Multicomponent, negatively charged supramolecular nanoparticles (SNPs) were formed by multivalent host-guest interactions without the need of a stopper in water and in PBS. Their size and stability are controlled owing to a balance of forces between attractive supramolecular and repulsive electrostatic interactions.

We developed al uminescentp robe for the selective and sensitive detection of an explosive, i.e.,p icric acid (PA), based on the luminescence quenching of Ce III and Tb III co-doped Sr 2 GdF 7 nanocrystals. An ew colloidal synthesis route at low temperature (80 8C) was developed to synthesize the luminescentn anocrystals host matrix Sr 2 GdF 7 .T he nanocrystals showeds trong green emission under UV excitation (290 nm) by efficient energy transfer from Ce III to Tb III ions. The functionalization of the nanocrystals with l-cysteine (Cys) rendered the luminescent probe water dispersible. The presence of the ÀNH 2 groups of Cys allowed the selectivei nteraction of the probe with PA among other nitro explosives. This caused a9 2% reduction of the photoluminescence intensity of Tb III in the Sr 2 GdF 7 nanocrystals, and led to the selectived etection of PA with an unprecedented limit of detection (LOD) of approx. 4nm.