Preparation of glucose-responsive and fluorescent micelles via a combination of RAFT polymerization and chemoenzymatic transesterification for controlled release of insulin

A glucose-responsive and fluorescent copolymer was prepared via a one-pot method that combines RAFT polymerization and enzymatic transesterification. The as-prepared copolymer tended to self-assemble into spherical micelles that were confirmed using 1H NMR, FT-IR and GPC, and transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Due to the attachment of fluorescent side groups, the optical properties of the micelles were analyzed using a UV-Vis spectrometer, fluorescence spectrophotometer and confocal laser scanning microscopy (CLSM). Owing to the amphiphilic and glucose-responsive properties, the micelles could be used as carriers for loaded insulin. The insulin release behaviour was evaluated when triggered by glucose in vitro. In addition, the resultant micelles exhibited relatively lower cytotoxicity and excellent stability against a protein solution. The insulin retained its structure stability after release, investigated through circular dichroism (CD) spectra analysis. These results showed that the obtained glucose-responsive and fluorescent polymer micelles with a good biological imaging performance and biocompatibility could be one of the effective candidate carriers for controllable release of insulin.