Design and synthesis europium-based metal-organic supramolecular nanofiber for fluoroquinolones antibiotics visual detection

Abstract

Supramolecular lanthanide compounds as a class of optical materials are of interest because of their desirable applications in biological, physical and chemical sciences. Considering the unique optical properties of nanoscale materials, especially for sensing applications, the nanoscale metal-organic supramolecular compounds of (H₂pip)₃[Eu(DPA)₃]₂.21H₂O (1), dipicolinic acid (DPA) and piperazine (H₂pip), were prepared by sonochemical reaction in the presence of methanol as an anti-solvent. Results show that the size and morphology of nanoscale 1 depend on the amount of the anti-solvent. Optical studies revealed that the highest emission intensity was related to the nanofiber morphology, and the red emission of nanofibers with a maximum at 620 nm was successfully used for the visual detection of ciprofloxacin (CIP) and ofloxacin (OFLX) by fluorescent color changes (red changes to blue for CIP and to green for OFLX). More importantly, the nanoscale 1 was fabricated into a paper microchip due to the small amount of sample (10 μL) required for this method. The CIP and OFLX visual assays were coupled with a smartphone to prepare a portable paper-based sensor. Furthermore, the low detection limits of 0.710 and 0.548 ppb for CIP and OFLX approve the potential application of nanoscale 1 as a highly sensitive optical sensor for the detection of CIP and OFLX.