pH-Responsive Antibacterial Hydrogel formed by Nitro-Catechol-Boronate Complexation

摘要

Polymeric hydrogels represent an attractive kind of soft material, in which three dimensional polymeric networks are cross-linked by covalent or noncovalent interactions in aqueous solution, making hydrogels one of the most extensively studied class of biomaterials~1. A large body of research has been performed on stimuli-responsive hydrogels for their capability of responding to external circumstances like pH and temperature, and for their potential use in biomedicine and tissue engineering~2. Previously we reported the preparation of polymer hydrogels based on reversible catechol-boronate complexation, which are stable at high pH (>8) but which disintegrate at neutral or acidic pH.~3 Here we report the use of electron-withdrawing group substitutions that allow such hydrogels to be stable at physiological pH condition. A nitro-substituted statistical copolymer, poly(N,N'-dimethylamino ethyl methacrylate)-co-poly(6-nitro-2-(3,4-dihydroxy-6-nitrophenyl)ethyl methacrylamide) (PDMA-co-PNDHPMA), and crosslinker, 3-nitro-4-phenylboronic acid PEG 3-nitro-4-phenylboronic acid (NPBA-PEG-NPBA) were designed and used in this system(Scheme 1). Due to the protonation of PDMA units at neutral pH, the hydrogel prepared thereof possesses antibacterial property, making it potentially useful as an antibacterial hydrogel or device coating.