Nanoflower-Shaped Biocatalyst with Peroxidase Activity Enhances the Reversible Addition–Fragmentation Chain Transfer Polymerization of Methacrylate Monomers

Organic–inorganic hybrid nanoflowers, facilely made from bovine serum albumin and copper phosphate (BSA–Cu3(PO4)2·3H2O), have attracted considerable attention for the application of biocatalysts in recent years. The improved stability and activity of above-mentioned nanoflowers enhanced the efficiency of reversible addition–fragmentation chain transfer (RAFT) polymerization of functional methacrylate monomers with the assistance of acetylacetone (ACAC) and hydrogen peroxide (H2O2) in a mixed solvent of DMF and H2O. Such RAFT strategy can be employed for the polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA500), in which both poly(DMAEMA) and poly(PEGMA500) could be synthesized in a controllable manner with typical RAFT features, e.g., precise control of molecular weight, specific molecular structure, and narrow polydispersity index (Mw/Mn). Significantly, the low-cost nanoflowers could be easily separated from reaction mixture after polymerization and will not adhere to resulting polymers as same as enzymes. Moreover, 1H NMR characterization of the retaining end groups of the resultant polymers and the chain extension experiments confirmed the mechanism of RAFT polymerization. The present biocatalytic system can serve as optimal alternatives of free enzymes in RAFT polymerization, which will hopefully enrich the methodology toward the construction of vinyl-based polymers with controlled radical polymerization (CRP).