Electrochemical aptasensor for carbendazim based on a rationally designed truncated aptamer and ratio-engineered urea-derived Co–Ni microflowers/rGO interface

Published: 2026
Environmental Technology & Innovation
ISBN/ISSN: 2352-1864

Abstract

Carbendazim (CBZ), a widely used fungicide, requires rapid and sensitive monitoring due to its persistence and potential risks to food safety and the environment. Herein, we report an electrochemical aptasensor based on dual engineering of the aptamer recognition element and a urea-derived Co–Ni microflowers/rGO sensing interface. Three truncated aptamer sequences were designed based on secondary structure analysis and experimentally screened to identify the sequence exhibiting the highest CBZ-induced electrochemical response. In parallel, the Co:Ni molar ratio within the Co–Ni microflowers was systematically optimized based on the electrochemical performance of the sensing interface. The optimized Co–Ni/rGO interface combined the electroactive characteristics of the bimetallic Co–Ni material with the conductivity of rGO, resulting in enhanced electrochemical performance. Immobilization of the selected truncated aptamer onto the optimized Co–Ni/rGO interface via a pyrene-based linker produced a highly sensitive aptasensor with a wide linear range and a detection limit of 0.8 pg mL⁻¹ . The proposed platform enabled CBZ detection in tomato, strawberry, water, and milk samples, with recoveries ranging from 90.5% to 125%. Overall, this work demonstrates the potential of concurrently engineering the recognition element and sensing interface to improve electrochemical aptasensor performance for food safety and environmental monitoring.