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

Fumonisin B 1 ( FB 1 ) is the most common species with the highest toxicity among fumonisins. In order to develop a sensitive and simple approach for the detection of FB 1 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 FB 1 . 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 FB 1 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.