Enzymatic Polymerization: a Green Technique for Polymer Synthesis

Green polymer synthesis routes especially for enzymatic polymerization, have become a hot spot in the preparation of biomedical polymers owing to its characteristics of mild reaction conditions, low dispersity index, no residue of metal catalysts, and high enantio-and regio-selectivity. Oxidoreductases, hydrolases and transferases have been successfully applied in the polymer synthesis. Among them, lipase-catalyzed polycondensation and ring-opening polymerization were most widely studied, which dramatically facilitated the preparation of polymeric materials with high molecular mass and narrow distribution. Meanwhile, enzymatic reversible deactivation radical polymerization including reversible addition-fragmentation chain transfer polymerization and atom transfer radical polymerization has been rapidly developed because of its unique advantages of mild reaction, high efficiency and oxygen resistance. In addition, to solve the limitations of structure, property and application of polymers, enzymatic polymerization has been combined with chemical routes including atom transfer radical polymerization and ring-opening metathesis polymerization, and the polymers have been applied in the field of drug/gene delivery. Based on the existing literatures, this paper reviewed the progress of lipase-catalyzed polymerization, enzyme-catalyzed reversible radical polymerization and chemoenzymatic polymerization, and the limitations of current research and the future directions were also discussed.