Schematic drawings of (A) different designs of assay probes for cocaine detection: (left) monolithic aptamer (MA), (middle) double-fragment aptamer (DFA), and (right) triple-fragment aptamer (TFA); (B) gold nanoparticle based optical cocaine detection using TFA. The same oligonucletide sequences were drawn in the same colors.
Chinese scientists have developed a colorimetric sensor consisting of a triple-fragment aptamer (TFA) that is able to assemble in the presence of cocaine. Xinhui Lou and Yueying Liu and co-workers at the Capital Normal University in Beijing, showed that the aptasensor was specific for cocaine and worked equally well in complex urine samples containing 100 μM cocaine or filtered serum containing cocaine.
This new type of aptamer probe design showed a gradual colour change from red to blue when the concentrations of cocaine was increased from 0 to 200 μM . “TFA broadens the repertoire of probe designs and provides good opportunities for the future development of novel detection approaches and for nanostructure constructions,” says Liu et al.
Even though the assays need to be conducted at low temperature (4 °C), the authors believe that the detection method can be further improved by increasing the stem length.
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Highly specific triple-fragment aptamer for optical detection of cocaine
Ruxing Zou , Xinhui Lou , Huichao Ou , Ying Zhang , Wenjie Wang , Min Yuan , Ming Guan , Zhaofeng Luo and Yueying Liu
RSC Adv., 2012,2, 4636-4638
DOI: 10.1039/C2RA20307C
