Label-Free DNA Electrochemical Aptasensor for Fumonisin B 1 Detection in Maize Based on Graphene and Gold Nanocomposite

Fumonisin B1 (FB1) is the most common species with the highest toxicity among fumonisins. In order to develop a sensitive and simple approach for the detection of FB1 in maize, we designed a new label-free and simple DNA electrochemical aptasensor. Au nanoparticles and graphene oxide (GO) were utilized and chemically modified to amplify the electrochemical signal and afford anchor sites for the modification of recognition probe for FB1. Besides, thionine, an excellent electrochemical indicator, was conjugated on GO–Au complex surface based on the π–π interaction between thionine and GO. To measure FB1 with high specificity and decrease the interference signal produced in real sample measurement, its aptamer was functionalized on Au particle surface via Au−S bond. The proposed biosensor demonstrates a wide linear range between 1 × 10–11 to 1 × 10–4 g/mL with a low detection limit of 10 pg/mL. Importantly, it exhibits acceptable practicability and good stability in real sample detection.