Novel Electrochemical Aptasensor Based on Floral Zinc Oxide/Reduced Graphene Oxide/Colloidal Gold Composite for the Detection of Tetracycline, Doxycycline and Oxytetracycline in Milk

Abstract

In this research, an electrochemical aptamer sensor based on the specific recognition of tetracycline, doxycycline and oxytetracycline was developed through flower-like zinc oxide/reduced graphene oxide/nano-gold composites. Firstly, floral zinc oxide had a large contact area, which bound more gold nanoparticles, and bound more adapters through Au–S bonds. Next, due to the poor conductivity of floral zinc oxide, the combination of floral zinc oxide and rGO was able to improve the conductivity. Finally, the rGO–ZnO–AuNPs composite was used as a platform to improve the electron transport rate on the glassy carbon electrode surface, enhance the electrochemical strength, and provide enough active sites for the capture of aptamers. After condition optimization, the lowest detection concentrations for tetracycline, doxycycline and oxytetracycline were 0.33, 0.28 and 0.3 ng·ml−1 respectively. In addition, this aptasensor had good stability, selectivity, anti-interference and reproducibility. It would be further applied to the detection of antibiotics in milk.