Octahedral Cu₂O nanomaterials as electrochemical aptasensor for sensitive detection of tetracycline in milk

In this work, A novel label-free electrochemical biosensor based on octahedral Cu₂O @ Au nanocomposites was developed for the detection of tetracycline. The gold nanoparticles (AuNPs) on the surface of Cu₂O nanomaterials not only improve the electrochemical performance, but also can be used as a binding site for thiol-modified tetracycline aptamers, which can specifically bind to tetracycline. Cu₂O @ Au nanocomposites provide a synergistic effect of electrochemical signal amplification and tetracycline recognition strategy. Under the optimal conditions, the proposed biosensor exhibited different electrochemical reactions for different concentrations of tetracycline, with a linear range of 1 nM-1000 μM and a detection limit of 0.16 nM. This work provides a new idea for rapid and sensitive detection of tetracycline by using a simple and economical tetracycline aptamer combined with Cu₂O @ Au biosensor platform.