Ratiometric fluorescence sensing of hazardous ciprofloxacin based on aggregation induced emission enhancement of thiolate-protected gold nanoclusters induced by La3+ ion

Ashraf M Mahmoud; Mater H Mahnashi; Mohamed M El-Wekil

doi:10.1016/j.saa.2023.123347

Ratiometric fluorescence sensing of hazardous ciprofloxacin based on aggregation induced emission enhancement of thiolate-protected gold nanoclusters induced by La³⁺ ion

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Jan 5:304:123347. doi: 10.1016/j.saa.2023.123347. Epub 2023 Sep 5.

Authors

Ashraf M Mahmoud¹, Mater H Mahnashi¹, Mohamed M El-Wekil²

Affiliations

¹ Department of Pharmaceutical Chemistry, College of Pharmacy, Najran University, Najran, Saudi Arabia.
² Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt. Electronic address: mohamed.elwakeel@pharm.aun.edu.eg.

PMID: 37688885
DOI: 10.1016/j.saa.2023.123347

Abstract

In this research work, ultrasensitive and reliable ratiometric sensor was designed for assay of ciprofloxacin (CIPRO). The platform consists of thiolate-protected gold nanoclusters (GSH@AuNCs) with high fluorescence quantum yield and long-term stability. In the existence of lanthanum (La³⁺) ion, the GSH@AuNCs emission was sharply raised owing to the formation of La³⁺/GSH@AuNCs system accompanied with aggregation-induced emission enhancement (AIEE). Addition of CIPRO, a good La³⁺ ion coordinator, decreased the fluorescence emission of La³⁺/GSH@AuNCs system at 610 nm significantly as a result of disaggregation caused by the removal of La³⁺ ion from GSH@AuNCs surface. Furthermore, the blue emission of La³⁺-CIPRO coordination complex appears at 440 nm. Under optimized conditions, the fluorescence ratios (F₄₄₀/F₆₁₀) were linearly increased with increasing the CIPRO amount within the range of 0.003-200 µM with a limit of detection equal to 0.2 nM (S/N = 3). The as-fabricated La³⁺/GSH@AuNCs system possesses outstanding reliability and sensitivity for the detection of CIPRO. The system was effectively used to assay CIPRO in human urine and milk specimens with recoveries % of 97.6-102.3 % and 96.7-105.7 % for urine and milk samples, respectively and RSD % did not exceed 2.5 %, suggesting the accuracy of the method.

Keywords: AIEE; Ciprofloxacin; Fluorometry; GSH@AuNCs; Ratiometric response.