Rare Earth-based colloidal luminescent nanoparticles: fundamental studies at the single particle scale and applications as biolabels

Abstract

Rare earth-based compounds are well known for being used in several application fields, with a notorious importance in the elaboration of luminescent materials. Particularly, luminescent inorganic nanoparticles containing rare earths are highly promising systems for the development of new technologies in illumination and visualisation devices, as well as in biological labelling. In this sense, the improvement and the accurate elucidation of the mechanisms involved in the colloidal synthesis methodologies are primordial for the adaptation of the structural and morphological properties of the nanoparticles to the restrictions imposed by each particular application. In addition, a more precise comprehension of the determinant characteristics of the nanoparticles can be accessed through investigations at the single particle level, in order to describe the effect of parameters such as particle sizes, crystallinity, surface state, and dielectric environment on the observed spectroscopic properties. Therefore, the present research project aims to study the methodologies and mechanisms of colloidal synthesis of rare earth phosphate, vanadate and fluoride nanoparticles and core@shell structures for further investigations at the single particle level. For this, we intend to apply confocal microscopy techniques, besides the use and adaptation of plasmonic optical tweezers for the trapping of the particles in controlled dielectric environments and the study of their interactions with other nanostructured systems. Finally, we also intent to apply the selected nanostructures and methodologies of single particle studies for the detection of oxidizing agents in biologic systems, with the actual evaluation of their activity as luminescent biosensors in cellular media. (AU)