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A photoinduced reversible addition-fragmentation chain-transfer (photo-RAFT) polymerization technique in the presence of sodium pyruvate (SP) and pyruvic acid derivatives was developed. 

Abstract Photoinduced initiators for continuous activator regeneration atom transfer radical polymerization (PICAR ATRP) using sodium pyruvate and blue light (λ_max = 456 nm) is reported. Water‐soluble oligo(ethylene oxide) methyl ether methacrylate (OEOMA₅₀₀) was polymerized under biologically relevant conditions. Polymerizations were conducted with 1000 ppm (with respect to the monomer) concentrations of CuBr₂, tris(2‐pyridylmethyl)amine, and 1000 ppm or less FeCl₃as a cocatalyst in water. Well‐defined polymers with up to 90% monomer conversion, high molecular weights (M_n > 190,000), and low dispersity (1.14 < Ð < 1.19) were synthesized in less than 60 min. The polymerization rate and dispersity were tuned by varying the concentration of sodium pyruvate (SP), iron, and supporting halide, as well as light intensity. The Cu/Fe dual catalysis provided oxygen tolerance enabling rapid, well‐controlled, aqueous PICAR ATRP of OEOMA₅₀₀without deoxygenation. 

Abstract Atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) monomethyl ether methacrylate (OEOMA₅₀₀) in water is enabled using CuBr₂with tris(2‐pyridylmethyl)amine (TPMA) as a ligand under blue or green‐light irradiation without requiring any additional reagent, such as a photo‐reductant, or the need for prior deoxygenation. Polymers with low dispersity (Đ = 1.18–1.25) are synthesized at high conversion (>95%) using TPMA from three different suppliers, while no polymerization occurred with TPMA is synthesized and purified in the laboratory. Based on spectroscopic studies, it is proposed that TPMA impurities (i.e., imine and nitrone dipyridine), which absorb blue and green light, can act as photosensitive co‐catalyst(s) in a light region where neither pure TPMA nor [(TPMA)CuBr]⁺absorbs light. 

Abstract The unique properties of cationic nanogels, such as their hydrophilicity and high loading capacity, make them a promising platform as drug delivery agents, particularly for the delivery of hydrophilic biomolecules. Although several synthetic methods exist for cationic nanogels, polymerization in dispersed media is advantageous due to its ability to provide control over composition and high monomer conversion. However, polymer droplets typically suffer from a significant increase in size during polymerization due to the Ostwald ripening process. Herein, the preparation of cationic nanogels by atom transfer radical polymerization under inverse microemulsion conditions of a hydrophilic inimer that prevents monomer diffusion and hence limits droplets’ growth during polymerization is reported. Additionally, the surface functionality of the nanogels can be modulated by the application of hydrophobic reactive surfactants or by grafting hydrophilic shells to form core‐shell cationic nanogels. The synthesized cationic nanogels are biocompatible, internalized to HEK 293 cells, and have a high complexation ability for plasmid DNA. 

Abstract Hyperbranched polymethacrylates were synthesized by green‐light‐induced atom transfer radical polymerization (ATRP) under biologically relevant conditions in the open air. Sodium 2‐bromoacrylate (SBA) was prepared in situ from commercially available 2‐bromoacrylic acid and used as a water‐soluble inibramer to induce branching during the copolymerization of methacrylate monomers. As a result, well‐defined branched polymethacrylates were obtained in less than 30 min with predetermined molecular weights (36 000<M_n<170 000), tunable degree of branching, and low dispersity values (1.14≤Đ≤1.33). Moreover, the use of SBA inibramer enabled the synthesis of bioconjugates with a well‐controlled branched architecture.