Smartphone-assisted electrochemiluminescence imaging test strips towards dual-signal visualized and sensitive monitoring of aflatoxin B1 in corn samples

Aflatoxins B1 (AFB1) contamination in agro-food holds great threaten to human and animal health. Conventional test strips for rapid AFB1 visualized monitoring remains challenged by improvement of sensitivity and matrix interference resistance. In this case, we developed a portable electrochemiluminescence (ECL) imaging test strip with dual-signal outputs for AFB1 quantification in corn samples. Ru-PEI@SiO2@Au nanospheres were synthesized for bonding with anti-AFB1 antibody and then colorimetrical signal-reported on test line through the capillary flow at strips. Meanwhile, ECL imaging signal of the constructed carbon-ink-based working electrode on polyvinyl chloride substrate of strips was exported under an applied potential of 1.25 V. The whole ECL test strips not only endowed convenient colorimetric responses but guaranteed quick-witted ECL image distinguishment even at extremely low AFB1 content. The detection limit of this ECL imaging-integrated mode was 10-fold lower than that of only colorimetric mode. Furthermore, satisfactory selectivity, reliability and practicability of the as-proposed ECL test strips were demonstrated. This work offered a promising platform for on-site, accurate and sensitive detection of pollutants in foods.