Revisiting Monomer Synthesis and Radical Ring Opening Polymerization of Dimethylated MDO Towards Biodegradable Nanoparticles for Enzymes

Radical ring opening polymerization is a powerful tool to achieve a polyester via radical polymerization. We used it to obtain a dimethylated version of poly(caprolactone) (PdmCL) from dimethylated MDO (DMMDO). First, we revisited monomer synthesis and achieved a milder synthetic protocol by introducing a cobalt-based catalyst. We also developed a new route towards DMMDO via a cyclic carbonate using the Petasis chemistry. Amphiphilic block-copolymers were then generated by free radical polymerization of DMMDO with a PEG-based macroinitiator. The resulting polyesters self-assembled into nanoparticles that were biodegradable as well as biocompatible. The nanoparticles proved to be an effective protective shell for an entrapped enzyme that was released upon degradation of the polyester by esterase. We are confident that our results will spur further research into block-copolymers resulting from RROP.