Glucose-sensitive polyelectrolyte nanocapsules based on layer-by-layer technique for protein drug delivery.

The glucose-responsive nanocapsules [CS-NAC/p(GAMA-r-AAPBA)] were readily fabricated with modified chitosan (CS-NAC) and random glycopolymer poly(D-gluconamidoethyl methacrylate-r-3-acrylamidophenylboronic acid) p(GAMA-r-AAPBA) as the alternant multilayered polyelectrolyte hybrid shell via layer-by-layer self-assembly after etching the amino functionalized SiO2 spheres by NH4F/HF. The spherical and hollow structure of nanocapsules was confirmed by TEM analysis and there was no clear collapse found after removal of the sacrificial cores. The reversible zeta potential changes of the nanocapsule materials evaluated the reversible glucose sensitivity. Besides, this system demonstrated a good capacity for encapsulation and loading insulin entrapped in nanocapsules as model protein drug. A good biocompatibility of the material was confirmed by the cell viability. In vitro release of insulin experiments revealed that no obvious release was found in acidic condition and the release could be normally conducted at physiological pH. These results implied that it was feasible for nanocapsules to be used in controlled release drug delivery system.