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Cooperative-binding Split Aptamer Assay for Rapid, Specific and Ultra-sensitive Fluorescence Detection of Cocaine in Saliva

NCJ Number
251245
Date Published
Author(s)
H. Yu, J. Canoura, B. Guntupalli, X. Lou, Y. Xiao
Annotation
This article reports on a project that developed a split cocaine-binding aptamer that achieves improved target-binding affinity through cooperative binding.
Abstract
This aptamer incorporates two binding domains, such that target binding at one domain greatly increases the affinity of the second domain. The research experimentally demonstrated that the resulting cooperative-binding split aptamer (CBSA) exhibits higher target-binding affinity and is far more responsive in terms of target-induced aptamer assembly compared to the single-domain parent split aptamer (PSA) from which it was derived. The project further confirmed that the target-binding affinity of the CBSA can be affected by the cooperation of its binding domains and the intrinsic affinity of its PSA. To the researchers’ knowledge, CBSA-5335 has the highest cocaine affinity of any split aptamer described to date. The CBSA-based assay also demonstrates excellent performance in target detection in complex samples. Using this CBSA, researchers achieved specific, ultra-sensitive, one-step fluorescence-detection of cocaine within 15 minutes at concentrations as low as 50 nM in 10-percent saliva without signal amplification. This limit of detection meets the standards recommended by the European Union's Driving under the Influence of Drugs, Alcohol and Medicines program. The assay also demonstrated excellent reproducibility of results, confirming that this CBSA-platform represents a robust and sensitive means for cocaine detection in actual clinical samples. Researchers experimentally demonstrated that the resulting cooperative-binding split aptamer (CBSA) exhibits higher Target-binding affinity and is far more responsive in terms of target-induced aptamer assembly compared to the single-domain parent split aptamer (PSA) from which it was derived. Researchers further confirmed that the target-binding affinity of the CBSA can be affected by the cooperativeness of its binding domains and the intrinsic affinity of its PSA. The researchers believe CBSA-5335 has the highest cocaine affinity of any split aptamer described to date. 7 figures and 15 references (Publisher abstract modified)
Date Created: December 17, 2017