Silica particles decorated with luminescent complexes for application in sensors and cellular imaging

Abstract

Luminescence is an important tool for sensor and image cells in search and quantification of a variety of diseases. Heavy-metal complexes stand out in this field over molecular biomarkers for they show large pseudo-Stokes shift and long emission times, leading in a better image quality for diminish the self-fluorescence, inherent of biological media. The insertion of an inert carrier adds advantages to the system, as increases the "solubility" and stability and diminishes the toxicity of the system. By those means, silica particles are an excellent choice, since they make those material biocompatible, allowing the functionalization of their surfaces. Nonetheless, for those materials be considerate satisfactory, it is necessary the optimization of some properties, likewise emission intensity, and emission lifetime. In this sense, by combining metallic particles and lanthanoid ions (Ln3+) in a single architecture one can achieve a biomarker with intensified luminescent properties due to the Surface Plasmon Resonance (SPR), that directly influences the intra-configurasional transitions of such ions, modifying the emission intensity, quantum efficiency, and (non-)radiative rates. The SPR effect depends on the distance between the emitter and metallic centre, leading to a more efficient probe, yet the direct contact of metallic particles and the emitter work as a quencher. The combination of those two components is possible by intermedium of silica in a core@shell system, throughout recovering metallic nanoparticles with silica, followed by its surface functionalization and graft it with luminescent complexes. Therefore, this project aims the synthesis, characterization, and study of photophysical properties of dense silica and metallic particles covered by silica, grafted with lanthanoid or iridium complexes, and test these hybrid materials as sensors and cellular imaging by confocal and fluorescence microscopy. (AU)