Hybrid inorganic-organic fluorescent silica nanoparticles—influence of dye binding modes on dye leaching

Abstract Silica nanoparticles with embedded fluorescent dyes represent an important class of markers for example in biological imaging. We systematically studied the various incorporation mechanisms xanthene 30–40 nm silica nanoparticles. An parameter was interaction dye matrix material, either by weak electrostatic or strong covalent interactions, which also has implications on stability fluorescence and brightness dyes. Factors that can influence leaching such as position particles intensity particle-dye were investigated using solvatochromic effect stationary anisotropy measurements. compared uranine rhodamine B, physically embedded, modified fluorescein isothiocyanate B isothiocyanate, covalently bound to within a usual Stöber synthesis. Systematic studies time spans up 4 days revealed bonding like is necessary stability, since physical tend leach out porous networks. Coverage hydrophobic protection layers alkyltrialkoxysilanes hydrophilic polyethylene glycol (PEG) groups resulted better retention physisorbed provides possibility adapt polarity medium. Best results archived PEG groups, but even small trimethylsilyl (TMS) already reduce leaching.