Core/shell fluorescent silica nanopartictes for chemical sensing: Towards single-particle laboratories

A class of monodisperse fluorescent core/shell silica nanoparticles was developed for chemical sensing. The particles were assembled in a core/shell architecture using a modified Stöber synthesis with the dye molecules sequestered within the particle core. The assembly leads to a variety of enhanced properties, including reduced photobleaching, minimized solvatochromic shift, and increased fluorescent efficiency relative to free dye in aqueous solution. This increases per-particle brightness and long-term single-particle tracking because the encapsulated dye molecules are decoupled from each other, and thus are not suffered by intermittent blinking under continuous excitation suffered by single-emitter systems such as green fluorescent protein (GFP) or quantum dots.