Aqueous photoinduced living/controlled polymerization: tailoring for bioconjugation

We report a photoinduced living polymerization technique able to polymerize a large range of monomers, including methacrylates, acrylates and acrylamides, in water and biological media as well as organic solvents. This polymerization technique employs ultra-low concentrations of a ruthenium-based photoredox catalyst (typically 1 ppm to monomers) and enables low energy visible LED light to afford well-defined polymers with narrow polydispersities (M-w/M-n < 1.3). In this paper, different parameters, including photocatalyst concentrations and solvent effects, were thoroughly investigated. In addition, successful polymerizations in biological media have been reported with good control of the molecular weights and molecular weight distributions (M-w/M-n < 1.4). Finally, protein polymer bioconjugates using a "grafting from" approach were demonstrated using bovine serum albumin as a model biomacromolecule. The enzymatic bioactivity of the protein was demonstrated to be maintained using a standard assay.