Mesoporous Silica-Templated Assembly of Luminescent Polyester Particles

We report the template assembly of luminescent poly-3-hydroxybutyrate (PHB) particles doped with rare-earth complexes. The hydrophobic polymer, PHB, has been infiltrated into the nanopores of mesoporous silica (MS) particles in organic solvent. Because of the van der Waals interaction ofthe polymer chains, PHB loaded in the nanopores yields replicated particles following removal ofthe MS template. To prevent aggregation of the hydrophobic PHB particles in aqueous media, the PHB-loaded mesoporous silica particles were coated with a polyelectrolyte multilayer (PEM) shell through the layer-by-layer (LbL) assembly of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS). Following removal of the silica core, the PEM-coated PHB replicas were used to effectively coordinate rare-earth complexes (europium beta-diketone, EuC). The EuC-loaded PHB replicas coated with PAH/PSS emit intense luminescence over a wide pH range (3-11) and for at least several months in aqueous solution, which is due to the intramolecular energy transfer from the ligand to the luminescent center in the rare-earth complexes. The PHB replicas, with stable and intense luminescence, may find application in diagnostics and drug delivery.