Strong luminescence and sharp heavy metal ion sensitivity of water-soluble hybrid polysaccharide nanoparticles with Eu3+ and Tb3+ inclusions

In this work, we contributed new lanthanide (Eu 3+ and Tb 3+ ) complexes that were embedded in both positively and negatively charged polyelectrolyte complex nanoparticles (PCN). Luminescent Eu 3+ complexes [Eu(TTA) 3 Phen] are formed from Eu 3+ using 2-thenoyltrifluoroacetone (TTA) and 1,10-phenanothroline hydrate (Phen) as ligands. Luminescent Tb 3+ complexes [Tb(AcAc) 3 Phen] are formed from Tb 3+ using acetyl acetone (AcAc) and Phen as ligands. Then, polyelectrolyte complex nanoparticles(PCN) are applied to embed lanthanide (Eu 3+ and Tb 3+ ) complexes with two forms of positive charged and negative charged PCNs. PCN/Eu(TTA) 3 Phen and PCN/Tb(AcAc) 3 Phen show that the particle sizes are 40–60 nm and 30–80 nm, respectively. Notably, both hybrid PCN nanoparticles with Eu 3+ and Tb 3+ inclusions behave excellent characteristic luminescence properties. The red emission hybrid nanoparticles of PCN/Eu(TTA) 3 Phen indicate high luminescence intensities at low concentration of 10 −5  M whereas The green emission hybrid nanoparticles of PCN/Eu(TTA) 3 Phen show high luminescence intensity at high concentration of 10 −3  M. Furthermore, concentration-dependent luminescence quenching by heavy metal ions (Ni 2+ , Co 2+ , Cu 2+ , Fe 3+ , and Zn 2+ ) at concentrations as low as 10 −5  M is also reported. This quenching effect of heavy metal ions on the fluorescence property of PCN/Eu(TTA) 3 Phen and PCN/Tb(AcAc) 3 Phen nanoparticles will be valuable for sensing application on bio- and environmental fields. The charged polyelectrolyte polymeric shells of both PCN/Eu(TTA) 3 Phen and PCN/Tb(AcAc) 3 Phen nanoparticles make the lanthanide(Eu 3+ and Tb 3+ ) complexes be compatible in biological and aqueous environmental systems.