Bifunctional mesoporous silica nanoparticles with Europium(Ⅲ) and pyrene for visual detection and discriminative identification of six fluoroquinolone antibiotics

Abstract

Fluoroquinolones (FQs) are widely used antibiotics with known health and environmental risks due to their overuse, long-term persistence, and bioaccumulation. The detection of FQ residues in complex samples requires highly sensitive and accurate methods. Herein, we report the development of a ratiometric fluorescent nanoprobe, Py@MSN-Eu, designed by integrating pyrene (Py) and chelating Eu³⁺ (trivalent europium) into NH₂-functionalized mesoporous silica nanoparticles (MSN). Upon binding with FQs, the nanoprobe exhibited a fluorescence shift from blue to red owing to the antenna effect of Eu³⁺, enabling precise detection through smartphone-based color recognition. The efficacy of the nanoprobe was validated across diverse samples including eggs, milk, tap water, lake water, urine, and fruit surfaces. The nanoprobe demonstrated detection limits of 4.2 nM in aqueous solution and 9.1 nM in egg liquid, and exhibited robust resistance against common interferences. Additionally, the nanoprobe facilitated the discriminative identification of six FQ antibiotics via fluorescence spectral analysis. This study presents a sensitive, portable, and reliable approach for the detection and discrimination of multiple FQs, underscoring its potential for practical application in environmental and food safety monitoring.