Aptamer-Functionalized Screen-Printed Carbon Electrodes Coated with Polymerized Catecholamine Film for Capacitive Sensing of Acetamiprid

Abstract

The detection of acetamiprid (ACE) residues remains a critical challenge in environmental and food safety monitoring. Herein, a novel biosensing platform is presented, based on screen-printed carbon electrodes (SPCEs) modified with an electrodeposited catecholamine film and a specific anti-ACE aptamer as the biorecognition element. The electroactive polymeric film was electrochemically deposited onto the SPCE surface, providing enhanced electron transfer properties and increased electroactive surface area. The subsequent immobilization of an anti-ACE aptamer created a selective biosensing interface. Using redox capacitance spectroscopy, it is demonstrated that the interaction between ACE and the biomodified electrode surface induced measurable changes in interfacial charge distribution and capacitance. The biosensor exhibited a linear response across a wide dynamic range of ACE concentrations (1 fg·mL⁻¹ to 10 pg·mL⁻¹), with a detection limit of 0.57 fg·mL⁻¹ (∼2.56 aM) (S/N = 3). The practical utility of the sensor was validated through recovery studies on lettuce and tomatoes, demonstrating its potential for routine ACE monitoring in vegetables. This label-free electrochemical approach offers a promising platform for the rapid and sensitive detection of pesticides in complex matrices.