abstract
The incorporation of europium polyoxometalates into silica nanoparticles can lead to a biocompatible nanomaterial with luminescent properties suitable for applications in biosensors, biological probes, and imaging. Keggin-type europium polyoxometalates Eu(PW11)x (x = 1 and 2) with different europium coordination environments were prepared by using simple methodologies and no expensive reactants. These luminescent compounds were then encapsulated into silica nanoparticles for the first time through the water-in-oil microemulsion methodology with a nonionic surfactant. The europium polyoxometalates and the nanoparticles were characterized by using several techniques [FTIR, FT-Raman, 31P magic angle spinning (MAS) NMR, and TEM/energy-dispersive X-ray spectroscopy (TEM-EDS), AFM, dynamic light scattering (DLS), and inductively coupled plasma MS (ICP-MS) analysis]. The stability of the material and the integrity of the europium compounds incorporated were also examined. Furthermore, the photoluminescence properties of the Eu(PW11)x@SiO2 nanomaterials were evaluated and compared with those of the free europium polyoxometalates. The silica surface of the most stable nanoparticles was successfully functionalized with appropriate organosilanes to enable the covalent binding of oligonucleotides.
keywords
BIS(UNDECATUNGSTOPHOSPHATE) LANTHANATES; LUMINESCENT; CATALYSTS; SPHERES; ANION; COMPLEXES; ALCOHOLS; HYBRIDS; DRUG
subject category
Chemistry
authors
Neves, CS; Granadeiro, CM; Cunha-Silva, L; Ananias, D; Gago, S; Feio, G; Carvalho, PA; Eaton, P; Balula, SS; Pereira, E
our authors
Carlos Miguel Cardeal Enes Granadeiro
Post-Doc Fellowship
Duarte Ananias
Assistant Researcheracknowledgements
The authors acknowledge the Fundacao para a Ciencia e a Tecnologia (FCT, MEC, Portugal) for general financial support through the strategic projects Pest-C/EQB/LA0006/2011 (to the Associated Laboratory REQUIMTE), and Pest-C/CTM/LA0025/2011 (to the Associated Laboratory I3N-CENIMAT), the Portuguese Nuclear Magnetic Resonance Network (PTNMR) (to the NMR equipment of CENIMAT), and also of the R&D projects (project numbers PTDC/CTM-NAN/109877/2009 and PTDC/EQUEQU/121677/2010), and the fellowships SFRH/BD/61137/2009 (to C. S. N.) and SFRH/BPD/73191/2010 (to C. M. G.).