A sensitive aflatoxin B1 electrochemical aptasensor based on ferrocene-functionalized hollow porous carbon spheres as signal amplifier

Due to the high toxicity and carcinogenicity of Aflatoxin B1 (AFB1), a sensitive, low-cost and simple method to accurately detect AFB1 in foodstuffs is highly desirable. Herein, a sensitive and selective AFB1 electrochemical aptasensor was developed by using ferrocene immobilized hollow porous carbon spheres (HPCS-Fc) as the electrochemical signal tag. Attributed to the large surface and high conductivity of HPCS, the prepared Fc-HPCS showed the high load amount of Fc and HPCS-Fc labelled GC electrode displayed large oxidation peak current. To further improve the biosensing ability, tetrahedral DNA nanostructures (TDNs) was attached on the biosensing interface to control the orientation of HPCS-Fc-cDNA. Based on the above advantages, the HPCS-Fc labelled electrochemical aptasensor exhibited high sensitivity towards AFB1 in a wide linear range from 1.0 × 10⁻² pg mL⁻¹ to 100.0 μg mL⁻¹ and a low detection limit down to 3.3 × 10⁻⁵ ng mL⁻¹. Furthermore, the developed aptasensor was applied to detect AFB1 in wheat powder samples with satisfactory recoveries of 91.7%∼107.7%, demonstrating its potential application in testing AFB1 in food samples.