Glucose-Sensitive Polyphosphoester Diblock Copolymer for Insulin Delivery System

In this study, we report a diblock copolymer based on a polyphosphate backbone and pendant phenylboronic acid with glucose sensitivity. The copolymer, abbreviated as (PBYP-g-MPBA)-b-PEEP, was prepared via a combination of ring-opening copolymerization (ROP), “click” chemistry and amide reaction, in which the PBYP and PEEP blocks respectively represent two kinds of polyphosphoester structures , and MPBA represents 3-mercaptopropionic acid modified with 3-aminophenylboronic acid (APBA). The amphiphilic copolymers (PBYP-g-MPBA)-b-PEEP could self-assemble into core-shell nanoparticles (NPs) in aqueous solution. The average particle size and morphology of the NPs were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The phenomenon that the NPs swelled at different glucose concentrations is due to the formation of boronate esters between the diol groups of glucose and boronic acid groups of phenylboronic acids. Fluorescein isothiocyanate (FITC)-insulin was loa...