A molecularly imprinted electrochemical aptasensor based on graphene and tin dioxide composite with electrodeposited gold nanoparticles for dual recognition of enrofloxacin

In this work, a molecularly imprinted electrochemical aptamer sensor (MIEAS) for the detection of enrofloxacin (ENR) was developed using SnO 2 -graphene (SnO 2 -Gr) and gold nanoparticles (AuNPs) as electrode modification materials. The SnO 2 -Gr composite material has a large specific surface area and can enhance the conductivity of the sensing platform. The aptamer, serving as a biofunctional monomer, was immobilized on the electrode surface via Au-S bonds. Using ENR as the template molecule and nicotinamide (NA) as the chemical functional monomer, a molecularly imprinted polymer (MIP) film was prepared by electropolymerization. Benefiting from the synergistic effect of MIP and aptamer, this MIEAS exhibits a good linear relationship with ENR in the range of 10 −14 to 10 −5  M, and the detection limit is as low as 1.65 × 10 −15  M. Satisfactory recovery was obtained in milk and environmental water samples, indicating the potential for application in food and environmental analysis.