Enzyme-polymer hybrid nanogels fabricated by thiol-disulfide exchange reaction.

In this paper a novel method for the fabrication of hybrid nanogels based on thiol-disulfide exchange reaction is reported. Poly(oligo(ethylene glycol) monomethyl ether methacrylate-co-di(ethylene glycol) methyl ether methacrylate-co-2-(2-pyridyldisulfide) ethyl methacrylate) (POEGMA-co-PDEGMA-co-PDSMA) was synthesized by reversible addition-fragmentation chain transfer polymerization. Pyridyl disulfide functionalized porcine pancreatic lipase (PPL-S-S-Py) was prepared by treatment of PPL with Traut's reagent (2-iminothiolane) and 2,2'-dithiodipyridine. Upon addition of meso-2,3-dimercaptosuccinic acid into aqueous solutions of PPL-S-S-Py and POEGMA-co-PDEGMA-co-PDSMA, enzyme-polymer hybrid nanogels were prepared. The hybrid nanogels show thermal responsiveness. With an increase in the content of PPL in the nanogels, the lower critical solution temperature (LCST) shifts to the higher temperature. At a temperature below LCST, PPL molecules are in the shells of the nanogels, and at a temperature above LCST, PPL molecules are embedded inside the nanosized structures. The immobilized PPL show enhanced heat resistance and good reusability.