine and methamphetamine at low ng/mL concentrations in mL volumes of oral fluid with a visible red-to-blue color change. The project successfully developed a specific, EATR-amplified and AuNP-reported screening platform for cocaine, using a newly engineered cocaine-binding CBSA. Colorimetric detection of 1 uM cocaine was achieved within 15 minutes. The project also modified different colorimetric assays for use in a six-channel, paper-based, microfluidic device. This paper microfluidic device can detect multiple drugs of abuse within 5 minutes. The paper chips are stable for up to 3 months. In parallel, the project also developed a rapid assay based on split aptamers for the detection of cocaine and is in the process of adapting this assay for use in a paper-based microfluidic device. 7 figures, 16 references, and a listing of publications and presentations on the project