Dual-Signaling Amplification Electrochemical Aptasensor Based on Hollow Polymeric Nanospheres for Acetamiprid Detection

In this work, we first reported a dual-signaling electrochemical aptasensor based on layer-by-layer template technology and catalytic amplification for acetamiprid detection. Herein, the signal probe of the ferrocene (Fc)-based hollow polymeric nanospheres (Fc-HPNs) were prepared with repeated electrostatic adsorption between anionic poly(acrylic acid) and hyperbranched cationic polyethylenimine. In addition, ascorbic acid (AA) as an enhancer can catalyze the reduction of Fc-HPNs, which results in significant enhancement of the oxidation peak current of Fc-HPNs. Remarkably, the Fc-HPNs played dual roles: as nanocarriers to significantly increase the load amount of Fc and as nanoreducers to effectively catalyze reduction by AA for further signal amplification. Therefore, because of the special nanostructures of Fc-HPNs and the effective catalytic effect of AA, a dual-signaling electrochemical aptasensor was proposed. Surprisingly, this proposed assay for trace amounts of target detection exhibits excellent sensitivity with a linear range from 10 nM to 1 fM and a limit of detection down to 0.33 fM (S/N = 3), which opened a novel avenue and versatile strategy for monitoring of acetamiprid.