Electrochemical/Photoelectrochemical Dual-Mode Aptasensor for Sensitive Aflatoxin B1 Assay Based on Distance-Modulation Strategy Using AU NPs/PC _zif-8-ZnO as Sensing Substrate

Abstract

Aflatoxin B1 (AFB1), as a hepatotoxic and carcinogenic food contaminant, is commonly found in agricultural food. Developing a sensitive and accurate strategy for AFB1 analysis is significant to avoid potential health risk. Herein, we presented a ratiometric electrochemical (EC) and “off-on” photoelectrochemical (PEC) dual-mode paper-based aptasensor based on a distance-modulation sensing strategy, using Au NPs anchored ZIF-8-derived porous carbon-ZnO (Au NPs/PCZIF-8-ZnO) as sensing substrate. The independent signal transduction mechanisms and output mode not only broaden a dynamic detection range but also give a self-verification to assay results, improving the sensitivity and reliability. The dual-mode AFB1 aptasensor exhibited the detection range of 0.1 pg/mL-100 ng/mL and 0.02 pg/mL-100 ng/mL for EC and PEC mode with the detection limits of 36.7 and 9.3 fg/mL, respectively. Furthermore, it exhibited good practicability for AFB1 assay in peanut samples, holding great potential applications for food safety evaluation.

Keywords: Aflatoxin B1, dual-mode aptasensor, distance-modulation, Au NPs/PCZIF-8-ZnO, self-verification