Synthesis of Water-Soluble Glycopolymers Bearing Porphyrin by Means of Glycopolymer Assembly and Physical Properties of Glycopolymers Including Ability for Singlet Oxygen Production

Although photodynamic therapy (PDT) is expected to offer advantages in terms of selectivity, increased efficacy, and reduced side effects, the low solubilities of photosensitizers in aqueous media are significant issues. In this study, porphyrin-based monomers were synthesized by acryloylation of known tetraphenylporphyrin [5-(4-aminophenyl)-10,15,20-(triphenyl)porphyrin] (TPP). Simple radical polymerization of the porphyrin monomer and known glycosyl monomers in the presence of acrylamide to avoid steric hindrance yielded the corresponding polymeric photosensitizers, water-soluble glycopolymers with porphyrin moieties. The introduction of a porphyrin core gave polymer fluorescence and reactive oxygen species generation properties, and the addition of d-lactose and <i>N</i>-acetyl-d-glucosamine, respectively, remarkably improved solubility in water. The glycopolymers had high optical absorption, emission, and excitation in the visible light range and a singlet oxygen (SO) generation characteristic of porphyrins in aqueous solution, suggesting incorporation of the TPP into the linear polymer. The glycopolymers are promising not only for PDT but also as anticancer agents.