Reduction-Controlled Release of Organic Nanoparticles from Disulfide Cross-linked Porous Polymer

Reduction-controlled release is favored for many applications. The cleavage of disulfide bonds is known to be sensitive to reducing agents. Here, a cross-linker containing a disulfide bond is prepared and then used to prepare cross-linked porous polymer via an emulsion templating approach. Oil-in-water (O/W) emulsions are first formed where an organic dye is dissolved in the oil droplet phase and monomer/cross-linker/surfactant are added into the continuous aqueous phase. By polymerizing the O/W emulsion followed by freeze-drying, organic nanoparticles are formed in situ within the disulfide-crosslinked porous polymer. The release of organic nanoparticles in water is demonstrated and can be tuned by the presence of reducing agents such as dithiothreitol and tris(2-carboxyethyl)phospine. This approach has the potential to be used for the reduction-controlled release of poorly water-soluble drug nanoparticles from porous polymers or hydrogels.