Sensitive spectrofluorometric detection of fluoroquinolone antibiotics via a hybrid nanoprobe of L-cysteine-stabilized copper nanoclusters and silicon quantum dots.

Authors

Seyed Mohammad Hosseini, Susan Sadeghi

Published in

Analytical methods : advancing methods and applications. Jul 10, 2026. Epub Jul 10, 2026.

Abstract

In this study, silicon quantum dots (SiQDs) combined with L-cysteine stabilized copper nanoclusters (Cys@CuNCs) were synthesized and utilized for the direct and sensitive spectrofluorometric detection of ciprofloxacin (CIP) and ofloxacin (OFL). The fluorescence emission of the water-soluble Cys@CuNCs was significantly enhanced in the presence of SiQDs, because of the favorable interactions between cysteine and the surface functional groups of SiQDs. Upon excitation at 330 nm, the integrated SiQD-Cys@CuNC system exhibited strong fluorescence emission at 440 nm, which was effectively quenched by CIP and OFL based on the inner filter effect (IFE). The calculated binding constant indicated that a strong interaction between SiQDs-Cys@CuNCs and CIP/OFL occurred, which may be due to the hydrogen bonding between the fluoroquinolones and the functional groups of the nanohybrid. However, OFL strongly binds to SiQDs-Cys@CuNCs. Calibration curves based on the Stern-Volmer equation showed linearity in the concentration range of 0.005-0.600 µg mL^-1 for both antibiotics. The limit of detection (LOD) was calculated to be 0.0016 µg mL^-1 for CIP and 0.0014 µg mL^-1 for OFL. The method exhibited good repeatability, with relative standard deviations (RSDs) of 1.3% for CIP and 1.7% for OFL. The applicability of this method was validated by detecting CIP and OFL in real samples including drinking water, human urine and blood serum, and milk, with recoveries ranging from 93.3% to 110.0%. Overall, the developed fluorescence-based platform offers a simple, eco-friendly, and ultrasensitive approach for the detection of fluoroquinolone residues in complex biological and environmental matrices.

PMID:
42429057
Bibliographic data and abstract were imported from PubMed on 10 Jul 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.