pH- and glucose-sensitive glycopolymer nanoparticles based on phenylboronic acid for triggered release of insulin.

Amphiphilic poly(acrylic acid-co-acrylamidophenylboronic acid)-block-poly(2-acryloxyethyl galactose)-block-poly(acrylic acid-co-acrylamidophenylboronic acid) (((PAA-co-PAAPBA)-b-)₂PAEG) copolymer was fabricated: The poly(2-acryloyloxyethyl pentaacetylgalactoside) (PAEAcG) with narrow molecular weight distributions (Mw/Mn≤1.22) was prepared by atom transfer radical polymerization (ATRP) using dibromo-p-xylene (DBX) as initiator. Then the well-defined triblock copolymer poly(t-butyl acrylate)-b-poly(2-acryloyloxyethyl pentaacetylgalactoside)-b-poly(t-butyl acrylate) (PtBA-b-PAEAcG-b-PtBA) was synthesized by ATRP of tBA using PAEAcG homopolymer with dibromo end groups as macroinitiator. After hydrolysis of t-butyl acrylate block, amide linkage and deacetylation, the final copolymer ((PAA-co-PAAPBA)-b-)₂PAEG was obtained. Because of characteristics of three different segments, amphiphilic ((PAA-co-PAAPBA)-b-)₂PAEG can self-assemble into pH- and glucose-responsive nanoparticles studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Furthermore, the in vitro release profiles of insulin also revealed obvious pH- and glucose-sensitivity of the nanoparticles. The analysis of cell viability suggested that the copolymer nanoparticles had good cytocompatibility.