Structure and Behavior of Fluorescent Core-Shell Silica Nanoparticles

The synthesis and characterization of nanoparticles for the sustainable development of highly functional nanomaterials for applications ranging from bioimaging to nanomedicine has been the center of enormous efforts in the scientific community. Despite progress substantial challenges remain. This includes quantitative assessment of particle structural and compositional heterogeneities, in particular for nanoparticles obtained from batch reactions, as well as the development of synthesis approaches scalable to reaction volumes addressing industrial needs. In this talk a class of ultrasmall fluorescent core-shell nanoparticles are discussed comprising a fluorescent dye-encapsulating silica core and poly(ethylene glycol) shell. After describing batch synthesis methodologies in water as solvent toward ultrasmall particles sizes (hydrodynamic diameters below 7 nm) and high degrees of control over surface functionalization, new inorganic-organic hybrid nanoparticle characterization techniques are being introduced. This includes high-performance liquid chromatography (HPLC) and its coupling with gel permeation chromatography (GPC) to quantitatively assess hitherto inaccessible details of their structure, composition, and associated heterogeneities. In all cases experimental results are compared with computer simulations to fundamentally understand the origin of observed behavior and properties. At the end, a few highlights are presented of applications of these nanoparticles in the medical field of oncology.