Elaborately manufacturing an electrochemical aptasensor based on gold nanoparticle/COF composites for amplified detection performance

Abstract

Gold (Au) nanoparticle-embedded covalent organic frameworks (namely Au@COFs) were ingeniously designed and prepared by using a straightforward impregnation-reduction method. This composite not only owns outstanding stability, rich π functional sites, superior electroconductibility, high surface area, and well-ordered porous structures, but also possesses relatively strong non-covalent affinity toward aptamers, synergistically resulting in the establishment of highly efficient electrochemical aptasensors for detecting analytes. Ciprofloxacin (CIP), for instance, is selected and investigated as a research model to estimate the feasibility and superiority of Au@COF-based aptasensors. The as-made Au@COF-based aptasensor exhibits awesome sensing performance with the lowest limit of detection of 2.34 fg mL⁻¹ (7.06 fM) in a concentration range from 1.0 × 10⁻⁵ to 0.5 ng mL⁻¹ as determined by analyzing electrochemical impedance signals, which is approximately attributed to numerous aptamer strands on the surface of COFs via strong π–π stacking interaction and the contribution of electrical conductivity from trapped Au nanoparticles. Concurrently, the fabricated aptasensor reveals excellent repeatability, circularity, selectivity, and stability as well as precise detection capability in a variety of real samples. This strategy provides a workable concept for developing and synthesizing of metal nanoparticle-built-in COF composites and their aptasensors in the extended electrochemical detection field.