A Turn-on Biosensor-Based Aptamer-Mediated Carbon Quantum Dots Nanoaggregate for Acetamiprid Detection in Complex Samples

In this paper, we developed a new biosensor-based on aptamer-mediated carbon quantum dots (apt-CQDs) nanoaggregate for acetamiprid detection. The acetamiprid aptamer, 5'- and its complementary DNA were labeled on CQDs, respectively. The hybridization of aptamer and its complementary DNA triggered the formation of nanoaggregate of CQDs, leading to the fluorescence quenching of the CQDs. Upon addition of acetamiprid, specific recognition of acetamiprid caused the release of the cDNA-CQDs and the fluorescence intensity recovered which was linearly related to the concentration of acetamiprid. The sensor provided a linear range from 0.2 to 20 ng/L for acetamiprid with a detection limit of 0.04 ng/L in an aqueous buffer. The same linear range was obtained in spiked human serum samples and lettuce samples with similar detection limits (0.15 and 0.11 ng/L), demonstrating high robustness of the sensor in a complex sample matrix. The as-prepared biosensor was used to monitor acetamiprid level in real samples with recovery ranged from 86 to 107%, and RSDs ranged from 1.3-6.9% (n = 3). The proposed study not only provided a simple method through CQDs nanoaggregate and also provided a turn-on detection mode for acetamiprid in real samples with high signal-to-noise ratios.