Sodium-silicate route to submicrometer hybrid PEG@silica particles

In a recent series of papers, a general methodology has been developed for the synthesis of polymer@silica submicrometer particles, which is based on the entrapment of a hydrophobic organic polymer in a polycondensating tetraethoxysilane (TEOS) oil-in-water (O/W) emulsion. As this system could not handle hydrophilic polymers, the development of a "mirror" W/O emulsion system was needed. Here we report the successful achievement of that goal, by demonstrating the synthesis of poly(ethylene glycol) @ silica submicrometer particles from (the cheaper, greener) sodium silicate, which is a less common monomer compared to TEOS in submicrometer silica particle synthesis. Indeed, finding the right conditions for preparing these particles required screening of many procedures, some of which are briefly mentioned. Full characterization of the hybrid particles is provided. As both PEG and silica are biocompatible, so are the hybrid particles.