Amperometric Biosensor for Brucella Testing through Molecular Orientation Technology in Combination with Signal Amplification Technology

Brucellosisis a global zoonotic disease causing abortion and infertility in animals. Based on an oriented immobilization technique of using a biomolecule in combination with a signal amplification technology, a novel biosensor forBrucelladetection was designed. Graphene oxide/polypyrrole nanohybrids (GO/Ppy) modified a screen-printed gold electrode through co-electrodeposition for the oriented immobilization of a primary antibody (Ab(1)). Ab(1)was successfully immobilized by using cyclic voltammetry (CV). A new second antibody nanoprobe GO/Fe3O4/MB/Ab(2)(graphene oxide/nano-iron oxide/methylene blue/Ab(2)) was accomplished by using physical and chemical methods to amplify the electrical signal. The successful fabrication of the biosensor was characterized by using SEM, AFM, Raman, and FTIR spectroscopy. The prepared biosensor was also tested in theBrucellasolution by using differential pulse voltammetry (DPV). The results showed that the corresponding current was positively correlated with the logarithm ofBrucellaconcentration, with a low detection limit of 2.2x10(2) CFU/mL. Moreover, the results of the biosensor's reproducibility, repeatability, specificity and standard recovery were satisfactory. New methodologies in fabricating the biosensor may be applied to detect other harmful microorganisms.