# Design, Synthesis and Sensing Application of Novel Dual Lanthanide Doped Core–Shell Fluorescent Silica-Based Nanoparticles

## TL;DR

Researchers created a new type of nanoparticle that can detect a specific chemical by measuring changes in fluorescence.

## Contribution

A novel dual lanthanide-doped core–shell nanoparticle was developed for ratiometric fluorescence sensing of DPA.

## Key findings

- The nanoparticle shows a linear response to DPA concentrations between 10–100 μM.
- The detection limit is as low as 1.38 μM with high selectivity for DPA.
- The F545/F617 fluorescence ratio is sensitive to DPA concentration changes.

## Abstract

The synthesis of lanthanide fluorescent nanoparticles and the investigation of their fluorescence sensing applications have attracted a great deal of attention in materials science over the past decades. In this study, we designed and synthesized a core–shell fluorescent nanoparticle based on dual-center emission from the europium and terbium complexes, and demonstrated its application as a ratiometric fluorescence sensor for the detection of 2,6-pyridinedicarboxylic acid (DPA). The europium complex is embedded in the inner core, providing a stable fluorescence signal at 617 nm, while the terbium complex is positioned in the outer shell and exhibits a fluorescence “Turn-ON” response at 545 nm upon interaction with DPA molecules. The fluorescence intensity ratio F545/F617 exhibits a sensitive response to the DPA concentration. Experimental results demonstrate that the as-prepared SiO2@Eu@SiO2@Tb nanoparticle exhibits a linear response in the DPA concentration range of 10–100 μM, with a detection limit (LOD) of 1.38 μM and well selectivity for DPA sensing. This strategy offers new insights into the development of novel lanthanide-based ratiometric fluorescence sensors.