Luminescent polystyrene latex nanoparticles doped with β-diketone europium chelate and methacrylic acid

[Display omitted] •Europium based luminescent latex nanoparticles was designed and developed.•Thermodynamic equilibrium calculations in Eu3+H+Cl− system are performed.•The MAA retains the constant polarization of Eu3+ ions against photobleaching.•As prepared latex nanoparticles in less than 10μg/mL had no cytotoxicity on PC12 cells. Luminescent polystyrene latex NPs with a diameter of 83nm are prepared by stepwise process of chelation of β-diketonate europium complexes followed by conjugation on poly(St-co-DVB-co-NaSS-co-MAA) [St=styrene; DVB=divinylbenzene; Nass; 4-styrenesulfonic acid sodium salt hydrate; MAA=methacrylic acid] NPs. The europium complexes composed of mixed-ligands of β-diketone [1-(2-Naphthoyl)-3,3,3-trifluoroacetone (NTA)], phosphorous-containing neutral ancillary ligand [triphenylphosphine (TPP)] and carboxylic acid are studied by the luminescent spectroscopy. The PL spectra of the EuNPs composed of typical Eu3+ show red emission, assigned to the transition between the first excited state and the multiplet. The integrated intensity ratio of 5D0→7F2 to 5D0→7F1 of EuNPs is significantly enhanced due to the hypersensitive effects because of strong PS-Eu3+ interaction. The MAA retains the constant polarization of Eu3+ ions against photobleaching because carboxylic group in MAA protects the distortion of the symmetry around the Eu3+ ions due to influence from pH or strong chelating with Eu3+. The cytotoxic effects of EN2T doped PSDNMA latex NPs are evaluated on PC12 cell lines by Annexin V assay.