Interference-resistant aptasensor with tetrahedral DNA nanostructure for profenofos detection based on the composites of graphene oxide and polyaniline

•A gold-tetrahedral DNA nanostructure (Au-TDN) was independently designed.•Au-TDN can make its aptamers keep in a highly ordered vertical direction.•Au-TDN could improve the binding efficiency of aptamer and target pesticide.•GO@PANI was prepared using graphene oxide (GO) and polyaniline (PANI). In this work, an interference-resistant electrochemical aptasensor that could detect profenofos in vegetables was constructed based on complexes of graphene oxide and polyaniline (GO@PANI) and gold nanoparticles-tetrahedral DNA nanostructure (Au-TDN). Compared with a single chain aptamer, the tetrahedral DNA nanostructure is highly stable and allows the aptamer on this structure to stand in a highly ordered position on an electrode surface. Moreover, the AuNPs are biocompatible and can protect the activity of the aptamer, which can improve the assembly success rate of Au-TDN. Besides, the conductivity of PANI had been tremendously enhanced thanks to the existence of GO, which improved the dispersion of PANI. The GO@PANI was prepared by a chemical synthesis method, which had a large surface area and was able to adsorb many Au-TDN. Under optimal working parameters, the constructed aptasensor exhibited good electrochemical sensing performance with a detection limit of 10.50 pg/mL and a linear range of 1.0 × 102–1.0 × 107 pg/mL. In addition, it was employed in detecting profenofos in vegetables with a good recovery rate of 90.41–116.37 %. More importantly, the aptasensor also has excellent stability and high selectivity. This study provides a promising method to avoid interference in the detection of profenofos by sensors.