Luminescent Nanoparticles with Lanthanide-Containing Poly(ethylene glycol)–Poly(ε-caprolactone) Block Copolymers

Lanthanide-containing nanoparticles have attracted much attention due to their unique optical properties and potential in nanotechnological applications. An amphiphilic block copolymer of poly­(ethylene glycol)-<i>b</i>-poly­(ε-caprolactone) methyl ether (mPEG-PCL) was functionalized with a dipicolinic acid (dpa) moiety and coordinated to lanthanide ions to afford [Ln­(dpa-PCL-PEG-OCH₃)₃]­(HNEt₃)₃ (Ln = Eu³⁺, Tb³⁺). Micelle-like nanoparticles of dpa-PCL-PEG-OCH₃ macroligand and metal-centered polymers were prepared by solvent displacement methods. Dynamic light scattering analysis (DLS) and cryogenic transmission electron microscopy images confirmed the presence of solid sphere (<47 nm in diameter) and vesicle (>47 nm in diameter) morphologies. The viability and stability of the lanthanide complexes in micelle-like nanoparticles was explored by DLS and luminescence spectroscopy, and found to be stable for several weeks