Ultra-sensitive electrochemical aptasensor for label-free detection of Aflatoxin B1 in wheat flour sample using factorial design experiments

Considering the significance of mycotoxin detection in food industries, herein, an ultrasensitive aptasensor was developed based on aflatoxin B1 aptamer immobilized on Carbon quantum dots/octahedral Cu2O nano composite. Electrochemical measurements were based on Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV). Since the effective parameters (pH, temperature, incubation time and concentration of aptamers) are interdependent, so their dependent study can be nonideal. Taguchi method has solved this problem and optimized the experimental conditions using a smaller number of experiments. Under optimum conditions, the electrochemical signals declined as AFB1 concentrations increased with a dynamic range of 3 ag.ml(-1) -1.9 mu g.ml(-1) and a low limit of detection (LOD) of 0.9 +/- 0.04 ag ml(-1). The obtained results proved sufficient repeatability (RSD = 2.4%), reproducibility (RSD = 2.56%), accuracy (97.2-104.4% recovery), and robustness (RSD = 3.25%). Furthermore, considerable selectivity, stability and reliability of the aptasensor confirmed the capability to work in future real assays.

Automated summary

An ultrasensitive aptasensor based on carbon quantum dots/octahedral Cu2O nano composite and AFB1 aptamer was developed, showing fast detection and accuracy of AFB1 concentrations under optimized experimental conditions. The sensor exhibited considerable repeatability, reproducibility, accuracy, and robustness, with sufficient selectivity, stability, and reliability for future practical assays.