A Novel Colorimetric and ECL Dual-Mode Aptasensor for Detecting Malathion Based on CuFe₂O₄ Nanocrystalline Cluster

To achieve rapid, efficient, and cost-effective screening and quantification of malathion in agricultural products and environmental samples, a novel dual-mode aptasensor strategy was developed, including colorimetric and electrochemiluminescent (ECL) methods. The synthesized CuFe 2 O 4 exhibited enhanced enzyme-loading capacity while the established aptamer system could preserve enzymatic activity. As a result, the ascorbic acid generated by enzymatic hydrolysis effectively accelerated the decolorization of methylene blue in the colorimetric mode, as well as quenched the luminescence of luminol in the ECL mode. The samples could be rapidly screened through visual assessment in the colorimetric mode, and be further quantified by dual-mode detection. The linear detection ranges for the colorimetric and ECL modes were determined to be 1.0 pM ∼1.0 μM and 1.0 fM ∼1.0 nM, with corresponding detection limits of 0.7 pM and 0.1 fM, respectively. This dual-mode aptasensor platform enabled both qualitative and quantitative analysis. Significantly, it could dramatically improve detection efficiency and reduce operational costs. Furthermore, the proposed strategy demonstrated exceptional selectivity and stability. Consequently, this detection method was successfully applied to detect malathion residues in environmental as well as agricultural products, and demonstrated substantial potential for practical applications.