Luminescence resonance energy transfer sensors based on the assemblies of oppositely charged lanthanide/gold nanoparticles in aqueous solution.

This work demonstrates luminescence resonance energy transfer (LRET) sensors based on lanthanide-doped nanoparticles as donors (D) and gold nanoparticles as acceptors (A), combined through electrostatic interactions between the oppositely charged nanoparticles. Negatively charged lanthanide-doped nanoparticles, YVO(4):Eu and LaPO(4):Ce,Tb, with high luminescence quantum yield and good water-solubility, are synthesized through a polymer-assisted hydrothermal method. Positively charged polyhedral and spherical gold nanoparticles exhibit surface plasmon resonance (SPR) bands centered at 623 and 535 nm, respectively. These bands overlap well with the emission of the Eu(3+) and Tb(3+) ions within the lanthanide nanoparticles. Herein, the gold nanoparticles are synthesized through a seed-mediated cetyltrimethylammonium bromide (CTAB)-assisted method. The assemblies of the oppositely charged donors and acceptors are developed into LRET-based sensors exhibiting a donor quenching efficiency close to 100 %.