Glucose Oxidase Initiates Radical Polymerizations by Direct Electron Transfer to Monomers

Glucose oxidase (GOx) is a widely used and studied enzyme, yet it continues to surprise with previously unknown activities. We report GOx to initiate radical polymerizations of acrylamides and methacrylates without the need for initiators or irradiation by light, simply by carrying out the polymerizations in the absence of oxygen at high glucose concentrations. The enzyme oxidizes glucose and concomitantly transfers an electron and a proton to a monomer, thereby creating a radical species that starts the polymerization. Computational docking studies revealed specific orientations of monomers in the enzyme's active site. GOx's ability to deoxygenate solutions was combined with its initiation activity to achieve polymerizations in nondeoxygenated conditions, allowing polymerizations in a 96-well plate format, and a fluorescence assay was developed to screen the enzyme's polymerization activity. GOx's polymerization activity opens the route to polymer synthesis under mild and biological relevant conditions and allows integration of GOx-catalyzed radical polymerizations into biosensors as well as living and synthetic cells.