Natural dye-mediated signal tracer strategy: a green route for ultra-efficient immunochromatographic detection of antibiotics

Abstract

Immunochromatographic assay (ICA) has attracted increasing attention in antibiotic detection. Driven by global sustainability and environmentalism goals, green and sustainable detection strategies are in high demand. Inspired by the characteristics of natural dyes and their wide-ranging application scenarios, we excavated natural plant-extracted alizarin as a novel synthetic-free label for ICA (NAST-ICA) to meet the challenges. By regulating the proportions of ethanol/water solution, the dissolution of alizarin was optimized, ensuring the protection of antibody activity and color rendering of alizarin labels, and achieving the stability of sensitive detection performance. The rich functional groups endow alizarin tags with the ability to be directly incorporated into antibodies within 5 min to form efficient and stable detection probes. As a proof of concept, NAST-ICA showed a limit of detection (LOD) of 1.69 ng mL⁻¹ for streptomycin. More importantly, the reliability of the actual detection application scenario was verified: realizing acceptable total recoveries of 87.17–123.85% and RSD values of 1.99–3.64% in spiked milk, honey, and actual water samples. The proposed nature-derived synthetic-free signal tracer assay demonstrated an efficient and stable detecting strategy for antibiotics, paving a green way for ICA applications.