Synthesis of porous PEG microgels using CaCO3 microspheres as hard templates.

Porous poly(ethylene glycol) (PEG) microgels of both 17.6 and 8.3 μm in diameter are synthesized via hard templating with calcium carbonate (CaCO(3)) microparticles. The synthesis is performed in three steps: loading of PEG macromonomers into CaCO(3) microparticles, crosslinking via photopolymerization, and removal of the CaCO(3) template under acidic conditions. The resulting porous PEG microgels are inverse replicates of their templates as indicated by light microscopy, cryo-scanning electron microscopy (cryo-SEM), and permeability studies. Thus this process allows for the straightforward and highly reproducible synthesis of porous hydrogel particles of two different diameters and porosities that show great potential as carriers for drugs or nanomaterials.