Label-Free Aptamer-for Detection of Cocaine in Biofluids – IP 1426

Antibody-basedscreens often suffer from poor specificity, and existing aptamer-baseddetection generally rely on polymerase amplification, enzymes or enzyme-linkedassays to achieve sensitive cocaine detection at low nanomolar concentrations.Preparation for these multi-step assays is complex and usually requires atleast several hours. FIUinventors have created a rapid and specific target-displaced, aptamer-basedmethod for one-step cocaine detection with minimal reagent requirement. Thediscovery of the interaction between the ATMND molecule and the cocaine-bindingaptamer, 38-GC, has called for the design of a unique sensor. The new sensor platform relies on thedisplacement of ATMND from the 38-GC aptamer by cocaine through competitivebinding. The 38-GC aptamer was engineered through the introduction of sequencechanges into the MNS-4.1 and exhibits higher affinity to both ligands whilereducing background signals and increasing signal gain. Through successfultesting, the sensor has demonstrated detection of cocaine within seconds atconcentrations as low as 200 nM, which is 50-fold lower than the assays basedon target-induced conformational change. Moreover, signal gain reportedlyincreased with the increase of cocaine concentration, reaching a limit ofdetection of 10.4 µM, 18.4 µM, and 36 µM in undiluted saliva, urine, and serumsamples respectively. The label-free detection is performed at room temperaturein a single tube containing the aptamer-ATMND complex and the sample ofinterest. Anne Laure Schmitt Olivier aschmitt@fiu.edu 305-348-5948