A pH Gated, Glucose-Sensitive Nanoparticle Based on Worm-Like Mesoporous Silica for Controlled Insulin Release

This study prepares a kind of core–shell hybrid nanoparticles, which is worm-like, pH gated, and glucose-sensitive. It has a mesoporous silica nanoparticle (MSN) core and polymer shell (cross-linked and non-cross-linked), bearing 3-acrylamidophenylboronic acid (AAPBA) and N-isopropylacrylamide (NIPAM) as sensor moieties. The shell of the nanoparticles has presented a distinct transition from swollen state to collapsed state as the temperature increases, which offers easy access to drug loading. Here, insulin is applied as a model drug and the behaviors of its loading/release are investigated. Insulin loading is up to 15% via mesoporous silica core. In vitro experiment shows that the cumulative release of insulin is dependent on glucose concentration, and the glucose sensitivity could be adjusted simply by different pH values. Simultaneously, compared with the non-cross-linked shell, the cross-linked shell, using dextran-maleic acid (Dex-Ma) as a macromolecule cross-link, enables insulin to release more persistently. Also, cell viability assay indicates that these nanoparticles have good biocompatibility. Consequently, the novel, pH gated, glucose-sensitive core–shell nanoparticles may have potential applications as a vehicle of self-regulated insulin delivery system.