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

Abstract

In this work, we contributed new lanthanide (Eu3+ and Tb3+) complexes that were embedded in both positively and negatively charged polyelectrolyte complex nanoparticles (PCN). Luminescent Eu3+ complexes [Eu(TTA)3Phen] are formed from Eu3+ using 2-thenoyltrifluoroacetone (TTA) and 1,10-phenanothroline hydrate (Phen) as ligands. Luminescent Tb3+ complexes [Tb(AcAc)3Phen] are formed from Tb3+ using acetyl acetone (AcAc) and Phen as ligands. Then, polyelectrolyte complex nanoparticles(PCN) are applied to embed lanthanide (Eu3+ and Tb3+) complexes with two forms of positive charged and negative charged PCNs. PCN/Eu(TTA)3Phen and PCN/Tb(AcAc)3Phen show that the particle sizes are 40–60 nm and 30–80 nm, respectively. Notably, both hybrid PCN nanoparticles with Eu3+ and Tb3+ inclusions behave excellent characteristic luminescence properties. The red emission hybrid nanoparticles of PCN/Eu(TTA)3Phen indicate high luminescence intensities at low concentration of 10−5 M whereas The green emission hybrid nanoparticles of PCN/Eu(TTA)3Phen show high luminescence intensity at high concentration of 10−3 M. Furthermore, concentration-dependent luminescence quenching by heavy metal ions (Ni2+, Co2+, Cu2+, Fe3+, and Zn2+) 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)3Phen and PCN/Tb(AcAc)3Phen nanoparticles will be valuable for sensing application on bio- and environmental fields. The charged polyelectrolyte polymeric shells of both PCN/Eu(TTA)3Phen and PCN/Tb(AcAc)3Phen nanoparticles make the lanthanide(Eu3+ and Tb3+) complexes be compatible in biological and aqueous environmental systems.