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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. [ABSTRACT FROM AUTHOR]

Chitosan‐N‐2‐hydroxypropyl trimethyl ammonium chloride (QTS) was prepared by reaction of chitosan with glycidyl trimethylammonium chloride, which was characterized by FTIR. QTS with different molecular weights (Mw 41.55 × 104, 9.02 × 104, 3.57 × 104, and 0.17 × 104) showed biocidal activity on Staphylococcua aureus, Bacillus subtilis, Staphylococcua epidermidis, and Candida albicans. QTS with high molecular weight had high biocidal activity on the gram‐positive bacteria, and the biocidal effect of QTS decreased with decreasing molecular weight from 9.02 × 104 to 0.17 × 104. QTS with Mw 41.55 × 104 exhibits slightly lower biocidal activity on Candida albicans than other QTS samples. However, no remarkable biocidal activity of QTS was found on gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa at the concentration up to 10 g L−1. Existence of cationic surfactant, amphoteric surfactant, nonionic surfactant, Ca2 and Mg2 had no remarkable effect on microbiocidal activity of these QTS samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3851–3856, 2007 [ABSTRACT FROM AUTHOR]

We reported a reactive probe for HSO3-, which showed a colorimetric and ratiometric fluorescence response to HSO3- with fast response (t1/2 = 20 s), good specificity and low detection limit (3.0 nM). The probe was cell membrane permeable and successfully used for visualizing trace SO2 derivatives in living cells. [ABSTRACT FROM AUTHOR]