Highly emissive hybrid mesoporous organometallo-silica nanoparticles for bioimaging

Abstract

Production of mesoporous silica nanoparticles (MSNs) with uniform textural characteristics and imaging properties on a large scale is still a challenge. Thus, the design of simple and scalable methods to obtain reproducible functionalized MSNs has become even more relevant. Herein, we describe an in situ strategy for the synthesis and surface functionalization of highly luminescent mesoporous organometallo-silica nanoparticles. Using the [Ir(dfppy)₂(dasipy)]PF₆ chromophore and TEOS as sol–gel precursors and different capping agents, such as DMDES or APTES, three different emissive MSNs were prepared (NP_OH_IS, NP_Me_IS and NP_NH2_IS), each containing hydroxyl, methyl and amine groups on their surfaces, respectively. All three were tested on human tumor A549 (lung carcinoma) and HeLa (cervix carcinoma) cell lines, showing intense and stable yellow phosphorescence, biocompatibility and efficient internalization. Moreover, NP_Me_IS nanoparticles showed excellent colloidal stability, both in water and biological media, and a BET area of 1120 m² g⁻¹, making them not only luminescent biomarkers, but potentially also controlled delivery vectors.