Establishment of an electrochemical RNA aptamer-based biosensor to trace nanomolar concentrations of codeine

Codeine is an opium alkaloid with a great potential of abuse among opioid consumers. Detection of codeine is a routine procedure in the military and government of some countries for personnel recruitment. Therefore, a specific, selective, and easy to use method would be an important improvement in such detection procedures. According to previous reports, short single-stranded DNA or RNA sequences with high affnity and specificity to their targets, aptamers, could be used for designing an accurate and specific biosensor for codeine. This study introduces an aptamerbased biosensor for codeine detection in nanomolar concentrations by an electrochemical method, and ferrocene carboxylic acid was used as the redox molecule. The data show an improvement in codeine detection in comparison with the previous reports by other methods. The fabricated aptasensor offers a simpler and faster method with a lower limit of detection for codeine. The results demonstrate the reliability and robustness of the constructed aptasensor in codeine detection and measurement.