A novel electrochemical approach for the ultrasensitive detection of fluoroquinolones based on a double-labelled aptamer to surpass complementary strands of aptamer lying flat

Abstract This study develops a novel electrochemical detection strategy for determination of fluoroquinolones (FQs) which was formed with a double-labelled aptamer as the detection element, methylene blue (MB) as redox agent and complementary strands of aptamer (CSs). This method exhibited excellent sensitivity for detection of ciprofloxacin as a member of FQs due to its ability to outstrip CSs lying flat on the electrode surface as a major challenge. Simplicity is another characteristic of this approach. The dynamic detection range was from 300 pM to 450 nM and the detection limit was 100 pM for ciprofloxacin. Also, the system displayed high selectivity towards FQs. The aptasensor succeeded in detection of ciprofloxacin in the spiked real samples, including human serum, milk and water samples. Altogether, the designed approach can introduce an effective and functional foundation for small molecules analysis to ensure food and human safety by applying corresponding aptamer sequences.