A widely used approach for the preparation of the cores is the use of organosilanes for the synthesis of spherical silica nanoparticles. At Fraunhofer IGB we synthesize silica (SiO2) - particle nuclei with diameters from 30 nanometers to 1 micrometer - in this way using the sol-gel process.
During synthesis, functional elements such as dyes, fluorescent dyes or polymers such as polyethylene glycol (PEG) can be incorporated into the core or core shell. The particle surface is independently functionalized with organic anchor groups, which enable the coupling of further functional or biofunctional building blocks. Unmodified silica cores or cores coated with ionizable groups form long-term stable suspensions in aqueous media.