A disposable microfluidic aptasensor for one-step and real-time detection of sub-femtomolar-level aflatoxin B₁ in...

Aflatoxin B₁ (AFB₁) is a highly toxic substance found in food, necessitating rapid and sensitive detection methods. Combining interfacial capacitive sensing with AC electrothermal (ACET) enrichment, an aptasensor based on a PCB electrode array is developed for real-time detection of trace AFB₁. Owing to the sensitive solid-liquid capacitance with a pF-level resolution, AFB₁ detection at sub-femtomolar level is achieved. The induced ACET flows enrich AFB₁ molecules towards the electrode surface during capacitance measurement, enabling a one-step detection containing target enrichment, with an overall time of 20 s without any extra concentrating devices or processes. This sensor has a low detection limit of 620 aM, a selectivity of 2262:1 against interferences, and a wide semi-log linear range from 1 fM to 10 pM. It is with a cost below 1 US dollar for disposable detection and a convenient operation for on-site application. The detection of AFB₁ in three types of quality control samples demonstrates a good feasibility for food safety inspection.