Highly luminescent and long-term anti-photobleaching Eu(TTA)3(TOP)3 conjugated poly(St-co-DVB-co-NaSS-co-MAA) nanoparticles

- Highly luminescent and anti-photobleaching for a long period, Eu3+ complexes labelled polymer nanoparticles are synthesized.
- Highly monodispersed Poly(St-co-DVB-co-NaSS-co-MAA) nanoparticles with a diameter of 77 nm are synthesized.
- Coordination of carboxylic acid on Eu(TTA)3(TOP)3 complex shows a high anti-photobleaching effect for a long term.
- Eu doped latex nanoparticles show relatively low cytotoxicity in the concentration range of <100 μg/mL.

Highly luminescent and stable against photobleaching for a long period, Eu3+ complexes labelled polymer nanoparticles with a quantum yield of 78% are presented. Europium complexes are prepared by chelating Eu3+ with 4,4,4-trifluoro-1-(2-Thienyl)-1,3-butanedione (TTA) and trioctylphosphine (TOP). Poly(St-co-DVB-co-NaSS-co-MAA) (St = styrene; DVB = divinylbenzene; NaSS; 4-styrenesulfonic acid sodium salt hydrate; MAA = methacrylic acid) with a diameter of 77 nm are modified with Eu(TTA)3(TOP)3. Scanning electron microscopy (SEM) results shows that Eu(TTA)3(TOP)3 modified Poly(St-co-DVB-co-NaSS-co-MAA) is monodispersed with a diameter of 83 nm. The intensity fractions of 5D0 → 7F2-5D0 → 7F1 of EuNPs defines that Eu3+ could be existed as a more polarized structural states and comparatively stronger hypersensitive performance at 5D0 → 7F2 transition. The results show that the role of MAA in this system is important to maintain the continuous polarization of Eu3+ ions against photobleaching because carboxylic group from MAA protects the dissociation of the symmetry around the Eu3+ ions due to the influence of pH or external light source. The cell viability of PC 12 cells shows that in the range of 10-100 μg/mL concentrations is more than 70%. Thus, EuNPs show relatively low cytotoxicity in the concentration range of <100 μg/mL and incubation times examined in this study.

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